Bug 1090537, part 3 - Pass receiver argument through from JSObject::setGeneric and setElement to Proxy::set. r=efaust.

ES6 specifies [[Set]] as an operation taking both a "this" object and a "receiver" parameter. Both JSObject::setGeneric and Proxy::set support the receiver parameter, but ObjectOps::setGeneric does not; in this patch, we add a little workaround for that. The test shows how this is observable using only standard builtins.

The changes in JSObject::setElement are untestable since currently all call sites pass the same value for obj as for receiver.

(This was reviewed as "part 2" but it was necessary to switch parts 2 and 3 and add part 2b.)

--HG--
extra : rebase_source : 617decfa9be34b01a0f923a9717ad2544d913af9

js/src/jit-test/tests/proxy/testDirectProxySetNested.js

@@ -0,0 +1,15 @@
+// The receiver argument is passed through proxies with no "set" handler.
+
+var hits;
+var a = new Proxy({}, {
+    set(t, id, value, receiver) {
+        assertEq(id, "prop");
+        assertEq(value, 3);
+        assertEq(receiver, b);
+        hits++;
+    }
+});
+var b = new Proxy(a, {});
+hits = 0;
+b.prop = 3;
+assertEq(hits, 1);

js/src/jsobj.cpp

@@ -1840,7 +1840,7 @@ js::CreateThisForFunction(JSContext *cx, HandleObject callee, NewObjectKind newK
 }
 
 /* static */ bool
-JSObject::nonNativeSetProperty(JSContext *cx, HandleObject obj,
+JSObject::nonNativeSetProperty(JSContext *cx, HandleObject obj, HandleObject receiver,
                                HandleId id, MutableHandleValue vp, bool strict)
 {
     if (MOZ_UNLIKELY(obj->watched())) {
@@ -1848,11 +1848,13 @@ JSObject::nonNativeSetProperty(JSContext *cx, HandleObject obj,
         if (wpmap && !wpmap->triggerWatchpoint(cx, obj, id, vp))
             return false;
     }
+    if (obj->is<ProxyObject>())
+        return Proxy::set(cx, obj, receiver, id, strict, vp);
     return obj->getOps()->setGeneric(cx, obj, id, vp, strict);
 }
 
 /* static */ bool
-JSObject::nonNativeSetElement(JSContext *cx, HandleObject obj,
+JSObject::nonNativeSetElement(JSContext *cx, HandleObject obj, HandleObject receiver,
                               uint32_t index, MutableHandleValue vp, bool strict)
 {
     if (MOZ_UNLIKELY(obj->watched())) {
@@ -1864,6 +1866,11 @@ JSObject::nonNativeSetElement(JSContext *cx, HandleObject obj,
         if (wpmap && !wpmap->triggerWatchpoint(cx, obj, id, vp))
             return false;
     }
+    if (obj->is<ProxyObject>()) {
+        RootedId id(cx);
+        return IndexToId(cx, index, &id) &&
+               Proxy::set(cx, obj, receiver, id, strict, vp);
+    }
     return obj->getOps()->setElement(cx, obj, index, vp, strict);
 }
 

js/src/jsobj.h

@@ -655,9 +655,11 @@ class JSObject : public js::gc::Cell
                                   uint32_t index, js::MutableHandleValue vp, bool strict);
 
     static bool nonNativeSetProperty(JSContext *cx, js::HandleObject obj,
-                                     js::HandleId id, js::MutableHandleValue vp, bool strict);
+                                     js::HandleObject receiver, js::HandleId id,
+                                     js::MutableHandleValue vp, bool strict);
     static bool nonNativeSetElement(JSContext *cx, js::HandleObject obj,
-                                    uint32_t index, js::MutableHandleValue vp, bool strict);
+                                    js::HandleObject receiver, uint32_t index,
+                                    js::MutableHandleValue vp, bool strict);
 
     static inline bool getGenericAttributes(JSContext *cx, js::HandleObject obj,
                                             js::HandleId id, unsigned *attrsp);

js/src/vm/NativeObject.h

@@ -1414,7 +1414,7 @@ JSObject::setGeneric(JSContext *cx, js::HandleObject obj, js::HandleObject recei
                      js::HandleId id, js::MutableHandleValue vp, bool strict)
 {
     if (obj->getOps()->setGeneric)
-        return nonNativeSetProperty(cx, obj, id, vp, strict);
+        return nonNativeSetProperty(cx, obj, receiver, id, vp, strict);
     return js::baseops::SetPropertyHelper<js::SequentialExecution>(
         cx, obj.as<js::NativeObject>(), receiver, id, js::baseops::Qualified, vp, strict);
 }
@@ -1424,7 +1424,7 @@ JSObject::setElement(JSContext *cx, js::HandleObject obj, js::HandleObject recei
                      uint32_t index, js::MutableHandleValue vp, bool strict)
 {
     if (obj->getOps()->setElement)
-        return nonNativeSetElement(cx, obj, index, vp, strict);
+        return nonNativeSetElement(cx, obj, receiver, index, vp, strict);
     return js::baseops::SetElementHelper(cx, obj.as<js::NativeObject>(),
                                          receiver, index, vp, strict);
 }