Bug 513065 - Part 3, compute scope in the engine before calling the thisObject hook. r=mrbkap.

js/src/jsinterp.cpp

@@ -371,11 +371,17 @@ js_GetPrimitiveThis(JSContext *cx, jsval *vp, JSClass *clasp, jsval *thisvp)
 
 /* Some objects (e.g., With) delegate 'this' to another object. */
 static inline JSObject *
-CallThisObjectHook(JSContext *cx, JSObject *obj, jsval *argv)
+CallThisObjectHook(JSContext *cx, JSObject *obj, JSObject *scope, jsval *argv)
 {
-    JSObject *thisp = obj->thisObject(cx);
-    if (!thisp)
-        return NULL;
+    JSObject *thisp = obj;
+    if (JSThisObjectOp thisObject = obj->map->ops->thisObject) {
+        if (!scope)
+            scope = JSVAL_TO_OBJECT(argv[-2])->getGlobal();
+        thisp = thisObject(cx, obj, scope);
+        if (!thisp)
+            return NULL;
+    }
+
     argv[-1] = OBJECT_TO_JSVAL(thisp);
     return thisp;
 }
@@ -398,45 +404,29 @@ CallThisObjectHook(JSContext *cx, JSObject *obj, jsval *argv)
 JS_STATIC_INTERPRET JSObject *
 js_ComputeGlobalThis(JSContext *cx, jsval *argv)
 {
-    JSObject *thisp;
-
-    if (JSVAL_IS_PRIMITIVE(argv[-2]) ||
-        !JSVAL_TO_OBJECT(argv[-2])->getParent()) {
-        thisp = cx->globalObject;
-    } else {
-        thisp = JSVAL_TO_OBJECT(argv[-2])->getGlobal();
-    }
-
-    return CallThisObjectHook(cx, thisp, argv);
-}
-
-static JSObject *
-ComputeThis(JSContext *cx, jsval *argv)
-{
-    JSObject *thisp;
-
-    JS_ASSERT(!JSVAL_IS_NULL(argv[-1]));
-    if (!JSVAL_IS_OBJECT(argv[-1])) {
-        if (!js_PrimitiveToObject(cx, &argv[-1]))
-            return NULL;
-        thisp = JSVAL_TO_OBJECT(argv[-1]);
-        return thisp;
-    } 
-
-    thisp = JSVAL_TO_OBJECT(argv[-1]);
-    if (thisp->getClass() == &js_CallClass || thisp->getClass() == &js_BlockClass)
-        return js_ComputeGlobalThis(cx, argv);
-
-    return CallThisObjectHook(cx, thisp, argv);
+    JSObject *thisp = JSVAL_TO_OBJECT(argv[-2])->getGlobal();
+    return CallThisObjectHook(cx, thisp, thisp, argv);
 }
 
 JSObject *
 js_ComputeThis(JSContext *cx, jsval *argv)
 {
     JS_ASSERT(argv[-1] != JSVAL_HOLE);  // check for SynthesizeFrame poisoning
+
     if (JSVAL_IS_NULL(argv[-1]))
         return js_ComputeGlobalThis(cx, argv);
-    return ComputeThis(cx, argv);
+
+    if (!JSVAL_IS_OBJECT(argv[-1])) {
+        if (!js_PrimitiveToObject(cx, &argv[-1]))
+            return NULL;
+        return JSVAL_TO_OBJECT(argv[-1]);
+    } 
+
+    JSObject *thisp = JSVAL_TO_OBJECT(argv[-1]);
+    if (thisp->getClass() == &js_CallClass || thisp->getClass() == &js_BlockClass)
+        return js_ComputeGlobalThis(cx, argv);
+
+    return CallThisObjectHook(cx, thisp, NULL, argv);
 }
 
 #if JS_HAS_NO_SUCH_METHOD
@@ -1058,7 +1048,7 @@ js_Execute(JSContext *cx, JSObject *chain, JSScript *script,
             return false;
         frame.scopeChain = chain;
 
-        JSObject *thisp = JSVAL_TO_OBJECT(frame.thisv)->thisObject(cx);
+        JSObject *thisp = JSVAL_TO_OBJECT(frame.thisv)->thisObject(cx, chain);
         if (!thisp)
             return false;
         frame.thisv = OBJECT_TO_JSVAL(thisp);

js/src/jsobj.cpp

@@ -2947,12 +2947,12 @@ with_TypeOf(JSContext *cx, JSObject *obj)
 }
 
 static JSObject *
-with_ThisObject(JSContext *cx, JSObject *obj)
+with_ThisObject(JSContext *cx, JSObject *obj, JSObject *scope)
 {
     JSObject *proto = obj->getProto();
     if (!proto)
         return obj;
-    return proto->thisObject(cx);
+    return proto->thisObject(cx, scope);
 }
 
 JS_FRIEND_DATA(JSObjectOps) js_WithObjectOps = {

js/src/jsobj.h

@@ -161,7 +161,7 @@ struct JSObjectOps {
     JSTraceOp           trace;
 
     /* Optionally non-null members start here. */
-    JSObjectOp          thisObject;
+    JSThisObjectOp      thisObject;
     JSPropertyRefOp     dropProperty;
     JSNative            call;
     JSNative            construct;
@@ -634,8 +634,8 @@ struct JSObject {
     }
 
     /* These four are time-optimized to avoid stub calls. */
-    JSObject *thisObject(JSContext *cx) {
-        return map->ops->thisObject ? map->ops->thisObject(cx, this) : this;
+    JSObject *thisObject(JSContext *cx, JSObject *scope) {
+        return map->ops->thisObject ? map->ops->thisObject(cx, this, scope) : this;
     }
 
     void dropProperty(JSContext *cx, JSProperty *prop) {

js/src/jspubtd.h

@@ -423,9 +423,19 @@ typedef JSBool
 (* JSEqualityOp)(JSContext *cx, JSObject *obj, jsval v, JSBool *bp);
 
 /*
- * A generic type for functions mapping an object to another object, or null
- * if an error or exception was thrown on cx.  Used by JSObjectOps.thisObject
- * at present.
+ * The type of JSObjectOps::thisObject. Return a "stunt this" object for obj,
+ * having a parent chain that ends in scope; or NULL on error.
+ *
+ * The engine guarantees that obj->map->ops->thisObject == the callback
+ * and that cx, obj, and scope are non-null.
+ */
+typedef JSObject *
+(* JSThisObjectOp)(JSContext *cx, JSObject *obj, JSObject *scope);
+
+/*
+ * A generic type for functions mapping an object to another object, or null if
+ * an error or exception was thrown on cx. Used by JSObjectOps.innerObject and
+ * outerObject at present.
  */
 typedef JSObject *
 (* JSObjectOp)(JSContext *cx, JSObject *obj);

js/src/jstracer.cpp

@@ -9516,7 +9516,7 @@ TraceRecorder::getThis(LIns*& this_ins)
 
     this_ins = get(&thisv);
 
-    JSObject* wrappedGlobal = globalObj->thisObject(cx);
+    JSObject* wrappedGlobal = globalObj->thisObject(cx, globalObj);
     if (!wrappedGlobal)
         RETURN_ERROR("globalObj->thisObject hook threw in getThis");
 

js/src/shell/js.cpp

@@ -2763,7 +2763,7 @@ split_outerObject(JSContext *cx, JSObject *obj)
 }
 
 static JSObject *
-split_thisObject(JSContext *cx, JSObject *obj)
+split_thisObject(JSContext *cx, JSObject *obj, JSObject */*scope*/)
 {
     OBJ_TO_OUTER_OBJECT(cx, obj);
     if (!obj)

js/src/xpconnect/src/xpcJSWeakReference.cpp

@@ -133,13 +133,16 @@ xpcJSWeakReference::Get()
             // nsXPConnect::GetWrapperForObject. But it takes a lot of
             // arguments! It turns out that the thisObject hook on XPConnect
             // objects does the right thing though, so...
-
-            if (obj->map->ops->thisObject &&
-                !(obj = obj->map->ops->thisObject(cx, obj)))
+            if (obj->map->ops->thisObject)
             {
-                return NS_ERROR_FAILURE;
+                JSObject *scope = JS_GetScopeChain(cx);
+                if (!scope)
+                    return NS_ERROR_FAILURE;
+                scope = JS_GetGlobalForObject(cx, scope);
+                obj = obj->map->ops->thisObject(cx, obj, scope);
+                if (!obj)
+                    return NS_ERROR_FAILURE;
             }
-
             *retval = OBJECT_TO_JSVAL(obj);
         }
     }

js/src/xpconnect/src/xpcwrappednativejsops.cpp

@@ -1477,7 +1477,7 @@ private:
 } // namespace
 
 static JSObject*
-XPC_WN_JSOp_ThisObject(JSContext *cx, JSObject *obj)
+XPC_WN_JSOp_ThisObject(JSContext *cx, JSObject *obj, JSObject *scope)
 {
     // None of the wrappers we could potentially hand out are threadsafe so
     // just hand out the given object.
@@ -1488,15 +1488,6 @@ XPC_WN_JSOp_ThisObject(JSContext *cx, JSObject *obj)
     if(!obj)
         return nsnull;
 
-    JSObject *scope = JS_GetScopeChain(cx);
-    if(!scope)
-    {
-        XPCThrower::Throw(NS_ERROR_FAILURE, cx);
-        return nsnull;
-    }
-
-    scope = JS_GetGlobalForObject(cx, scope);
-
     XPCPerThreadData *threadData = XPCPerThreadData::GetData(cx);
     if(!threadData)
     {