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Diffstat (limited to 'layout/xul/tree/nsTreeStyleCache.cpp')
-rw-r--r-- | layout/xul/tree/nsTreeStyleCache.cpp | 103 |
1 files changed, 103 insertions, 0 deletions
diff --git a/layout/xul/tree/nsTreeStyleCache.cpp b/layout/xul/tree/nsTreeStyleCache.cpp new file mode 100644 index 0000000000..d5823ac38e --- /dev/null +++ b/layout/xul/tree/nsTreeStyleCache.cpp @@ -0,0 +1,103 @@ +/* -*- 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/. */ + +#include "nsTreeStyleCache.h" +#include "mozilla/ComputedStyleInlines.h" +#include "mozilla/dom/Element.h" +#include "mozilla/ServoStyleSet.h" +#include "nsPresContextInlines.h" + +using namespace mozilla; + +nsTreeStyleCache::Transition::Transition(DFAState aState, nsAtom* aSymbol) + : mState(aState), mInputSymbol(aSymbol) {} + +bool nsTreeStyleCache::Transition::operator==(const Transition& aOther) const { + return aOther.mState == mState && aOther.mInputSymbol == mInputSymbol; +} + +uint32_t nsTreeStyleCache::Transition::Hash() const { + // Make a 32-bit integer that combines the low-order 16 bits of the state and + // the input symbol. + uint32_t hb = mState << 16; + uint32_t lb = (NS_PTR_TO_UINT32(mInputSymbol.get()) << 16) >> 16; + return hb + lb; +} + +// The ComputedStyle cache impl +ComputedStyle* nsTreeStyleCache::GetComputedStyle( + nsPresContext* aPresContext, nsIContent* aContent, ComputedStyle* aStyle, + nsCSSAnonBoxPseudoStaticAtom* aPseudoElement, const AtomArray& aInputWord) { + MOZ_ASSERT(nsCSSAnonBoxes::IsTreePseudoElement(aPseudoElement)); + + uint32_t count = aInputWord.Length(); + + // Go ahead and init the transition table. + if (!mTransitionTable) { + // Automatic miss. Build the table + mTransitionTable = MakeUnique<TransitionTable>(); + } + + // The first transition is always made off the supplied pseudo-element. + Transition transition(0, aPseudoElement); + DFAState currState = mTransitionTable->Get(transition); + + if (!currState) { + // We had a miss. Make a new state and add it to our hash. + currState = mNextState; + mNextState++; + mTransitionTable->InsertOrUpdate(transition, currState); + } + + for (uint32_t i = 0; i < count; i++) { + Transition transition(currState, aInputWord[i]); + currState = mTransitionTable->Get(transition); + + if (!currState) { + // We had a miss. Make a new state and add it to our hash. + currState = mNextState; + mNextState++; + mTransitionTable->InsertOrUpdate(transition, currState); + } + } + + // We're in a final state. + // Look up our ComputedStyle for this state. + ComputedStyle* result = nullptr; + if (mCache) { + result = mCache->GetWeak(currState); + } + if (!result) { + // We missed the cache. Resolve this pseudo-style. + RefPtr<ComputedStyle> newResult = + aPresContext->StyleSet()->ResolveXULTreePseudoStyle( + aContent->AsElement(), aPseudoElement, aStyle, aInputWord); + + // Normally we rely on nsIFrame::Init / RestyleManager to call this, but + // these are weird and don't use a frame, yet ::-moz-tree-twisty definitely + // pokes at list-style-image. + newResult->StartImageLoads(*aPresContext->Document()); + + // Even though xul-tree pseudos are defined in nsCSSAnonBoxList, nothing has + // ever treated them as an anon box, and they don't ever get boxes anyway. + // + // This is really weird, and probably nothing really relies on the result of + // these assert, but it's here just to avoid changing them accidentally. + MOZ_ASSERT(newResult->GetPseudoType() == PseudoStyleType::XULTree); + MOZ_ASSERT(!newResult->IsAnonBox()); + MOZ_ASSERT(!newResult->IsPseudoElement()); + + // Put the ComputedStyle in our table, transferring the owning reference to + // the table. + if (!mCache) { + mCache = MakeUnique<ComputedStyleCache>(); + } + result = newResult.get(); + mCache->InsertOrUpdate(currState, std::move(newResult)); + } + + return result; +} |