Bug 1090592 - GetPrototypeOf hook for CPOWProxyHandler. r=billm

dom/base/test/chrome/cpows_child.js

@@ -64,11 +64,18 @@ function make_object()
 
   let for_json = { "n": 3, "a": array, "s": "hello", o: { "x": 10 } };
 
+  let proto = { data: 42 };
+  let with_proto = Object.create(proto);
+
+  let with_null_proto = Object.create(null);
+
   return { "data": o,
            "throwing": throwing,
            "document": content.document,
            "array": array,
-           "for_json": for_json
+           "for_json": for_json,
+           "with_proto": with_proto,
+           "with_null_proto": with_null_proto
          };
 }
 

dom/base/test/chrome/cpows_parent.xul

@@ -126,6 +126,14 @@
       ok(j2.a[2] === 3, "JSON array index");
       ok(j2.s === "hello", "JSON string property");
       ok(j2.o.x === 10, "JSON object property");
+
+      let with_proto = message.objects.with_proto;
+      let proto = Object.getPrototypeOf(with_proto);
+      ok(proto.data == 42, "Object.getPrototypeOf works on CPOW");
+
+      let with_null_proto = message.objects.with_null_proto;
+      proto = Object.getPrototypeOf(with_null_proto);
+      ok(proto === null, "Object.getPrototypeOf works on CPOW (null proto)");
     }
 
     function recvAsyncMessage(message) {

js/ipc/JavaScriptBase.h

@@ -99,6 +99,9 @@ class JavaScriptBase : public WrapperOwner, public WrapperAnswer, public Base
     bool RecvClassName(const uint64_t &objId, nsString *result) {
         return Answer::RecvClassName(ObjectId::deserialize(objId), result);
     }
+    bool RecvGetPrototypeOf(const uint64_t &objId, ReturnStatus *rs, ObjectOrNullVariant *result) {
+        return Answer::RecvGetPrototypeOf(ObjectId::deserialize(objId), rs, result);
+    }
     bool RecvRegExpToShared(const uint64_t &objId, ReturnStatus *rs, nsString *source, uint32_t *flags) {
         return Answer::RecvRegExpToShared(ObjectId::deserialize(objId), rs, source, flags);
     }
@@ -188,6 +191,9 @@ class JavaScriptBase : public WrapperOwner, public WrapperAnswer, public Base
     bool SendClassName(const ObjectId &objId, nsString *result) {
         return Base::SendClassName(objId.serialize(), result);
     }
+    bool SendGetPrototypeOf(const ObjectId &objId, ReturnStatus *rs, ObjectOrNullVariant *result) {
+        return Base::SendGetPrototypeOf(objId.serialize(), rs, result);
+     }
 
     bool SendRegExpToShared(const ObjectId &objId, ReturnStatus *rs,
                             nsString *source, uint32_t *flags) {

js/ipc/PJavaScript.ipdl

@@ -40,6 +40,7 @@ both:
     prio(high) sync HasInstance(uint64_t objId, JSVariant v) returns (ReturnStatus rs, bool has);
     prio(high) sync ObjectClassIs(uint64_t objId, uint32_t classValue) returns (bool result);
     prio(high) sync ClassName(uint64_t objId) returns (nsString name);
+    prio(high) sync GetPrototypeOf(uint64_t objId) returns (ReturnStatus rs, ObjectOrNullVariant result);
     prio(high) sync RegExpToShared(uint64_t objId) returns (ReturnStatus rs, nsString source, uint32_t flags);
 
     prio(high) sync GetPropertyKeys(uint64_t objId, uint32_t flags) returns (ReturnStatus rs, JSIDVariant[] ids);

js/ipc/WrapperAnswer.cpp

@@ -556,6 +556,32 @@ WrapperAnswer::RecvClassName(const ObjectId &objId, nsString *name)
     return true;
 }
 
+bool
+WrapperAnswer::RecvGetPrototypeOf(const ObjectId &objId, ReturnStatus *rs, ObjectOrNullVariant *result)
+{
+    *result = NullVariant();
+
+    AutoJSAPI jsapi;
+    if (NS_WARN_IF(!jsapi.Init(scopeForTargetObjects())))
+        return false;
+    JSContext *cx = jsapi.cx();
+
+    RootedObject obj(cx, findObjectById(cx, objId));
+    if (!obj)
+        return fail(cx, rs);
+
+    JS::RootedObject proto(cx);
+    if (!JS_GetPrototype(cx, obj, &proto))
+        return fail(cx, rs);
+
+    if (!toObjectOrNullVariant(cx, proto, result))
+        return fail(cx, rs);
+
+    LOG("getPrototypeOf(%s)", ReceiverObj(objId));
+
+    return ok(rs);
+}
+
 bool
 WrapperAnswer::RecvRegExpToShared(const ObjectId &objId, ReturnStatus *rs,
                                   nsString *source, uint32_t *flags)

js/ipc/WrapperAnswer.h

@@ -53,6 +53,7 @@ class WrapperAnswer : public virtual JavaScriptShared
     bool RecvObjectClassIs(const ObjectId &objId, const uint32_t &classValue,
                            bool *result);
     bool RecvClassName(const ObjectId &objId, nsString *result);
+    bool RecvGetPrototypeOf(const ObjectId &objId, ReturnStatus *rs, ObjectOrNullVariant *result);
     bool RecvRegExpToShared(const ObjectId &objId, ReturnStatus *rs, nsString *source, uint32_t *flags);
 
     bool RecvGetPropertyKeys(const ObjectId &objId, const uint32_t &flags,

js/ipc/WrapperOwner.cpp

@@ -120,6 +120,7 @@ class CPOWProxyHandler : public BaseProxyHandler
     virtual void objectMoved(JSObject *proxy, const JSObject *old) const MOZ_OVERRIDE;
     virtual bool isCallable(JSObject *obj) const MOZ_OVERRIDE;
     virtual bool isConstructor(JSObject *obj) const MOZ_OVERRIDE;
+    virtual bool getPrototypeOf(JSContext *cx, HandleObject proxy, MutableHandleObject protop) const MOZ_OVERRIDE;
 
     static const char family;
     static const CPOWProxyHandler singleton;
@@ -678,6 +679,32 @@ WrapperOwner::className(JSContext *cx, HandleObject proxy)
     return ToNewCString(name);
 }
 
+bool
+CPOWProxyHandler::getPrototypeOf(JSContext *cx, HandleObject proxy, MutableHandleObject objp) const
+{
+    FORWARD(getPrototypeOf, (cx, proxy, objp));
+}
+
+bool
+WrapperOwner::getPrototypeOf(JSContext *cx, HandleObject proxy, MutableHandleObject objp)
+{
+    ObjectId objId = idOf(proxy);
+
+    ObjectOrNullVariant val;
+    ReturnStatus status;
+    if (!SendGetPrototypeOf(objId, &status, &val))
+        return ipcfail(cx);
+
+    LOG_STACK();
+
+    if (!ok(cx, status))
+        return false;
+
+    objp.set(fromObjectOrNullVariant(cx, val));
+
+    return true;
+}
+
 bool
 CPOWProxyHandler::regexp_toShared(JSContext *cx, HandleObject proxy, RegExpGuard *g) const
 {
@@ -986,11 +1013,15 @@ WrapperOwner::fromRemoteObjectVariant(JSContext *cx, RemoteObject objVar)
         RootedObject junkScope(cx, xpc::PrivilegedJunkScope());
         JSAutoCompartment ac(cx, junkScope);
         RootedValue v(cx, UndefinedValue());
+        // We need to setLazyProto for the getPrototypeOf hook.
+        ProxyOptions options;
+        options.setLazyProto(true);
         obj = NewProxyObject(cx,
                              &CPOWProxyHandler::singleton,
                              v,
                              nullptr,
-                             junkScope);
+                             junkScope,
+                             options);
         if (!obj)
             return nullptr;
 

js/ipc/WrapperOwner.h

@@ -54,6 +54,8 @@ class WrapperOwner : public virtual JavaScriptShared
     bool hasInstance(JSContext *cx, JS::HandleObject proxy, JS::MutableHandleValue v, bool *bp);
     bool objectClassIs(JSContext *cx, JS::HandleObject obj, js::ESClassValue classValue);
     const char* className(JSContext *cx, JS::HandleObject proxy);
+    bool getPrototypeOf(JSContext *cx, JS::HandleObject proxy, JS::MutableHandleObject protop);
+
     bool regexp_toShared(JSContext *cx, JS::HandleObject proxy, js::RegExpGuard *g);
 
     nsresult instanceOf(JSObject *obj, const nsID *id, bool *bp);
@@ -134,6 +136,7 @@ class WrapperOwner : public virtual JavaScriptShared
     virtual bool SendObjectClassIs(const ObjectId &objId, const uint32_t &classValue,
                                    bool *result) = 0;
     virtual bool SendClassName(const ObjectId &objId, nsString *result) = 0;
+    virtual bool SendGetPrototypeOf(const ObjectId &objId, ReturnStatus *rs, ObjectOrNullVariant *result) = 0;
     virtual bool SendRegExpToShared(const ObjectId &objId, ReturnStatus *rs, nsString *source,
                                     uint32_t *flags) = 0;