[sbcl.git] / contrib / asdf / asdf.lisp

;;; -*- mode: Common-Lisp; Base: 10 ; Syntax: ANSI-Common-Lisp -*-
;;; This is ASDF 2.019: Another System Definition Facility.
;;;
;;; Feedback, bug reports, and patches are all welcome:
;;; please mail to <asdf-devel@common-lisp.net>.
;;; Note first that the canonical source for ASDF is presently
;;; <URL:http://common-lisp.net/project/asdf/>.
;;;
;;; If you obtained this copy from anywhere else, and you experience
;;; trouble using it, or find bugs, you may want to check at the
;;; location above for a more recent version (and for documentation
;;; and test files, if your copy came without them) before reporting
;;; bugs.  There are usually two "supported" revisions - the git master
;;; branch is the latest development version, whereas the git release
;;; branch may be slightly older but is considered `stable'

;;; -- LICENSE START
;;; (This is the MIT / X Consortium license as taken from
;;;  http://www.opensource.org/licenses/mit-license.html on or about
;;;  Monday; July 13, 2009)
;;;
;;; Copyright (c) 2001-2011 Daniel Barlow and contributors
;;;
;;; Permission is hereby granted, free of charge, to any person obtaining
;;; a copy of this software and associated documentation files (the
;;; "Software"), to deal in the Software without restriction, including
;;; without limitation the rights to use, copy, modify, merge, publish,
;;; distribute, sublicense, and/or sell copies of the Software, and to
;;; permit persons to whom the Software is furnished to do so, subject to
;;; the following conditions:
;;;
;;; The above copyright notice and this permission notice shall be
;;; included in all copies or substantial portions of the Software.
;;;
;;; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
;;; EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
;;; MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
;;; NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
;;; LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
;;; OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
;;; WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
;;;
;;; -- LICENSE END

;;; The problem with writing a defsystem replacement is bootstrapping:
;;; we can't use defsystem to compile it.  Hence, all in one file.

#+xcvb (module ())

(cl:in-package #-genera :common-lisp-user #+genera :future-common-lisp-user)

#-(or abcl allegro clisp clozure cmu cormanlisp ecl gcl genera lispworks mcl sbcl scl xcl)
(error "ASDF is not supported on your implementation. Please help us port it.")

#+gcl (defpackage :asdf (:use :cl)) ;; GCL treats defpackage magically and needs this

(eval-when (:compile-toplevel :load-toplevel :execute)
  ;;; Implementation-dependent tweaks
  ;; (declaim (optimize (speed 1) (debug 3) (safety 3))) ; NO: trust implementation defaults.
  #+allegro
  (setf excl::*autoload-package-name-alist*
        (remove "asdf" excl::*autoload-package-name-alist*
                :test 'equalp :key 'car)) ; need that BEFORE any mention of package ASDF as below
  #+ecl (unless (member :ecl-bytecmp *features*) (require :cmp))
  #+gcl ;; Debian's GCL 2.7 has bugs with compiling multiple-value stuff, but can run ASDF 2.011
  (when (or (< system::*gcl-major-version* 2) ;; GCL 2.6 fails to fully compile ASDF at all
            (and (= system::*gcl-major-version* 2)
                 (< system::*gcl-minor-version* 7)))
    (pushnew :gcl-pre2.7 *features*))
  ;;; make package if it doesn't exist yet.
  ;;; DEFPACKAGE may cause errors on discrepancies, so we avoid it.
  (unless (find-package :asdf)
    (make-package :asdf :use '(:common-lisp))))

(in-package :asdf)

;;;; Create packages in a way that is compatible with hot-upgrade.
;;;; See https://bugs.launchpad.net/asdf/+bug/485687
;;;; See more near the end of the file.

(eval-when (:load-toplevel :compile-toplevel :execute)
  (defvar *asdf-version* nil)
  (defvar *upgraded-p* nil)
  (defvar *asdf-verbose* nil) ; was t from 2.000 to 2.014.12.
  (defun find-symbol* (s p)
    (find-symbol (string s) p))
  ;; Strip out formatting that is not supported on Genera.
  ;; Has to be inside the eval-when to make Lispworks happy (!)
  (defun strcat (&rest strings)
    (apply 'concatenate 'string strings))
  (defmacro compatfmt (format)
    #-(or gcl genera) format
    #+(or gcl genera)
    (loop :for (unsupported . replacement) :in
      (append
       '(("~3i~_" . ""))
       #+genera '(("~@<" . "") ("; ~@;" . "; ") ("~@:>" . "") ("~:>" . ""))) :do
      (loop :for found = (search unsupported format) :while found :do
        (setf format (strcat (subseq format 0 found) replacement
                             (subseq format (+ found (length unsupported)))))))
    format)
  (let* (;; For bug reporting sanity, please always bump this version when you modify this file.
         ;; Please also modify asdf.asd to reflect this change. The script bin/bump-version
         ;; can help you do these changes in synch (look at the source for documentation).
         ;; Relying on its automation, the version is now redundantly present on top of this file.
         ;; "2.345" would be an official release
         ;; "2.345.6" would be a development version in the official upstream
         ;; "2.345.0.7" would be your seventh local modification of official release 2.345
         ;; "2.345.6.7" would be your seventh local modification of development version 2.345.6
         (asdf-version "2.019")
         (existing-asdf (find-class 'component nil))
         (existing-version *asdf-version*)
         (already-there (equal asdf-version existing-version)))
    (unless (and existing-asdf already-there)
      (when (and existing-asdf *asdf-verbose*)
        (format *trace-output*
                (compatfmt "~&~@<; ~@;Upgrading ASDF ~@[from version ~A ~]to version ~A~@:>~%")
                existing-version asdf-version))
      (labels
          ((present-symbol-p (symbol package)
             (member (nth-value 1 (find-symbol* symbol package)) '(:internal :external)))
           (present-symbols (package)
             ;; #-genera (loop :for s :being :the :present-symbols :in package :collect s) #+genera
             (let (l)
               (do-symbols (s package)
                 (when (present-symbol-p s package) (push s l)))
               (reverse l)))
           (unlink-package (package)
             (let ((u (find-package package)))
               (when u
                 (ensure-unintern u (present-symbols u))
                 (loop :for p :in (package-used-by-list u) :do
                   (unuse-package u p))
                 (delete-package u))))
           (ensure-exists (name nicknames use)
             (let ((previous
                    (remove-duplicates
                     (mapcar #'find-package (cons name nicknames))
                     :from-end t)))
               ;; do away with packages with conflicting (nick)names
               (map () #'unlink-package (cdr previous))
               ;; reuse previous package with same name
               (let ((p (car previous)))
                 (cond
                   (p
                    (rename-package p name nicknames)
                    (ensure-use p use)
                    p)
                   (t
                    (make-package name :nicknames nicknames :use use))))))
           (intern* (symbol package)
             (intern (string symbol) package))
           (remove-symbol (symbol package)
             (let ((sym (find-symbol* symbol package)))
               (when sym
                 #-cormanlisp (unexport sym package)
                 (unintern sym package)
                 sym)))
           (ensure-unintern (package symbols)
             (loop :with packages = (list-all-packages)
               :for sym :in symbols
               :for removed = (remove-symbol sym package)
               :when removed :do
               (loop :for p :in packages :do
                 (when (eq removed (find-symbol* sym p))
                   (unintern removed p)))))
           (ensure-shadow (package symbols)
             (shadow symbols package))
           (ensure-use (package use)
             (dolist (used (reverse use))
               (do-external-symbols (sym used)
                 (unless (eq sym (find-symbol* sym package))
                   (remove-symbol sym package)))
               (use-package used package)))
           (ensure-fmakunbound (package symbols)
             (loop :for name :in symbols
               :for sym = (find-symbol* name package)
               :when sym :do (fmakunbound sym)))
           (ensure-export (package export)
             (let ((formerly-exported-symbols nil)
                   (bothly-exported-symbols nil)
                   (newly-exported-symbols nil))
               (do-external-symbols (sym package)
                 (if (member sym export :test 'string-equal)
                     (push sym bothly-exported-symbols)
                     (push sym formerly-exported-symbols)))
               (loop :for sym :in export :do
                 (unless (member sym bothly-exported-symbols :test 'equal)
                   (push sym newly-exported-symbols)))
               (loop :for user :in (package-used-by-list package)
                 :for shadowing = (package-shadowing-symbols user) :do
                 (loop :for new :in newly-exported-symbols
                   :for old = (find-symbol* new user)
                   :when (and old (not (member old shadowing)))
                   :do (unintern old user)))
               (loop :for x :in newly-exported-symbols :do
                 (export (intern* x package)))))
           (ensure-package (name &key nicknames use unintern
                                 shadow export redefined-functions)
             (let* ((p (ensure-exists name nicknames use)))
               (ensure-unintern p unintern)
               (ensure-shadow p shadow)
               (ensure-export p export)
               (ensure-fmakunbound p redefined-functions)
               p)))
        (macrolet
            ((pkgdcl (name &key nicknames use export
                           redefined-functions unintern shadow)
                 `(ensure-package
                   ',name :nicknames ',nicknames :use ',use :export ',export
                   :shadow ',shadow
                   :unintern ',unintern
                   :redefined-functions ',redefined-functions)))
          (pkgdcl
           :asdf
           :nicknames (:asdf-utilities) ;; DEPRECATED! Do not use, for backward compatibility only.
           :use (:common-lisp)
           :redefined-functions
           (#:perform #:explain #:output-files #:operation-done-p
            #:perform-with-restarts #:component-relative-pathname
            #:system-source-file #:operate #:find-component #:find-system
            #:apply-output-translations #:translate-pathname* #:resolve-location
            #:system-relative-pathname
            #:inherit-source-registry #:process-source-registry
            #:process-source-registry-directive
            #:compile-file* #:source-file-type)
           :unintern
           (#:*asdf-revision* #:around #:asdf-method-combination
            #:split #:make-collector #:do-dep #:do-one-dep
            #:resolve-relative-location-component #:resolve-absolute-location-component
            #:output-files-for-system-and-operation) ; obsolete ASDF-BINARY-LOCATION function
           :export
           (#:defsystem #:oos #:operate #:find-system #:locate-system #:run-shell-command
            #:system-definition-pathname #:with-system-definitions
            #:search-for-system-definition #:find-component #:component-find-path
            #:compile-system #:load-system #:load-systems #:test-system #:clear-system
            #:operation #:compile-op #:load-op #:load-source-op #:test-op
            #:feature #:version #:version-satisfies
            #:upgrade-asdf
            #:implementation-identifier #:implementation-type
            #:input-files #:output-files #:output-file #:perform
            #:operation-done-p #:explain

            #:component #:source-file
            #:c-source-file #:cl-source-file #:java-source-file
            #:cl-source-file.cl #:cl-source-file.lsp
            #:static-file
            #:doc-file
            #:html-file
            #:text-file
            #:source-file-type
            #:module                     ; components
            #:system
            #:unix-dso

            #:module-components          ; component accessors
            #:module-components-by-name  ; component accessors
            #:component-pathname
            #:component-relative-pathname
            #:component-name
            #:component-version
            #:component-parent
            #:component-property
            #:component-system

            #:component-depends-on

            #:system-description
            #:system-long-description
            #:system-author
            #:system-maintainer
            #:system-license
            #:system-licence
            #:system-source-file
            #:system-source-directory
            #:system-relative-pathname
            #:map-systems

            #:operation-description
            #:operation-on-warnings
            #:operation-on-failure
            #:component-visited-p
            ;;#:*component-parent-pathname*
            #:*system-definition-search-functions*
            #:*central-registry*         ; variables
            #:*compile-file-warnings-behaviour*
            #:*compile-file-failure-behaviour*
            #:*resolve-symlinks*
            #:*require-asdf-operator*
            #:*asdf-verbose*
            #:*verbose-out*

            #:asdf-version

            #:operation-error #:compile-failed #:compile-warned #:compile-error
            #:error-name
            #:error-pathname
            #:load-system-definition-error
            #:error-component #:error-operation
            #:system-definition-error
            #:missing-component
            #:missing-component-of-version
            #:missing-dependency
            #:missing-dependency-of-version
            #:circular-dependency        ; errors
            #:duplicate-names

            #:try-recompiling
            #:retry
            #:accept                     ; restarts
            #:coerce-entry-to-directory
            #:remove-entry-from-registry

            #:clear-configuration
            #:*output-translations-parameter*
            #:initialize-output-translations
            #:disable-output-translations
            #:clear-output-translations
            #:ensure-output-translations
            #:apply-output-translations
            #:compile-file*
            #:compile-file-pathname*
            #:enable-asdf-binary-locations-compatibility
            #:*default-source-registries*
            #:*source-registry-parameter*
            #:initialize-source-registry
            #:compute-source-registry
            #:clear-source-registry
            #:ensure-source-registry
            #:process-source-registry
            #:system-registered-p
            #:asdf-message
            #:user-output-translations-pathname
            #:system-output-translations-pathname
            #:user-output-translations-directory-pathname
            #:system-output-translations-directory-pathname
            #:user-source-registry
            #:system-source-registry
            #:user-source-registry-directory
            #:system-source-registry-directory

            ;; Utilities
            #:absolute-pathname-p
            ;; #:aif #:it
            ;; #:appendf #:orf
            #:coerce-name
            #:directory-pathname-p
            ;; #:ends-with
            #:ensure-directory-pathname
            #:getenv
            ;; #:length=n-p
            ;; #:find-symbol*
            #:merge-pathnames* #:coerce-pathname #:subpathname
            #:pathname-directory-pathname
            #:read-file-forms
            ;; #:remove-keys
            ;; #:remove-keyword
            #:resolve-symlinks
            #:split-string
            #:component-name-to-pathname-components
            #:split-name-type
            #:subdirectories
            #:truenamize
            #:while-collecting)))
        #+genera (import 'scl:boolean :asdf)
        (setf *asdf-version* asdf-version
              *upgraded-p* (if existing-version
                               (cons existing-version *upgraded-p*)
                               *upgraded-p*))))))

;;;; -------------------------------------------------------------------------
;;;; User-visible parameters
;;;;
(defvar *resolve-symlinks* t
  "Determine whether or not ASDF resolves symlinks when defining systems.

Defaults to T.")

(defvar *compile-file-warnings-behaviour*
  (or #+clisp :ignore :warn)
  "How should ASDF react if it encounters a warning when compiling a file?
Valid values are :error, :warn, and :ignore.")

(defvar *compile-file-failure-behaviour*
  (or #+sbcl :error #+clisp :ignore :warn)
  "How should ASDF react if it encounters a failure (per the ANSI spec of COMPILE-FILE)
when compiling a file?  Valid values are :error, :warn, and :ignore.
Note that ASDF ALWAYS raises an error if it fails to create an output file when compiling.")

(defvar *verbose-out* nil)

(defparameter +asdf-methods+
  '(perform-with-restarts perform explain output-files operation-done-p))

#+allegro
(eval-when (:compile-toplevel :execute)
  (defparameter *acl-warn-save*
                (when (boundp 'excl:*warn-on-nested-reader-conditionals*)
                  excl:*warn-on-nested-reader-conditionals*))
  (when (boundp 'excl:*warn-on-nested-reader-conditionals*)
    (setf excl:*warn-on-nested-reader-conditionals* nil)))

;;;; -------------------------------------------------------------------------
;;;; Resolve forward references

(declaim (ftype (function (t) t)
                format-arguments format-control
                error-name error-pathname error-condition
                duplicate-names-name
                error-component error-operation
                module-components module-components-by-name
                circular-dependency-components
                condition-arguments condition-form
                condition-format condition-location
                coerce-name)
         (ftype (function (&optional t) (values)) initialize-source-registry)
         #-(or cormanlisp gcl-pre2.7)
         (ftype (function (t t) t) (setf module-components-by-name)))

;;;; -------------------------------------------------------------------------
;;;; Compatibility various implementations
#+cormanlisp
(progn
  (deftype logical-pathname () nil)
  (defun make-broadcast-stream () *error-output*)
  (defun file-namestring (p)
    (setf p (pathname p))
    (format nil "~@[~A~]~@[.~A~]" (pathname-name p) (pathname-type p))))

#.(or #+mcl ;; the #$ doesn't work on other lisps, even protected by #+mcl
      (read-from-string
       "(eval-when (:compile-toplevel :load-toplevel :execute)
          (ccl:define-entry-point (_getenv \"getenv\") ((name :string)) :string)
          (ccl:define-entry-point (_system \"system\") ((name :string)) :int)
          ;; Note: ASDF may expect user-homedir-pathname to provide
          ;; the pathname of the current user's home directory, whereas
          ;; MCL by default provides the directory from which MCL was started.
          ;; See http://code.google.com/p/mcl/wiki/Portability
          (defun current-user-homedir-pathname ()
            (ccl::findfolder #$kuserdomain #$kCurrentUserFolderType))
          (defun probe-posix (posix-namestring)
            \"If a file exists for the posix namestring, return the pathname\"
            (ccl::with-cstrs ((cpath posix-namestring))
              (ccl::rlet ((is-dir :boolean)
                          (fsref :fsref))
                (when (eq #$noerr (#_fspathmakeref cpath fsref is-dir))
                  (ccl::%path-from-fsref fsref is-dir))))))"))

;;;; -------------------------------------------------------------------------
;;;; General Purpose Utilities

(macrolet
    ((defdef (def* def)
       `(defmacro ,def* (name formals &rest rest)
          `(progn
             #+(or ecl (and gcl (not gcl-pre2.7))) (fmakunbound ',name)
             #-gcl ; gcl 2.7.0 notinline functions lose secondary return values :-(
             ,(when (and #+ecl (symbolp name)) ; fails for setf functions on ecl
                `(declaim (notinline ,name)))
             (,',def ,name ,formals ,@rest)))))
  (defdef defgeneric* defgeneric)
  (defdef defun* defun))

(defmacro while-collecting ((&rest collectors) &body body)
  "COLLECTORS should be a list of names for collections.  A collector
defines a function that, when applied to an argument inside BODY, will
add its argument to the corresponding collection.  Returns multiple values,
a list for each collection, in order.
   E.g.,
\(while-collecting \(foo bar\)
           \(dolist \(x '\(\(a 1\) \(b 2\) \(c 3\)\)\)
             \(foo \(first x\)\)
             \(bar \(second x\)\)\)\)
Returns two values: \(A B C\) and \(1 2 3\)."
  (let ((vars (mapcar #'(lambda (x) (gensym (symbol-name x))) collectors))
        (initial-values (mapcar (constantly nil) collectors)))
    `(let ,(mapcar #'list vars initial-values)
       (flet ,(mapcar #'(lambda (c v) `(,c (x) (push x ,v) (values))) collectors vars)
         ,@body
         (values ,@(mapcar #'(lambda (v) `(reverse ,v)) vars))))))

(defmacro aif (test then &optional else)
  `(let ((it ,test)) (if it ,then ,else)))

(defun* pathname-directory-pathname (pathname)
  "Returns a new pathname with same HOST, DEVICE, DIRECTORY as PATHNAME,
and NIL NAME, TYPE and VERSION components"
  (when pathname
    (make-pathname :name nil :type nil :version nil :defaults pathname)))

(defun* normalize-pathname-directory-component (directory)
  (cond
    #-(or cmu sbcl scl)
    ((stringp directory) `(:absolute ,directory) directory)
    #+gcl
    ((and (consp directory) (stringp (first directory)))
     `(:absolute ,@directory))
    ((or (null directory)
         (and (consp directory) (member (first directory) '(:absolute :relative))))
     directory)
    (t
     (error (compatfmt "~@<Unrecognized pathname directory component ~S~@:>") directory))))

(defun* merge-pathname-directory-components (specified defaults)
  (let ((directory (normalize-pathname-directory-component specified)))
    (ecase (first directory)
      ((nil) defaults)
      (:absolute specified)
      (:relative
       (let ((defdir (normalize-pathname-directory-component defaults))
             (reldir (cdr directory)))
         (cond
           ((null defdir)
            directory)
           ((not (eq :back (first reldir)))
            (append defdir reldir))
           (t
            (loop :with defabs = (first defdir)
              :with defrev = (reverse (rest defdir))
              :while (and (eq :back (car reldir))
                          (or (and (eq :absolute defabs) (null defrev))
                              (stringp (car defrev))))
              :do (pop reldir) (pop defrev)
              :finally (return (cons defabs (append (reverse defrev) reldir)))))))))))

(defun* ununspecific (x)
  (if (eq x :unspecific) nil x))

(defun* merge-pathnames* (specified &optional (defaults *default-pathname-defaults*))
  "MERGE-PATHNAMES* is like MERGE-PATHNAMES except that
if the SPECIFIED pathname does not have an absolute directory,
then the HOST and DEVICE both come from the DEFAULTS, whereas
if the SPECIFIED pathname does have an absolute directory,
then the HOST and DEVICE both come from the SPECIFIED.
Also, if either argument is NIL, then the other argument is returned unmodified."
  (when (null specified) (return-from merge-pathnames* defaults))
  (when (null defaults) (return-from merge-pathnames* specified))
  #+scl
  (ext:resolve-pathname specified defaults)
  #-scl
  (let* ((specified (pathname specified))
         (defaults (pathname defaults))
         (directory (normalize-pathname-directory-component (pathname-directory specified)))
         (name (or (pathname-name specified) (pathname-name defaults)))
         (type (or (pathname-type specified) (pathname-type defaults)))
         (version (or (pathname-version specified) (pathname-version defaults))))
    (labels ((unspecific-handler (p)
               (if (typep p 'logical-pathname) #'ununspecific #'identity)))
      (multiple-value-bind (host device directory unspecific-handler)
          (ecase (first directory)
            ((:absolute)
             (values (pathname-host specified)
                     (pathname-device specified)
                     directory
                     (unspecific-handler specified)))
            ((nil :relative)
             (values (pathname-host defaults)
                     (pathname-device defaults)
                     (merge-pathname-directory-components directory (pathname-directory defaults))
                     (unspecific-handler defaults))))
        (make-pathname :host host :device device :directory directory
                       :name (funcall unspecific-handler name)
                       :type (funcall unspecific-handler type)
                       :version (funcall unspecific-handler version))))))

(defun* pathname-parent-directory-pathname (pathname)
  "Returns a new pathname with same HOST, DEVICE, DIRECTORY as PATHNAME,
and NIL NAME, TYPE and VERSION components"
  (when pathname
    (make-pathname :name nil :type nil :version nil
                   :directory (merge-pathname-directory-components
                               '(:relative :back) (pathname-directory pathname))
                   :defaults pathname)))

(define-modify-macro appendf (&rest args)
  append "Append onto list") ;; only to be used on short lists.

(define-modify-macro orf (&rest args)
  or "or a flag")

(defun* first-char (s)
  (and (stringp s) (plusp (length s)) (char s 0)))

(defun* last-char (s)
  (and (stringp s) (plusp (length s)) (char s (1- (length s)))))


(defun* asdf-message (format-string &rest format-args)
  (declare (dynamic-extent format-args))
  (apply 'format *verbose-out* format-string format-args))

(defun* split-string (string &key max (separator '(#\Space #\Tab)))
  "Split STRING into a list of components separated by
any of the characters in the sequence SEPARATOR.
If MAX is specified, then no more than max(1,MAX) components will be returned,
starting the separation from the end, e.g. when called with arguments
 \"a.b.c.d.e\" :max 3 :separator \".\" it will return (\"a.b.c\" \"d\" \"e\")."
  (catch nil
    (let ((list nil) (words 0) (end (length string)))
      (flet ((separatorp (char) (find char separator))
             (done () (throw nil (cons (subseq string 0 end) list))))
        (loop
          :for start = (if (and max (>= words (1- max)))
                           (done)
                           (position-if #'separatorp string :end end :from-end t)) :do
          (when (null start)
            (done))
          (push (subseq string (1+ start) end) list)
          (incf words)
          (setf end start))))))

(defun* split-name-type (filename)
  (let ((unspecific
         ;; Giving :unspecific as argument to make-pathname is not portable.
         ;; See CLHS make-pathname and 19.2.2.2.3.
         ;; We only use it on implementations that support it.
         (or #+(or clozure gcl lispworks sbcl) :unspecific)))
    (destructuring-bind (name &optional (type unspecific))
        (split-string filename :max 2 :separator ".")
      (if (equal name "")
          (values filename unspecific)
          (values name type)))))

(defun* component-name-to-pathname-components (s &key force-directory force-relative)
  "Splits the path string S, returning three values:
A flag that is either :absolute or :relative, indicating
   how the rest of the values are to be interpreted.
A directory path --- a list of strings, suitable for
   use with MAKE-PATHNAME when prepended with the flag
   value.
A filename with type extension, possibly NIL in the
   case of a directory pathname.
FORCE-DIRECTORY forces S to be interpreted as a directory
pathname \(third return value will be NIL, final component
of S will be treated as part of the directory path.

The intention of this function is to support structured component names,
e.g., \(:file \"foo/bar\"\), which will be unpacked to relative
pathnames."
  (check-type s string)
  (when (find #\: s)
    (error (compatfmt "~@<A portable ASDF pathname designator cannot include a #\: character: ~3i~_~S~@:>") s))
  (let* ((components (split-string s :separator "/"))
         (last-comp (car (last components))))
    (multiple-value-bind (relative components)
        (if (equal (first components) "")
            (if (equal (first-char s) #\/)
                (progn
                  (when force-relative
                    (error (compatfmt "~@<Absolute pathname designator not allowed: ~3i~_~S~@:>") s))
                  (values :absolute (cdr components)))
                (values :relative nil))
          (values :relative components))
      (setf components (remove-if #'(lambda (x) (member x '("" ".") :test #'equal)) components))
      (setf components (substitute :back ".." components :test #'equal))
      (cond
        ((equal last-comp "")
         (values relative components nil)) ; "" already removed
        (force-directory
         (values relative components nil))
        (t
         (values relative (butlast components) last-comp))))))

(defun* remove-keys (key-names args)
  (loop :for (name val) :on args :by #'cddr
    :unless (member (symbol-name name) key-names
                    :key #'symbol-name :test 'equal)
    :append (list name val)))

(defun* remove-keyword (key args)
  (loop :for (k v) :on args :by #'cddr
    :unless (eq k key)
    :append (list k v)))

(defun* getenv (x)
  (declare (ignorable x))
  #+(or abcl clisp ecl xcl) (ext:getenv x)
  #+allegro (sys:getenv x)
  #+clozure (ccl:getenv x)
  #+(or cmu scl) (cdr (assoc x ext:*environment-list* :test #'string=))
  #+cormanlisp
  (let* ((buffer (ct:malloc 1))
         (cname (ct:lisp-string-to-c-string x))
         (needed-size (win:getenvironmentvariable cname buffer 0))
         (buffer1 (ct:malloc (1+ needed-size))))
    (prog1 (if (zerop (win:getenvironmentvariable cname buffer1 needed-size))
               nil
               (ct:c-string-to-lisp-string buffer1))
      (ct:free buffer)
      (ct:free buffer1)))
  #+gcl (system:getenv x)
  #+genera nil
  #+lispworks (lispworks:environment-variable x)
  #+mcl (ccl:with-cstrs ((name x))
          (let ((value (_getenv name)))
            (unless (ccl:%null-ptr-p value)
              (ccl:%get-cstring value))))
  #+sbcl (sb-ext:posix-getenv x)
  #-(or abcl allegro clisp clozure cmu cormanlisp ecl gcl genera lispworks mcl sbcl scl xcl)
  (error "~S is not supported on your implementation" 'getenv))

(defun* directory-pathname-p (pathname)
  "Does PATHNAME represent a directory?

A directory-pathname is a pathname _without_ a filename. The three
ways that the filename components can be missing are for it to be NIL,
:UNSPECIFIC or the empty string.

Note that this does _not_ check to see that PATHNAME points to an
actually-existing directory."
  (when pathname
    (let ((pathname (pathname pathname)))
      (flet ((check-one (x)
               (member x '(nil :unspecific "") :test 'equal)))
        (and (not (wild-pathname-p pathname))
             (check-one (pathname-name pathname))
             (check-one (pathname-type pathname))
             t)))))

(defun* ensure-directory-pathname (pathspec)
  "Converts the non-wild pathname designator PATHSPEC to directory form."
  (cond
   ((stringp pathspec)
    (ensure-directory-pathname (pathname pathspec)))
   ((not (pathnamep pathspec))
    (error (compatfmt "~@<Invalid pathname designator ~S~@:>") pathspec))
   ((wild-pathname-p pathspec)
    (error (compatfmt "~@<Can't reliably convert wild pathname ~3i~_~S~@:>") pathspec))
   ((directory-pathname-p pathspec)
    pathspec)
   (t
    (make-pathname :directory (append (or (pathname-directory pathspec)
                                          (list :relative))
                                      (list (file-namestring pathspec)))
                   :name nil :type nil :version nil
                   :defaults pathspec))))

#+genera
(unless (fboundp 'ensure-directories-exist)
  (defun* ensure-directories-exist (path)
    (fs:create-directories-recursively (pathname path))))

(defun* absolute-pathname-p (pathspec)
  (and (typep pathspec '(or pathname string))
       (eq :absolute (car (pathname-directory (pathname pathspec))))))

(defun* length=n-p (x n) ;is it that (= (length x) n) ?
  (check-type n (integer 0 *))
  (loop
    :for l = x :then (cdr l)
    :for i :downfrom n :do
    (cond
      ((zerop i) (return (null l)))
      ((not (consp l)) (return nil)))))

(defun* ends-with (s suffix)
  (check-type s string)
  (check-type suffix string)
  (let ((start (- (length s) (length suffix))))
    (and (<= 0 start)
         (string-equal s suffix :start1 start))))

(defun* read-file-forms (file)
  (with-open-file (in file)
    (loop :with eof = (list nil)
     :for form = (read in nil eof)
     :until (eq form eof)
     :collect form)))

(defun* pathname-root (pathname)
  (make-pathname :directory '(:absolute)
                 :name nil :type nil :version nil
                 :defaults pathname ;; host device, and on scl, *some*
                 ;; scheme-specific parts: port username password, not others:
                 . #.(or #+scl '(:parameters nil :query nil :fragment nil))))

(defun* probe-file* (p)
  "when given a pathname P, probes the filesystem for a file or directory
with given pathname and if it exists return its truename."
  (etypecase p
    (null nil)
    (string (probe-file* (parse-namestring p)))
    (pathname (unless (wild-pathname-p p)
                #.(or #+(or allegro clozure cmu cormanlisp ecl lispworks sbcl scl)
                      '(probe-file p)
                      #+clisp (aif (find-symbol* '#:probe-pathname :ext)
                                   `(ignore-errors (,it p)))
                      '(ignore-errors (truename p)))))))

(defun* truenamize (pathname &optional (defaults *default-pathname-defaults*))
  "Resolve as much of a pathname as possible"
  (block nil
    (when (typep pathname '(or null logical-pathname)) (return pathname))
    (let ((p (merge-pathnames* pathname defaults)))
      (when (typep p 'logical-pathname) (return p))
      (let ((found (probe-file* p)))
        (when found (return found)))
      (unless (absolute-pathname-p p)
        (let ((true-defaults (ignore-errors (truename defaults))))
          (when true-defaults
            (setf p (merge-pathnames pathname true-defaults)))))
      (unless (absolute-pathname-p p) (return p))
      (let ((sofar (probe-file* (pathname-root p))))
        (unless sofar (return p))
        (flet ((solution (directories)
                 (merge-pathnames*
                  (make-pathname :host nil :device nil
                                 :directory `(:relative ,@directories)
                                 :name (pathname-name p)
                                 :type (pathname-type p)
                                 :version (pathname-version p))
                  sofar)))
          (loop :with directory = (normalize-pathname-directory-component
                                   (pathname-directory p))
            :for component :in (cdr directory)
            :for rest :on (cdr directory)
            :for more = (probe-file*
                         (merge-pathnames*
                          (make-pathname :directory `(:relative ,component))
                          sofar)) :do
            (if more
                (setf sofar more)
                (return (solution rest)))
            :finally
            (return (solution nil))))))))

(defun* resolve-symlinks (path)
  #-allegro (truenamize path)
  #+allegro (if (typep path 'logical-pathname)
                path
                (excl:pathname-resolve-symbolic-links path)))

(defun* resolve-symlinks* (path)
  (if *resolve-symlinks*
      (and path (resolve-symlinks path))
      path))

(defun* ensure-pathname-absolute (path)
  (cond
    ((absolute-pathname-p path) path)
    ((stringp path) (ensure-pathname-absolute (pathname path)))
    ((not (pathnamep path)) (error "not a valid pathname designator ~S" path))
    (t (let ((resolved (resolve-symlinks path)))
         (assert (absolute-pathname-p resolved))
         resolved))))

(defun* default-directory ()
  (truenamize (pathname-directory-pathname *default-pathname-defaults*)))

(defun* lispize-pathname (input-file)
  (make-pathname :type "lisp" :defaults input-file))

(defparameter *wild* #-cormanlisp :wild #+cormanlisp "*")
(defparameter *wild-file*
  (make-pathname :name *wild* :type *wild*
                 :version (or #-(or abcl xcl) *wild*) :directory nil))
(defparameter *wild-directory*
  (make-pathname :directory `(:relative ,*wild*) :name nil :type nil :version nil))
(defparameter *wild-inferiors*
  (make-pathname :directory '(:relative :wild-inferiors) :name nil :type nil :version nil))
(defparameter *wild-path*
  (merge-pathnames *wild-file* *wild-inferiors*))

(defun* wilden (path)
  (merge-pathnames* *wild-path* path))

#-scl
(defun* directory-separator-for-host (&optional (pathname *default-pathname-defaults*))
  (let ((foo (make-pathname :directory '(:absolute "FOO") :defaults pathname)))
    (last-char (namestring foo))))

#-scl
(defun* directorize-pathname-host-device (pathname)
  (let* ((root (pathname-root pathname))
         (wild-root (wilden root))
         (absolute-pathname (merge-pathnames* pathname root))
         (separator (directory-separator-for-host root))
         (root-namestring (namestring root))
         (root-string
          (substitute-if #\/
                         #'(lambda (x) (or (eql x #\:)
                                           (eql x separator)))
                         root-namestring)))
    (multiple-value-bind (relative path filename)
        (component-name-to-pathname-components root-string :force-directory t)
      (declare (ignore relative filename))
      (let ((new-base
             (make-pathname :defaults root
                            :directory `(:absolute ,@path))))
        (translate-pathname absolute-pathname wild-root (wilden new-base))))))

#+scl
(defun* directorize-pathname-host-device (pathname)
  (let ((scheme (ext:pathname-scheme pathname))
        (host (pathname-host pathname))
        (port (ext:pathname-port pathname))
        (directory (pathname-directory pathname)))
    (if (or (ununspecific port)
            (and (ununspecific host) (plusp (length host)))
            (ununspecific scheme))
        (let ((prefix ""))
          (when (ununspecific port)
            (setf prefix (format nil ":~D" port)))
          (when (and (ununspecific host) (plusp (length host)))
            (setf prefix (strcat host prefix)))
          (setf prefix (strcat ":" prefix))
          (when (ununspecific scheme)
            (setf prefix (strcat scheme prefix)))
          (assert (and directory (eq (first directory) :absolute)))
          (make-pathname :directory `(:absolute ,prefix ,@(rest directory))
                         :defaults pathname)))
    pathname))

;;;; -------------------------------------------------------------------------
;;;; ASDF Interface, in terms of generic functions.
(defgeneric* find-system (system &optional error-p))
(defgeneric* perform-with-restarts (operation component))
(defgeneric* perform (operation component))
(defgeneric* operation-done-p (operation component))
(defgeneric* mark-operation-done (operation component))
(defgeneric* explain (operation component))
(defgeneric* output-files (operation component))
(defgeneric* input-files (operation component))
(defgeneric* component-operation-time (operation component))
(defgeneric* operation-description (operation component)
  (:documentation "returns a phrase that describes performing this operation
on this component, e.g. \"loading /a/b/c\".
You can put together sentences using this phrase."))

(defgeneric* system-source-file (system)
  (:documentation "Return the source file in which system is defined."))

(defgeneric* component-system (component)
  (:documentation "Find the top-level system containing COMPONENT"))

(defgeneric* component-pathname (component)
  (:documentation "Extracts the pathname applicable for a particular component."))

(defgeneric* component-relative-pathname (component)
  (:documentation "Returns a pathname for the component argument intended to be
interpreted relative to the pathname of that component's parent.
Despite the function's name, the return value may be an absolute
pathname, because an absolute pathname may be interpreted relative to
another pathname in a degenerate way."))

(defgeneric* component-property (component property))

(defgeneric* (setf component-property) (new-value component property))

(eval-when (#-gcl :compile-toplevel :load-toplevel :execute)
  (defgeneric* (setf module-components-by-name) (new-value module)))

(defgeneric* version-satisfies (component version))

(defgeneric* find-component (base path)
  (:documentation "Finds the component with PATH starting from BASE module;
if BASE is nil, then the component is assumed to be a system."))

(defgeneric* source-file-type (component system))

(defgeneric* operation-ancestor (operation)
  (:documentation
   "Recursively chase the operation's parent pointer until we get to
the head of the tree"))

(defgeneric* component-visited-p (operation component)
  (:documentation "Returns the value stored by a call to
VISIT-COMPONENT, if that has been called, otherwise NIL.
This value stored will be a cons cell, the first element
of which is a computed key, so not interesting.  The
CDR wil be the DATA value stored by VISIT-COMPONENT; recover
it as (cdr (component-visited-p op c)).
  In the current form of ASDF, the DATA value retrieved is
effectively a boolean, indicating whether some operations are
to be performed in order to do OPERATION X COMPONENT.  If the
data value is NIL, the combination had been explored, but no
operations needed to be performed."))

(defgeneric* visit-component (operation component data)
  (:documentation "Record DATA as being associated with OPERATION
and COMPONENT.  This is a side-effecting function:  the association
will be recorded on the ROOT OPERATION \(OPERATION-ANCESTOR of the
OPERATION\).
  No evidence that DATA is ever interesting, beyond just being
non-NIL.  Using the data field is probably very risky; if there is
already a record for OPERATION X COMPONENT, DATA will be quietly
discarded instead of recorded.
  Starting with 2.006, TRAVERSE will store an integer in data,
so that nodes can be sorted in decreasing order of traversal."))


(defgeneric* (setf visiting-component) (new-value operation component))

(defgeneric* component-visiting-p (operation component))

(defgeneric* component-depends-on (operation component)
  (:documentation
   "Returns a list of dependencies needed by the component to perform
    the operation.  A dependency has one of the following forms:

      (<operation> <component>*), where <operation> is a class
        designator and each <component> is a component
        designator, which means that the component depends on
        <operation> having been performed on each <component>; or

      (FEATURE <feature>), which means that the component depends
        on <feature>'s presence in *FEATURES*.

    Methods specialized on subclasses of existing component types
    should usually append the results of CALL-NEXT-METHOD to the
    list."))

(defgeneric* component-self-dependencies (operation component))

(defgeneric* traverse (operation component)
  (:documentation
"Generate and return a plan for performing OPERATION on COMPONENT.

The plan returned is a list of dotted-pairs. Each pair is the CONS
of ASDF operation object and a COMPONENT object. The pairs will be
processed in order by OPERATE."))


;;;; -------------------------------------------------------------------------
;;; Methods in case of hot-upgrade. See https://bugs.launchpad.net/asdf/+bug/485687
(when *upgraded-p*
   (when (find-class 'module nil)
     (eval
      '(defmethod update-instance-for-redefined-class :after
           ((m module) added deleted plist &key)
         (declare (ignorable deleted plist))
         (when *asdf-verbose*
           (asdf-message (compatfmt "~&~@<; ~@;Updating ~A for ASDF ~A~@:>~%")
                         m (asdf-version)))
         (when (member 'components-by-name added)
           (compute-module-components-by-name m))
         (when (typep m 'system)
           (when (member 'source-file added)
             (%set-system-source-file
              (probe-asd (component-name m) (component-pathname m)) m)
             (when (equal (component-name m) "asdf")
               (setf (component-version m) *asdf-version*))))))))

;;;; -------------------------------------------------------------------------
;;;; Classes, Conditions

(define-condition system-definition-error (error) ()
  ;; [this use of :report should be redundant, but unfortunately it's not.
  ;; cmucl's lisp::output-instance prefers the kernel:slot-class-print-function
  ;; over print-object; this is always conditions::%print-condition for
  ;; condition objects, which in turn does inheritance of :report options at
  ;; run-time.  fortunately, inheritance means we only need this kludge here in
  ;; order to fix all conditions that build on it.  -- rgr, 28-Jul-02.]
  #+cmu (:report print-object))

(define-condition formatted-system-definition-error (system-definition-error)
  ((format-control :initarg :format-control :reader format-control)
   (format-arguments :initarg :format-arguments :reader format-arguments))
  (:report (lambda (c s)
               (apply 'format s (format-control c) (format-arguments c)))))

(define-condition load-system-definition-error (system-definition-error)
  ((name :initarg :name :reader error-name)
   (pathname :initarg :pathname :reader error-pathname)
   (condition :initarg :condition :reader error-condition))
  (:report (lambda (c s)
             (format s (compatfmt "~@<Error while trying to load definition for system ~A from pathname ~A: ~3i~_~A~@:>")
                     (error-name c) (error-pathname c) (error-condition c)))))

(define-condition circular-dependency (system-definition-error)
  ((components :initarg :components :reader circular-dependency-components))
  (:report (lambda (c s)
             (format s (compatfmt "~@<Circular dependency: ~3i~_~S~@:>")
                     (circular-dependency-components c)))))

(define-condition duplicate-names (system-definition-error)
  ((name :initarg :name :reader duplicate-names-name))
  (:report (lambda (c s)
             (format s (compatfmt "~@<Error while defining system: multiple components are given same name ~A~@:>")
                     (duplicate-names-name c)))))

(define-condition missing-component (system-definition-error)
  ((requires :initform "(unnamed)" :reader missing-requires :initarg :requires)
   (parent :initform nil :reader missing-parent :initarg :parent)))

(define-condition missing-component-of-version (missing-component)
  ((version :initform nil :reader missing-version :initarg :version)))

(define-condition missing-dependency (missing-component)
  ((required-by :initarg :required-by :reader missing-required-by)))

(define-condition missing-dependency-of-version (missing-dependency
                                                 missing-component-of-version)
  ())

(define-condition operation-error (error)
  ((component :reader error-component :initarg :component)
   (operation :reader error-operation :initarg :operation))
  (:report (lambda (c s)
               (format s (compatfmt "~@<Error while invoking ~A on ~A~@:>")
                       (error-operation c) (error-component c)))))
(define-condition compile-error (operation-error) ())
(define-condition compile-failed (compile-error) ())
(define-condition compile-warned (compile-error) ())

(define-condition invalid-configuration ()
  ((form :reader condition-form :initarg :form)
   (location :reader condition-location :initarg :location)
   (format :reader condition-format :initarg :format)
   (arguments :reader condition-arguments :initarg :arguments :initform nil))
  (:report (lambda (c s)
               (format s (compatfmt "~@<~? (will be skipped)~@:>")
                       (condition-format c)
                       (list* (condition-form c) (condition-location c)
                              (condition-arguments c))))))
(define-condition invalid-source-registry (invalid-configuration warning)
  ((format :initform (compatfmt "~@<Invalid source registry ~S~@[ in ~S~]~@{ ~@?~}~@:>"))))
(define-condition invalid-output-translation (invalid-configuration warning)
  ((format :initform (compatfmt "~@<Invalid asdf output-translation ~S~@[ in ~S~]~@{ ~@?~}~@:>"))))

(defclass component ()
  ((name :accessor component-name :initarg :name :type string :documentation
         "Component name: designator for a string composed of portable pathname characters")
   ;; We might want to constrain version with
   ;; :type (and string (satisfies parse-version))
   ;; but we cannot until we fix all systems that don't use it correctly!
   (version :accessor component-version :initarg :version)
   (description :accessor component-description :initarg :description)
   (long-description :accessor component-long-description :initarg :long-description)
   ;; This one below is used by POIU - http://www.cliki.net/poiu
   ;; a parallelizing extension of ASDF that compiles in multiple parallel
   ;; slave processes (forked on demand) and loads in the master process.
   ;; Maybe in the future ASDF may use it internally instead of in-order-to.
   (load-dependencies :accessor component-load-dependencies :initform nil)
   ;; In the ASDF object model, dependencies exist between *actions*
   ;; (an action is a pair of operation and component). They are represented
   ;; alists of operations to dependencies (other actions) in each component.
   ;; There are two kinds of dependencies, each stored in its own slot:
   ;; in-order-to and do-first dependencies. These two kinds are related to
   ;; the fact that some actions modify the filesystem,
   ;; whereas other actions modify the current image, and
   ;; this implies a difference in how to interpret timestamps.
   ;; in-order-to dependencies will trigger re-performing the action
   ;; when the timestamp of some dependency
   ;; makes the timestamp of current action out-of-date;
   ;; do-first dependencies do not trigger such re-performing.
   ;; Therefore, a FASL must be recompiled if it is obsoleted
   ;; by any of its FASL dependencies (in-order-to); but
   ;; it needn't be recompiled just because one of these dependencies
   ;; hasn't yet been loaded in the current image (do-first).
   ;; The names are crap, but they have been the official API since Dan Barlow's ASDF 1.52!
   ;; See our ASDF 2 paper for more complete explanations.
   (in-order-to :initform nil :initarg :in-order-to
                :accessor component-in-order-to)
   (do-first :initform nil :initarg :do-first
             :accessor component-do-first)
   ;; methods defined using the "inline" style inside a defsystem form:
   ;; need to store them somewhere so we can delete them when the system
   ;; is re-evaluated
   (inline-methods :accessor component-inline-methods :initform nil)
   (parent :initarg :parent :initform nil :reader component-parent)
   ;; no direct accessor for pathname, we do this as a method to allow
   ;; it to default in funky ways if not supplied
   (relative-pathname :initarg :pathname)
   ;; the absolute-pathname is computed based on relative-pathname...
   (absolute-pathname)
   (operation-times :initform (make-hash-table)
                    :accessor component-operation-times)
   (around-compile :initarg :around-compile)
   ;; XXX we should provide some atomic interface for updating the
   ;; component properties
   (properties :accessor component-properties :initarg :properties
               :initform nil)))

(defun* component-find-path (component)
  (reverse
   (loop :for c = component :then (component-parent c)
     :while c :collect (component-name c))))

(defmethod print-object ((c component) stream)
  (print-unreadable-object (c stream :type t :identity nil)
    (format stream "~{~S~^ ~}" (component-find-path c))))


;;;; methods: conditions

(defmethod print-object ((c missing-dependency) s)
  (format s (compatfmt "~@<~A, required by ~A~@:>")
          (call-next-method c nil) (missing-required-by c)))

(defun* sysdef-error (format &rest arguments)
  (error 'formatted-system-definition-error :format-control
         format :format-arguments arguments))

;;;; methods: components

(defmethod print-object ((c missing-component) s)
  (format s (compatfmt "~@<Component ~S not found~@[ in ~A~]~@:>")
          (missing-requires c)
          (when (missing-parent c)
            (coerce-name (missing-parent c)))))

(defmethod print-object ((c missing-component-of-version) s)
  (format s (compatfmt "~@<Component ~S does not match version ~A~@[ in ~A~]~@:>")
          (missing-requires c)
          (missing-version c)
          (when (missing-parent c)
            (coerce-name (missing-parent c)))))

(defmethod component-system ((component component))
  (aif (component-parent component)
       (component-system it)
       component))

(defvar *default-component-class* 'cl-source-file)

(defun* compute-module-components-by-name (module)
  (let ((hash (make-hash-table :test 'equal)))
    (setf (module-components-by-name module) hash)
    (loop :for c :in (module-components module)
      :for name = (component-name c)
      :for previous = (gethash name (module-components-by-name module))
      :do
      (when previous
        (error 'duplicate-names :name name))
      :do (setf (gethash name (module-components-by-name module)) c))
    hash))

(defclass module (component)
  ((components
    :initform nil
    :initarg :components
    :accessor module-components)
   (components-by-name
    :accessor module-components-by-name)
   ;; What to do if we can't satisfy a dependency of one of this module's
   ;; components.  This allows a limited form of conditional processing.
   (if-component-dep-fails
    :initform :fail
    :initarg :if-component-dep-fails
    :accessor module-if-component-dep-fails)
   (default-component-class
    :initform *default-component-class*
    :initarg :default-component-class
    :accessor module-default-component-class)))

(defun* component-parent-pathname (component)
  ;; No default anymore (in particular, no *default-pathname-defaults*).
  ;; If you force component to have a NULL pathname, you better arrange
  ;; for any of its children to explicitly provide a proper absolute pathname
  ;; wherever a pathname is actually wanted.
  (let ((parent (component-parent component)))
    (when parent
      (component-pathname parent))))

(defmethod component-pathname ((component component))
  (if (slot-boundp component 'absolute-pathname)
      (slot-value component 'absolute-pathname)
      (let ((pathname
             (merge-pathnames*
              (component-relative-pathname component)
              (pathname-directory-pathname (component-parent-pathname component)))))
        (unless (or (null pathname) (absolute-pathname-p pathname))
          (error (compatfmt "~@<Invalid relative pathname ~S for component ~S~@:>")
                 pathname (component-find-path component)))
        (setf (slot-value component 'absolute-pathname) pathname)
        pathname)))

(defmethod component-property ((c component) property)
  (cdr (assoc property (slot-value c 'properties) :test #'equal)))

(defmethod (setf component-property) (new-value (c component) property)
  (let ((a (assoc property (slot-value c 'properties) :test #'equal)))
    (if a
        (setf (cdr a) new-value)
        (setf (slot-value c 'properties)
              (acons property new-value (slot-value c 'properties)))))
  new-value)

(defclass proto-system () ; slots to keep when resetting a system
  ;; To preserve identity for all objects, we'd need keep the components slots
  ;; but also to modify parse-component-form to reset the recycled objects.
  ((name) #|(components) (components-by-names)|#))

(defclass system (module proto-system)
  (;; description and long-description are now available for all component's,
   ;; but now also inherited from component, but we add the legacy accessor
   (description :accessor system-description :initarg :description)
   (long-description :accessor system-long-description :initarg :long-description)
   (author :accessor system-author :initarg :author)
   (maintainer :accessor system-maintainer :initarg :maintainer)
   (licence :accessor system-licence :initarg :licence
            :accessor system-license :initarg :license)
   (source-file :reader %system-source-file :initarg :source-file ; for CLISP upgrade
                :writer %set-system-source-file)
   (defsystem-depends-on :reader system-defsystem-depends-on :initarg :defsystem-depends-on)))

;;;; -------------------------------------------------------------------------
;;;; version-satisfies

(defmethod version-satisfies ((c component) version)
  (unless (and version (slot-boundp c 'version))
    (when version
      (warn "Requested version ~S but component ~S has no version" version c))
    (return-from version-satisfies t))
  (version-satisfies (component-version c) version))

(defun* asdf-version ()
  "Exported interface to the version of ASDF currently installed. A string.
You can compare this string with e.g.:
(ASDF:VERSION-SATISFIES (ASDF:ASDF-VERSION) \"2.345.67\")."
  *asdf-version*)

(defun* parse-version (string &optional on-error)
  "Parse a version string as a series of natural integers separated by dots.
Return a (non-null) list of integers if the string is valid, NIL otherwise.
If on-error is error, warn, or designates a function of compatible signature,
the function is called with an explanation of what is wrong with the argument.
NB: ignores leading zeroes, and so doesn't distinguish between 2.003 and 2.3"
  (and
   (or (stringp string)
       (when on-error
         (funcall on-error "~S: ~S is not a string"
                  'parse-version string)) nil)
   (or (loop :for prev = nil :then c :for c :across string
         :always (or (digit-char-p c)
                     (and (eql c #\.) prev (not (eql prev #\.))))
         :finally (return (and c (digit-char-p c))))
       (when on-error
         (funcall on-error "~S: ~S doesn't follow asdf version numbering convention"
                  'parse-version string)) nil)
   (mapcar #'parse-integer (split-string string :separator "."))))

(defmethod version-satisfies ((cver string) version)
  (let ((x (parse-version cver 'warn))
        (y (parse-version version 'warn)))
    (labels ((bigger (x y)
               (cond ((not y) t)
                     ((not x) nil)
                     ((> (car x) (car y)) t)
                     ((= (car x) (car y))
                      (bigger (cdr x) (cdr y))))))
      (and x y (= (car x) (car y))
           (or (not (cdr y)) (bigger (cdr x) (cdr y)))))))

;;;; -----------------------------------------------------------------
;;;; Windows shortcut support.  Based on:
;;;;
;;;; Jesse Hager: The Windows Shortcut File Format.
;;;; http://www.wotsit.org/list.asp?fc=13

#-(or clisp genera) ; CLISP doesn't need it, and READ-SEQUENCE annoys old Genera.
(progn
(defparameter *link-initial-dword* 76)
(defparameter *link-guid* #(1 20 2 0 0 0 0 0 192 0 0 0 0 0 0 70))

(defun* read-null-terminated-string (s)
  (with-output-to-string (out)
    (loop :for code = (read-byte s)
      :until (zerop code)
      :do (write-char (code-char code) out))))

(defun* read-little-endian (s &optional (bytes 4))
  (loop :for i :from 0 :below bytes
    :sum (ash (read-byte s) (* 8 i))))

(defun* parse-file-location-info (s)
  (let ((start (file-position s))
        (total-length (read-little-endian s))
        (end-of-header (read-little-endian s))
        (fli-flags (read-little-endian s))
        (local-volume-offset (read-little-endian s))
        (local-offset (read-little-endian s))
        (network-volume-offset (read-little-endian s))
        (remaining-offset (read-little-endian s)))
    (declare (ignore total-length end-of-header local-volume-offset))
    (unless (zerop fli-flags)
      (cond
        ((logbitp 0 fli-flags)
          (file-position s (+ start local-offset)))
        ((logbitp 1 fli-flags)
          (file-position s (+ start
                              network-volume-offset
                              #x14))))
      (strcat (read-null-terminated-string s)
              (progn
                (file-position s (+ start remaining-offset))
                (read-null-terminated-string s))))))

(defun* parse-windows-shortcut (pathname)
  (with-open-file (s pathname :element-type '(unsigned-byte 8))
    (handler-case
        (when (and (= (read-little-endian s) *link-initial-dword*)
                   (let ((header (make-array (length *link-guid*))))
                     (read-sequence header s)
                     (equalp header *link-guid*)))
          (let ((flags (read-little-endian s)))
            (file-position s 76)        ;skip rest of header
            (when (logbitp 0 flags)
              ;; skip shell item id list
              (let ((length (read-little-endian s 2)))
                (file-position s (+ length (file-position s)))))
            (cond
              ((logbitp 1 flags)
                (parse-file-location-info s))
              (t
                (when (logbitp 2 flags)
                  ;; skip description string
                  (let ((length (read-little-endian s 2)))
                    (file-position s (+ length (file-position s)))))
                (when (logbitp 3 flags)
                  ;; finally, our pathname
                  (let* ((length (read-little-endian s 2))
                         (buffer (make-array length)))
                    (read-sequence buffer s)
                    (map 'string #'code-char buffer)))))))
      (end-of-file ()
        nil)))))

;;;; -------------------------------------------------------------------------
;;;; Finding systems

(defun* make-defined-systems-table ()
  (make-hash-table :test 'equal))

(defvar *defined-systems* (make-defined-systems-table)
  "This is a hash table whose keys are strings, being the
names of the systems, and whose values are pairs, the first
element of which is a universal-time indicating when the
system definition was last updated, and the second element
of which is a system object.")

(defun* coerce-name (name)
  (typecase name
    (component (component-name name))
    (symbol (string-downcase (symbol-name name)))
    (string name)
    (t (sysdef-error (compatfmt "~@<Invalid component designator: ~3i~_~A~@:>") name))))

(defun* system-registered-p (name)
  (gethash (coerce-name name) *defined-systems*))

(defun* register-system (system)
  (check-type system system)
  (let ((name (component-name system)))
    (check-type name string)
    (asdf-message (compatfmt "~&~@<; ~@;Registering ~3i~_~A~@:>~%") system)
    (unless (eq system (cdr (gethash name *defined-systems*)))
      (setf (gethash name *defined-systems*)
            (cons (get-universal-time) system)))))

(defun* clear-system (name)
  "Clear the entry for a system in the database of systems previously loaded.
Note that this does NOT in any way cause the code of the system to be unloaded."
  ;; There is no "unload" operation in Common Lisp, and
  ;; a general such operation cannot be portably written,
  ;; considering how much CL relies on side-effects to global data structures.
  (remhash (coerce-name name) *defined-systems*))

(defun* map-systems (fn)
  "Apply FN to each defined system.

FN should be a function of one argument. It will be
called with an object of type asdf:system."
  (maphash #'(lambda (_ datum)
               (declare (ignore _))
               (destructuring-bind (_ . def) datum
                 (declare (ignore _))
                 (funcall fn def)))
           *defined-systems*))

;;; for the sake of keeping things reasonably neat, we adopt a
;;; convention that functions in this list are prefixed SYSDEF-

(defvar *system-definition-search-functions* '())

(setf *system-definition-search-functions*
      (append
       ;; Remove known-incompatible sysdef functions from ancient sbcl asdf.
       (remove 'contrib-sysdef-search *system-definition-search-functions*)
       ;; Tuck our defaults at the end of the list if they were absent.
       ;; This is imperfect, in case they were removed on purpose,
       ;; but then it will be the responsibility of whoever does that
       ;; to upgrade asdf before he does such a thing rather than after.
       (remove-if #'(lambda (x) (member x *system-definition-search-functions*))
                  '(sysdef-central-registry-search
                    sysdef-source-registry-search
                    sysdef-find-asdf))))

(defun* search-for-system-definition (system)
  (some (let ((name (coerce-name system))) #'(lambda (x) (funcall x name)))
        (cons 'find-system-if-being-defined
              *system-definition-search-functions*)))

(defvar *central-registry* nil
"A list of 'system directory designators' ASDF uses to find systems.

A 'system directory designator' is a pathname or an expression
which evaluates to a pathname. For example:

    (setf asdf:*central-registry*
          (list '*default-pathname-defaults*
                #p\"/home/me/cl/systems/\"
                #p\"/usr/share/common-lisp/systems/\"))

This is for backward compatibilily.
Going forward, we recommend new users should be using the source-registry.
")

(defun* featurep (x &optional (features *features*))
  (cond
    ((atom x)
     (and (member x features) t))
    ((eq :not (car x))
     (assert (null (cddr x)))
     (not (featurep (cadr x) features)))
    ((eq :or (car x))
     (some #'(lambda (x) (featurep x features)) (cdr x)))
    ((eq :and (car x))
     (every #'(lambda (x) (featurep x features)) (cdr x)))
    (t
     (error "Malformed feature specification ~S" x))))

(defun* os-unix-p ()
  (featurep '(:or :unix :cygwin :darwin)))

(defun* os-windows-p ()
  (and (not (os-unix-p)) (featurep '(:or :win32 :windows :mswindows :mingw32))))

(defun* probe-asd (name defaults)
  (block nil
    (when (directory-pathname-p defaults)
      (let ((file (make-pathname
                   :defaults defaults :name name
                   :version :newest :case :local :type "asd")))
        (when (probe-file* file)
          (return file)))
      #-(or clisp genera) ; clisp doesn't need it, plain genera doesn't have read-sequence(!)
      (when (os-windows-p)
        (let ((shortcut
               (make-pathname
                :defaults defaults :version :newest :case :local
                :name (strcat name ".asd")
                :type "lnk")))
          (when (probe-file* shortcut)
            (let ((target (parse-windows-shortcut shortcut)))
              (when target
                (return (pathname target))))))))))

(defun* sysdef-central-registry-search (system)
  (let ((name (coerce-name system))
        (to-remove nil)
        (to-replace nil))
    (block nil
      (unwind-protect
           (dolist (dir *central-registry*)
             (let ((defaults (eval dir)))
               (when defaults
                 (cond ((directory-pathname-p defaults)
                        (let ((file (probe-asd name defaults)))
                          (when file
                            (return file))))
                       (t
                        (restart-case
                            (let* ((*print-circle* nil)
                                   (message
                                    (format nil
                                            (compatfmt "~@<While searching for system ~S: ~3i~_~S evaluated to ~S which is not a directory.~@:>")
                                            system dir defaults)))
                              (error message))
                          (remove-entry-from-registry ()
                            :report "Remove entry from *central-registry* and continue"
                            (push dir to-remove))
                          (coerce-entry-to-directory ()
                            :report (lambda (s)
                                      (format s (compatfmt "~@<Coerce entry to ~a, replace ~a and continue.~@:>")
                                              (ensure-directory-pathname defaults) dir))
                            (push (cons dir (ensure-directory-pathname defaults)) to-replace))))))))
        ;; cleanup
        (dolist (dir to-remove)
          (setf *central-registry* (remove dir *central-registry*)))
        (dolist (pair to-replace)
          (let* ((current (car pair))
                 (new (cdr pair))
                 (position (position current *central-registry*)))
            (setf *central-registry*
                  (append (subseq *central-registry* 0 position)
                          (list new)
                          (subseq *central-registry* (1+ position))))))))))

(defun* make-temporary-package ()
  (flet ((try (counter)
           (ignore-errors
             (make-package (format nil "~A~D" :asdf counter)
                           :use '(:cl :asdf)))))
    (do* ((counter 0 (+ counter 1))
          (package (try counter) (try counter)))
         (package package))))

(defun* safe-file-write-date (pathname)
  ;; If FILE-WRITE-DATE returns NIL, it's possible that
  ;; the user or some other agent has deleted an input file.
  ;; Also, generated files will not exist at the time planning is done
  ;; and calls operation-done-p which calls safe-file-write-date.
  ;; So it is very possible that we can't get a valid file-write-date,
  ;; and we can survive and we will continue the planning
  ;; as if the file were very old.
  ;; (or should we treat the case in a different, special way?)
  (or (and pathname (probe-file* pathname) (ignore-errors (file-write-date pathname)))
      (progn
        (when (and pathname *asdf-verbose*)
          (warn (compatfmt "~@<Missing FILE-WRITE-DATE for ~S, treating it as zero.~@:>")
                pathname))
        0)))

(defmethod find-system ((name null) &optional (error-p t))
  (declare (ignorable name))
  (when error-p
    (sysdef-error (compatfmt "~@<NIL is not a valid system name~@:>"))))

(defmethod find-system (name &optional (error-p t))
  (find-system (coerce-name name) error-p))

(defvar *systems-being-defined* nil
  "A hash-table of systems currently being defined keyed by name, or NIL")

(defun* find-system-if-being-defined (name)
  (when *systems-being-defined*
    (gethash (coerce-name name) *systems-being-defined*)))

(defun* call-with-system-definitions (thunk)
  (if *systems-being-defined*
      (funcall thunk)
      (let ((*systems-being-defined* (make-hash-table :test 'equal)))
        (funcall thunk))))

(defmacro with-system-definitions ((&optional) &body body)
  `(call-with-system-definitions #'(lambda () ,@body)))

(defun* load-sysdef (name pathname)
  ;; Tries to load system definition with canonical NAME from PATHNAME.
  (with-system-definitions ()
    (let ((package (make-temporary-package)))
      (unwind-protect
           (handler-bind
               ((error #'(lambda (condition)
                           (error 'load-system-definition-error
                                  :name name :pathname pathname
                                  :condition condition))))
             (let ((*package* package)
                   (*default-pathname-defaults*
                    (pathname-directory-pathname pathname)))
               (asdf-message (compatfmt "~&~@<; ~@;Loading system definition from ~A into ~A~@:>~%")
                             pathname package)
               (load pathname)))
        (delete-package package)))))

(defun* locate-system (name)
  "Given a system NAME designator, try to locate where to load the system from.
Returns four values: FOUND-SYSTEM PATHNAME PREVIOUS PREVIOUS-TIME
FOUNDP is true when a new was found, either a new unregistered one or a previously registered one.
FOUND-SYSTEM when not null is a SYSTEM object that may be REGISTER-SYSTEM'ed as is
PATHNAME when not null is a path from where to load the system, associated with FOUND-SYSTEM, or with the PREVIOUS system.
PREVIOUS when not null is a previously loaded SYSTEM object of same name.
PREVIOUS-TIME when not null is the time at which the PREVIOUS system was loaded."
  (let* ((name (coerce-name name))
         (in-memory (system-registered-p name)) ; load from disk if absent or newer on disk
         (previous (cdr in-memory))
         (previous (and (typep previous 'system) previous))
         (previous-time (car in-memory))
           (found (search-for-system-definition name))
         (found-system (and (typep found 'system) found))
         (pathname (or (and (typep found '(or pathname string)) (pathname found))
                       (and found-system (system-source-file found-system))
                       (and previous (system-source-file previous))))
         (foundp (and (or found-system pathname previous) t)))
    (check-type found (or null pathname system))
    (when foundp
      (setf pathname (resolve-symlinks* pathname))
      (when (and pathname (not (absolute-pathname-p pathname)))
        (setf pathname (ensure-pathname-absolute pathname))
        (when found-system
          (%set-system-source-file pathname found-system)))
      (when (and previous (not (#-cormanlisp equal #+cormanlisp equalp
                                             (system-source-file previous) pathname)))
        (%set-system-source-file pathname previous)
        (setf previous-time nil))
      (values foundp found-system pathname previous previous-time))))

(defmethod find-system ((name string) &optional (error-p t))
  (with-system-definitions ()
    (loop
      (restart-case
          (multiple-value-bind (foundp found-system pathname previous previous-time)
              (locate-system name)
            (declare (ignore foundp))
            (when (and found-system (not previous))
              (register-system found-system))
            (when (and pathname
                       (or (not previous-time)
                           ;; don't reload if it's already been loaded,
                           ;; or its filestamp is in the future which means some clock is skewed
                           ;; and trying to load might cause an infinite loop.
                           (< previous-time (safe-file-write-date pathname) (get-universal-time))))
              (load-sysdef name pathname))
            (let ((in-memory (system-registered-p name))) ; try again after loading from disk if needed
              (return
                (cond
                  (in-memory
                   (when pathname
                     (setf (car in-memory) (safe-file-write-date pathname)))
                   (cdr in-memory))
                  (error-p
                   (error 'missing-component :requires name))))))
        (reinitialize-source-registry-and-retry ()
          :report (lambda (s)
                    (format s "~@<Retry finding system ~A after reinitializing the source-registry.~@:>" name))
          (initialize-source-registry))))))

(defun* find-system-fallback (requested fallback &rest keys &key source-file &allow-other-keys)
  (setf fallback (coerce-name fallback)
        requested (coerce-name requested))
  (when (equal requested fallback)
    (let ((registered (cdr (gethash fallback *defined-systems*))))
      (or registered
          (apply 'make-instance 'system
                 :name fallback :source-file source-file keys)))))

(defun* sysdef-find-asdf (name)
  ;; Bug: :version *asdf-version* won't be updated when ASDF is updated.
  (find-system-fallback name "asdf" :version *asdf-version*))


;;;; -------------------------------------------------------------------------
;;;; Finding components

(defmethod find-component ((base string) path)
  (let ((s (find-system base nil)))
    (and s (find-component s path))))

(defmethod find-component ((base symbol) path)
  (cond
    (base (find-component (coerce-name base) path))
    (path (find-component path nil))
    (t    nil)))

(defmethod find-component ((base cons) path)
  (find-component (car base) (cons (cdr base) path)))

(defmethod find-component ((module module) (name string))
  (unless (slot-boundp module 'components-by-name) ;; SBCL may miss the u-i-f-r-c method!!!
    (compute-module-components-by-name module))
  (values (gethash name (module-components-by-name module))))

(defmethod find-component ((component component) (name symbol))
  (if name
      (find-component component (coerce-name name))
      component))

(defmethod find-component ((module module) (name cons))
  (find-component (find-component module (car name)) (cdr name)))


;;; component subclasses

(defclass source-file (component)
  ((type :accessor source-file-explicit-type :initarg :type :initform nil)))

(defclass cl-source-file (source-file)
  ((type :initform "lisp")))
(defclass cl-source-file.cl (cl-source-file)
  ((type :initform "cl")))
(defclass cl-source-file.lsp (cl-source-file)
  ((type :initform "lsp")))
(defclass c-source-file (source-file)
  ((type :initform "c")))
(defclass java-source-file (source-file)
  ((type :initform "java")))
(defclass static-file (source-file) ())
(defclass doc-file (static-file) ())
(defclass html-file (doc-file)
  ((type :initform "html")))

(defmethod source-file-type ((component module) (s module))
  (declare (ignorable component s))
  :directory)
(defmethod source-file-type ((component source-file) (s module))
  (declare (ignorable s))
  (source-file-explicit-type component))

(defun* coerce-pathname (name &key type defaults)
  "coerce NAME into a PATHNAME.
When given a string, portably decompose it into a relative pathname:
#\\/ separates subdirectories. The last #\\/-separated string is as follows:
if TYPE is NIL, its last #\\. if any separates name and type from from type;
if TYPE is a string, it is the type, and the whole string is the name;
if TYPE is :DIRECTORY, the string is a directory component;
if the string is empty, it's a directory.
Any directory named .. is read as :BACK.
Host, device and version components are taken from DEFAULTS."
  ;; The defaults are required notably because they provide the default host
  ;; to the below make-pathname, which may crucially matter to people using
  ;; merge-pathnames with non-default hosts,  e.g. for logical-pathnames.
  ;; NOTE that the host and device slots will be taken from the defaults,
  ;; but that should only matter if you later merge relative pathnames with
  ;; CL:MERGE-PATHNAMES instead of ASDF:MERGE-PATHNAMES*
  (etypecase name
    ((or null pathname)
     name)
    (symbol
     (coerce-pathname (string-downcase name) :type type :defaults defaults))
    (string
     (multiple-value-bind (relative path filename)
         (component-name-to-pathname-components name :force-directory (eq type :directory)
                                                :force-relative t)
       (multiple-value-bind (name type)
           (cond
             ((or (eq type :directory) (null filename))
              (values nil nil))
             (type
              (values filename type))
             (t
              (split-name-type filename)))
         (apply 'make-pathname :directory (cons relative path) :name name :type type
                (when defaults `(:defaults ,defaults))))))))

(defun* merge-component-name-type (name &key type defaults)
  ;; For backwards compatibility only, for people using internals.
  ;; Will be removed in a future release, e.g. 2.016.
  (warn "Please don't use ASDF::MERGE-COMPONENT-NAME-TYPE. Use ASDF:COERCE-PATHNAME.")
  (coerce-pathname name :type type :defaults defaults))

(defmethod component-relative-pathname ((component component))
  (coerce-pathname
   (or (slot-value component 'relative-pathname)
       (component-name component))
   :type (source-file-type component (component-system component))
   :defaults (component-parent-pathname component)))

(defun* subpathname (pathname subpath &key type)
  (and pathname (merge-pathnames* (coerce-pathname subpath :type type)
                                  (pathname-directory-pathname pathname))))

(defun subpathname* (pathname subpath &key type)
  (and pathname
       (subpathname (ensure-directory-pathname pathname) subpath :type type)))

;;;; -------------------------------------------------------------------------
;;;; Operations

;;; one of these is instantiated whenever #'operate is called

(defclass operation ()
  (;; as of danb's 2003-03-16 commit e0d02781, :force can be:
   ;; T to force the inside of the specified system,
   ;;   but not recurse to other systems we depend on.
   ;; :ALL (or any other atom) to force all systems
   ;;   including other systems we depend on.
   ;; (SYSTEM1 SYSTEM2 ... SYSTEMN)
   ;;   to force systems named in a given list
   ;; However, but this feature has only ever worked but starting with ASDF 2.014.5
   (forced :initform nil :initarg :force :accessor operation-forced)
   (original-initargs :initform nil :initarg :original-initargs
                      :accessor operation-original-initargs)
   (visited-nodes :initform (make-hash-table :test 'equal) :accessor operation-visited-nodes)
   (visiting-nodes :initform (make-hash-table :test 'equal) :accessor operation-visiting-nodes)
   (parent :initform nil :initarg :parent :accessor operation-parent)))

(defmethod print-object ((o operation) stream)
  (print-unreadable-object (o stream :type t :identity t)
    (ignore-errors
      (prin1 (operation-original-initargs o) stream))))

(defmethod shared-initialize :after ((operation operation) slot-names
                                     &key force
                                     &allow-other-keys)
  (declare (ignorable operation slot-names force))
  ;; empty method to disable initarg validity checking
  (values))

(defun* node-for (o c)
  (cons (class-name (class-of o)) c))

(defmethod operation-ancestor ((operation operation))
  (aif (operation-parent operation)
       (operation-ancestor it)
       operation))


(defun* make-sub-operation (c o dep-c dep-o)
  "C is a component, O is an operation, DEP-C is another
component, and DEP-O, confusingly enough, is an operation
class specifier, not an operation."
  (let* ((args (copy-list (operation-original-initargs o)))
         (force-p (getf args :force)))
    ;; note explicit comparison with T: any other non-NIL force value
    ;; (e.g. :recursive) will pass through
    (cond ((and (null (component-parent c))
                (null (component-parent dep-c))
                (not (eql c dep-c)))
           (when (eql force-p t)
             (setf (getf args :force) nil))
           (apply 'make-instance dep-o
                  :parent o
                  :original-initargs args args))
          ((subtypep (type-of o) dep-o)
           o)
          (t
           (apply 'make-instance dep-o
                  :parent o :original-initargs args args)))))


(defmethod visit-component ((o operation) (c component) data)
  (unless (component-visited-p o c)
    (setf (gethash (node-for o c)
                   (operation-visited-nodes (operation-ancestor o)))
          (cons t data))))

(defmethod component-visited-p ((o operation) (c component))
  (gethash (node-for o c)
           (operation-visited-nodes (operation-ancestor o))))

(defmethod (setf visiting-component) (new-value operation component)
  ;; MCL complains about unused lexical variables
  (declare (ignorable operation component))
  new-value)

(defmethod (setf visiting-component) (new-value (o operation) (c component))
  (let ((node (node-for o c))
        (a (operation-ancestor o)))
    (if new-value
        (setf (gethash node (operation-visiting-nodes a)) t)
        (remhash node (operation-visiting-nodes a)))
    new-value))

(defmethod component-visiting-p ((o operation) (c component))
  (let ((node (node-for o c)))
    (gethash node (operation-visiting-nodes (operation-ancestor o)))))

(defmethod component-depends-on ((op-spec symbol) (c component))
  ;; Note: we go from op-spec to operation via make-instance
  ;; to allow for specialization through defmethod's, even though
  ;; it's a detour in the default case below.
  (component-depends-on (make-instance op-spec) c))

(defmethod component-depends-on ((o operation) (c component))
  (cdr (assoc (type-of o) (component-in-order-to c))))

(defmethod component-self-dependencies ((o operation) (c component))
  (remove-if-not
   #'(lambda (x) (member (component-name c) (cdr x) :test #'string=))
   (component-depends-on o c)))

(defmethod input-files ((operation operation) (c component))
  (let ((parent (component-parent c))
        (self-deps (component-self-dependencies operation c)))
    (if self-deps
        (mapcan #'(lambda (dep)
                    (destructuring-bind (op name) dep
                      (output-files (make-instance op)
                                    (find-component parent name))))
                self-deps)
        ;; no previous operations needed?  I guess we work with the
        ;; original source file, then
        (list (component-pathname c)))))

(defmethod input-files ((operation operation) (c module))
  (declare (ignorable operation c))
  nil)

(defmethod component-operation-time (o c)
  (gethash (type-of o) (component-operation-times c)))

(defmethod operation-done-p ((o operation) (c component))
  (let ((out-files (output-files o c))
        (in-files (input-files o c))
        (op-time (component-operation-time o c)))
    (flet ((earliest-out ()
             (reduce #'min (mapcar #'safe-file-write-date out-files)))
           (latest-in ()
             (reduce #'max (mapcar #'safe-file-write-date in-files))))
      (cond
        ((and (not in-files) (not out-files))
         ;; arbitrary decision: an operation that uses nothing to
         ;; produce nothing probably isn't doing much.
         ;; e.g. operations on systems, modules that have no immediate action,
         ;; but are only meaningful through traversed dependencies
         t)
        ((not out-files)
         ;; an operation without output-files is probably meant
         ;; for its side-effects in the current image,
         ;; assumed to be idem-potent,
         ;; e.g. LOAD-OP or LOAD-SOURCE-OP of some CL-SOURCE-FILE.
         (and op-time (>= op-time (latest-in))))
        ((not in-files)
         ;; an operation with output-files and no input-files
         ;; is probably meant for its side-effects on the file-system,
         ;; assumed to have to be done everytime.
         ;; (I don't think there is any such case in ASDF unless extended)
         nil)
        (t
         ;; an operation with both input and output files is assumed
         ;; as computing the latter from the former,
         ;; assumed to have been done if the latter are all older
         ;; than the former.
         ;; e.g. COMPILE-OP of some CL-SOURCE-FILE.
         ;; We use >= instead of > to play nice with generated files.
         ;; This opens a race condition if an input file is changed
         ;; after the output is created but within the same second
         ;; of filesystem time; but the same race condition exists
         ;; whenever the computation from input to output takes more
         ;; than one second of filesystem time (or just crosses the
         ;; second). So that's cool.
         (and
          (every #'probe-file* in-files)
          (every #'probe-file* out-files)
          (>= (earliest-out) (latest-in))))))))



;;; For 1.700 I've done my best to refactor TRAVERSE
;;; by splitting it up in a bunch of functions,
;;; so as to improve the collection and use-detection algorithm. --fare
;;; The protocol is as follows: we pass around operation, dependency,
;;; bunch of other stuff, and a force argument. Return a force flag.
;;; The returned flag is T if anything has changed that requires a rebuild.
;;; The force argument is a list of components that will require a rebuild
;;; if the flag is T, at which point whoever returns the flag has to
;;; mark them all as forced, and whoever recurses again can use a NIL list
;;; as a further argument.

(defvar *forcing* nil
  "This dynamically-bound variable is used to force operations in
recursive calls to traverse.")

(defgeneric* do-traverse (operation component collect))

(defun* resolve-dependency-name (component name &optional version)
  (loop
    (restart-case
        (return
          (let ((comp (find-component (component-parent component) name)))
            (unless comp
              (error 'missing-dependency
                     :required-by component
                     :requires name))
            (when version
              (unless (version-satisfies comp version)
                (error 'missing-dependency-of-version
                       :required-by component
                       :version version
                       :requires name)))
            comp))
      (retry ()
        :report (lambda (s)
                  (format s "~@<Retry loading ~3i~_~A.~@:>" name))
        :test
        (lambda (c)
          (or (null c)
              (and (typep c 'missing-dependency)
                   (eq (missing-required-by c) component)
                   (equal (missing-requires c) name))))))))

(defun* resolve-dependency-spec (component dep-spec)
  (cond
    ((atom dep-spec)
     (resolve-dependency-name component dep-spec))
    ;; Structured dependencies --- this parses keywords.
    ;; The keywords could conceivably be broken out and cleanly (extensibly)
    ;; processed by EQL methods. But for now, here's what we've got.
    ((eq :version (first dep-spec))
     ;; https://bugs.launchpad.net/asdf/+bug/527788
     (resolve-dependency-name component (second dep-spec) (third dep-spec)))
    ((eq :feature (first dep-spec))
     ;; This particular subform is not documented and
     ;; has always been broken in the past.
     ;; Therefore no one uses it, and I'm cerroring it out,
     ;; after fixing it
     ;; See https://bugs.launchpad.net/asdf/+bug/518467
     (cerror "Continue nonetheless."
             "Congratulations, you're the first ever user of FEATURE dependencies! Please contact the asdf-devel mailing-list.")
     (when (find (second dep-spec) *features* :test 'string-equal)
       (resolve-dependency-name component (third dep-spec))))
    (t
     (error (compatfmt "~@<Bad dependency ~s.  Dependencies must be (:version <name> <version>), (:feature <feature> <name>), or <name>.~@:>") dep-spec))))

(defun* do-one-dep (op c collect dep-op dep-c)
  ;; Collects a partial plan for performing dep-op on dep-c
  ;; as dependencies of a larger plan involving op and c.
  ;; Returns t if this should force recompilation of those who depend on us.
  ;; dep-op is an operation class name (not an operation object),
  ;; whereas dep-c is a component object.n
  (do-traverse (make-sub-operation c op dep-c dep-op) dep-c collect))

(defun* do-dep (op c collect dep-op-spec dep-c-specs)
  ;; Collects a partial plan for performing dep-op-spec on each of dep-c-specs
  ;; as dependencies of a larger plan involving op and c.
  ;; Returns t if this should force recompilation of those who depend on us.
  ;; dep-op-spec is either an operation class name (not an operation object),
  ;; or the magic symbol asdf:feature.
  ;; If dep-op-spec is asdf:feature, then the first dep-c-specs is a keyword,
  ;; and the plan will succeed if that keyword is present in *feature*,
  ;; or fail if it isn't
  ;; (at which point c's :if-component-dep-fails will kick in).
  ;; If dep-op-spec is an operation class name,
  ;; then dep-c-specs specifies a list of sibling component of c,
  ;; as per resolve-dependency-spec, such that operating op on c
  ;; depends on operating dep-op-spec on each of them.
  (cond ((eq dep-op-spec 'feature)
         (if (member (car dep-c-specs) *features*)
             nil
             (error 'missing-dependency
                    :required-by c
                    :requires (list :feature (car dep-c-specs)))))
        (t
         (let ((flag nil))
           (dolist (d dep-c-specs)
             (when (do-one-dep op c collect dep-op-spec
                               (resolve-dependency-spec c d))
               (setf flag t)))
           flag))))

(defvar *visit-count* 0) ; counter that allows to sort nodes from operation-visited-nodes

(defun* do-collect (collect x)
  (funcall collect x))

(defmethod do-traverse ((operation operation) (c component) collect)
  (let ((*forcing* *forcing*)
        (flag nil)) ;; return value: must we rebuild this and its dependencies?
    (labels
        ((update-flag (x)
           (orf flag x))
         (dep (op comp)
           (update-flag (do-dep operation c collect op comp))))
      ;; Have we been visited yet? If so, just process the result.
      (aif (component-visited-p operation c)
           (progn
             (update-flag (cdr it))
             (return-from do-traverse flag)))
      ;; dependencies
      (when (component-visiting-p operation c)
        (error 'circular-dependency :components (list c)))
      (setf (visiting-component operation c) t)
      (unwind-protect
           (progn
             (let ((f (operation-forced
                       (operation-ancestor operation))))
               (when (and f (or (not (consp f)) ;; T or :ALL
                                (and (typep c 'system) ;; list of names of systems to force
                                     (member (component-name c) f
                                             :test #'string=))))
                 (setf *forcing* t)))
             ;; first we check and do all the dependencies for the module.
             ;; Operations planned in this loop will show up
             ;; in the results, and are consumed below.
             (let ((*forcing* nil))
               ;; upstream dependencies are never forced to happen just because
               ;; the things that depend on them are....
               (loop
                 :for (required-op . deps) :in (component-depends-on operation c)
                 :do (dep required-op deps)))
             ;; constituent bits
             (let ((module-ops
                    (when (typep c 'module)
                      (let ((at-least-one nil)
                            ;; This is set based on the results of the
                            ;; dependencies and whether we are in the
                            ;; context of a *forcing* call...
                            ;; inter-system dependencies do NOT trigger
                            ;; building components
                            (*forcing*
                             (or *forcing*
                                 (and flag (not (typep c 'system)))))
                            (error nil))
                        (while-collecting (internal-collect)
                          (dolist (kid (module-components c))
                            (handler-case
                                (update-flag
                                 (do-traverse operation kid #'internal-collect))
                              #-genera
                              (missing-dependency (condition)
                                (when (eq (module-if-component-dep-fails c)
                                          :fail)
                                  (error condition))
                                (setf error condition))
                              (:no-error (c)
                                (declare (ignore c))
                                (setf at-least-one t))))
                          (when (and (eq (module-if-component-dep-fails c)
                                         :try-next)
                                     (not at-least-one))
                            (error error)))))))
               (update-flag (or *forcing* (not (operation-done-p operation c))))
                 ;; For sub-operations, check whether
                 ;; the original ancestor operation was forced,
                 ;; or names us amongst an explicit list of things to force...
                 ;; except that this check doesn't distinguish
                 ;; between all the things with a given name. Sigh.
                 ;; BROKEN!
               (when flag
                 (let ((do-first (cdr (assoc (class-name (class-of operation))
                                             (component-do-first c)))))
                   (loop :for (required-op . deps) :in do-first
                     :do (do-dep operation c collect required-op deps)))
                 (do-collect collect (vector module-ops))
                 (do-collect collect (cons operation c)))))
             (setf (visiting-component operation c) nil)))
      (visit-component operation c (when flag (incf *visit-count*)))
      flag))

(defun* flatten-tree (l)
  ;; You collected things into a list.
  ;; Most elements are just things to collect again.
  ;; A (simple-vector 1) indicate that you should recurse into its contents.
  ;; This way, in two passes (rather than N being the depth of the tree),
  ;; you can collect things with marginally constant-time append,
  ;; achieving linear time collection instead of quadratic time.
  (while-collecting (c)
    (labels ((r (x)
               (if (typep x '(simple-vector 1))
                   (r* (svref x 0))
                   (c x)))
             (r* (l)
               (dolist (x l) (r x))))
      (r* l))))

(defmethod traverse ((operation operation) (c component))
  (when (consp (operation-forced operation))
    (setf (operation-forced operation)
          (mapcar #'coerce-name (operation-forced operation))))
  (flatten-tree
   (while-collecting (collect)
     (let ((*visit-count* 0))
       (do-traverse operation c #'collect)))))

(defmethod perform ((operation operation) (c source-file))
  (sysdef-error
   (compatfmt "~@<Required method PERFORM not implemented for operation ~A, component ~A~@:>")
   (class-of operation) (class-of c)))

(defmethod perform ((operation operation) (c module))
  (declare (ignorable operation c))
  nil)

(defmethod mark-operation-done ((operation operation) (c component))
  (setf (gethash (type-of operation) (component-operation-times c))
    (reduce #'max
            (cons (get-universal-time)
                  (mapcar #'safe-file-write-date (input-files operation c))))))

(defmethod perform-with-restarts (operation component)
  ;; TOO verbose, especially as the default. Add your own :before method
  ;; to perform-with-restart or perform if you want that:
  #|(when *asdf-verbose* (explain operation component))|#
  (perform operation component))

(defmethod perform-with-restarts :around (operation component)
  (loop
    (restart-case
        (return (call-next-method))
      (retry ()
        :report
        (lambda (s)
          (format s (compatfmt "~@<Retry ~A.~@:>")
                  (operation-description operation component))))
      (accept ()
        :report
        (lambda (s)
          (format s (compatfmt "~@<Continue, treating ~A as having been successful.~@:>")
                  (operation-description operation component)))
        (mark-operation-done operation component)
        (return)))))

(defmethod explain ((operation operation) (component component))
  (asdf-message (compatfmt "~&~@<; ~@;~A~:>~%")
                (operation-description operation component)))

(defmethod operation-description (operation component)
  (format nil (compatfmt "~@<~A on ~A~@:>")
          (class-of operation) component))

;;;; -------------------------------------------------------------------------
;;;; compile-op

(defclass compile-op (operation)
  ((proclamations :initarg :proclamations :accessor compile-op-proclamations :initform nil)
   (on-warnings :initarg :on-warnings :accessor operation-on-warnings
                :initform *compile-file-warnings-behaviour*)
   (on-failure :initarg :on-failure :accessor operation-on-failure
               :initform *compile-file-failure-behaviour*)
   (flags :initarg :flags :accessor compile-op-flags
          :initform nil)))

(defun* output-file (operation component)
  "The unique output file of performing OPERATION on COMPONENT"
  (let ((files (output-files operation component)))
    (assert (length=n-p files 1))
    (first files)))

(defun* ensure-all-directories-exist (pathnames)
   (loop :for pn :in pathnames
     :for pathname = (if (typep pn 'logical-pathname)
                         (translate-logical-pathname pn)
                         pn)
     :do (ensure-directories-exist pathname)))

(defmethod perform :before ((operation compile-op) (c source-file))
  (ensure-all-directories-exist (asdf:output-files operation c)))

(defmethod perform :after ((operation operation) (c component))
  (mark-operation-done operation c))

(defgeneric* around-compile-hook (component))
(defgeneric* call-with-around-compile-hook (component thunk))

(defmethod around-compile-hook ((c component))
  (cond
    ((slot-boundp c 'around-compile)
     (slot-value c 'around-compile))
    ((component-parent c)
     (around-compile-hook (component-parent c)))))

(defun ensure-function (fun &key (package :asdf))
  (etypecase fun
    ((or symbol function) fun)
    (cons (eval `(function ,fun)))
    (string (eval `(function ,(with-standard-io-syntax
                               (let ((*package* (find-package package)))
                                 (read-from-string fun))))))))

(defmethod call-with-around-compile-hook ((c component) thunk)
  (let ((hook (around-compile-hook c)))
    (if hook
        (funcall (ensure-function hook) thunk)
        (funcall thunk))))

(defvar *compile-op-compile-file-function* 'compile-file*
  "Function used to compile lisp files.")

;;; perform is required to check output-files to find out where to put
;;; its answers, in case it has been overridden for site policy
(defmethod perform ((operation compile-op) (c cl-source-file))
  #-:broken-fasl-loader
  (let ((source-file (component-pathname c))
        ;; on some implementations, there are more than one output-file,
        ;; but the first one should always be the primary fasl that gets loaded.
        (output-file (first (output-files operation c)))
        (*compile-file-warnings-behaviour* (operation-on-warnings operation))
        (*compile-file-failure-behaviour* (operation-on-failure operation)))
    (multiple-value-bind (output warnings-p failure-p)
        (call-with-around-compile-hook
         c #'(lambda ()
               (apply *compile-op-compile-file-function* source-file
                      :output-file output-file (compile-op-flags operation))))
      (unless output
        (error 'compile-error :component c :operation operation))
      (when failure-p
        (case (operation-on-failure operation)
          (:warn (warn
                  (compatfmt "~@<COMPILE-FILE failed while performing ~A on ~A.~@:>")
                  operation c))
          (:error (error 'compile-failed :component c :operation operation))
          (:ignore nil)))
      (when warnings-p
        (case (operation-on-warnings operation)
          (:warn (warn
                  (compatfmt "~@<COMPILE-FILE warned while performing ~A on ~A.~@:>")
                  operation c))
          (:error (error 'compile-warned :component c :operation operation))
          (:ignore nil))))))

(defmethod output-files ((operation compile-op) (c cl-source-file))
  (declare (ignorable operation))
  (let ((p (lispize-pathname (component-pathname c))))
    #-broken-fasl-loader (list (compile-file-pathname p))
    #+broken-fasl-loader (list p)))

(defmethod perform ((operation compile-op) (c static-file))
  (declare (ignorable operation c))
  nil)

(defmethod output-files ((operation compile-op) (c static-file))
  (declare (ignorable operation c))
  nil)

(defmethod input-files ((operation compile-op) (c static-file))
  (declare (ignorable operation c))
  nil)

(defmethod operation-description ((operation compile-op) component)
  (declare (ignorable operation))
  (format nil (compatfmt "~@<compiling ~3i~_~A~@:>") component))

(defmethod operation-description ((operation compile-op) (component module))
  (declare (ignorable operation))
  (format nil (compatfmt "~@<compiled ~3i~_~A~@:>") component))


;;;; -------------------------------------------------------------------------
;;;; load-op

(defclass basic-load-op (operation) ())

(defclass load-op (basic-load-op) ())

(defmethod perform-with-restarts ((o load-op) (c cl-source-file))
  (loop
    (restart-case
        (return (call-next-method))
      (try-recompiling ()
        :report (lambda (s)
                  (format s "Recompile ~a and try loading it again"
                          (component-name c)))
        (perform (make-sub-operation c o c 'compile-op) c)))))

(defmethod perform ((o load-op) (c cl-source-file))
  (map () #'load (input-files o c)))

(defmethod perform ((operation load-op) (c static-file))
  (declare (ignorable operation c))
  nil)

(defmethod operation-done-p ((operation load-op) (c static-file))
  (declare (ignorable operation c))
  t)

(defmethod output-files ((operation operation) (c component))
  (declare (ignorable operation c))
  nil)

(defmethod component-depends-on ((operation load-op) (c component))
  (declare (ignorable operation))
  (cons (list 'compile-op (component-name c))
        (call-next-method)))

(defmethod operation-description ((operation load-op) component)
  (declare (ignorable operation))
  (format nil (compatfmt "~@<loading ~3i~_~A~@:>")
          component))

(defmethod operation-description ((operation load-op) (component cl-source-file))
  (declare (ignorable operation))
  (format nil (compatfmt "~@<loading FASL for ~3i~_~A~@:>")
          component))

(defmethod operation-description ((operation load-op) (component module))
  (declare (ignorable operation))
  (format nil (compatfmt "~@<loaded ~3i~_~A~@:>")
          component))

;;;; -------------------------------------------------------------------------
;;;; load-source-op

(defclass load-source-op (basic-load-op) ())

(defmethod perform ((o load-source-op) (c cl-source-file))
  (declare (ignorable o))
  (let ((source (component-pathname c)))
    (setf (component-property c 'last-loaded-as-source)
          (and (call-with-around-compile-hook c #'(lambda () (load source)))
               (get-universal-time)))))

(defmethod perform ((operation load-source-op) (c static-file))
  (declare (ignorable operation c))
  nil)

(defmethod output-files ((operation load-source-op) (c component))
  (declare (ignorable operation c))
  nil)

;;; FIXME: We simply copy load-op's dependencies.  This is Just Not Right.
(defmethod component-depends-on ((o load-source-op) (c component))
  (declare (ignorable o))
  (loop :with what-would-load-op-do = (component-depends-on 'load-op c)
    :for (op . co) :in what-would-load-op-do
    :when (eq op 'load-op) :collect (cons 'load-source-op co)))

(defmethod operation-done-p ((o load-source-op) (c source-file))
  (declare (ignorable o))
  (if (or (not (component-property c 'last-loaded-as-source))
          (> (safe-file-write-date (component-pathname c))
             (component-property c 'last-loaded-as-source)))
      nil t))

(defmethod operation-description ((operation load-source-op) component)
  (declare (ignorable operation))
  (format nil (compatfmt "~@<Loading source of ~3i~_~A~@:>")
          component))

(defmethod operation-description ((operation load-source-op) (component module))
  (declare (ignorable operation))
  (format nil (compatfmt "~@<Loaded source of ~3i~_~A~@:>") component))


;;;; -------------------------------------------------------------------------
;;;; test-op

(defclass test-op (operation) ())

(defmethod perform ((operation test-op) (c component))
  (declare (ignorable operation c))
  nil)

(defmethod operation-done-p ((operation test-op) (c system))
  "Testing a system is _never_ done."
  (declare (ignorable operation c))
  nil)

(defmethod component-depends-on :around ((o test-op) (c system))
  (declare (ignorable o))
  (cons `(load-op ,(component-name c)) (call-next-method)))


;;;; -------------------------------------------------------------------------
;;;; Invoking Operations

(defgeneric* operate (operation-class system &key &allow-other-keys))
(defgeneric* perform-plan (plan &key))

;;;; Separating this into a different function makes it more forward-compatible
(defun* cleanup-upgraded-asdf (old-version)
  (let ((new-version (asdf:asdf-version)))
    (unless (equal old-version new-version)
      (cond
        ((version-satisfies new-version old-version)
         (asdf-message (compatfmt "~&~@<; ~@;Upgraded ASDF from version ~A to version ~A~@:>~%")
                       old-version new-version))
        ((version-satisfies old-version new-version)
         (warn (compatfmt "~&~@<; ~@;Downgraded ASDF from version ~A to version ~A~@:>~%")
               old-version new-version))
        (t
         (asdf-message (compatfmt "~&~@<; ~@;Changed ASDF from version ~A to incompatible version ~A~@:>~%")
                       old-version new-version)))
      (let ((asdf (funcall (find-symbol* 'find-system :asdf) :asdf)))
        ;; Invalidate all systems but ASDF itself.
        (setf *defined-systems* (make-defined-systems-table))
        (register-system asdf)
        ;; If we're in the middle of something, restart it.
        (when *systems-being-defined*
          (let ((l (loop :for name :being :the :hash-keys :of *systems-being-defined* :collect name)))
            (clrhash *systems-being-defined*)
            (dolist (s l) (find-system s nil))))
        t))))

;;;; Try to upgrade of ASDF. If a different version was used, return T.
;;;; We need do that before we operate on anything that depends on ASDF.
(defun* upgrade-asdf ()
  (let ((version (asdf:asdf-version)))
    (handler-bind (((or style-warning warning) #'muffle-warning))
      (operate 'load-op :asdf :verbose nil))
    (cleanup-upgraded-asdf version)))

(defmethod perform-plan ((steps list) &key)
  (let ((*package* *package*)
        (*readtable* *readtable*))
    (with-compilation-unit ()
      (loop :for (op . component) :in steps :do
        (perform-with-restarts op component)))))

(defmethod operate (operation-class system &rest args
                    &key ((:verbose *asdf-verbose*) *asdf-verbose*) version force
                    &allow-other-keys)
  (declare (ignore force))
  (with-system-definitions ()
    (let* ((op (apply 'make-instance operation-class
                      :original-initargs args
                      args))
           (*verbose-out* (if *asdf-verbose* *standard-output* (make-broadcast-stream)))
           (system (etypecase system
                     (system system)
                     ((or string symbol) (find-system system)))))
      (unless (version-satisfies system version)
        (error 'missing-component-of-version :requires system :version version))
      (let ((steps (traverse op system)))
        (when (and (not (equal '("asdf") (component-find-path system)))
                   (find '("asdf") (mapcar 'cdr steps)
                         :test 'equal :key 'component-find-path)
                   (upgrade-asdf))
          ;; If we needed to upgrade ASDF to achieve our goal,
          ;; then do it specially as the first thing, then
          ;; invalidate all existing system
          ;; retry the whole thing with the new OPERATE function,
          ;; which on some implementations
          ;; has a new symbol shadowing the current one.
          (return-from operate
            (apply (find-symbol* 'operate :asdf) operation-class system args)))
        (perform-plan steps)
        (values op steps)))))

(defun* oos (operation-class system &rest args &key force verbose version
            &allow-other-keys)
  (declare (ignore force verbose version))
  (apply 'operate operation-class system args))

(let ((operate-docstring
  "Operate does three things:

1. It creates an instance of OPERATION-CLASS using any keyword parameters
as initargs.
2. It finds the  asdf-system specified by SYSTEM (possibly loading
it from disk).
3. It then calls TRAVERSE with the operation and system as arguments

The traverse operation is wrapped in WITH-COMPILATION-UNIT and error
handling code. If a VERSION argument is supplied, then operate also
ensures that the system found satisfies it using the VERSION-SATISFIES
method.

Note that dependencies may cause the operation to invoke other
operations on the system or its components: the new operations will be
created with the same initargs as the original one.
"))
  (setf (documentation 'oos 'function)
        (format nil
                "Short for _operate on system_ and an alias for the OPERATE function.~%~%~a"
                operate-docstring))
  (setf (documentation 'operate 'function)
        operate-docstring))

(defun* load-system (system &rest args &key force verbose version &allow-other-keys)
  "Shorthand for `(operate 'asdf:load-op system)`.
See OPERATE for details."
  (declare (ignore force verbose version))
  (apply 'operate 'load-op system args)
  t)

(defun* load-systems (&rest systems)
  (map () 'load-system systems))

(defun* compile-system (system &rest args &key force verbose version
                       &allow-other-keys)
  "Shorthand for `(operate 'asdf:compile-op system)`. See OPERATE
for details."
  (declare (ignore force verbose version))
  (apply 'operate 'compile-op system args)
  t)

(defun* test-system (system &rest args &key force verbose version
                    &allow-other-keys)
  "Shorthand for `(operate 'asdf:test-op system)`. See OPERATE for
details."
  (declare (ignore force verbose version))
  (apply 'operate 'test-op system args)
  t)

;;;; -------------------------------------------------------------------------
;;;; Defsystem

(defun* load-pathname ()
  (resolve-symlinks* (or *load-pathname* *compile-file-pathname*)))

(defun* determine-system-pathname (pathname)
  ;; The defsystem macro calls us to determine
  ;; the pathname of a system as follows:
  ;; 1. the one supplied,
  ;; 2. derived from *load-pathname* via load-pathname
  ;; 3. taken from the *default-pathname-defaults* via default-directory
  (let* ((file-pathname (load-pathname))
         (directory-pathname (and file-pathname (pathname-directory-pathname file-pathname))))
    (or (and pathname (subpathname directory-pathname pathname :type :directory))
        directory-pathname
        (default-directory))))

(defun* class-for-type (parent type)
  (or (loop :for symbol :in (list
                             type
                             (find-symbol* type *package*)
                             (find-symbol* type :asdf))
        :for class = (and symbol (find-class symbol nil))
        :when (and class
                   (#-cormanlisp subtypep #+cormanlisp cl::subclassp
                                 class (find-class 'component)))
        :return class)
      (and (eq type :file)
           (or (and parent (module-default-component-class parent))
               (find-class *default-component-class*)))
      (sysdef-error "don't recognize component type ~A" type)))

(defun* maybe-add-tree (tree op1 op2 c)
  "Add the node C at /OP1/OP2 in TREE, unless it's there already.
Returns the new tree (which probably shares structure with the old one)"
  (let ((first-op-tree (assoc op1 tree)))
    (if first-op-tree
        (progn
          (aif (assoc op2 (cdr first-op-tree))
               (if (find c (cdr it) :test #'equal)
                   nil
                   (setf (cdr it) (cons c (cdr it))))
               (setf (cdr first-op-tree)
                     (acons op2 (list c) (cdr first-op-tree))))
          tree)
        (acons op1 (list (list op2 c)) tree))))

(defun* union-of-dependencies (&rest deps)
  (let ((new-tree nil))
    (dolist (dep deps)
      (dolist (op-tree dep)
        (dolist (op  (cdr op-tree))
          (dolist (c (cdr op))
            (setf new-tree
                  (maybe-add-tree new-tree (car op-tree) (car op) c))))))
    new-tree))


(defvar *serial-depends-on* nil)

(defun* sysdef-error-component (msg type name value)
  (sysdef-error (strcat msg (compatfmt "~&~@<The value specified for ~(~A~) ~A is ~S~@:>"))
                type name value))

(defun* check-component-input (type name weakly-depends-on
                              depends-on components in-order-to)
  "A partial test of the values of a component."
  (unless (listp depends-on)
    (sysdef-error-component ":depends-on must be a list."
                            type name depends-on))
  (unless (listp weakly-depends-on)
    (sysdef-error-component ":weakly-depends-on must be a list."
                            type name weakly-depends-on))
  (unless (listp components)
    (sysdef-error-component ":components must be NIL or a list of components."
                            type name components))
  (unless (and (listp in-order-to) (listp (car in-order-to)))
    (sysdef-error-component ":in-order-to must be NIL or a list of components."
                            type name in-order-to)))

(defun* %remove-component-inline-methods (component)
  (dolist (name +asdf-methods+)
    (map ()
         ;; this is inefficient as most of the stored
         ;; methods will not be for this particular gf
         ;; But this is hardly performance-critical
         #'(lambda (m)
             (remove-method (symbol-function name) m))
         (component-inline-methods component)))
  ;; clear methods, then add the new ones
  (setf (component-inline-methods component) nil))

(defun* %define-component-inline-methods (ret rest)
  (dolist (name +asdf-methods+)
    (let ((keyword (intern (symbol-name name) :keyword)))
      (loop :for data = rest :then (cddr data)
        :for key = (first data)
        :for value = (second data)
        :while data
        :when (eq key keyword) :do
        (destructuring-bind (op qual (o c) &body body) value
          (pushnew
           (eval `(defmethod ,name ,qual ((,o ,op) (,c (eql ,ret)))
                             ,@body))
           (component-inline-methods ret)))))))

(defun* %refresh-component-inline-methods (component rest)
  (%remove-component-inline-methods component)
  (%define-component-inline-methods component rest))

(defun* parse-component-form (parent options)
  (destructuring-bind
        (type name &rest rest &key
              ;; the following list of keywords is reproduced below in the
              ;; remove-keys form.  important to keep them in sync
              components pathname default-component-class
              perform explain output-files operation-done-p
              weakly-depends-on
              depends-on serial in-order-to do-first
              (version nil versionp)
              ;; list ends
              &allow-other-keys) options
    (declare (ignorable perform explain output-files operation-done-p))
    (check-component-input type name weakly-depends-on depends-on components in-order-to)

    (when (and parent
               (find-component parent name)
               ;; ignore the same object when rereading the defsystem
               (not
                (typep (find-component parent name)
                       (class-for-type parent type))))
      (error 'duplicate-names :name name))

    (when versionp
      (unless (parse-version version nil)
        (warn (compatfmt "~@<Invalid version ~S for component ~S~@[ of ~S~]~@:>")
              version name parent)))

    (let* ((args (list* :name (coerce-name name)
                        :pathname pathname
                        :parent parent
                        (remove-keys
                         '(components pathname default-component-class
                           perform explain output-files operation-done-p
                           weakly-depends-on depends-on serial in-order-to)
                         rest)))
           (ret (find-component parent name)))
      (when weakly-depends-on
        (appendf depends-on (remove-if (complement #'find-system) weakly-depends-on)))
      (when *serial-depends-on*
        (push *serial-depends-on* depends-on))
      (if ret ; preserve identity
          (apply 'reinitialize-instance ret args)
          (setf ret (apply 'make-instance (class-for-type parent type) args)))
      (component-pathname ret) ; eagerly compute the absolute pathname
      (when (typep ret 'module)
        (setf (module-default-component-class ret)
              (or default-component-class
                  (and (typep parent 'module)
                       (module-default-component-class parent))))
        (let ((*serial-depends-on* nil))
          (setf (module-components ret)
                (loop
                  :for c-form :in components
                  :for c = (parse-component-form ret c-form)
                  :for name = (component-name c)
                  :collect c
                  :when serial :do (setf *serial-depends-on* name))))
        (compute-module-components-by-name ret))

      (setf (component-load-dependencies ret) depends-on) ;; Used by POIU

      (setf (component-in-order-to ret)
            (union-of-dependencies
             in-order-to
             `((compile-op (compile-op ,@depends-on))
               (load-op (load-op ,@depends-on)))))
      (setf (component-do-first ret)
            (union-of-dependencies
             do-first
             `((compile-op (load-op ,@depends-on)))))

      (%refresh-component-inline-methods ret rest)
      ret)))

(defun* reset-system (system &rest keys &key &allow-other-keys)
  (change-class (change-class system 'proto-system) 'system)
  (apply 'reinitialize-instance system keys))

(defun* do-defsystem (name &rest options
                           &key pathname (class 'system)
                           defsystem-depends-on &allow-other-keys)
  ;; The system must be registered before we parse the body,
  ;; otherwise we recur when trying to find an existing system
  ;; of the same name to reuse options (e.g. pathname) from.
  ;; To avoid infinite recursion in cases where you defsystem a system
  ;; that is registered to a different location to find-system,
  ;; we also need to remember it in a special variable *systems-being-defined*.
  (with-system-definitions ()
    (let* ((name (coerce-name name))
           (registered (system-registered-p name))
           (registered! (if registered
                            (rplaca registered (get-universal-time))
                            (register-system (make-instance 'system :name name))))
           (system (reset-system (cdr registered!)
                                :name name :source-file (load-pathname)))
           (component-options (remove-keys '(:class) options)))
      (setf (gethash name *systems-being-defined*) system)
      (apply 'load-systems defsystem-depends-on)
      ;; We change-class (when necessary) AFTER we load the defsystem-dep's
      ;; since the class might not be defined as part of those.
      (let ((class (class-for-type nil class)))
        (unless (eq (type-of system) class)
          (change-class system class)))
      (parse-component-form
       nil (list*
            :module name
            :pathname (determine-system-pathname pathname)
            component-options)))))

(defmacro defsystem (name &body options)
  `(apply 'do-defsystem ',name ',options))

;;;; ---------------------------------------------------------------------------
;;;; run-shell-command
;;;;
;;;; run-shell-command functions for other lisp implementations will be
;;;; gratefully accepted, if they do the same thing.
;;;; If the docstring is ambiguous, send a bug report.
;;;;
;;;; WARNING! The function below is mostly dysfunctional.
;;;; For instance, it will probably run fine on most implementations on Unix,
;;;; which will hopefully use the shell /bin/sh (which we force in some cases)
;;;; which is hopefully reasonably compatible with a POSIX *or* Bourne shell.
;;;; But behavior on Windows may vary wildly between implementations,
;;;; either relying on your having installed a POSIX sh, or going through
;;;; the CMD.EXE interpreter, for a totally different meaning, depending on
;;;; what is easily expressible in said implementation.
;;;;
;;;; We probably should move this functionality to its own system and deprecate
;;;; use of it from the asdf package. However, this would break unspecified
;;;; existing software, so until a clear alternative exists, we can't deprecate
;;;; it, and even after it's been deprecated, we will support it for a few
;;;; years so everyone has time to migrate away from it. -- fare 2009-12-01
;;;;
;;;; As a suggested replacement which is portable to all ASDF-supported
;;;; implementations and operating systems except Genera, I recommend
;;;; xcvb-driver's xcvb-driver:run-program/process-output-stream and its
;;;; derivatives such as xcvb-driver:run-program/for-side-effects.

(defun* run-shell-command (control-string &rest args)
  "Interpolate ARGS into CONTROL-STRING as if by FORMAT, and
synchronously execute the result using a Bourne-compatible shell, with
output to *VERBOSE-OUT*.  Returns the shell's exit code."
  (let ((command (apply 'format nil control-string args)))
    (asdf-message "; $ ~A~%" command)

    #+abcl
    (ext:run-shell-command command :output *verbose-out*)

    #+allegro
    ;; will this fail if command has embedded quotes - it seems to work
    (multiple-value-bind (stdout stderr exit-code)
        (excl.osi:command-output
         #-mswindows (vector "/bin/sh" "/bin/sh" "-c" command)
         #+mswindows command ; BEWARE!
         :input nil :whole nil
         #+mswindows :show-window #+mswindows :hide)
      (asdf-message "~{~&~a~%~}~%" stderr)
      (asdf-message "~{~&~a~%~}~%" stdout)
      exit-code)

    #+clisp
    ;; CLISP returns NIL for exit status zero.
    (if *verbose-out*
        (let* ((new-command (format nil "( ~A ) ; r=$? ; echo ; echo ASDF-EXIT-STATUS $r"
                                    command))
               (outstream (ext:run-shell-command new-command :output :stream :wait t)))
            (multiple-value-bind (retval out-lines)
                (unwind-protect
                     (parse-clisp-shell-output outstream)
                  (ignore-errors (close outstream)))
              (asdf-message "~{~&~a~%~}~%" out-lines)
              retval))
        ;; there will be no output, just grab up the exit status
        (or (ext:run-shell-command command :output nil :wait t) 0))

    #+clozure
    (nth-value 1
               (ccl:external-process-status
                (ccl:run-program
                 (cond
                   ((os-unix-p) "/bin/sh")
                   ((os-windows-p) (strcat "CMD /C " command)) ; BEWARE!
                   (t (error "Unsupported OS")))
                 (if (os-unix-p) (list "-c" command) '())
                 :input nil :output *verbose-out* :wait t)))

    #+(or cmu scl)
    (ext:process-exit-code
     (ext:run-program
      "/bin/sh"
      (list "-c" command)
      :input nil :output *verbose-out*))

    #+cormanlisp
    (win32:system command)

    #+ecl ;; courtesy of Juan Jose Garcia Ripoll
    (ext:system command)

    #+gcl
    (lisp:system command)

    #+lispworks
    (apply 'system:call-system-showing-output command
           :show-cmd nil :prefix "" :output-stream *verbose-out*
           (when (os-unix-p) '(:shell-type "/bin/sh")))

    #+mcl
    (ccl::with-cstrs ((%command command)) (_system %command))

    #+sbcl
    (sb-ext:process-exit-code
     (apply 'sb-ext:run-program
            #+win32 "sh" #-win32 "/bin/sh"
            (list  "-c" command)
            :input nil :output *verbose-out*
            #+win32 '(:search t) #-win32 nil))

    #+xcl
    (ext:run-shell-command command)

    #-(or abcl allegro clisp clozure cmu ecl gcl lispworks mcl sbcl scl xcl)
    (error "RUN-SHELL-COMMAND not implemented for this Lisp")))

#+clisp
(defun* parse-clisp-shell-output (stream)
  "Helper function for running shell commands under clisp.  Parses a specially-
crafted output string to recover the exit status of the shell command and a
list of lines of output."
  (loop :with status-prefix = "ASDF-EXIT-STATUS "
    :with prefix-length = (length status-prefix)
    :with exit-status = -1 :with lines = ()
    :for line = (read-line stream nil nil)
    :while line :do (push line lines) :finally
    (let* ((last (car lines))
           (status (and last (>= (length last) prefix-length)
                        (string-equal last status-prefix :end1 prefix-length)
                        (parse-integer last :start prefix-length :junk-allowed t))))
      (when status
        (setf exit-status status)
        (pop lines) (when (equal "" (car lines)) (pop lines)))
      (return (values exit-status (reverse lines))))))

;;;; ---------------------------------------------------------------------------
;;;; system-relative-pathname

(defun* system-definition-pathname (x)
  ;; As of 2.014.8, we mean to make this function obsolete,
  ;; but that won't happen until all clients have been updated.
  ;;(cerror "Use ASDF:SYSTEM-SOURCE-FILE instead"
  "Function ASDF:SYSTEM-DEFINITION-PATHNAME is obsolete.
It used to expose ASDF internals with subtle differences with respect to
user expectations, that have been refactored away since.
We recommend you use ASDF:SYSTEM-SOURCE-FILE instead
for a mostly compatible replacement that we're supporting,
or even ASDF:SYSTEM-SOURCE-DIRECTORY or ASDF:SYSTEM-RELATIVE-PATHNAME
if that's whay you mean." ;;)
  (system-source-file x))

(defmethod system-source-file ((system system))
  (%system-source-file system))
(defmethod system-source-file ((system-name string))
  (%system-source-file (find-system system-name)))
(defmethod system-source-file ((system-name symbol))
  (%system-source-file (find-system system-name)))

(defun* system-source-directory (system-designator)
  "Return a pathname object corresponding to the
directory in which the system specification (.asd file) is
located."
  (pathname-directory-pathname (system-source-file system-designator)))

(defun* relativize-directory (directory)
  (cond
    ((stringp directory)
     (list :relative directory))
    ((eq (car directory) :absolute)
     (cons :relative (cdr directory)))
    (t
     directory)))

(defun* relativize-pathname-directory (pathspec)
  (let ((p (pathname pathspec)))
    (make-pathname
     :directory (relativize-directory (pathname-directory p))
     :defaults p)))

(defun* system-relative-pathname (system name &key type)
  (subpathname (system-source-directory system) name :type type))


;;; ---------------------------------------------------------------------------
;;; implementation-identifier
;;;
;;; produce a string to identify current implementation.
;;; Initially stolen from SLIME's SWANK, rewritten since.
;;; We're back to runtime checking, for the sake of e.g. ABCL.

(defun* first-feature (features)
  (dolist (x features)
    (multiple-value-bind (val feature)
        (if (consp x) (values (first x) (cons :or (rest x))) (values x x))
      (when (featurep feature) (return val)))))

(defun implementation-type ()
  (first-feature
   '(:abcl (:acl :allegro) (:ccl :clozure) :clisp (:corman :cormanlisp) :cmu
     :ecl :gcl (:lw :lispworks) :mcl :sbcl :scl :symbolics :xcl)))

(defun operating-system ()
  (first-feature
   '(:cygwin (:win :windows :mswindows :win32 :mingw32) ;; try cygwin first!
     (:linux :linux :linux-target) ;; for GCL at least, must appear before :bsd
     (:macosx :macosx :darwin :darwin-target :apple) ; also before :bsd
     (:solaris :solaris :sunos) (:bsd :bsd :freebsd :netbsd :openbsd) :unix
     :genera)))

(defun architecture ()
  (first-feature
   '((:x64 :amd64 :x86-64 :x86_64 :x8664-target (:and :word-size=64 :pc386))
     (:x86 :x86 :i386 :i486 :i586 :i686 :pentium3 :pentium4 :pc386 :iapx386 :x8632-target)
     (:ppc64 :ppc64 :ppc64-target) (:ppc32 :ppc32 :ppc32-target :ppc :powerpc)
     :hppa64 :hppa :sparc64 (:sparc32 :sparc32 :sparc)
     :mipsel :mipseb :mips :alpha (:arm :arm :arm-target) :imach
     ;; Java comes last: if someone uses C via CFFI or otherwise JNA or JNI,
     ;; we may have to segregate the code still by architecture.
     (:java :java :java-1.4 :java-1.5 :java-1.6 :java-1.7))))

(defun lisp-version-string ()
  (let ((s (lisp-implementation-version)))
    (car ; as opposed to OR, this idiom prevents some unreachable code warning
     (list
      #+allegro
      (format nil "~A~A~@[~A~]"
              excl::*common-lisp-version-number*
              ;; ANSI vs MoDeRn - thanks to Robert Goldman and Charley Cox
              (if (eq excl:*current-case-mode* :case-sensitive-lower) "M" "A")
              ;; Note if not using International ACL
              ;; see http://www.franz.com/support/documentation/8.1/doc/operators/excl/ics-target-case.htm
              (excl:ics-target-case (:-ics "8")))
      #+armedbear (format nil "~a-fasl~a" s system::*fasl-version*)
      #+clisp
      (subseq s 0 (position #\space s)) ; strip build information (date, etc.)
      #+clozure
      (format nil "~d.~d-f~d" ; shorten for windows
              ccl::*openmcl-major-version*
              ccl::*openmcl-minor-version*
              (logand ccl::fasl-version #xFF))
      #+cmu (substitute #\- #\/ s)
      #+scl (format nil "~A~A" s
                    ;; ANSI upper case vs lower case.
                    (ecase ext:*case-mode* (:upper "") (:lower "l")))
      #+ecl (format nil "~A~@[-~A~]" s
                    (let ((vcs-id (ext:lisp-implementation-vcs-id)))
                      (subseq vcs-id 0 (min (length vcs-id) 8))))
      #+gcl (subseq s (1+ (position #\space s)))
      #+genera
      (multiple-value-bind (major minor) (sct:get-system-version "System")
        (format nil "~D.~D" major minor))
      #+mcl (subseq s 8) ; strip the leading "Version "
      s))))

(defun* implementation-identifier ()
  (substitute-if
   #\_ #'(lambda (x) (find x " /:;&^\\|?<>(){}[]$#`'\""))
   (format nil "~(~a~@{~@[-~a~]~}~)"
           (or (implementation-type) (lisp-implementation-type))
           (or (lisp-version-string) (lisp-implementation-version))
           (or (operating-system) (software-type))
           (or (architecture) (machine-type)))))


;;; ---------------------------------------------------------------------------
;;; Generic support for configuration files

(defun inter-directory-separator ()
  (if (os-unix-p) #\: #\;))

(defun* user-homedir ()
  (truenamize
   (pathname-directory-pathname
    #+mcl (current-user-homedir-pathname)
    #-mcl (user-homedir-pathname))))

(defun* user-configuration-directories ()
  (let ((dirs
         `(,@(when (os-unix-p)
               (cons
                (subpathname* (getenv "XDG_CONFIG_HOME") "common-lisp/")
                (loop :with dirs = (getenv "XDG_CONFIG_DIRS")
                  :for dir :in (split-string dirs :separator ":")
                  :collect (subpathname* dir "common-lisp/"))))
           ,@(when (os-windows-p)
               `(,(subpathname* (or #+lispworks (sys:get-folder-path :local-appdata)
                                    (getenv "LOCALAPPDATA"))
                               "common-lisp/config/")
                 ;; read-windows-registry HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\User Shell Folders\AppData
                 ,(subpathname* (or #+lispworks (sys:get-folder-path :appdata)
                                    (getenv "APPDATA"))
                                "common-lisp/config/")))
           ,(subpathname (user-homedir) ".config/common-lisp/"))))
    (remove-duplicates (remove-if-not #'absolute-pathname-p dirs)
                       :from-end t :test 'equal)))

(defun* system-configuration-directories ()
  (cond
    ((os-unix-p) '(#p"/etc/common-lisp/"))
    ((os-windows-p)
     (aif
      ;; read-windows-registry HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\User Shell Folders\Common AppData
      (subpathname* (or #+lispworks (sys:get-folder-path :common-appdata)
                        (getenv "ALLUSERSAPPDATA")
                        (subpathname* (getenv "ALLUSERSPROFILE") "Application Data/"))
                    "common-lisp/config/")
      (list it)))))

(defun* in-first-directory (dirs x &key (direction :input))
  (loop :with fun = (ecase direction
                      ((nil :input :probe) 'probe-file*)
                      ((:output :io) 'identity))
    :for dir :in dirs
    :thereis (and dir (funcall fun (merge-pathnames* x (ensure-directory-pathname dir))))))

(defun* in-user-configuration-directory (x &key (direction :input))
  (in-first-directory (user-configuration-directories) x :direction direction))
(defun* in-system-configuration-directory (x &key (direction :input))
  (in-first-directory (system-configuration-directories) x :direction direction))

(defun* configuration-inheritance-directive-p (x)
  (let ((kw '(:inherit-configuration :ignore-inherited-configuration)))
    (or (member x kw)
        (and (length=n-p x 1) (member (car x) kw)))))

(defun* report-invalid-form (reporter &rest args)
  (etypecase reporter
    (null
     (apply 'error 'invalid-configuration args))
    (function
     (apply reporter args))
    ((or symbol string)
     (apply 'error reporter args))
    (cons
     (apply 'apply (append reporter args)))))

(defvar *ignored-configuration-form* nil)

(defun* validate-configuration-form (form tag directive-validator
                                    &key location invalid-form-reporter)
  (unless (and (consp form) (eq (car form) tag))
    (setf *ignored-configuration-form* t)
    (report-invalid-form invalid-form-reporter :form form :location location)
    (return-from validate-configuration-form nil))
  (loop :with inherit = 0 :with ignore-invalid-p = nil :with x = (list tag)
    :for directive :in (cdr form)
    :when (cond
            ((configuration-inheritance-directive-p directive)
             (incf inherit) t)
            ((eq directive :ignore-invalid-entries)
             (setf ignore-invalid-p t) t)
            ((funcall directive-validator directive)
             t)
            (ignore-invalid-p
             nil)
            (t
             (setf *ignored-configuration-form* t)
             (report-invalid-form invalid-form-reporter :form directive :location location)
             nil))
    :do (push directive x)
    :finally
    (unless (= inherit 1)
      (report-invalid-form invalid-form-reporter
             :arguments (list (compatfmt "~@<One and only one of ~S or ~S is required.~@:>")
                              :inherit-configuration :ignore-inherited-configuration)))
    (return (nreverse x))))

(defun* validate-configuration-file (file validator &key description)
  (let ((forms (read-file-forms file)))
    (unless (length=n-p forms 1)
      (error (compatfmt "~@<One and only one form allowed for ~A. Got: ~3i~_~S~@:>~%")
             description forms))
    (funcall validator (car forms) :location file)))

(defun* hidden-file-p (pathname)
  (equal (first-char (pathname-name pathname)) #\.))

(defun* directory* (pathname-spec &rest keys &key &allow-other-keys)
  (apply 'directory pathname-spec
         (append keys '#.(or #+allegro '(:directories-are-files nil :follow-symbolic-links nil)
                             #+clozure '(:follow-links nil)
                             #+clisp '(:circle t :if-does-not-exist :ignore)
                             #+(or cmu scl) '(:follow-links nil :truenamep nil)
                             #+sbcl (when (find-symbol* :resolve-symlinks '#:sb-impl)
                                      '(:resolve-symlinks nil))))))

(defun* validate-configuration-directory (directory tag validator &key invalid-form-reporter)
  "Map the VALIDATOR across the .conf files in DIRECTORY, the TAG will
be applied to the results to yield a configuration form.  Current
values of TAG include :source-registry and :output-translations."
  (let ((files (sort (ignore-errors
                       (remove-if
                        'hidden-file-p
                        (directory* (make-pathname :name :wild :type "conf" :defaults directory))))
                     #'string< :key #'namestring)))
    `(,tag
      ,@(loop :for file :in files :append
          (loop :with ignore-invalid-p = nil
            :for form :in (read-file-forms file)
            :when (eq form :ignore-invalid-entries)
              :do (setf ignore-invalid-p t)
            :else
              :when (funcall validator form)
                :collect form
              :else
                :when ignore-invalid-p
                  :do (setf *ignored-configuration-form* t)
                :else
                  :do (report-invalid-form invalid-form-reporter :form form :location file)))
      :inherit-configuration)))


;;; ---------------------------------------------------------------------------
;;; asdf-output-translations
;;;
;;; this code is heavily inspired from
;;; asdf-binary-translations, common-lisp-controller and cl-launch.
;;; ---------------------------------------------------------------------------

(defvar *output-translations* ()
  "Either NIL (for uninitialized), or a list of one element,
said element itself being a sorted list of mappings.
Each mapping is a pair of a source pathname and destination pathname,
and the order is by decreasing length of namestring of the source pathname.")

(defvar *user-cache*
  (flet ((try (x &rest sub) (and x `(,x ,@sub))))
    (or
     (try (getenv "XDG_CACHE_HOME") "common-lisp" :implementation)
     (when (os-windows-p)
       (try (or #+lispworks (sys:get-folder-path :local-appdata)
                (getenv "LOCALAPPDATA")
                #+lispworks (sys:get-folder-path :appdata)
                (getenv "APPDATA"))
            "common-lisp" "cache" :implementation))
     '(:home ".cache" "common-lisp" :implementation))))

(defun* output-translations ()
  (car *output-translations*))

(defun* (setf output-translations) (new-value)
  (setf *output-translations*
        (list
         (stable-sort (copy-list new-value) #'>
                      :key #'(lambda (x)
                               (etypecase (car x)
                                 ((eql t) -1)
                                 (pathname
                                  (let ((directory (pathname-directory (car x))))
                                    (if (listp directory) (length directory) 0))))))))
  new-value)

(defun* output-translations-initialized-p ()
  (and *output-translations* t))

(defun* clear-output-translations ()
  "Undoes any initialization of the output translations.
You might want to call that before you dump an image that would be resumed
with a different configuration, so the configuration would be re-read then."
  (setf *output-translations* '())
  (values))

(declaim (ftype (function (t &key (:directory boolean) (:wilden boolean))
                          (values (or null pathname) &optional))
                resolve-location))

(defun* resolve-relative-location-component (x &key directory wilden)
  (let ((r (etypecase x
             (pathname x)
             (string (coerce-pathname x :type (when directory :directory)))
             (cons
              (if (null (cdr x))
                  (resolve-relative-location-component
                   (car x) :directory directory :wilden wilden)
                  (let* ((car (resolve-relative-location-component
                               (car x) :directory t :wilden nil)))
                    (merge-pathnames*
                     (resolve-relative-location-component
                      (cdr x) :directory directory :wilden wilden)
                     car))))
             ((eql :default-directory)
              (relativize-pathname-directory (default-directory)))
             ((eql :*/) *wild-directory*)
             ((eql :**/) *wild-inferiors*)
             ((eql :*.*.*) *wild-file*)
             ((eql :implementation)
              (coerce-pathname (implementation-identifier) :type :directory))
             ((eql :implementation-type)
              (coerce-pathname (string-downcase (implementation-type)) :type :directory)))))
    (when (absolute-pathname-p r)
      (error (compatfmt "~@<pathname ~S is not relative~@:>") x))
    (if (or (pathnamep x) (not wilden)) r (wilden r))))

(defvar *here-directory* nil
  "This special variable is bound to the currect directory during calls to
PROCESS-SOURCE-REGISTRY in order that we be able to interpret the :here
directive.")

(defun* resolve-absolute-location-component (x &key directory wilden)
  (let* ((r
          (etypecase x
            (pathname x)
            (string (let ((p (#+mcl probe-posix #-mcl parse-namestring x)))
                      #+mcl (unless p (error "POSIX pathname ~S does not exist" x))
                      (if directory (ensure-directory-pathname p) p)))
            (cons
             (return-from resolve-absolute-location-component
               (if (null (cdr x))
                   (resolve-absolute-location-component
                    (car x) :directory directory :wilden wilden)
                   (merge-pathnames*
                    (resolve-relative-location-component
                     (cdr x) :directory directory :wilden wilden)
                    (resolve-absolute-location-component
                     (car x) :directory t :wilden nil)))))
            ((eql :root)
             ;; special magic! we encode such paths as relative pathnames,
             ;; but it means "relative to the root of the source pathname's host and device".
             (return-from resolve-absolute-location-component
               (let ((p (make-pathname :directory '(:relative))))
                 (if wilden (wilden p) p))))
            ((eql :home) (user-homedir))
            ((eql :here)
             (resolve-location (or *here-directory*
                                   ;; give semantics in the case of use interactively
                                   :default-directory)
                          :directory t :wilden nil))
            ((eql :user-cache) (resolve-location *user-cache* :directory t :wilden nil))
            ((eql :system-cache)
             (error "Using the :system-cache is deprecated. ~%~
Please remove it from your ASDF configuration"))
            ((eql :default-directory) (default-directory))))
         (s (if (and wilden (not (pathnamep x)))
                (wilden r)
                r)))
    (unless (absolute-pathname-p s)
      (error (compatfmt "~@<Invalid designator for an absolute pathname: ~3i~_~S~@:>") x))
    s))

(defun* resolve-location (x &key directory wilden)
  (if (atom x)
      (resolve-absolute-location-component x :directory directory :wilden wilden)
      (loop :with path = (resolve-absolute-location-component
                          (car x) :directory (and (or directory (cdr x)) t)
                          :wilden (and wilden (null (cdr x))))
        :for (component . morep) :on (cdr x)
        :for dir = (and (or morep directory) t)
        :for wild = (and wilden (not morep))
        :do (setf path (merge-pathnames*
                        (resolve-relative-location-component
                         component :directory dir :wilden wild)
                        path))
        :finally (return path))))

(defun* location-designator-p (x)
  (flet ((absolute-component-p (c)
           (typep c '(or string pathname
                      (member :root :home :here :user-cache :system-cache :default-directory))))
         (relative-component-p (c)
           (typep c '(or string pathname
                      (member :default-directory :*/ :**/ :*.*.*
                        :implementation :implementation-type)))))
    (or (typep x 'boolean)
        (absolute-component-p x)
        (and (consp x) (absolute-component-p (first x)) (every #'relative-component-p (rest x))))))

(defun* location-function-p (x)
  (and
   (consp x)
   (length=n-p x 2)
   (or (and (equal (first x) :function)
            (typep (second x) 'symbol))
       (and (equal (first x) 'lambda)
            (cddr x)
            (length=n-p (second x) 2)))))

(defun* validate-output-translations-directive (directive)
  (or (member directive '(:enable-user-cache :disable-cache nil))
      (and (consp directive)
           (or (and (length=n-p directive 2)
                    (or (and (eq (first directive) :include)
                             (typep (second directive) '(or string pathname null)))
                        (and (location-designator-p (first directive))
                             (or (location-designator-p (second directive))
                                 (location-function-p (second directive))))))
               (and (length=n-p directive 1)
                    (location-designator-p (first directive)))))))

(defun* validate-output-translations-form (form &key location)
  (validate-configuration-form
   form
   :output-translations
   'validate-output-translations-directive
   :location location :invalid-form-reporter 'invalid-output-translation))

(defun* validate-output-translations-file (file)
  (validate-configuration-file
   file 'validate-output-translations-form :description "output translations"))

(defun* validate-output-translations-directory (directory)
  (validate-configuration-directory
   directory :output-translations 'validate-output-translations-directive
   :invalid-form-reporter 'invalid-output-translation))

(defun* parse-output-translations-string (string &key location)
  (cond
    ((or (null string) (equal string ""))
     '(:output-translations :inherit-configuration))
    ((not (stringp string))
     (error (compatfmt "~@<Environment string isn't: ~3i~_~S~@:>") string))
    ((eql (char string 0) #\")
     (parse-output-translations-string (read-from-string string) :location location))
    ((eql (char string 0) #\()
     (validate-output-translations-form (read-from-string string) :location location))
    (t
     (loop
      :with inherit = nil
      :with directives = ()
      :with start = 0
      :with end = (length string)
      :with source = nil
      :with separator = (inter-directory-separator)
      :for i = (or (position separator string :start start) end) :do
      (let ((s (subseq string start i)))
        (cond
          (source
           (push (list source (if (equal "" s) nil s)) directives)
           (setf source nil))
          ((equal "" s)
           (when inherit
             (error (compatfmt "~@<Only one inherited configuration allowed: ~3i~_~S~@:>")
                    string))
           (setf inherit t)
           (push :inherit-configuration directives))
          (t
           (setf source s)))
        (setf start (1+ i))
        (when (> start end)
          (when source
            (error (compatfmt "~@<Uneven number of components in source to destination mapping: ~3i~_~S~@:>")
                   string))
          (unless inherit
            (push :ignore-inherited-configuration directives))
          (return `(:output-translations ,@(nreverse directives)))))))))

(defparameter *default-output-translations*
  '(environment-output-translations
    user-output-translations-pathname
    user-output-translations-directory-pathname
    system-output-translations-pathname
    system-output-translations-directory-pathname))

(defun* wrapping-output-translations ()
  `(:output-translations
    ;; Some implementations have precompiled ASDF systems,
    ;; so we must disable translations for implementation paths.
    #+sbcl ,(let ((h (getenv "SBCL_HOME")))
                 (when (plusp (length h)) `((,(truenamize h) ,*wild-inferiors*) ())))
    ;; The below two are not needed: no precompiled ASDF system there
    ;; #+ecl (,(translate-logical-pathname "SYS:**;*.*") ())
    ;; #+clozure ,(ignore-errors (list (wilden (let ((*default-pathname-defaults* #p"")) (truename #p"ccl:"))) ()))
    ;; All-import, here is where we want user stuff to be:
    :inherit-configuration
    ;; These are for convenience, and can be overridden by the user:
    #+abcl (#p"/___jar___file___root___/**/*.*" (:user-cache #p"**/*.*"))
    #+abcl (#p"jar:file:/**/*.jar!/**/*.*" (:function translate-jar-pathname))
    ;; We enable the user cache by default, and here is the place we do:
    :enable-user-cache))

(defparameter *output-translations-file* (coerce-pathname "asdf-output-translations.conf"))
(defparameter *output-translations-directory* (coerce-pathname "asdf-output-translations.conf.d/"))

(defun* user-output-translations-pathname (&key (direction :input))
  (in-user-configuration-directory *output-translations-file* :direction direction))
(defun* system-output-translations-pathname (&key (direction :input))
  (in-system-configuration-directory *output-translations-file* :direction direction))
(defun* user-output-translations-directory-pathname (&key (direction :input))
  (in-user-configuration-directory *output-translations-directory* :direction direction))
(defun* system-output-translations-directory-pathname (&key (direction :input))
  (in-system-configuration-directory *output-translations-directory* :direction direction))
(defun* environment-output-translations ()
  (getenv "ASDF_OUTPUT_TRANSLATIONS"))

(defgeneric* process-output-translations (spec &key inherit collect))
(declaim (ftype (function (t &key (:collect (or symbol function))) t)
                inherit-output-translations))
(declaim (ftype (function (t &key (:collect (or symbol function)) (:inherit list)) t)
                process-output-translations-directive))

(defmethod process-output-translations ((x symbol) &key
                                        (inherit *default-output-translations*)
                                        collect)
  (process-output-translations (funcall x) :inherit inherit :collect collect))
(defmethod process-output-translations ((pathname pathname) &key inherit collect)
  (cond
    ((directory-pathname-p pathname)
     (process-output-translations (validate-output-translations-directory pathname)
                                  :inherit inherit :collect collect))
    ((probe-file* pathname)
     (process-output-translations (validate-output-translations-file pathname)
                                  :inherit inherit :collect collect))
    (t
     (inherit-output-translations inherit :collect collect))))
(defmethod process-output-translations ((string string) &key inherit collect)
  (process-output-translations (parse-output-translations-string string)
                               :inherit inherit :collect collect))
(defmethod process-output-translations ((x null) &key inherit collect)
  (declare (ignorable x))
  (inherit-output-translations inherit :collect collect))
(defmethod process-output-translations ((form cons) &key inherit collect)
  (dolist (directive (cdr (validate-output-translations-form form)))
    (process-output-translations-directive directive :inherit inherit :collect collect)))

(defun* inherit-output-translations (inherit &key collect)
  (when inherit
    (process-output-translations (first inherit) :collect collect :inherit (rest inherit))))

(defun* process-output-translations-directive (directive &key inherit collect)
  (if (atom directive)
      (ecase directive
        ((:enable-user-cache)
         (process-output-translations-directive '(t :user-cache) :collect collect))
        ((:disable-cache)
         (process-output-translations-directive '(t t) :collect collect))
        ((:inherit-configuration)
         (inherit-output-translations inherit :collect collect))
        ((:ignore-inherited-configuration :ignore-invalid-entries nil)
         nil))
      (let ((src (first directive))
            (dst (second directive)))
        (if (eq src :include)
            (when dst
              (process-output-translations (pathname dst) :inherit nil :collect collect))
            (when src
              (let ((trusrc (or (eql src t)
                                (let ((loc (resolve-location src :directory t :wilden t)))
                                  (if (absolute-pathname-p loc) (truenamize loc) loc)))))
                (cond
                  ((location-function-p dst)
                   (funcall collect
                            (list trusrc
                                  (if (symbolp (second dst))
                                      (fdefinition (second dst))
                                      (eval (second dst))))))
                  ((eq dst t)
                   (funcall collect (list trusrc t)))
                  (t
                   (let* ((trudst (if dst
                                      (resolve-location dst :directory t :wilden t)
                                      trusrc))
                          (wilddst (merge-pathnames* *wild-file* trudst)))
                     (funcall collect (list wilddst t))
                     (funcall collect (list trusrc trudst)))))))))))

(defun* compute-output-translations (&optional parameter)
  "read the configuration, return it"
  (remove-duplicates
   (while-collecting (c)
     (inherit-output-translations
      `(wrapping-output-translations ,parameter ,@*default-output-translations*) :collect #'c))
   :test 'equal :from-end t))

(defvar *output-translations-parameter* nil)

(defun* initialize-output-translations (&optional (parameter *output-translations-parameter*))
  "read the configuration, initialize the internal configuration variable,
return the configuration"
  (setf *output-translations-parameter* parameter
        (output-translations) (compute-output-translations parameter)))

(defun* disable-output-translations ()
  "Initialize output translations in a way that maps every file to itself,
effectively disabling the output translation facility."
  (initialize-output-translations
   '(:output-translations :disable-cache :ignore-inherited-configuration)))

;; checks an initial variable to see whether the state is initialized
;; or cleared. In the former case, return current configuration; in
;; the latter, initialize.  ASDF will call this function at the start
;; of (asdf:find-system).
(defun* ensure-output-translations ()
  (if (output-translations-initialized-p)
      (output-translations)
      (initialize-output-translations)))

(defun* translate-pathname* (path absolute-source destination &optional root source)
  (declare (ignore source))
  (cond
    ((functionp destination)
     (funcall destination path absolute-source))
    ((eq destination t)
     path)
    ((not (pathnamep destination))
     (error "Invalid destination"))
    ((not (absolute-pathname-p destination))
     (translate-pathname path absolute-source (merge-pathnames* destination root)))
    (root
     (translate-pathname (directorize-pathname-host-device path) absolute-source destination))
    (t
     (translate-pathname path absolute-source destination))))

(defun* apply-output-translations (path)
  #+cormanlisp (truenamize path) #-cormanlisp
  (etypecase path
    (logical-pathname
     path)
    ((or pathname string)
     (ensure-output-translations)
     (loop :with p = (truenamize path)
       :for (source destination) :in (car *output-translations*)
       :for root = (when (or (eq source t)
                             (and (pathnamep source)
                                  (not (absolute-pathname-p source))))
                     (pathname-root p))
       :for absolute-source = (cond
                                ((eq source t) (wilden root))
                                (root (merge-pathnames* source root))
                                (t source))
       :when (or (eq source t) (pathname-match-p p absolute-source))
       :return (translate-pathname* p absolute-source destination root source)
       :finally (return p)))))

(defmethod output-files :around (operation component)
  "Translate output files, unless asked not to"
  operation component ;; hush genera, not convinced by declare ignorable(!)
  (values
   (multiple-value-bind (files fixedp) (call-next-method)
     (if fixedp
         files
         (mapcar #'apply-output-translations files)))
   t))

(defun* compile-file-pathname* (input-file &rest keys &key output-file &allow-other-keys)
  (if (absolute-pathname-p output-file)
      ;; what cfp should be doing, w/ mp* instead of mp
      (let* ((type (pathname-type (apply 'compile-file-pathname "x.lisp" keys)))
             (defaults (make-pathname
                        :type type :defaults (merge-pathnames* input-file))))
        (merge-pathnames* output-file defaults))
      (apply-output-translations
       (apply 'compile-file-pathname input-file keys))))

(defun* tmpize-pathname (x)
  (make-pathname
   :name (strcat "ASDF-TMP-" (pathname-name x))
   :defaults x))

(defun* delete-file-if-exists (x)
  (when (and x (probe-file* x))
    (delete-file x)))

(defun* compile-file* (input-file &rest keys &key output-file &allow-other-keys)
  (let* ((output-file (apply 'compile-file-pathname* input-file :output-file output-file keys))
         (tmp-file (tmpize-pathname output-file))
         (status :error))
    (multiple-value-bind (output-truename warnings-p failure-p)
        (apply 'compile-file input-file :output-file tmp-file keys)
      (cond
        (failure-p
         (setf status *compile-file-failure-behaviour*))
        (warnings-p
         (setf status *compile-file-warnings-behaviour*))
        (t
         (setf status :success)))
      (ecase status
        ((:success :warn :ignore)
         (delete-file-if-exists output-file)
         (when output-truename
           (rename-file output-truename output-file)
           (setf output-truename output-file)))
        (:error
         (delete-file-if-exists output-truename)
         (setf output-truename nil)))
      (values output-truename warnings-p failure-p))))

#+abcl
(defun* translate-jar-pathname (source wildcard)
  (declare (ignore wildcard))
  (let* ((p (pathname (first (pathname-device source))))
         (root (format nil "/___jar___file___root___/~@[~A/~]"
                       (and (find :windows *features*)
                            (pathname-device p)))))
    (apply-output-translations
     (merge-pathnames*
      (relativize-pathname-directory source)
      (merge-pathnames*
       (relativize-pathname-directory (ensure-directory-pathname p))
       root)))))

;;;; -----------------------------------------------------------------
;;;; Compatibility mode for ASDF-Binary-Locations

(defmethod operate :before (operation-class system &rest args &key &allow-other-keys)
  (declare (ignorable operation-class system args))
  (when (find-symbol* '#:output-files-for-system-and-operation :asdf)
    (error "ASDF 2 is not compatible with ASDF-BINARY-LOCATIONS, which you are using.
ASDF 2 now achieves the same purpose with its builtin ASDF-OUTPUT-TRANSLATIONS,
which should be easier to configure. Please stop using ASDF-BINARY-LOCATIONS,
and instead use ASDF-OUTPUT-TRANSLATIONS. See the ASDF manual for details.
In case you insist on preserving your previous A-B-L configuration, but
do not know how to achieve the same effect with A-O-T, you may use function
ASDF:ENABLE-ASDF-BINARY-LOCATIONS-COMPATIBILITY as documented in the manual;
call that function where you would otherwise have loaded and configured A-B-L.")))

(defun* enable-asdf-binary-locations-compatibility
    (&key
     (centralize-lisp-binaries nil)
     (default-toplevel-directory
         (subpathname (user-homedir) ".fasls/")) ;; Use ".cache/common-lisp/" instead ???
     (include-per-user-information nil)
     (map-all-source-files (or #+(or ecl clisp) t nil))
     (source-to-target-mappings nil))
  #+(or ecl clisp)
  (when (null map-all-source-files)
    (error "asdf:enable-asdf-binary-locations-compatibility doesn't support :map-all-source-files nil on ECL and CLISP"))
  (let* ((fasl-type (pathname-type (compile-file-pathname "foo.lisp")))
         (mapped-files (if map-all-source-files *wild-file*
                           (make-pathname :type fasl-type :defaults *wild-file*)))
         (destination-directory
          (if centralize-lisp-binaries
              `(,default-toplevel-directory
                ,@(when include-per-user-information
                        (cdr (pathname-directory (user-homedir))))
                :implementation ,*wild-inferiors*)
              `(:root ,*wild-inferiors* :implementation))))
    (initialize-output-translations
     `(:output-translations
       ,@source-to-target-mappings
       ((:root ,*wild-inferiors* ,mapped-files)
        (,@destination-directory ,mapped-files))
       (t t)
       :ignore-inherited-configuration))))

;;;; -----------------------------------------------------------------
;;;; Source Registry Configuration, by Francois-Rene Rideau
;;;; See the Manual and https://bugs.launchpad.net/asdf/+bug/485918

;; Using ack 1.2 exclusions
(defvar *default-source-registry-exclusions*
  '(".bzr" ".cdv"
    ;; "~.dep" "~.dot" "~.nib" "~.plst" ; we don't support ack wildcards
    ".git" ".hg" ".pc" ".svn" "CVS" "RCS" "SCCS" "_darcs"
    "_sgbak" "autom4te.cache" "cover_db" "_build"
    "debian")) ;; debian often builds stuff under the debian directory... BAD.

(defvar *source-registry-exclusions* *default-source-registry-exclusions*)

(defvar *source-registry* nil
  "Either NIL (for uninitialized), or an equal hash-table, mapping
system names to pathnames of .asd files")

(defun* source-registry-initialized-p ()
  (typep *source-registry* 'hash-table))

(defun* clear-source-registry ()
  "Undoes any initialization of the source registry.
You might want to call that before you dump an image that would be resumed
with a different configuration, so the configuration would be re-read then."
  (setf *source-registry* nil)
  (values))

(defparameter *wild-asd*
  (make-pathname :directory nil :name *wild* :type "asd" :version :newest))

(defun* filter-logical-directory-results (directory entries merger)
  (if (typep directory 'logical-pathname)
      ;; Try hard to not resolve logical-pathname into physical pathnames;
      ;; otherwise logical-pathname users/lovers will be disappointed.
      ;; If directory* could use some implementation-dependent magic,
      ;; we will have logical pathnames already; otherwise,
      ;; we only keep pathnames for which specifying the name and
      ;; translating the LPN commute.
      (loop :for f :in entries
        :for p = (or (and (typep f 'logical-pathname) f)
                     (let* ((u (ignore-errors (funcall merger f))))
                       ;; The first u avoids a cumbersome (truename u) error
                       (and u (equal (ignore-errors (truename u)) f) u)))
        :when p :collect p)
      entries))

(defun* directory-files (directory &optional (pattern *wild-file*))
  (when (wild-pathname-p directory)
    (error "Invalid wild in ~S" directory))
  (unless (member (pathname-directory pattern) '(() (:relative)) :test 'equal)
    (error "Invalid file pattern ~S" pattern))
  (let ((entries (ignore-errors (directory* (merge-pathnames* pattern directory)))))
    (filter-logical-directory-results
     directory entries
     #'(lambda (f)
         (make-pathname :defaults directory
                        :name (pathname-name f) :type (ununspecific (pathname-type f))
                        :version (ununspecific (pathname-version f)))))))

(defun* directory-asd-files (directory)
  (directory-files directory *wild-asd*))

(defun* subdirectories (directory)
  (let* ((directory (ensure-directory-pathname directory))
         #-(or abcl cormanlisp genera xcl)
         (wild (merge-pathnames*
                #-(or abcl allegro cmu lispworks sbcl scl xcl)
                *wild-directory*
                #+(or abcl allegro cmu lispworks sbcl scl xcl) "*.*"
                directory))
         (dirs
          #-(or abcl cormanlisp genera xcl)
          (ignore-errors
            (directory* wild . #.(or #+clozure '(:directories t :files nil)
                                     #+mcl '(:directories t))))
          #+(or abcl xcl) (system:list-directory directory)
          #+cormanlisp (cl::directory-subdirs directory)
          #+genera (fs:directory-list directory))
         #+(or abcl allegro cmu genera lispworks sbcl scl xcl)
         (dirs (loop :for x :in dirs
                 :for d = #+(or abcl xcl) (extensions:probe-directory x)
                          #+allegro (excl:probe-directory x)
                          #+(or cmu sbcl scl) (directory-pathname-p x)
                          #+genera (getf (cdr x) :directory)
                          #+lispworks (lw:file-directory-p x)
                 :when d :collect #+(or abcl allegro xcl) d
                                  #+genera (ensure-directory-pathname (first x))
                                  #+(or cmu lispworks sbcl scl) x)))
    (filter-logical-directory-results
     directory dirs
     (let ((prefix (normalize-pathname-directory-component
                    (pathname-directory directory))))
       #'(lambda (d)
           (let ((dir (normalize-pathname-directory-component
                       (pathname-directory d))))
             (and (consp dir) (consp (cdr dir))
                  (make-pathname
                   :defaults directory :name nil :type nil :version nil
                   :directory (append prefix (last dir))))))))))

(defun* collect-asds-in-directory (directory collect)
  (map () collect (directory-asd-files directory)))

(defun* collect-sub*directories (directory collectp recursep collector)
  (when (funcall collectp directory)
    (funcall collector directory))
  (dolist (subdir (subdirectories directory))
    (when (funcall recursep subdir)
      (collect-sub*directories subdir collectp recursep collector))))

(defun* collect-sub*directories-asd-files
    (directory &key
     (exclude *default-source-registry-exclusions*)
     collect)
  (collect-sub*directories
   directory
   (constantly t)
   #'(lambda (x) (not (member (car (last (pathname-directory x))) exclude :test #'equal)))
   #'(lambda (dir) (collect-asds-in-directory dir collect))))

(defun* validate-source-registry-directive (directive)
  (or (member directive '(:default-registry))
      (and (consp directive)
           (let ((rest (rest directive)))
             (case (first directive)
               ((:include :directory :tree)
                (and (length=n-p rest 1)
                     (location-designator-p (first rest))))
               ((:exclude :also-exclude)
                (every #'stringp rest))
               ((:default-registry)
                (null rest)))))))

(defun* validate-source-registry-form (form &key location)
  (validate-configuration-form
   form :source-registry 'validate-source-registry-directive
   :location location :invalid-form-reporter 'invalid-source-registry))

(defun* validate-source-registry-file (file)
  (validate-configuration-file
   file 'validate-source-registry-form :description "a source registry"))

(defun* validate-source-registry-directory (directory)
  (validate-configuration-directory
   directory :source-registry 'validate-source-registry-directive
   :invalid-form-reporter 'invalid-source-registry))

(defun* parse-source-registry-string (string &key location)
  (cond
    ((or (null string) (equal string ""))
     '(:source-registry :inherit-configuration))
    ((not (stringp string))
     (error (compatfmt "~@<Environment string isn't: ~3i~_~S~@:>") string))
    ((find (char string 0) "\"(")
     (validate-source-registry-form (read-from-string string) :location location))
    (t
     (loop
      :with inherit = nil
      :with directives = ()
      :with start = 0
      :with end = (length string)
      :with separator = (inter-directory-separator)
      :for pos = (position separator string :start start) :do
      (let ((s (subseq string start (or pos end))))
        (flet ((check (dir)
                 (unless (absolute-pathname-p dir)
                   (error (compatfmt "~@<source-registry string must specify absolute pathnames: ~3i~_~S~@:>") string))
                 dir))
          (cond
            ((equal "" s) ; empty element: inherit
             (when inherit
               (error (compatfmt "~@<Only one inherited configuration allowed: ~3i~_~S~@:>")
                      string))
             (setf inherit t)
             (push ':inherit-configuration directives))
            ((ends-with s "//") ;; TODO: allow for doubling of separator even outside Unix?
             (push `(:tree ,(check (subseq s 0 (- (length s) 2)))) directives))
            (t
             (push `(:directory ,(check s)) directives))))
        (cond
          (pos
           (setf start (1+ pos)))
          (t
           (unless inherit
             (push '(:ignore-inherited-configuration) directives))
           (return `(:source-registry ,@(nreverse directives))))))))))

(defun* register-asd-directory (directory &key recurse exclude collect)
  (if (not recurse)
      (collect-asds-in-directory directory collect)
      (collect-sub*directories-asd-files
       directory :exclude exclude :collect collect)))

(defparameter *default-source-registries*
  '(environment-source-registry
    user-source-registry
    user-source-registry-directory
    system-source-registry
    system-source-registry-directory
    default-source-registry))

(defparameter *source-registry-file* (coerce-pathname "source-registry.conf"))
(defparameter *source-registry-directory* (coerce-pathname "source-registry.conf.d/"))

(defun* wrapping-source-registry ()
  `(:source-registry
    #+sbcl (:tree ,(truenamize (getenv "SBCL_HOME")))
    :inherit-configuration
    #+cmu (:tree #p"modules:")
    #+scl (:tree #p"file://modules/")))
(defun* default-source-registry ()
  `(:source-registry
    #+sbcl (:directory ,(subpathname (user-homedir) ".sbcl/systems/"))
    (:directory ,(default-directory))
      ,@(loop :for dir :in
          `(,@(when (os-unix-p)
                `(,(or (getenv "XDG_DATA_HOME")
                       (subpathname (user-homedir) ".local/share/"))
                  ,@(split-string (or (getenv "XDG_DATA_DIRS")
                                      "/usr/local/share:/usr/share")
                                  :separator ":")))
            ,@(when (os-windows-p)
                `(,(or #+lispworks (sys:get-folder-path :local-appdata)
                       (getenv "LOCALAPPDATA"))
                  ,(or #+lispworks (sys:get-folder-path :appdata)
                       (getenv "APPDATA"))
                  ,(or #+lispworks (sys:get-folder-path :common-appdata)
                       (getenv "ALLUSERSAPPDATA")
                       (subpathname* (getenv "ALLUSERSPROFILE") "Application Data/")))))
          :collect `(:directory ,(subpathname* dir "common-lisp/systems/"))
          :collect `(:tree ,(subpathname* dir "common-lisp/source/")))
      :inherit-configuration))
(defun* user-source-registry (&key (direction :input))
  (in-user-configuration-directory *source-registry-file* :direction direction))
(defun* system-source-registry (&key (direction :input))
  (in-system-configuration-directory *source-registry-file* :direction direction))
(defun* user-source-registry-directory (&key (direction :input))
  (in-user-configuration-directory *source-registry-directory* :direction direction))
(defun* system-source-registry-directory (&key (direction :input))
  (in-system-configuration-directory *source-registry-directory* :direction direction))
(defun* environment-source-registry ()
  (getenv "CL_SOURCE_REGISTRY"))

(defgeneric* process-source-registry (spec &key inherit register))
(declaim (ftype (function (t &key (:register (or symbol function))) t)
                inherit-source-registry))
(declaim (ftype (function (t &key (:register (or symbol function)) (:inherit list)) t)
                process-source-registry-directive))

(defmethod process-source-registry ((x symbol) &key inherit register)
  (process-source-registry (funcall x) :inherit inherit :register register))
(defmethod process-source-registry ((pathname pathname) &key inherit register)
  (cond
    ((directory-pathname-p pathname)
     (let ((*here-directory* (truenamize pathname)))
       (process-source-registry (validate-source-registry-directory pathname)
                                :inherit inherit :register register)))
    ((probe-file* pathname)
     (let ((*here-directory* (pathname-directory-pathname pathname)))
       (process-source-registry (validate-source-registry-file pathname)
                                :inherit inherit :register register)))
    (t
     (inherit-source-registry inherit :register register))))
(defmethod process-source-registry ((string string) &key inherit register)
  (process-source-registry (parse-source-registry-string string)
                           :inherit inherit :register register))
(defmethod process-source-registry ((x null) &key inherit register)
  (declare (ignorable x))
  (inherit-source-registry inherit :register register))
(defmethod process-source-registry ((form cons) &key inherit register)
  (let ((*source-registry-exclusions* *default-source-registry-exclusions*))
    (dolist (directive (cdr (validate-source-registry-form form)))
      (process-source-registry-directive directive :inherit inherit :register register))))

(defun* inherit-source-registry (inherit &key register)
  (when inherit
    (process-source-registry (first inherit) :register register :inherit (rest inherit))))

(defun* process-source-registry-directive (directive &key inherit register)
  (destructuring-bind (kw &rest rest) (if (consp directive) directive (list directive))
    (ecase kw
      ((:include)
       (destructuring-bind (pathname) rest
         (process-source-registry (resolve-location pathname) :inherit nil :register register)))
      ((:directory)
       (destructuring-bind (pathname) rest
         (when pathname
           (funcall register (resolve-location pathname :directory t)))))
      ((:tree)
       (destructuring-bind (pathname) rest
         (when pathname
           (funcall register (resolve-location pathname :directory t)
                    :recurse t :exclude *source-registry-exclusions*))))
      ((:exclude)
       (setf *source-registry-exclusions* rest))
      ((:also-exclude)
       (appendf *source-registry-exclusions* rest))
      ((:default-registry)
       (inherit-source-registry '(default-source-registry) :register register))
      ((:inherit-configuration)
       (inherit-source-registry inherit :register register))
      ((:ignore-inherited-configuration)
       nil)))
  nil)

(defun* flatten-source-registry (&optional parameter)
  (remove-duplicates
   (while-collecting (collect)
     (let ((*default-pathname-defaults* (default-directory)))
       (inherit-source-registry
        `(wrapping-source-registry
          ,parameter
          ,@*default-source-registries*)
        :register #'(lambda (directory &key recurse exclude)
                      (collect (list directory :recurse recurse :exclude exclude)))))
     :test 'equal :from-end t)))

;; Will read the configuration and initialize all internal variables.
(defun* compute-source-registry (&optional parameter (registry *source-registry*))
  (dolist (entry (flatten-source-registry parameter))
    (destructuring-bind (directory &key recurse exclude) entry
      (let* ((h (make-hash-table :test 'equal))) ; table to detect duplicates
        (register-asd-directory
         directory :recurse recurse :exclude exclude :collect
         #'(lambda (asd)
             (let* ((name (pathname-name asd))
                    (name (if (typep asd 'logical-pathname)
                              ;; logical pathnames are upper-case,
                              ;; at least in the CLHS and on SBCL,
                              ;; yet (coerce-name :foo) is lower-case.
                              ;; won't work well with (load-system "Foo")
                              ;; instead of (load-system 'foo)
                              (string-downcase name)
                              name)))
               (cond
                 ((gethash name registry) ; already shadowed by something else
                  nil)
                 ((gethash name h) ; conflict at current level
                  (when *asdf-verbose*
                    (warn (compatfmt "~@<In source-registry entry ~A~@[/~*~] ~
                                found several entries for ~A - picking ~S over ~S~:>")
                          directory recurse name (gethash name h) asd)))
                 (t
                  (setf (gethash name registry) asd)
                  (setf (gethash name h) asd))))))
        h)))
  (values))

(defvar *source-registry-parameter* nil)

(defun* initialize-source-registry (&optional (parameter *source-registry-parameter*))
  (setf *source-registry-parameter* parameter)
  (setf *source-registry* (make-hash-table :test 'equal))
  (compute-source-registry parameter))

;; Checks an initial variable to see whether the state is initialized
;; or cleared. In the former case, return current configuration; in
;; the latter, initialize.  ASDF will call this function at the start
;; of (asdf:find-system) to make sure the source registry is initialized.
;; However, it will do so *without* a parameter, at which point it
;; will be too late to provide a parameter to this function, though
;; you may override the configuration explicitly by calling
;; initialize-source-registry directly with your parameter.
(defun* ensure-source-registry (&optional parameter)
  (unless (source-registry-initialized-p)
    (initialize-source-registry parameter))
  (values))

(defun* sysdef-source-registry-search (system)
  (ensure-source-registry)
  (values (gethash (coerce-name system) *source-registry*)))

(defun* clear-configuration ()
  (clear-source-registry)
  (clear-output-translations))


;;; ECL support for COMPILE-OP / LOAD-OP
;;;
;;; In ECL, these operations produce both FASL files and the
;;; object files that they are built from. Having both of them allows
;;; us to later on reuse the object files for bundles, libraries,
;;; standalone executables, etc.
;;;
;;; This has to be in asdf.lisp and not asdf-ecl.lisp, or else it becomes
;;; a problem for asdf on ECL to compile asdf-ecl.lisp after loading asdf.lisp.
;;;
#+ecl
(progn
  (setf *compile-op-compile-file-function* 'ecl-compile-file)

  (defun use-ecl-byte-compiler-p ()
    (member :ecl-bytecmp *features*))

  (defun ecl-compile-file (input-file &rest keys &key &allow-other-keys)
    (if (use-ecl-byte-compiler-p)
        (apply 'compile-file* input-file keys)
        (multiple-value-bind (object-file flags1 flags2)
            (apply 'compile-file* input-file :system-p t keys)
          (values (and object-file
                       (c::build-fasl (compile-file-pathname object-file :type :fasl)
                                      :lisp-files (list object-file))
                       object-file)
                  flags1
                  flags2))))

  (defmethod output-files ((operation compile-op) (c cl-source-file))
    (declare (ignorable operation))
    (let* ((p (lispize-pathname (component-pathname c)))
           (f (compile-file-pathname p :type :fasl)))
      (if (use-ecl-byte-compiler-p)
          (list f)
          (list (compile-file-pathname p :type :object) f))))

  (defmethod perform ((o load-op) (c cl-source-file))
    (map () #'load
         (loop :for i :in (input-files o c)
           :unless (string= (pathname-type i) "fas")
               :collect (compile-file-pathname (lispize-pathname i))))))

;;;; -----------------------------------------------------------------
;;;; Hook into REQUIRE for ABCL, CLISP, ClozureCL, CMUCL, ECL and SBCL
;;;;
(defvar *require-asdf-operator* 'load-op)

(defun* module-provide-asdf (name)
  (handler-bind
      ((style-warning #'muffle-warning)
       #-genera
       (missing-component (constantly nil))
       (error #'(lambda (e)
                  (format *error-output* (compatfmt "~@<ASDF could not load ~(~A~) because ~A.~@:>~%")
                          name e))))
    (let ((*verbose-out* (make-broadcast-stream))
          (system (find-system (string-downcase name) nil)))
      (when system
        (operate *require-asdf-operator* system :verbose nil)
        t))))

#+(or abcl clisp clozure cmu ecl sbcl)
(let ((x (and #+clisp (find-symbol* '#:*module-provider-functions* :custom))))
  (when x
    (eval `(pushnew 'module-provide-asdf
            #+abcl sys::*module-provider-functions*
            #+clisp ,x
            #+clozure ccl:*module-provider-functions*
            #+(or cmu ecl) ext:*module-provider-functions*
            #+sbcl sb-ext:*module-provider-functions*))))


;;;; -------------------------------------------------------------------------
;;;; Cleanups after hot-upgrade.
;;;; Things to do in case we're upgrading from a previous version of ASDF.
;;;; See https://bugs.launchpad.net/asdf/+bug/485687
;;;;

;;; If a previous version of ASDF failed to read some configuration, try again.
(when *ignored-configuration-form*
  (clear-configuration)
  (setf *ignored-configuration-form* nil))

;;;; -----------------------------------------------------------------
;;;; Done!
(when *load-verbose*
  (asdf-message ";; ASDF, version ~a~%" (asdf-version)))

#+allegro
(eval-when (:compile-toplevel :execute)
  (when (boundp 'excl:*warn-on-nested-reader-conditionals*)
    (setf excl:*warn-on-nested-reader-conditionals* *acl-warn-save*)))

(pushnew :asdf *features*)
(pushnew :asdf2 *features*)

(provide :asdf)

;;; Local Variables:
;;; mode: lisp
;;; End: