fix bug 94752. Let xpconnect decide when to call JS_DestroyContext. It sometimes needs to defer the call until JS code running on the context is finished. r=dbradley sr=jst

git-svn-id: svn://10.0.0.236/trunk@101079 18797224-902f-48f8-a5cc-f745e15eee43

mozilla/dom/src/base/nsJSEnvironment.cpp

@@ -228,7 +228,8 @@ nsJSContext::DOMBranchCallback(JSContext *cx, JSScript *script)
 {
   // Get the native context
   nsJSContext *ctx = NS_STATIC_CAST(nsJSContext *, ::JS_GetContextPrivate(cx));
-  NS_ENSURE_TRUE(ctx, JS_TRUE);
+  if (!ctx)
+    return JS_TRUE;
 
   // Filter out most of the calls to this callback
   if (++ctx->mBranchCallbackCount & MAYBE_GC_BRANCH_COUNT_MASK)
@@ -383,15 +384,12 @@ nsJSContext::~nsJSContext()
                               this);
   }
 
-  /* Remove global object reference to window object, so it can be collected. */
-  ::JS_SetGlobalObject(mContext, nsnull); // XXX: Do we need this call?
-  ::JS_DestroyContext(mContext);
-
-  // Let xpconnect resync its JSContext tracker.
+  // Let xpconnect destroy the JSContext when it thinks the time is right.
   nsCOMPtr<nsIXPConnect> xpc(do_GetService(nsIXPConnect::GetCID()));
-
   if (xpc) {
-    xpc->SyncJSContexts();
+    xpc->ReleaseJSContext(mContext, PR_FALSE);
+  } else {
+    ::JS_DestroyContext(mContext);
   }
 }
 

mozilla/js/src/xpconnect/idl/nsIXPConnect.idl

@@ -569,6 +569,8 @@ interface nsIXPConnect : nsISupports
 
     attribute PRBool collectGarbageOnMainThreadOnly;
     attribute PRBool deferReleasesUntilAfterGarbageCollection;
+
+    void releaseJSContext(in JSContextPtr aJSContext, in PRBool noGC);
 };
 
 

mozilla/js/src/xpconnect/src/nsXPConnect.cpp

@@ -969,6 +969,51 @@ nsXPConnect::SetDeferReleasesUntilAfterGarbageCollection(PRBool aDeferReleasesUn
     return NS_OK;
 }
 
+/* void releaseJSContext (in JSContextPtr aJSContext, in PRBool noGC); */
+NS_IMETHODIMP 
+nsXPConnect::ReleaseJSContext(JSContext * aJSContext, PRBool noGC)
+{
+    NS_ASSERTION(aJSContext, "bad param");
+    XPCPerThreadData* tls = XPCPerThreadData::GetData();
+    if(tls)
+    {
+        XPCCallContext* ccx = nsnull;
+        for(XPCCallContext* cur = tls->GetCallContext(); 
+            cur; 
+            cur = cur->GetPrevCallContext())
+        {
+            if(cur->GetJSContext() == aJSContext)
+            {
+                ccx = cur;
+                // Keep looping to find the deepest matching call context.
+            }
+        }
+    
+        if(ccx)
+        {
+#ifdef DEBUG_xpc_hacker
+            printf("!xpc - deferring destruction of JSContext @ %0x\n", 
+                   aJSContext);
+#endif
+            ccx->SetDestroyJSContextInDestructor(JS_TRUE);
+            return NS_OK;
+        }
+        // else continue on and synchronously destroy the JSContext ...
+
+        NS_ASSERTION(!tls->GetJSContextStack() || 
+                     !tls->GetJSContextStack()->
+                        DEBUG_StackHasJSContext(aJSContext),
+                     "JSContext still in threadjscontextstack!");
+    }
+    
+    if(noGC)
+        JS_DestroyContextNoGC(aJSContext);
+    else
+        JS_DestroyContext(aJSContext);
+    SyncJSContexts();
+    return NS_OK;
+}
+
 /* void debugDump (in short depth); */
 NS_IMETHODIMP
 nsXPConnect::DebugDump(PRInt16 depth)

mozilla/js/src/xpconnect/src/xpccallcontext.cpp

@@ -51,6 +51,7 @@ XPCCallContext::XPCCallContext(XPCContext::LangType callerLanguage,
         mXPCContext(nsnull),
         mJSContext(cx),
         mContextPopRequired(JS_FALSE),
+        mDestroyJSContextInDestructor(JS_FALSE),
         mCallerLanguage(callerLanguage)
 {
     NS_INIT_ISUPPORTS();
@@ -312,8 +313,25 @@ XPCCallContext::~XPCCallContext()
     }
 
     if(mJSContext)
+    {
         if(mCallerLanguage == NATIVE_CALLER && JS_GetContextThread(mJSContext))
             JS_EndRequest(mJSContext);
+        
+        if(mDestroyJSContextInDestructor)
+        {
+#ifdef DEBUG_xpc_hacker
+            printf("!xpc - doing deferred destruction of JSContext @ %0x\n", 
+                   mJSContext);
+#endif
+            NS_ASSERTION(!mThreadData->GetJSContextStack() || 
+                         !mThreadData->GetJSContextStack()->
+                            DEBUG_StackHasJSContext(mJSContext),
+                         "JSContext still in threadjscontextstack!");
+        
+            JS_DestroyContext(mJSContext);
+            mXPC->SyncJSContexts();
+        }
+    }
 
     NS_IF_RELEASE(mXPC);
 }

mozilla/js/src/xpconnect/src/xpcinlines.h

@@ -315,6 +315,20 @@ XPCCallContext::SetMethodIndex(PRUint16 index)
     mMethodIndex = index;
 }
 
+inline JSBool   
+XPCCallContext::GetDestroyJSContextInDestructor() const
+{
+    CHECK_STATE(HAVE_CONTEXT);
+    return mDestroyJSContextInDestructor;
+}
+
+inline void
+XPCCallContext::SetDestroyJSContextInDestructor(JSBool b)
+{
+    CHECK_STATE(HAVE_CONTEXT);
+    mDestroyJSContextInDestructor = b;
+}
+
 /***************************************************************************/
 
 inline const nsIID*

mozilla/js/src/xpconnect/src/xpcprivate.h

@@ -763,6 +763,9 @@ public:
     inline PRUint16                     GetMethodIndex() const ;
     inline void                         SetMethodIndex(PRUint16 index) ;
 
+    inline JSBool   GetDestroyJSContextInDestructor() const;
+    inline void     SetDestroyJSContextInDestructor(JSBool b);
+
     inline jsval GetResolveName() const;
     inline jsval SetResolveName(jsval name);
 
@@ -816,6 +819,7 @@ private:
     XPCContext*                     mXPCContext;
     JSContext*                      mJSContext;
     JSBool                          mContextPopRequired;
+    JSBool                          mDestroyJSContextInDestructor;
 
     XPCContext::LangType            mCallerLanguage;
 
@@ -2464,6 +2468,10 @@ public:
     XPCJSContextStack();
     virtual ~XPCJSContextStack();
 
+#ifdef DEBUG
+    JSBool DEBUG_StackHasJSContext(JSContext*  aJSContext);
+#endif    
+
 private:
     void SyncJSContexts();
 

mozilla/js/src/xpconnect/src/xpcthreadcontext.cpp

@@ -103,6 +103,17 @@ XPCJSContextStack::Push(JSContext * cx)
     return NS_OK;
 }
 
+#ifdef DEBUG
+JSBool 
+XPCJSContextStack::DEBUG_StackHasJSContext(JSContext*  aJSContext)
+{
+    for(PRInt32 i; i < mStack.GetSize(); i++)
+        if(aJSContext == (JSContext*)mStack.ObjectAt(i))
+            return JS_TRUE;
+    return JS_FALSE;
+}
+#endif
+
 JS_STATIC_DLL_CALLBACK(JSBool)
 SafeGlobalResolve(JSContext *cx, JSObject *obj, jsval id)
 {

mozilla/xpfe/components/xfer/src/nsStreamXferOp.cpp

@@ -527,7 +527,8 @@ nsStreamXferOp::OnStopRequest( nsIRequest      *request,
 
     // Notify observer that the download is complete.
     if ( !mError && mObserver ) {
-        rv = mObserver->Observe( (nsIStreamTransferOperation*)this,
+        nsCOMPtr<nsIObserver> kungFuDeathGrip(mObserver);
+        rv = kungFuDeathGrip->Observe( (nsIStreamTransferOperation*)this,
                                   NS_ConvertASCIItoUCS2( NS_ISTREAMTRANSFER_CONTRACTID ";onCompletion" ).get(),
                                   nsnull );
         if ( NS_FAILED( rv ) ) {