gecko-dev/layout/style/CachedInheritingStyles.h
Emilio Cobos Álvarez dad3a20b22 Bug 1525955 - Include anon boxes in CSSPseudoElementType, to remove ComputedStyle::mPseudoTag. r=heycam
This is more consistent with what the Rust bits of the style system do, and
removes a pointer from ComputedStyle which is always nice.

This also aligns the Rust bits with the C++ bits re. not treating xul pseudos as
anonymous boxes. See the comment in nsTreeStyleCache.cpp regarding those.

Can't wait for XUL trees to die.

Depends on D19001

Differential Revision: https://phabricator.services.mozilla.com/D19002

--HG--
extra : moz-landing-system : lando
2019-02-19 13:44:33 +00:00

67 lines
1.9 KiB
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/. */
#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