another thread safety patch

[Chris Dean <ctdean at sokitomi dot com>]

Here's another patch that fixes one of the thread safety issues.
Specifically, when multiple threads try and load to the same procedure
at the same time when we were getting a NPE.

Regards,
Chris Dean


Index: kawa/lang/AutoloadProcedure.java
===================================================================
RCS file: /cvs/kawa/kawa/kawa/lang/AutoloadProcedure.java,v
retrieving revision 1.22
diff -u -w -r1.22 AutoloadProcedure.java
--- kawa/lang/AutoloadProcedure.java	21 Apr 2003 08:27:44 -0000	1.22
+++ kawa/lang/AutoloadProcedure.java	16 Jul 2004 05:20:45 -0000
@@ -72,39 +72,40 @@
   }
 
   /** Load the class named in className. */
-  void load ()
+  synchronized void load ()
   {
     Environment env = this.env != null ? this.env : Environment.getCurrent();
     String name = this.getName();
+    Procedure new_proc = null;
     try
       {
-	loaded = (Procedure) Class.forName (className).newInstance ();
-	if (loaded == this)
+	new_proc = (Procedure) Class.forName (className).newInstance ();
+	if (new_proc == this)
 	  throw_error("circularity detected");
-	if (loaded instanceof ModuleBody)
+	if (new_proc instanceof ModuleBody)
 	  {
-	    gnu.kawa.reflect.ClassMemberConstraint.defineAll(loaded, env);
-	    ((ModuleBody)loaded).run();
+	    gnu.kawa.reflect.ClassMemberConstraint.defineAll(new_proc, env);
+	    ((ModuleBody)new_proc).run();
 	    Object value = env.getSymbol(name).getProcedure();
 	    if (value == null
 		|| !(value instanceof Procedure))
 	      throw_error
 		("invalid ModuleBody class - does not define " + name);
-	    loaded = (Procedure) value;
+	    new_proc = (Procedure) value;
 	  }
 	else if (name != null)
 	  {
+	    if (new_proc.getName() == null)
+	      new_proc.setName(name);
 	    try
 	      {
 		// Should use something like isFunctionBound FIXME
 		if (env.getFunction(name) == this)
-		  env.putFunction(name, loaded);
+		  env.putFunction(name, new_proc);
 	      }
 	    catch (UnboundSymbol ex)
 	      {
 	      }
-	    if (loaded.getName() == null)
-	      loaded.setName(name);
 	  }
       }
     catch (ClassNotFoundException ex)
@@ -113,6 +114,8 @@
       { throw_error ("failed to instantiate class "); }
     catch (IllegalAccessException ex)
       { throw_error ("illegal access in class "); }
+
+    loaded = new_proc;
   }
 
   public Procedure getLoaded ()