зеркало из https://github.com/mozilla/gecko-dev.git
107 строки
3.4 KiB
C++
107 строки
3.4 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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/* base class for all rule types in a CSS style sheet */
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#include "Rule.h"
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#include "mozilla/css/GroupRule.h"
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#include "mozilla/dom/DocumentOrShadowRoot.h"
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#include "nsCCUncollectableMarker.h"
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#include "mozilla/dom/Document.h"
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#include "nsWrapperCacheInlines.h"
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using namespace mozilla;
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using namespace mozilla::dom;
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namespace mozilla {
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namespace css {
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NS_IMPL_CYCLE_COLLECTING_ADDREF(Rule)
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NS_IMPL_CYCLE_COLLECTING_RELEASE(Rule)
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NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(Rule)
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NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
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NS_INTERFACE_MAP_ENTRY(nsISupports)
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NS_INTERFACE_MAP_END
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NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE_0(Rule)
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bool Rule::IsCCLeaf() const { return !PreservingWrapper(); }
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bool Rule::IsKnownLive() const {
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if (HasKnownLiveWrapper()) {
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return true;
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}
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StyleSheet* sheet = GetStyleSheet();
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if (!sheet) {
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return false;
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}
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if (!sheet->IsKeptAliveByDocument()) {
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return false;
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}
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return nsCCUncollectableMarker::InGeneration(
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GetComposedDoc()->GetMarkedCCGeneration());
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}
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void Rule::UnlinkDeclarationWrapper(nsWrapperCache& aDecl) {
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// We have to be a bit careful here. We have two separate nsWrapperCache
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// instances, aDecl and this, that both correspond to the same CC participant:
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// this. If we just used ReleaseWrapper() on one of them, that would
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// unpreserve that one wrapper, then trace us with a tracer that clears JS
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// things, and we would clear the wrapper on the cache that has not
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// unpreserved the wrapper yet. That would violate the invariant that the
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// cache keeps caching the wrapper until the wrapper dies.
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//
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// So we reimplement a modified version of nsWrapperCache::ReleaseWrapper here
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// that unpreserves both wrappers before doing any clearing.
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bool needDrop = PreservingWrapper() || aDecl.PreservingWrapper();
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SetPreservingWrapper(false);
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aDecl.SetPreservingWrapper(false);
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if (needDrop) {
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DropJSObjects(this);
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}
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}
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NS_IMPL_CYCLE_COLLECTION_CAN_SKIP_BEGIN(Rule)
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return tmp->IsCCLeaf() || tmp->IsKnownLive();
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NS_IMPL_CYCLE_COLLECTION_CAN_SKIP_END
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NS_IMPL_CYCLE_COLLECTION_CAN_SKIP_IN_CC_BEGIN(Rule)
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// Please see documentation for nsCycleCollectionParticipant::CanSkip* for why
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// we need to check HasNothingToTrace here but not in the other two CanSkip
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// methods.
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return tmp->IsCCLeaf() || (tmp->IsKnownLive() && tmp->HasNothingToTrace(tmp));
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NS_IMPL_CYCLE_COLLECTION_CAN_SKIP_IN_CC_END
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NS_IMPL_CYCLE_COLLECTION_CAN_SKIP_THIS_BEGIN(Rule)
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return tmp->IsCCLeaf() || tmp->IsKnownLive();
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NS_IMPL_CYCLE_COLLECTION_CAN_SKIP_THIS_END
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/* virtual */
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void Rule::DropSheetReference() { mSheet = nullptr; }
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void Rule::SetCssText(const nsAString& aCssText) {
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// We used to throw for some rule types, but not all. Specifically, we did
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// not throw for StyleRule. Let's just always not throw.
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}
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Rule* Rule::GetParentRule() const { return mParentRule; }
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bool Rule::IsReadOnly() const {
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MOZ_ASSERT(!mSheet || !mParentRule ||
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mSheet->IsReadOnly() == mParentRule->IsReadOnly(),
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"a parent rule should be read only iff the owning sheet is "
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"read only");
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return mSheet && mSheet->IsReadOnly();
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}
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} // namespace css
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} // namespace mozilla
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