fune/dom/base/nsWrapperCache.cpp
Jon Coppeard 179b45025c Bug 1352532 - Part 1: Allow wrapper cache to handle changing a nursery wrapper to another nursery wrapper r=smaug
Previously this situation didn't arise and the existing code calls
NurseryWrapperAdded multiple times with the same wrapper in this case. This
causes assertion failures when the nursery wrapper list is processed later on.

Differential Revision: https://phabricator.services.mozilla.com/D146804
2022-06-28 08:43:46 +00:00

142 lines
4.6 KiB
C++

/* -*- 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 "jsfriendapi.h"
#include "js/Class.h"
#include "js/Proxy.h"
#include "mozilla/CycleCollectedJSRuntime.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,
JS::Zone* aWrapperZone) {
cyclecollector::HoldJSObjectsImpl(aScriptObjectHolder, aTracer, aWrapperZone);
if (mWrapper && !JS::ObjectIsTenured(mWrapper)) {
JS::HeapObjectPostWriteBarrier(&mWrapper, nullptr, mWrapper);
}
}
static inline bool IsNurseryWrapper(JSObject* aWrapper) {
return aWrapper && !JS::ObjectIsTenured(aWrapper);
}
void nsWrapperCache::SetWrapperJSObject(JSObject* aNewWrapper) {
JSObject* oldWrapper = mWrapper;
mWrapper = aNewWrapper;
UnsetWrapperFlags(kWrapperFlagsMask);
if (IsNurseryWrapper(aNewWrapper) && !IsNurseryWrapper(oldWrapper)) {
CycleCollectedJSRuntime::Get()->NurseryWrapperAdded(this);
}
}
void nsWrapperCache::ReleaseWrapper(void* aScriptObjectHolder) {
// If the behavior here changes in a substantive way, you may need
// to update css::Rule::UnlinkDeclarationWrapper as well.
if (PreservingWrapper()) {
SetPreservingWrapper(false);
cyclecollector::DropJSObjectsImpl(aScriptObjectHolder);
JS::HeapObjectPostWriteBarrier(&mWrapper, mWrapper, nullptr);
}
}
#ifdef DEBUG
void nsWrapperCache::AssertUpdatedWrapperZone(const JSObject* aNewObject,
const JSObject* aOldObject) {
MOZ_ASSERT(js::GetObjectZoneFromAnyThread(aNewObject) ==
js::GetObjectZoneFromAnyThread(aOldObject));
}
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) override {}
NS_IMETHOD_(void)
DescribeGCedNode(bool aIsMarked, const char* aObjName,
uint64_t aCompartmentAddress) override {}
NS_IMETHOD_(void) NoteJSChild(JS::GCCellPtr aChild) override {
if (aChild == mWrapper) {
mFound = true;
}
}
NS_IMETHOD_(void) NoteXPCOMChild(nsISupports* aChild) override {}
NS_IMETHOD_(void)
NoteNativeChild(void* aChild,
nsCycleCollectionParticipant* aHelper) override {}
NS_IMETHOD_(void) NoteNextEdgeName(const char* aName) override {}
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 = GetWrapperPreserveColor();
if (!wrapper) {
return;
}
// Temporarily make this a preserving wrapper so that TraceWrapper() traces
// it.
bool wasPreservingWrapper = PreservingWrapper();
SetPreservingWrapper(true);
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.");
SetPreservingWrapper(wasPreservingWrapper);
}
#endif // DEBUG