/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ /* vim: set ts=8 sts=2 et sw=2 tw=80: */ /* This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was not distributed with this * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ #include "nsWrapperCacheInlines.h" #include "js/Class.h" #include "js/Proxy.h" #include "mozilla/dom/DOMJSProxyHandler.h" #include "mozilla/CycleCollectedJSContext.h" #include "mozilla/HoldDropJSObjects.h" #include "nsCycleCollectionTraversalCallback.h" #include "nsCycleCollector.h" using namespace mozilla; using namespace mozilla::dom; #ifdef DEBUG /* static */ bool nsWrapperCache::HasJSObjectMovedOp(JSObject* aWrapper) { return js::HasObjectMovedOp(aWrapper); } #endif void nsWrapperCache::HoldJSObjects(void* aScriptObjectHolder, nsScriptObjectTracer* aTracer) { cyclecollector::HoldJSObjectsImpl(aScriptObjectHolder, aTracer); if (mWrapper && !JS::ObjectIsTenured(mWrapper)) { CycleCollectedJSContext::Get()->NurseryWrapperPreserved(mWrapper); } } void nsWrapperCache::SetWrapperJSObject(JSObject* aWrapper) { mWrapper = aWrapper; UnsetWrapperFlags(kWrapperFlagsMask & ~WRAPPER_IS_NOT_DOM_BINDING); if (aWrapper && !JS::ObjectIsTenured(aWrapper)) { CycleCollectedJSContext::Get()->NurseryWrapperAdded(this); } } void nsWrapperCache::ReleaseWrapper(void* aScriptObjectHolder) { if (PreservingWrapper()) { // PreserveWrapper puts new DOM bindings in the JS holders hash, but they // can also be in the DOM expando hash, so we need to try to remove them // from both here. JSObject* obj = GetWrapperPreserveColor(); if (IsDOMBinding() && obj && js::IsProxy(obj)) { DOMProxyHandler::ClearExternalRefsForWrapperRelease(obj); } SetPreservingWrapper(false); cyclecollector::DropJSObjectsImpl(aScriptObjectHolder); } } #ifdef DEBUG class DebugWrapperTraversalCallback : public nsCycleCollectionTraversalCallback { public: explicit DebugWrapperTraversalCallback(JSObject* aWrapper) : mFound(false) , mWrapper(JS::GCCellPtr(aWrapper)) { mFlags = WANT_ALL_TRACES; } NS_IMETHOD_(void) DescribeRefCountedNode(nsrefcnt aRefCount, const char* aObjName) { } NS_IMETHOD_(void) DescribeGCedNode(bool aIsMarked, const char* aObjName, uint64_t aCompartmentAddress) { } NS_IMETHOD_(void) NoteJSChild(const JS::GCCellPtr& aChild) { if (aChild == mWrapper) { mFound = true; } } NS_IMETHOD_(void) NoteXPCOMChild(nsISupports* aChild) { } NS_IMETHOD_(void) NoteNativeChild(void* aChild, nsCycleCollectionParticipant* aHelper) { } NS_IMETHOD_(void) NoteNextEdgeName(const char* aName) { } bool mFound; private: JS::GCCellPtr mWrapper; }; static void DebugWrapperTraceCallback(JS::GCCellPtr aPtr, const char* aName, void* aClosure) { DebugWrapperTraversalCallback* callback = static_cast<DebugWrapperTraversalCallback*>(aClosure); if (aPtr.is<JSObject>()) { callback->NoteJSChild(aPtr); } } void nsWrapperCache::CheckCCWrapperTraversal(void* aScriptObjectHolder, nsScriptObjectTracer* aTracer) { JSObject* wrapper = GetWrapper(); if (!wrapper) { return; } DebugWrapperTraversalCallback callback(wrapper); // The CC traversal machinery cannot trigger GC; however, the analysis cannot // see through the COM layer, so we use a suppression to help it. JS::AutoSuppressGCAnalysis suppress; aTracer->TraverseNativeAndJS(aScriptObjectHolder, callback); MOZ_ASSERT(callback.mFound, "Cycle collection participant didn't traverse to preserved " "wrapper! This will probably crash."); callback.mFound = false; aTracer->Trace(aScriptObjectHolder, TraceCallbackFunc(DebugWrapperTraceCallback), &callback); MOZ_ASSERT(callback.mFound, "Cycle collection participant didn't trace preserved wrapper! " "This will probably crash."); } #endif // DEBUG