The Tor Browser: layout/style/nsRuleData.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 "nsRuleData.h"

     8 #include "mozilla/Poison.h"

     9 #include <stdint.h>

    11 inline size_t

    12 nsRuleData::GetPoisonOffset()

    13 {

    14   // Fill in mValueOffsets such that mValueStorage + mValueOffsets[i]

    15   // will yield the frame poison value for all uninitialized value

    16   // offsets.

    17   static_assert(sizeof(uintptr_t) == sizeof(size_t),

    18                 "expect uintptr_t and size_t to be the same size");

    19   static_assert(uintptr_t(-1) > uintptr_t(0),

    20                 "expect uintptr_t to be unsigned");

    21   static_assert(size_t(-1) > size_t(0),

    22                 "expect size_t to be unsigned");

    23   uintptr_t framePoisonValue = mozPoisonValue();

    24   return size_t(framePoisonValue - uintptr_t(mValueStorage)) /

    25          sizeof(nsCSSValue);

    26 }

    28 nsRuleData::nsRuleData(uint32_t aSIDs, nsCSSValue* aValueStorage,

    29                        nsPresContext* aContext, nsStyleContext* aStyleContext)

    30   : mSIDs(aSIDs),

    31     mCanStoreInRuleTree(true),

    32     mPresContext(aContext),

    33     mStyleContext(aStyleContext),

    34     mValueStorage(aValueStorage)

    35 {

    36 #ifndef MOZ_VALGRIND

    37   size_t framePoisonOffset = GetPoisonOffset();

    38   for (size_t i = 0; i < nsStyleStructID_Length; ++i) {

    39     mValueOffsets[i] = framePoisonOffset;

    40   }

    41 #endif

    42 }

    44 #ifdef DEBUG

    45 nsRuleData::~nsRuleData()

    46 {

    47 #ifndef MOZ_VALGRIND

    48   // assert nothing in mSIDs has poison value

    49   size_t framePoisonOffset = GetPoisonOffset();

    50   for (size_t i = 0; i < nsStyleStructID_Length; ++i) {

    51     NS_ABORT_IF_FALSE(!(mSIDs & (1 << i)) ||

    52                       mValueOffsets[i] != framePoisonOffset,

    53                       "value in SIDs was left with poison offset");

    54   }

    55 #endif

    56 }

    57 #endif

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