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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-28 14:29:10 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-28 14:29:10 +0000 |
commit | 2aa4a82499d4becd2284cdb482213d541b8804dd (patch) | |
tree | b80bf8bf13c3766139fbacc530efd0dd9d54394c /layout/style/CachedInheritingStyles.h | |
parent | Initial commit. (diff) | |
download | firefox-upstream.tar.xz firefox-upstream.zip |
Adding upstream version 86.0.1.upstream/86.0.1upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'layout/style/CachedInheritingStyles.h')
-rw-r--r-- | layout/style/CachedInheritingStyles.h | 66 |
1 files changed, 66 insertions, 0 deletions
diff --git a/layout/style/CachedInheritingStyles.h b/layout/style/CachedInheritingStyles.h new file mode 100644 index 0000000000..cfe86594ca --- /dev/null +++ b/layout/style/CachedInheritingStyles.h @@ -0,0 +1,66 @@ +/* -*- 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/. */ + +#ifndef mozilla_CachedInheritingStyles_h +#define mozilla_CachedInheritingStyles_h + +#include "nsAtom.h" +#include "nsCOMPtr.h" +#include "nsTArray.h" + +class nsWindowSizes; + +namespace mozilla { + +enum class PseudoStyleType : uint8_t; +class ComputedStyle; + +// Cache of anonymous box and lazy pseudo styles that inherit from a given +// style. +// +// To minimize memory footprint, the cache is word-sized with a tagged pointer +// If there is only one entry, it's stored inline. If there are more, they're +// stored in an out-of-line buffer. See bug 1429126 comment 0 and comment 1 for +// the measurements and rationale that influenced the design. +class CachedInheritingStyles { + public: + void Insert(ComputedStyle* aStyle); + ComputedStyle* Lookup(PseudoStyleType) const; + + CachedInheritingStyles() : mBits(0) {} + ~CachedInheritingStyles() { + if (IsIndirect()) { + delete AsIndirect(); + } else if (!IsEmpty()) { + RefPtr<ComputedStyle> ref = dont_AddRef(AsDirect()); + } + } + + void AddSizeOfIncludingThis(nsWindowSizes& aSizes, size_t* aCVsSize) const; + + private: + // See bug 1429126 comment 1 for the choice of four here. + typedef AutoTArray<RefPtr<ComputedStyle>, 4> IndirectCache; + + bool IsEmpty() const { return !mBits; } + bool IsIndirect() const { return (mBits & 1); } + + ComputedStyle* AsDirect() const { + MOZ_ASSERT(!IsIndirect()); + return reinterpret_cast<ComputedStyle*>(mBits); + } + + IndirectCache* AsIndirect() const { + MOZ_ASSERT(IsIndirect()); + return reinterpret_cast<IndirectCache*>(mBits & ~1); + } + + uintptr_t mBits; +}; + +} // namespace mozilla + +#endif // mozilla_CachedInheritingStyles_h |