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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 "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->Traverse(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
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