Bug 1019191 part 22. Eliminate the effectively unused vp argument of xpc_qsUnwrapArgImpl. r=peterv

dom/bindings/BindingUtils.cpp

@@ -827,12 +827,10 @@ QueryInterface(JSContext* cx, unsigned argc, JS::Value* vp)
 
   // Switch this to UnwrapDOMObjectToISupports once our global objects are
   // using new bindings.
-  JS::Rooted<JS::Value> unusedVal(cx);
   nsISupports* native = nullptr;
   nsCOMPtr<nsISupports> nativeRef;
   UnwrapArg<nsISupports>(cx, obj, &native,
-                         static_cast<nsISupports**>(getter_AddRefs(nativeRef)),
-                         &unusedVal);
+                         static_cast<nsISupports**>(getter_AddRefs(nativeRef)));
   if (!native) {
     return Throw(cx, NS_ERROR_FAILURE);
   }
@@ -848,7 +846,7 @@ QueryInterface(JSContext* cx, unsigned argc, JS::Value* vp)
   nsIJSID* iid;
   SelfRef iidRef;
   obj = &args[0].toObject();
-  if (NS_FAILED(UnwrapArg<nsIJSID>(cx, obj, &iid, &iidRef.ptr, &unusedVal))) {
+  if (NS_FAILED(UnwrapArg<nsIJSID>(cx, obj, &iid, &iidRef.ptr))) {
     return Throw(cx, NS_ERROR_XPC_BAD_CONVERT_JS);
   }
   MOZ_ASSERT(iid);

dom/bindings/BindingUtils.h

@@ -41,7 +41,7 @@ class nsPIDOMWindow;
 
 extern nsresult
 xpc_qsUnwrapArgImpl(JSContext* cx, JS::Handle<JSObject*> src, const nsIID& iid, void** ppArg,
-                    nsISupports** ppArgRef, JS::MutableHandle<JS::Value> vp);
+                    nsISupports** ppArgRef);
 
 namespace mozilla {
 namespace dom {
@@ -60,12 +60,11 @@ struct SelfRef
 template <class Interface, class StrongRefType>
 inline nsresult
 UnwrapArg(JSContext* cx, JS::Handle<JSObject*> src, Interface** ppArg,
-          StrongRefType** ppArgRef, JS::MutableHandle<JS::Value> vp)
+          StrongRefType** ppArgRef)
 {
   nsISupports* argRef = *ppArgRef;
   nsresult rv = xpc_qsUnwrapArgImpl(cx, src, NS_GET_TEMPLATE_IID(Interface),
-                                    reinterpret_cast<void**>(ppArg), &argRef,
-                                    vp);
+                                    reinterpret_cast<void**>(ppArg), &argRef);
   *ppArgRef = static_cast<StrongRefType*>(argRef);
   return rv;
 }

dom/bindings/Codegen.py

@@ -3677,8 +3677,7 @@ class CastableObjectUnwrapper():
                   // want to be in that compartment for the UnwrapArg call.
                   JS::Rooted<JSObject*> source(cx, ${source});
                   JSAutoCompartment ac(cx, ${source});
-                  JS::Rooted<JS::Value> unused(cx);
-                  rv = UnwrapArg<${type}>(cx, source, &objPtr, &objRef.ptr, &unused);
+                  rv = UnwrapArg<${type}>(cx, source, &objPtr, &objRef.ptr);
                 }
                 """)
         else:
@@ -3686,8 +3685,7 @@ class CastableObjectUnwrapper():
             self.substitution["source"] = source
             xpconnectUnwrap = (
                 "JS::Rooted<JSObject*> source(cx, ${source});\n"
-                "JS::Rooted<JS::Value> unused(cx);\n"
-                "nsresult rv = UnwrapArg<${type}>(cx, source, &objPtr, &objRef.ptr, &unused);\n")
+                "nsresult rv = UnwrapArg<${type}>(cx, source, &objPtr, &objRef.ptr);\n")
 
         if descriptor.hasXPConnectImpls:
             self.substitution["codeOnFailure"] = string.Template(
@@ -4767,24 +4765,18 @@ def getJSToNativeConversionInfo(type, descriptorProvider, failureCode=None,
             else:
                 holderType = "nsRefPtr<" + typeName + ">"
             templateBody += (
-                "JS::Rooted<JSObject*> source(cx, &${val}.toObject());\n"
-                "JS::Rooted<JS::Value> tmpVal(cx);\n" +
+                "JS::Rooted<JSObject*> source(cx, &${val}.toObject());\n" +
                 typePtr + " tmp;\n"
-                "if (NS_FAILED(UnwrapArg<" + typeName + ">(cx, source, &tmp, static_cast<" + typeName + "**>(getter_AddRefs(${holderName})), &tmpVal))) {\n")
+                "if (NS_FAILED(UnwrapArg<" + typeName + ">(cx, source, &tmp, static_cast<" + typeName + "**>(getter_AddRefs(${holderName}))))) {\n")
             templateBody += CGIndenter(onFailureBadType(failureCode,
                                                         descriptor.interface.identifier.name)).define()
             templateBody += ("}\n"
                              "MOZ_ASSERT(tmp);\n")
 
             if not isDefinitelyObject and not forceOwningType:
-                # Our tmpVal will go out of scope, so we can't rely on it
-                # for rooting
                 templateBody += dedent("""
-                    if (tmpVal != ${val} && !${holderName}) {
-                      // We have to have a strong ref, because we got this off
-                      // some random object that might get GCed
-                      ${holderName} = tmp;
-                    }
+                    // UnwrapArg never sets **ppArg without also setting *ppArgRef
+                    MOZ_ASSERT(${holderName});
                     """)
 
             # And store our tmp, before it goes out of scope.

js/xpconnect/src/XPCQuickStubs.cpp

@@ -24,8 +24,7 @@ xpc_qsUnwrapArgImpl(JSContext *cx,
                     HandleObject src,
                     const nsIID &iid,
                     void **ppArg,
-                    nsISupports **ppArgRef,
-                    MutableHandleValue vp)
+                    nsISupports **ppArgRef)
 {
     nsISupports *iface = xpc::UnwrapReflectorToISupports(src);
     if (iface) {
@@ -59,7 +58,6 @@ xpc_qsUnwrapArgImpl(JSContext *cx,
     rv = wrappedJS->QueryInterface(iid, ppArg);
     if (NS_SUCCEEDED(rv)) {
         *ppArgRef = static_cast<nsISupports*>(*ppArg);
-        vp.setObjectOrNull(wrappedJS->GetJSObject());
     }
     return rv;
 }

js/xpconnect/src/XPCQuickStubs.h

@@ -13,6 +13,6 @@
 
 nsresult
 xpc_qsUnwrapArgImpl(JSContext *cx, JS::HandleObject src, const nsIID &iid, void **ppArg,
-                    nsISupports **ppArgRef, JS::MutableHandleValue vp);
+                    nsISupports **ppArgRef);
 
 #endif /* xpcquickstubs_h___ */