Quelle nsWrapperCache.cpp Sprache: 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)
  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

quality100%

¤ Dauer der Verarbeitung: 0.10 Sekunden (vorverarbeitet) ¤

Wurzel

Suchen

Beweissystem der NASA

Beweissystem Isabelle

NIST Cobol Testsuite

Cephes Mathematical Library

Wiener Entwicklungsmethode

Haftungshinweis

Die Informationen auf dieser Webseite wurden nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit, noch Qualität der bereit gestellten Informationen zugesichert.

Bemerkung:

Die farbliche Syntaxdarstellung ist noch experimentell.