gecko-dev/layout/xul/tree/nsTreeStyleCache.cpp

106 строки
3.4 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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 "nsStyleSet.h"
#include "mozilla/dom/Element.h"
#include "mozilla/StyleSetHandle.h"
#include "mozilla/StyleSetHandleInlines.h"
nsTreeStyleCache::Transition::Transition(DFAState aState, nsIAtom* 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 style context cache impl
nsStyleContext*
nsTreeStyleCache::GetStyleContext(nsICSSPseudoComparator* aComparator,
nsPresContext* aPresContext,
nsIContent* aContent,
nsStyleContext* aContext,
nsICSSAnonBoxPseudo* 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 = new 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->Put(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->Put(transition, currState);
}
}
// We're in a final state.
// Look up our style context for this state.
nsStyleContext* result = nullptr;
if (mCache) {
result = mCache->GetWeak(currState);
}
if (!result) {
// We missed the cache. Resolve this pseudo-style.
// XXXheycam ServoStyleSets do not support XUL tree styles.
RefPtr<nsStyleContext> newResult;
if (aPresContext->StyleSet()->IsServo()) {
NS_ERROR("stylo: ServoStyleSets should not support XUL tree styles yet");
newResult = aPresContext->StyleSet()->
ResolveStyleForPlaceholder();
} else {
newResult = aPresContext->StyleSet()->AsGecko()->
ResolveXULTreePseudoStyle(aContent->AsElement(), aPseudoElement,
aContext, aComparator);
}
// Put the style context in our table, transferring the owning reference to the table.
if (!mCache) {
mCache = new StyleContextCache();
}
result = newResult.get();
mCache->Put(currState, newResult.forget());
}
return result;
}