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/* -*- 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)
NoteWeakMapping(JSObject* aKey, nsISupports* aVal,
nsCycleCollectionParticipant* aValParticipant) 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
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