gecko-dev/parser/html/nsHtml5Portability.cpp
Markus Stange 943e3c05a7 Bug 1843946 - Use an atom for the full class attribute value, to reduce string hash key cost during the AtomArrayCache lookup. r=emilio
This generalizes the previous "set single class from parser" fast-path to
also apply when there are multiple classes in the class attribute.

The main benefit is the cheaper cache lookup.
Another benefit is that this avoids a string copy (the same copy that the original
"set single class from parser" optimization avoided).

We now always atomize the full class attribute value before parsing it,
e.g. when somebody uses setAttribute. In the common case of a single class,
this atomization cost would have been paid anyway.

Before: https://share.firefox.dev/4576ulw
After: https://share.firefox.dev/3rNGBsH (though this is not the full story
because the atomization work is moved outside of nsHtml5TreeOperation::SetHTMLElementAttributes)

Differential Revision: https://phabricator.services.mozilla.com/D183813
2023-08-17 19:02:40 +00:00

100 lines
3.3 KiB
C++

/* 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 "nsHtml5Portability.h"
#include "jArray.h"
#include "nsAtom.h"
#include "nsHtml5TreeBuilder.h"
#include "nsString.h"
#include "mozilla/CheckedInt.h"
int32_t nsHtml5Portability::checkedAdd(int32_t a, int32_t b) {
mozilla::CheckedInt<int32_t> sum(a);
sum += b;
MOZ_RELEASE_ASSERT(sum.isValid(),
"HTML input too large for signed 32-bit integer.");
return sum.value();
}
nsAtom* nsHtml5Portability::newLocalNameFromBuffer(char16_t* buf,
int32_t length,
nsHtml5AtomTable* interner) {
NS_ASSERTION(interner, "Didn't get an atom service.");
return interner->GetAtom(nsDependentSubstring(buf, buf + length));
}
nsHtml5String nsHtml5Portability::newStringFromBuffer(
char16_t* buf, int32_t offset, int32_t length,
nsHtml5TreeBuilder* treeBuilder, bool maybeAtomize) {
if (!length) {
return nsHtml5String::EmptyString();
}
if (maybeAtomize) {
return nsHtml5String::FromAtom(
NS_AtomizeMainThread(nsDependentSubstring(buf + offset, length)));
}
return nsHtml5String::FromBuffer(buf + offset, length, treeBuilder);
}
nsHtml5String nsHtml5Portability::newEmptyString() {
return nsHtml5String::EmptyString();
}
nsHtml5String nsHtml5Portability::newStringFromLiteral(const char* literal) {
return nsHtml5String::FromLiteral(literal);
}
nsHtml5String nsHtml5Portability::newStringFromString(nsHtml5String string) {
return string.Clone();
}
jArray<char16_t, int32_t> nsHtml5Portability::newCharArrayFromLocal(
nsAtom* local) {
nsAutoString temp;
local->ToString(temp);
int32_t len = temp.Length();
jArray<char16_t, int32_t> arr = jArray<char16_t, int32_t>::newJArray(len);
memcpy(arr, temp.BeginReading(), len * sizeof(char16_t));
return arr;
}
jArray<char16_t, int32_t> nsHtml5Portability::newCharArrayFromString(
nsHtml5String string) {
MOZ_RELEASE_ASSERT(string);
uint32_t len = string.Length();
MOZ_RELEASE_ASSERT(len < INT32_MAX);
jArray<char16_t, int32_t> arr = jArray<char16_t, int32_t>::newJArray(len);
string.CopyToBuffer(arr);
return arr;
}
bool nsHtml5Portability::localEqualsBuffer(nsAtom* local, char16_t* buf,
int32_t length) {
return local->Equals(buf, length);
}
bool nsHtml5Portability::lowerCaseLiteralIsPrefixOfIgnoreAsciiCaseString(
const char* lowerCaseLiteral, nsHtml5String string) {
return string.LowerCaseStartsWithASCII(lowerCaseLiteral);
}
bool nsHtml5Portability::lowerCaseLiteralEqualsIgnoreAsciiCaseString(
const char* lowerCaseLiteral, nsHtml5String string) {
return string.LowerCaseEqualsASCII(lowerCaseLiteral);
}
bool nsHtml5Portability::literalEqualsString(const char* literal,
nsHtml5String string) {
return string.EqualsASCII(literal);
}
bool nsHtml5Portability::stringEqualsString(nsHtml5String one,
nsHtml5String other) {
return one.Equals(other);
}
void nsHtml5Portability::initializeStatics() {}
void nsHtml5Portability::releaseStatics() {}