1.0.28.44: better MACHINE-VERSION answers on BSD'ish platforms

[sbcl.git] / src / code / hash-table.lisp

diff --git a/src/code/hash-table.lisp b/src/code/hash-table.lisp
index aeab5f1..784bc11 100644 (file)
--- a/src/code/hash-table.lisp
+++ b/src/code/hash-table.lisp
@@ -69,18 +69,23 @@
   ;; respective key.
   (hash-vector nil :type (or null (simple-array (unsigned-byte
                                                  #.sb!vm:n-word-bits) (*))))
-  ;; Used for locking GETHASH/(SETF GETHASH)/REMHASH for tables with :LOCK-P T
-  (spinlock (sb!thread::make-spinlock) :type sb!thread::spinlock)
+  ;; Used for locking GETHASH/(SETF GETHASH)/REMHASH
+  (spinlock (sb!thread::make-spinlock :name "hash-table lock")
+            :type sb!thread::spinlock :read-only t)
   ;; The GC will set this to T if it moves an EQ-based key. This used
   ;; to be signaled by a bit in the header of the kv vector, but that
   ;; implementation caused some concurrency issues when we stopped
   ;; inhibiting GC during hash-table lookup.
   (needs-rehash-p nil :type (member nil t))
+  ;; Has user requested synchronization?
+  (synchronized-p nil :type (member nil t) :read-only t)
   ;; For detecting concurrent accesses.
   #!+sb-hash-table-debug
-  (concurrent-access-error t :type (member nil t))
+  (signal-concurrent-access t :type (member nil t))
   #!+sb-hash-table-debug
-  (accessing-thread nil))
+  (reading-thread nil)
+  #!+sb-hash-table-debug
+  (writing-thread nil))
 
 ;; as explained by pmai on openprojects #lisp IRC 2002-07-30: #x80000000
 ;; is bigger than any possible nonEQ hash value, and thus indicates an
@@ -90,26 +95,32 @@
 ;; the generational garbage collector needs to know it.
 (defconstant +magic-hash-vector-value+ (ash 1 (1- sb!vm:n-word-bits)))
 
-\f
-(defmacro-mundanely with-hash-table-iterator ((function hash-table) &body body)
+(defmacro-mundanely with-hash-table-iterator ((name hash-table) &body body)
   #!+sb-doc
-  "WITH-HASH-TABLE-ITERATOR ((function hash-table) &body body)
+  "WITH-HASH-TABLE-ITERATOR ((name hash-table) &body body)
+
+Provides a method of manually looping over the elements of a hash-table. NAME
+is bound to a generator-macro that, within the scope of the invocation,
+returns one or three values. The first value tells whether any objects remain
+in the hash table. When the first value is non-NIL, the second and third
+values are the key and the value of the next object.
 
-Provides a method of manually looping over the elements of a hash-table.
-FUNCTION is bound to a generator-macro that, within the scope of the
-invocation, returns one or three values. The first value tells whether any
-objects remain in the hash table. When the first value is non-NIL, the second
-and third values are the key and the value of the next object."
+Consequences are undefined if HASH-TABLE is mutated during execution of BODY,
+except for changing or removing elements corresponding to the current key. The
+applies to all threads, not just the curren one -- even for synchronized
+hash-tables. If the table may be mutated by another thread during iteration,
+use eg. SB-EXT:WITH-LOCKED-HASH-TABLE to protect the WITH-HASH-TABLE-ITERATOR
+for."
   ;; This essentially duplicates MAPHASH, so any changes here should
   ;; be reflected there as well.
-  (let ((n-function (gensym "WITH-HASH-TABLE-ITERATOR-")))
-    `(let ((,n-function
+  (let ((function (make-symbol (concatenate 'string (symbol-name name) "-FUN"))))
+    `(let ((,function
             (let* ((table ,hash-table)
                    (length (length (hash-table-next-vector table)))
                    (index 1))
               (declare (type index/2 index))
               (labels
-                  ((,function ()
+                  ((,name ()
                      ;; (We grab the table again on each iteration just in
                      ;; case it was rehashed by a PUTHASH.)
                      (let ((kv-vector (hash-table-table table)))
@@ -119,8 +130,23 @@ and third values are the key and the value of the next object."
                                (value (aref kv-vector (1+ (* 2 index)))))
                            (incf index)
                            (unless (or (eq key +empty-ht-slot+)
-                                        (eq value +empty-ht-slot+))
+                                       (eq value +empty-ht-slot+))
                              (return (values t key value))))))))
-                #',function))))
-      (macrolet ((,function () '(funcall ,n-function)))
-        ,@body))))
+                #',name))))
+       (macrolet ((,name () '(funcall ,function)))
+         ,@body))))
+
+(defmacro-mundanely with-locked-hash-table ((hash-table) &body body)
+  #!+sb-doc
+  "Limits concurrent accesses to HASH-TABLE for the duration of BODY.
+If HASH-TABLE is synchronized, BODY will execute with exclusive
+ownership of the table. If HASH-TABLE is not synchronized, BODY will
+execute with other WITH-LOCKED-HASH-TABLE bodies excluded -- exclusion
+of hash-table accesses not surrounded by WITH-LOCKED-HASH-TABLE is
+unspecified."
+  ;; Needless to say, this also excludes some internal bits, but
+  ;; getting there is too much detail when "unspecified" says what
+  ;; is important -- unpredictable, but harmless.
+  `(sb!thread::with-recursive-system-spinlock
+       ((hash-table-spinlock ,hash-table))
+     ,@body))