зеркало из https://github.com/mozilla/gecko-dev.git
84 строки
2.5 KiB
C
84 строки
2.5 KiB
C
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef nsWrapperCacheInline_h___
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#define nsWrapperCacheInline_h___
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#include "nsWrapperCache.h"
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#include "js/TracingAPI.h"
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inline JSObject*
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nsWrapperCache::GetWrapperPreserveColor() const
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{
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JSObject* obj = mWrapper;
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if (obj && js::gc::EdgeNeedsSweepUnbarriered(&obj)) {
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// The object has been found to be dead and is in the process of being
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// finalized, so don't let the caller see it. As an optimisation, remove it
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// from the cache so we don't have to do this check in future.
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const_cast<nsWrapperCache*>(this)->ClearWrapper();
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return nullptr;
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}
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MOZ_ASSERT(obj == mWrapper);
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return obj;
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}
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inline JSObject*
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nsWrapperCache::GetWrapper() const
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{
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JSObject* obj = GetWrapperPreserveColor();
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if (obj) {
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JS::ExposeObjectToActiveJS(obj);
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}
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return obj;
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}
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inline bool
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nsWrapperCache::HasKnownLiveWrapper() const
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{
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// If we have a wrapper and it's not gray in the GC-marking sense, that means
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// that we can't be cycle-collected. That's because the wrapper is being kept
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// alive by the JS engine (and not just due to being traced from some
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// cycle-collectable thing), and the wrapper holds us alive, so we know we're
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// not collectable.
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JSObject* o = GetWrapperPreserveColor();
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return o && !JS::ObjectIsMarkedGray(o);
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}
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static void
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SearchGray(JS::GCCellPtr aGCThing, const char* aName, void* aClosure)
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{
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bool* hasGrayObjects = static_cast<bool*>(aClosure);
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if (!*hasGrayObjects && aGCThing && JS::GCThingIsMarkedGray(aGCThing)) {
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*hasGrayObjects = true;
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}
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}
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inline bool
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nsWrapperCache::HasNothingToTrace(nsISupports* aThis)
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{
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nsXPCOMCycleCollectionParticipant* participant = nullptr;
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CallQueryInterface(aThis, &participant);
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bool hasGrayObjects = false;
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participant->Trace(aThis, TraceCallbackFunc(SearchGray), &hasGrayObjects);
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return !hasGrayObjects;
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}
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inline bool
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nsWrapperCache::HasKnownLiveWrapperAndDoesNotNeedTracing(nsISupports* aThis)
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{
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return HasKnownLiveWrapper() && HasNothingToTrace(aThis);
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}
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inline void
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nsWrapperCache::MarkWrapperLive()
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{
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// Just call GetWrapper and ignore the return value. It will do the
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// gray-unmarking for us.
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GetWrapper();
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}
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#endif /* nsWrapperCache_h___ */
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