[Jython-checkins] SF.net SVN: jython:[6556] trunk/jython/src/org/python/compiler/CodeCompiler .java

[<th...@us...>]

Revision: 6556
          http://jython.svn.sourceforge.net/jython/?rev=6556&view=rev
Author:   thobes
Date:     2009-07-21 21:53:56 +0000 (Tue, 21 Jul 2009)

Log Message:
-----------
Fix for a problem I discovered with the thread state being stored on yield in
generators. This could have lead to faulty behaviour if the next resumption of
the generator is from another thread or memory leaks if the generator is kept
around longer than the lifetime of the thread.
This fix does not have ideal memory footprint, one slot in the stored stack
content array is left empty (where the thread state should have been), but it
works, such minor memory optimizations can be saved for later.

Modified Paths:
--------------
    trunk/jython/src/org/python/compiler/CodeCompiler.java

Modified: trunk/jython/src/org/python/compiler/CodeCompiler.java
===================================================================
--- trunk/jython/src/org/python/compiler/CodeCompiler.java	2009-07-21 20:55:55 UTC (rev 6555)
+++ trunk/jython/src/org/python/compiler/CodeCompiler.java	2009-07-21 21:53:56 UTC (rev 6556)
@@ -5,6 +5,7 @@
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.ListIterator;
 import java.util.Map;
 import java.util.Stack;
 import java.util.Vector;
@@ -635,15 +636,23 @@
             code.iconst(stack.size());
             code.anewarray("java/lang/Object");
             code.astore(array);
-            for (int i = 0; i < stack.size(); i++) {
-                code.aload(array);
-                // Stack: |- ... value array
-                code.swap();
-                code.iconst(i);
-                code.swap();
-                // Stack: |- ... array index value
-                code.aastore();
-                // Stack: |- ...
+            ListIterator<String> content = stack.listIterator(stack.size());
+            for (int i = 0; content.hasPrevious(); i++) {
+                String signature = content.previous();
+                if ("org/python/core/ThreadState".equals(signature)) {
+                    // Stack: ... threadstate
+                    code.pop();
+                    // Stack: ...
+                } else {
+                    code.aload(array);
+                    // Stack: |- ... value array
+                    code.swap();
+                    code.iconst(i++);
+                    code.swap();
+                    // Stack: |- ... array index value
+                    code.aastore();
+                    // Stack: |- ...
+                }
             }
             return array;
         } else {
@@ -655,12 +664,16 @@
         if (stack.size() > 0) {
             int i = stack.size() -1;
             for (String signature : stack) {
-                code.aload(array);
-                // Stack: |- ... array
-                code.iconst(i--);
-                code.aaload();
-                // Stack: |- ... value
-                code.checkcast(signature);
+                if ("org/python/core/ThreadState".equals(signature)) {
+                    loadThreadState();
+                } else {
+                    code.aload(array);
+                    // Stack: |- ... array
+                    code.iconst(i--);
+                    code.aaload();
+                    // Stack: |- ... value
+                    code.checkcast(signature);
+                }
             }
             code.freeLocal(array);
         }


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