зеркало из https://github.com/mozilla/gecko-dev.git
69 строки
1.9 KiB
C++
69 строки
1.9 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 mozilla_CachedInheritingStyles_h
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#define mozilla_CachedInheritingStyles_h
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#include "nsAtom.h"
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#include "nsCOMPtr.h"
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#include "nsTArray.h"
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class nsWindowSizes;
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namespace mozilla {
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class ServoStyleContext;
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// Cache of anonymous box and lazy pseudo styles that inherit from a given style.
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//
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// To minimize memory footprint, the cache is word-sized with a tagged pointer
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// If there is only one entry, it's stored inline. If there are more, they're
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// stored in an out-of-line buffer. See bug 1429126 comment 0 and comment 1 for
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// the measurements and rationale that influenced the design.
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class CachedInheritingStyles
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{
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public:
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void Insert(ServoStyleContext* aStyle);
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ServoStyleContext* Lookup(nsAtom* aPseudoTag) const;
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CachedInheritingStyles() : mBits(0) {}
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~CachedInheritingStyles()
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{
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if (IsIndirect()) {
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delete AsIndirect();
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} else if (!IsEmpty()) {
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RefPtr<ServoStyleContext> ref = dont_AddRef(AsDirect());
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}
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}
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void AddSizeOfIncludingThis(nsWindowSizes& aSizes, size_t* aCVsSize) const;
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private:
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// See bug 1429126 comment 1 for the choice of four here.
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typedef AutoTArray<RefPtr<ServoStyleContext>, 4> IndirectCache;
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bool IsEmpty() const { return !mBits; }
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bool IsIndirect() const { return (mBits & 1); }
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ServoStyleContext* AsDirect() const
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{
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MOZ_ASSERT(!IsIndirect());
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return reinterpret_cast<ServoStyleContext*>(mBits);
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}
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IndirectCache* AsIndirect() const
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{
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MOZ_ASSERT(IsIndirect());
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return reinterpret_cast<IndirectCache*>(mBits & ~1);
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}
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uintptr_t mBits;
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};
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} // namespace mozilla
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#endif // mozilla_CachedInheritingStyles_h
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