gecko-dev/dom/base/nsMappedAttributes.cpp

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/* -*- 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/. */
/*
* A unique per-element set of attributes that is used as an
* nsIStyleRule; used to implement presentational attributes.
*/
#include "nsMappedAttributes.h"
#include "nsHTMLStyleSheet.h"
#include "mozilla/DeclarationBlock.h"
#include "mozilla/HashFunctions.h"
#include "mozilla/MappedDeclarations.h"
#include "mozilla/MemoryReporting.h"
using namespace mozilla;
bool nsMappedAttributes::sShuttingDown = false;
nsTArray<void*>* nsMappedAttributes::sCachedMappedAttributeAllocations =
nullptr;
void nsMappedAttributes::Shutdown() {
sShuttingDown = true;
if (sCachedMappedAttributeAllocations) {
for (uint32_t i = 0; i < sCachedMappedAttributeAllocations->Length(); ++i) {
void* cachedValue = (*sCachedMappedAttributeAllocations)[i];
::operator delete(cachedValue);
}
}
delete sCachedMappedAttributeAllocations;
sCachedMappedAttributeAllocations = nullptr;
}
nsMappedAttributes::nsMappedAttributes(nsHTMLStyleSheet* aSheet,
nsMapRuleToAttributesFunc aMapRuleFunc)
: mAttrCount(0),
mSheet(aSheet),
mRuleMapper(aMapRuleFunc),
mServoStyle(nullptr) {
MOZ_ASSERT(mRefCnt == 0); // Ensure caching works as expected.
}
nsMappedAttributes::nsMappedAttributes(const nsMappedAttributes& aCopy)
: mAttrCount(aCopy.mAttrCount),
mSheet(aCopy.mSheet),
mRuleMapper(aCopy.mRuleMapper),
// This is only called by ::Clone, which is used to create independent
// nsMappedAttributes objects which should not share a DeclarationBlock
mServoStyle(nullptr) {
NS_ASSERTION(mBufferSize >= aCopy.mAttrCount, "can't fit attributes");
MOZ_ASSERT(mRefCnt == 0); // Ensure caching works as expected.
uint32_t i;
for (i = 0; i < mAttrCount; ++i) {
new (&Attrs()[i]) InternalAttr(aCopy.Attrs()[i]);
}
}
nsMappedAttributes::~nsMappedAttributes() {
if (mSheet) {
mSheet->DropMappedAttributes(this);
}
uint32_t i;
for (i = 0; i < mAttrCount; ++i) {
Attrs()[i].~InternalAttr();
}
}
nsMappedAttributes* nsMappedAttributes::Clone(bool aWillAddAttr) {
uint32_t extra = aWillAddAttr ? 1 : 0;
// This will call the overridden operator new
return new (mAttrCount + extra) nsMappedAttributes(*this);
}
void* nsMappedAttributes::operator new(size_t aSize,
uint32_t aAttrCount) noexcept(true) {
size_t size = aSize + aAttrCount * sizeof(InternalAttr);
// aSize will include the mAttrs buffer so subtract that.
// We don't want to under-allocate, however, so do not subtract
// if we have zero attributes. The zero attribute case only happens
// for <body>'s mapped attributes
if (aAttrCount != 0) {
size -= sizeof(void * [1]);
}
if (sCachedMappedAttributeAllocations) {
void* cached = sCachedMappedAttributeAllocations->SafeElementAt(aAttrCount);
if (cached) {
(*sCachedMappedAttributeAllocations)[aAttrCount] = nullptr;
return cached;
}
}
void* newAttrs = ::operator new(size);
#ifdef DEBUG
static_cast<nsMappedAttributes*>(newAttrs)->mBufferSize = aAttrCount;
#endif
return newAttrs;
}
void nsMappedAttributes::LastRelease() {
if (!sShuttingDown) {
if (!sCachedMappedAttributeAllocations) {
sCachedMappedAttributeAllocations = new nsTArray<void*>();
}
// Ensure the cache array is at least mAttrCount + 1 long and
// that each item is either null or pointing to a cached item.
// The size of the array is capped because mapped attributes are defined
// statically in element implementations.
sCachedMappedAttributeAllocations->SetCapacity(mAttrCount + 1);
for (uint32_t i = sCachedMappedAttributeAllocations->Length();
i < (uint32_t(mAttrCount) + 1); ++i) {
sCachedMappedAttributeAllocations->AppendElement(nullptr);
}
if (!(*sCachedMappedAttributeAllocations)[mAttrCount]) {
void* memoryToCache = this;
this->~nsMappedAttributes();
(*sCachedMappedAttributeAllocations)[mAttrCount] = memoryToCache;
return;
}
}
delete this;
}
void nsMappedAttributes::SetAndSwapAttr(nsAtom* aAttrName, nsAttrValue& aValue,
bool* aValueWasSet) {
MOZ_ASSERT(aAttrName, "null name");
*aValueWasSet = false;
uint32_t i;
for (i = 0; i < mAttrCount && !Attrs()[i].mName.IsSmaller(aAttrName); ++i) {
if (Attrs()[i].mName.Equals(aAttrName)) {
Attrs()[i].mValue.SwapValueWith(aValue);
*aValueWasSet = true;
return;
}
}
NS_ASSERTION(mBufferSize >= mAttrCount + 1, "can't fit attributes");
if (mAttrCount != i) {
memmove(&Attrs()[i + 1], &Attrs()[i],
(mAttrCount - i) * sizeof(InternalAttr));
}
new (&Attrs()[i].mName) nsAttrName(aAttrName);
new (&Attrs()[i].mValue) nsAttrValue();
Attrs()[i].mValue.SwapValueWith(aValue);
++mAttrCount;
}
const nsAttrValue* nsMappedAttributes::GetAttr(const nsAtom* aAttrName) const {
MOZ_ASSERT(aAttrName, "null name");
for (uint32_t i = 0; i < mAttrCount; ++i) {
if (Attrs()[i].mName.Equals(aAttrName)) {
return &Attrs()[i].mValue;
}
}
return nullptr;
}
const nsAttrValue* nsMappedAttributes::GetAttr(
const nsAString& aAttrName) const {
for (uint32_t i = 0; i < mAttrCount; ++i) {
if (Attrs()[i].mName.Atom()->Equals(aAttrName)) {
return &Attrs()[i].mValue;
}
}
return nullptr;
}
bool nsMappedAttributes::Equals(const nsMappedAttributes* aOther) const {
if (this == aOther) {
return true;
}
if (mRuleMapper != aOther->mRuleMapper || mAttrCount != aOther->mAttrCount) {
return false;
}
uint32_t i;
for (i = 0; i < mAttrCount; ++i) {
if (!Attrs()[i].mName.Equals(aOther->Attrs()[i].mName) ||
!Attrs()[i].mValue.Equals(aOther->Attrs()[i].mValue)) {
return false;
}
}
return true;
}
PLDHashNumber nsMappedAttributes::HashValue() const {
PLDHashNumber hash = HashGeneric(mRuleMapper);
uint32_t i;
for (i = 0; i < mAttrCount; ++i) {
hash = AddToHash(hash, Attrs()[i].mName.HashValue(),
Attrs()[i].mValue.HashValue());
}
return hash;
}
void nsMappedAttributes::SetStyleSheet(nsHTMLStyleSheet* aSheet) {
if (mSheet) {
mSheet->DropMappedAttributes(this);
}
mSheet = aSheet; // not ref counted
}
void nsMappedAttributes::RemoveAttrAt(uint32_t aPos, nsAttrValue& aValue) {
Attrs()[aPos].mValue.SwapValueWith(aValue);
Attrs()[aPos].~InternalAttr();
memmove(&Attrs()[aPos], &Attrs()[aPos + 1],
(mAttrCount - aPos - 1) * sizeof(InternalAttr));
mAttrCount--;
}
const nsAttrName* nsMappedAttributes::GetExistingAttrNameFromQName(
const nsAString& aName) const {
uint32_t i;
for (i = 0; i < mAttrCount; ++i) {
if (Attrs()[i].mName.IsAtom()) {
if (Attrs()[i].mName.Atom()->Equals(aName)) {
return &Attrs()[i].mName;
}
} else {
if (Attrs()[i].mName.NodeInfo()->QualifiedNameEquals(aName)) {
return &Attrs()[i].mName;
}
}
}
return nullptr;
}
int32_t nsMappedAttributes::IndexOfAttr(const nsAtom* aLocalName) const {
uint32_t i;
for (i = 0; i < mAttrCount; ++i) {
if (Attrs()[i].mName.Equals(aLocalName)) {
return i;
}
}
return -1;
}
size_t nsMappedAttributes::SizeOfIncludingThis(
MallocSizeOf aMallocSizeOf) const {
NS_ASSERTION(mAttrCount == mBufferSize,
"mBufferSize and mAttrCount are expected to be the same.");
size_t n = aMallocSizeOf(this);
for (uint16_t i = 0; i < mAttrCount; ++i) {
n += Attrs()[i].mValue.SizeOfExcludingThis(aMallocSizeOf);
}
return n;
}
void nsMappedAttributes::LazilyResolveServoDeclaration(dom::Document* aDoc) {
MOZ_ASSERT(!mServoStyle,
"LazilyResolveServoDeclaration should not be called if "
"mServoStyle is already set");
if (mRuleMapper) {
MappedDeclarations declarations(
aDoc, Servo_DeclarationBlock_CreateEmpty().Consume());
(*mRuleMapper)(this, declarations);
mServoStyle = declarations.TakeDeclarationBlock();
}
}