Changeset 431 for branches/thune/thread_safe/context.c

Timestamp:

07/16/07 03:30:29 (17 months ago)

Author:

krobillard

Message:

Atoms should now be thread safe. First thread experiment runs.

Files:

• branches/thune/thread_safe/context.c (modified) (11 diffs)

branches/thune/thread_safe/context.c

@@ -25 +25 @@
 
 #define LOWERCASE(c)    if(c >= 'A' && c <= 'Z') c -= 'A' - 'a'
+
+
+/*
+   UrlanEnv::atoms & UrlanEnv::atomNames can be made thread safe through one
+   of the following:
+
+   1. Use LOCK_ATOMS in or around these functions:
+        ur_internT()
+        ur_atomStrT()
+        ur_atomCStrT() (and all use of returned pointer)
+        ur_atomHash()
+        dumpAtoms()
+
+   2. Fix size of atom arrays and throw error/assert when full.
+      Must still lock these functions to access head/chain AtomRec members:
+        ur_internT()
+        dumpAtoms()
+
+   Option #2 is currently being used.
+*/
 
 
@@ -120 +140 @@
 void dumpAtoms( UThread* ut )
 {
-    LOCK_GLOBAL
+    LOCK_ATOMS
     {
     const char* names = ut->env->atomNames.ptr.c;
@@ -143 +163 @@
     }
     }
-    UNLOCK_GLOBAL
+    UNLOCK_ATOMS
 }
 #endif
@@ -151 +171 @@
   Add atom to environment.
 
-  If the environment has multiple threads, the caller must have called
-  LOCK_GLOBAL.
-
   \param str  Name of atom.
   \param len  Number of characters.
 
-  \returns Atom 
+  \return  Atom 
 */
 UAtom ur_internT( UThread* ut, const char* str, int len )
@@ -171 +188 @@
     AtomRec* node;
 
-
     assert( len > 0 );
 
 
     // Check if atom already exists.
+
+    hash = ur_hash( str, str + len );
+
+    LOCK_ATOMS
 
     atoms = &ut->env->atoms;
     table = (AtomRec*) atoms->ptr.v;
     names = &ut->env->atomNames;
-
-    hash = ur_hash( str, str + len );
 
     node = table + (hash % atoms->avail);
@@ -228 +246 @@
     // Nope, add new atom.
 
-    /* TODO: Make atoms & atomNames thread safe through one of the following:
-
-       1. Halt all other threads.
-       2. Fix size of atom arrays and throw error/assert when full.
-       3. Use LOCK_GLOBAL in or around these functions in addition to ur_intern:
-            ur_atomStrT()
-            ur_atomCStrT()
-            dumpAtoms()
-    */
-
     if( atoms->used == atoms->avail )
     {
+#if 1
+        // Atom table size is fixed so read only access does not need to be
+        // locked.  When the table is full, we are finished.
+        assert( 0 && "Atom table is full" );
+        return 0;       // TODO: Report fatal error
+#else
         ur_arrayReserve( atoms, sizeof(AtomRec), atoms->used + 1 );
         ur_rebuildAtomHash( atoms );
@@ -245 +259 @@
 
         HASH_INSERT( atoms, table, node, hash, atoms->used )
+#endif
     }
     node = table + atoms->used;
@@ -253 +268 @@
     node->nameLen   = len;
 
+#if 1
+    if( (names->used + len + 1) > names->avail )
+    {
+        assert( 0 && "Atom name buffer is full" );
+        return 0;       // TODO: Report fatal error
+    }
+#else
     ur_arrayReserve( names, sizeof(char), names->used + len + 1 );
+#endif
+
     cp = names->ptr.c + names->used;
     ep = cp + len;
@@ -267 +291 @@
 done:
 
-    return node - table;
+    c = node - table;
+
+    UNLOCK_ATOMS
+
+    return c;
 }
 
@@ -278 +306 @@
   If added, the word is initialied as unset.
 
-  \returns  Index of word in context.
+  \return  Index of word in context.
 */
 int ur_internWordT( UThread* ut, const UContext* ctx, UAtom atom )
@@ -424 +452 @@
 /**
   Find word in context by atom.
-  \returns  Word index or -1 if not found.
+  \return  Word index or -1 if not found.
 */
 int ur_lookupT( UThread* ut, const UContext* ctx, UAtom atom )