The Tor Browser: layout/xul/tree/nsTreeStyleCache.cpp@7e26c7da4463

     1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

     2 /* This Source Code Form is subject to the terms of the Mozilla Public

     3  * License, v. 2.0. If a copy of the MPL was not distributed with this

     4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

     6 #include "nsTreeStyleCache.h"

     7 #include "nsStyleSet.h"

     8 #include "mozilla/dom/Element.h"

    10 // The style context cache impl

    11 nsStyleContext*

    12 nsTreeStyleCache::GetStyleContext(nsICSSPseudoComparator* aComparator,

    13                                   nsPresContext* aPresContext,

    14                                   nsIContent* aContent,

    15                                   nsStyleContext* aContext,

    16                                   nsIAtom* aPseudoElement,

    17                                   const AtomArray & aInputWord)

    18 {

    19   uint32_t count = aInputWord.Length();

    20   nsDFAState startState(0);

    21   nsDFAState* currState = &startState;

    23   // Go ahead and init the transition table.

    24   if (!mTransitionTable) {

    25     // Automatic miss. Build the table

    26     mTransitionTable =

    27       new nsObjectHashtable(nullptr, nullptr, DeleteDFAState, nullptr);

    28   }

    30   // The first transition is always made off the supplied pseudo-element.

    31   nsTransitionKey key(currState->GetStateID(), aPseudoElement);

    32   currState = static_cast<nsDFAState*>(mTransitionTable->Get(&key));

    34   if (!currState) {

    35     // We had a miss. Make a new state and add it to our hash.

    36     currState = new nsDFAState(mNextState);

    37     mNextState++;

    38     mTransitionTable->Put(&key, currState);

    39   }

    41   for (uint32_t i = 0; i < count; i++) {

    42     nsTransitionKey key(currState->GetStateID(), aInputWord[i]);

    43     currState = static_cast<nsDFAState*>(mTransitionTable->Get(&key));

    45     if (!currState) {

    46       // We had a miss. Make a new state and add it to our hash.

    47       currState = new nsDFAState(mNextState);

    48       mNextState++;

    49       mTransitionTable->Put(&key, currState);

    50     }

    51   }

    53   // We're in a final state.

    54   // Look up our style context for this state.

    55   nsStyleContext* result = nullptr;

    56   if (mCache)

    57     result = static_cast<nsStyleContext*>(mCache->Get(currState));

    58   if (!result) {

    59     // We missed the cache. Resolve this pseudo-style.

    60     result = aPresContext->StyleSet()->

    61       ResolveXULTreePseudoStyle(aContent->AsElement(), aPseudoElement,

    62                                 aContext, aComparator).take();

    64     // Put the style context in our table, transferring the owning reference to the table.

    65     if (!mCache) {

    66       mCache = new nsObjectHashtable(nullptr, nullptr, ReleaseStyleContext, nullptr);

    67     }

    68     mCache->Put(currState, result);

    69   }

    71   return result;

    72 }

    74 bool

    75 nsTreeStyleCache::DeleteDFAState(nsHashKey *aKey,

    76                                  void *aData,

    77                                  void *closure)

    78 {

    79   nsDFAState* entry = static_cast<nsDFAState*>(aData);

    80   delete entry;

    81   return true;

    82 }

    84 bool

    85 nsTreeStyleCache::ReleaseStyleContext(nsHashKey *aKey,

    86                                       void *aData,

    87                                       void *closure)

    88 {

    89   nsStyleContext* context = static_cast<nsStyleContext*>(aData);

    90   context->Release();

    91   return true;

    92 }

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