blob: 059f337e34d059cd063440e0b2888d1c3711e208 [file] [log] [blame]
/*
* Copyright (C) 2016-2019 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include <JavaScriptCore/HeapCellInlines.h>
#include <JavaScriptCore/JSGlobalObjectInlines.h>
#include <JavaScriptCore/JSString.h>
#include <JavaScriptCore/KeyAtomStringCacheInlines.h>
#include <JavaScriptCore/MarkedBlockInlines.h>
#include <wtf/text/MakeString.h>
#include <wtf/text/ParsingUtilities.h>
namespace JSC {
ALWAYS_INLINE void JSString::destroy(JSCell* cell)
{
auto* string = static_cast<JSString*>(cell);
string->valueInternal().~String();
}
ALWAYS_INLINE void JSRopeString::destroy(JSCell* cell)
{
auto* string = static_cast<JSRopeString*>(cell);
if (string->isRope())
return;
string->valueInternal().~String();
}
bool JSString::equal(JSGlobalObject* globalObject, JSString* other) const
{
if (isRope() || other->isRope())
return equalSlowCase(globalObject, other);
return WTF::equal(*valueInternal().impl(), *other->valueInternal().impl());
}
ALWAYS_INLINE bool JSString::equalInline(JSGlobalObject* globalObject, JSString* other) const
{
VM& vm = globalObject->vm();
auto scope = DECLARE_THROW_SCOPE(vm);
unsigned length = this->length();
if (length != other->length())
return false;
auto str1 = view(globalObject);
RETURN_IF_EXCEPTION(scope, false);
auto str2 = other->view(globalObject);
RETURN_IF_EXCEPTION(scope, false);
ensureStillAliveHere(this);
ensureStillAliveHere(other);
return WTF::equal(str1, str2, length);
}
JSString* JSString::tryReplaceOneCharImpl(JSGlobalObject* globalObject, char16_t search, JSString* replacement, uint8_t* stackLimit, bool& found)
{
VM& vm = globalObject->vm();
auto scope = DECLARE_THROW_SCOPE(vm);
if (std::bit_cast<uint8_t*>(currentStackPointer()) < stackLimit) [[unlikely]]
return nullptr; // Stack overflow
if (this->isNonSubstringRope()) {
JSRopeString* rope = static_cast<JSRopeString*>(this);
JSString* oldFiber0 = rope->fiber0();
JSString* oldFiber1 = rope->fiber1();
JSString* oldFiber2 = rope->fiber2();
ASSERT(oldFiber0);
JSString* newFiber0 = oldFiber0->tryReplaceOneCharImpl(globalObject, search, replacement, stackLimit, found);
RETURN_IF_EXCEPTION(scope, nullptr);
if (!newFiber0) [[unlikely]]
return nullptr;
if (found)
RELEASE_AND_RETURN(scope, jsString(globalObject, newFiber0, oldFiber1, oldFiber2));
if (oldFiber1) {
JSString* newFiber1 = oldFiber1->tryReplaceOneCharImpl(globalObject, search, replacement, stackLimit, found);
RETURN_IF_EXCEPTION(scope, nullptr);
if (!newFiber1) [[unlikely]]
return nullptr;
if (found)
RELEASE_AND_RETURN(scope, jsString(globalObject, oldFiber0, newFiber1, oldFiber2));
}
if (oldFiber2) {
JSString* newFiber2 = oldFiber2->tryReplaceOneCharImpl(globalObject, search, replacement, stackLimit, found);
RETURN_IF_EXCEPTION(scope, nullptr);
if (!newFiber2) [[unlikely]]
return nullptr;
if (found)
RELEASE_AND_RETURN(scope, jsString(globalObject, oldFiber0, oldFiber1, newFiber2));
}
return this; // Not found.
}
auto thisView = this->view(globalObject);
RETURN_IF_EXCEPTION(scope, nullptr);
size_t index = thisView->find(search);
if (index == WTF::notFound)
return this; // Not found.
found = true;
// Case 1: The matched character is the only character in the string.
unsigned length = thisView->length();
if (length == 1)
return replacement;
// Case 2: The matched character is the last character in the string.
JSString* left = nullptr;
if (index) {
left = jsSubstring(globalObject, this, 0, index);
RETURN_IF_EXCEPTION(scope, nullptr);
// There is a match at this point, then length must be larger than zero.
if (index == length - 1)
RELEASE_AND_RETURN(scope, jsString(globalObject, left, replacement));
}
// Case 3: The matched character is the first character in the string.
size_t rightStart = index + 1; // At this point, the index must be less than length - 1.
JSString* right = jsSubstring(globalObject, this, rightStart, length - rightStart);
RETURN_IF_EXCEPTION(scope, nullptr);
if (!index)
RELEASE_AND_RETURN(scope, jsString(globalObject, replacement, right));
// Case 4: The matched character is in the middle of the string.
RELEASE_AND_RETURN(scope, jsString(globalObject, left, replacement, right));
}
JSString* JSString::tryReplaceOneChar(JSGlobalObject* globalObject, char16_t search, JSString* replacement)
{
uint8_t* stackLimit = std::bit_cast<uint8_t*>(globalObject->vm().softStackLimit());
bool found = false;
if (JSString* result = tryReplaceOneCharImpl(globalObject, search, replacement, stackLimit, found); result && found)
return result;
return nullptr;
}
template<typename StringType>
inline JSValue jsMakeNontrivialString(VM& vm, StringType&& string)
{
return jsNontrivialString(vm, std::forward<StringType>(string));
}
template<typename StringType, typename... StringTypes>
inline JSValue jsMakeNontrivialString(JSGlobalObject* globalObject, StringType&& string, StringTypes&&... strings)
{
VM& vm = getVM(globalObject);
auto scope = DECLARE_THROW_SCOPE(vm);
String result = tryMakeString(std::forward<StringType>(string), std::forward<StringTypes>(strings)...);
if (!result) [[unlikely]]
return throwOutOfMemoryError(globalObject, scope);
ASSERT(result.length() <= JSString::MaxLength);
return jsNontrivialString(vm, WTFMove(result));
}
template <typename CharacterType>
requires (std::same_as<CharacterType, Latin1Character> || std::same_as<CharacterType, char16_t>)
inline JSString* repeatCharacter(JSGlobalObject* globalObject, CharacterType character, unsigned repeatCount)
{
VM& vm = globalObject->vm();
auto scope = DECLARE_THROW_SCOPE(vm);
if (!repeatCount)
return jsEmptyString(vm);
std::span<CharacterType> buffer;
auto impl = StringImpl::tryCreateUninitialized(repeatCount, buffer);
if (!impl) {
throwOutOfMemoryError(globalObject, scope);
return nullptr;
}
*buffer.data() = character;
unsigned copied = 1;
while (copied < repeatCount) {
unsigned copyLen = std::min(copied, repeatCount - copied);
memcpySpan(buffer.subspan(copied, copyLen), buffer.subspan(0, copyLen));
copied += copyLen;
}
RELEASE_AND_RETURN(scope, jsString(vm, impl.releaseNonNull()));
}
inline void JSRopeString::convertToNonRope(String&& string) const
{
// Concurrent compiler threads can access String held by JSString. So we always emit
// store-store barrier here to ensure concurrent compiler threads see initialized String.
ASSERT(JSString::isRope());
WTF::storeStoreFence();
new (&uninitializedValueInternal()) String(WTFMove(string));
static_assert(sizeof(String) == sizeof(RefPtr<StringImpl>), "JSString's String initialization must be done in one pointer move.");
// We do not clear the trailing fibers and length information (fiber1 and fiber2) because we could be reading the length concurrently.
ASSERT(!JSString::isRope());
notifyNeedsDestruction();
}
inline StringImpl* JSRopeString::tryGetLHS(ASCIILiteral rhs) const
{
if (isSubstring())
return nullptr;
JSString* fiber2 = this->fiber2();
if (fiber2)
return nullptr;
JSString* fiber1 = this->fiber1();
ASSERT(fiber1);
if (fiber1->isRope())
return nullptr;
JSString* fiber0 = this->fiber0();
ASSERT(fiber0);
if (fiber0->isRope())
return nullptr;
if (fiber1->valueInternal() != rhs)
return nullptr;
return fiber0->valueInternal().impl();
}
// Overview: These functions convert a JSString from holding a string in rope form
// down to a simple String representation. It does so by building up the string
// backwards, since we want to avoid recursion, we expect that the tree structure
// representing the rope is likely imbalanced with more nodes down the left side
// (since appending to the string is likely more common) - and as such resolving
// in this fashion should minimize work queue size. (If we built the queue forwards
// we would likely have to place all of the constituent StringImpls into the
// Vector before performing any concatenation, but by working backwards we likely
// only fill the queue with the number of substrings at any given level in a
// rope-of-ropes.)
template<typename CharacterType>
NEVER_INLINE void JSRopeString::resolveToBufferSlow(JSString* fiber0, JSString* fiber1, JSString* fiber2, std::span<CharacterType> buffer, uint8_t*)
{
WTF_ALLOW_UNSAFE_BUFFER_USAGE_BEGIN
// Keep in mind that resolveToBufferSlow signature must be the same to resolveToBuffer to encourage tail-calls by clang, that's the reason why
// it takes the last stackLimit parameter still while it is not used here.
CharacterType* end = std::to_address(buffer.end()); // We will be working backwards over the rope.
CharacterType* position = end; // We will be working backwards over the rope.
Vector<JSString*, 32, UnsafeVectorOverflow> workQueue; // These strings are kept alive by the parent rope, so using a Vector is OK.
workQueue.append(fiber0);
if (fiber1) {
workQueue.append(fiber1);
if (fiber2)
workQueue.append(fiber2);
}
do {
JSString* currentFiber = workQueue.takeLast();
if (currentFiber->isRope()) {
JSRopeString* currentFiberAsRope = static_cast<JSRopeString*>(currentFiber);
if (currentFiberAsRope->isSubstring()) {
ASSERT(!currentFiberAsRope->substringBase()->isRope());
StringView view = *currentFiberAsRope->substringBase()->valueInternal().impl();
unsigned offset = currentFiberAsRope->substringOffset();
unsigned length = currentFiberAsRope->length();
position -= length;
view.substring(offset, length).getCharacters(unsafeMakeSpan(position, end - position));
continue;
}
for (size_t i = 0; i < JSRopeString::s_maxInternalRopeLength && currentFiberAsRope->fiber(i); ++i)
workQueue.append(currentFiberAsRope->fiber(i));
continue;
}
StringView view = *currentFiber->valueInternal().impl();
position -= view.length();
view.getCharacters(unsafeMakeSpan(position, end - position));
} while (!workQueue.isEmpty());
ASSERT(buffer.data() == position);
WTF_ALLOW_UNSAFE_BUFFER_USAGE_END
}
template<typename CharacterType>
inline void JSRopeString::resolveToBuffer(JSString* fiber0, JSString* fiber1, JSString* fiber2, std::span<CharacterType> buffer, uint8_t* stackLimit)
{
#if HAVE(MUST_TAIL_CALL)
ASSERT(fiber0);
// We must ensure that all JSRopeString::resolveToBufferSlow and JSRopeString::resolveToBuffer calls must be done directly from this function, and it has
// exact same signature to JSRopeString::resolveToBuffer, which will be esured by clang via MUST_TAIL_CALL attribute.
// This allows clang to make these calls tail-calls, constructing significantly efficient rope resolution here.
static_assert(3 == JSRopeString::s_maxInternalRopeLength);
// 3 fibers.
if (fiber2) {
if (fiber0->isRope()) {
auto* rope0 = static_cast<const JSRopeString*>(fiber0);
auto rope0Length = rope0->length();
if (rope0->isSubstring()) {
StringView view0 = *rope0->substringBase()->valueInternal().impl();
unsigned offset = rope0->substringOffset();
view0.substring(offset, rope0Length).getCharacters(buffer);
} else {
if (std::bit_cast<uint8_t*>(currentStackPointer()) < stackLimit) [[unlikely]]
MUST_TAIL_CALL return JSRopeString::resolveToBufferSlow(fiber0, fiber1, fiber2, buffer, stackLimit);
resolveToBuffer(rope0->fiber0(), rope0->fiber1(), rope0->fiber2(), buffer.first(rope0Length), stackLimit);
}
skip(buffer, rope0Length);
} else {
StringView view0 = fiber0->valueInternal().impl();
view0.getCharacters(buffer);
skip(buffer, view0.length());
}
fiber0 = fiber1;
fiber1 = fiber2;
fiber2 = nullptr;
// Fall through to the 2 fibers case.
}
// 2 fibers.
if (fiber1) [[likely]] {
if (fiber0->isRope()) {
if (fiber1->isRope()) {
if (std::bit_cast<uint8_t*>(currentStackPointer()) < stackLimit) [[unlikely]]
MUST_TAIL_CALL return JSRopeString::resolveToBufferSlow(fiber0, fiber1, fiber2, buffer, stackLimit);
auto* rope0 = static_cast<const JSRopeString*>(fiber0);
auto rope0Length = rope0->length();
if (rope0->isSubstring()) {
StringView view0 = *rope0->substringBase()->valueInternal().impl();
unsigned offset = rope0->substringOffset();
view0.substring(offset, rope0Length).getCharacters(buffer);
} else
resolveToBuffer(rope0->fiber0(), rope0->fiber1(), rope0->fiber2(), buffer.first(rope0Length), stackLimit);
// Both ropes are the same fibers! Then we can just copy the previously generated characters.
if (fiber0 == fiber1) {
memcpySpan(buffer.subspan(rope0Length, rope0Length), buffer.first(rope0Length));
return;
}
skip(buffer, rope0Length);
auto* rope1 = static_cast<const JSRopeString*>(fiber1);
auto rope1Length = rope1->length();
if (rope1->isSubstring()) {
StringView view1 = *rope1->substringBase()->valueInternal().impl();
unsigned offset = rope1->substringOffset();
view1.substring(offset, rope1Length).getCharacters(buffer);
return;
}
MUST_TAIL_CALL return resolveToBuffer(rope1->fiber0(), rope1->fiber1(), rope1->fiber2(), buffer.first(rope1Length), stackLimit);
}
auto* rope0 = static_cast<const JSRopeString*>(fiber0);
auto rope0Length = rope0->length();
{
StringView view1 = fiber1->valueInternal().impl();
view1.getCharacters(buffer.subspan(rope0Length));
}
if (rope0->isSubstring()) {
StringView view0 = *rope0->substringBase()->valueInternal().impl();
unsigned offset = rope0->substringOffset();
view0.substring(offset, rope0Length).getCharacters(buffer);
return;
}
MUST_TAIL_CALL return resolveToBuffer(rope0->fiber0(), rope0->fiber1(), rope0->fiber2(), buffer.first(rope0Length), stackLimit);
}
if (fiber1->isRope()) {
auto* rope1 = static_cast<const JSRopeString*>(fiber1);
auto rope1Length = rope1->length();
{
StringView view0 = fiber0->valueInternal().impl();
view0.getCharacters(buffer);
skip(buffer, view0.length());
}
if (rope1->isSubstring()) {
StringView view1 = *rope1->substringBase()->valueInternal().impl();
unsigned offset = rope1->substringOffset();
view1.substring(offset, rope1Length).getCharacters(buffer);
return;
}
MUST_TAIL_CALL return resolveToBuffer(rope1->fiber0(), rope1->fiber1(), rope1->fiber2(), buffer.first(rope1Length), stackLimit);
}
StringView view0 = fiber0->valueInternal().impl();
view0.getCharacters(buffer);
StringView view1 = fiber1->valueInternal().impl();
view1.getCharacters(buffer.subspan(view0.length()));
return;
}
// 1 fiber.
if (!fiber0->isRope()) {
StringView view0 = fiber0->valueInternal().impl();
view0.getCharacters(buffer);
return;
}
auto* rope0 = static_cast<const JSRopeString*>(fiber0);
auto rope0Length = rope0->length();
if (rope0->isSubstring()) {
StringView view0 = *rope0->substringBase()->valueInternal().impl();
unsigned offset = rope0->substringOffset();
view0.substring(offset, rope0Length).getCharacters(buffer);
return;
}
MUST_TAIL_CALL return resolveToBuffer(rope0->fiber0(), rope0->fiber1(), rope0->fiber2(), buffer.first(rope0Length), stackLimit);
#else
return JSRopeString::resolveToBufferSlow(fiber0, fiber1, fiber2, buffer, stackLimit);
#endif
}
inline JSString* jsAtomString(JSGlobalObject* globalObject, VM& vm, JSString* string)
{
auto scope = DECLARE_THROW_SCOPE(vm);
unsigned length = string->length();
if (length > KeyAtomStringCache::maxStringLengthForCache) {
scope.release();
string->toIdentifier(globalObject);
return string;
}
if (!string->isRope()) {
auto createFromNonRope = [&](VM& vm, auto&) {
AtomString atom(string->valueInternal());
if (!string->valueInternal().impl()->isAtom())
string->swapToAtomString(vm, RefPtr { atom.impl() });
return string;
};
if (string->valueInternal().is8Bit()) {
WTF::HashTranslatorCharBuffer<Latin1Character> buffer { string->valueInternal().span8(), string->valueInternal().hash() };
return vm.keyAtomStringCache.make(vm, buffer, createFromNonRope);
}
WTF::HashTranslatorCharBuffer<char16_t> buffer { string->valueInternal().span16(), string->valueInternal().hash() };
return vm.keyAtomStringCache.make(vm, buffer, createFromNonRope);
}
JSRopeString* ropeString = jsCast<JSRopeString*>(string);
auto createFromRope = [&](VM& vm, auto& buffer) {
auto impl = AtomStringImpl::add(buffer);
size_t sizeToReport = impl->hasOneRef() ? impl->cost() : 0;
ropeString->convertToNonRope(String { WTFMove(impl) });
vm.heap.reportExtraMemoryAllocated(ropeString, sizeToReport);
return ropeString;
};
if (!ropeString->isSubstring()) {
uint8_t* stackLimit = std::bit_cast<uint8_t*>(vm.softStackLimit());
JSString* fiber0 = ropeString->fiber0();
JSString* fiber1 = ropeString->fiber1();
JSString* fiber2 = ropeString->fiber2();
if (ropeString->is8Bit()) {
std::array<Latin1Character, KeyAtomStringCache::maxStringLengthForCache> characters;
JSRopeString::resolveToBuffer(fiber0, fiber1, fiber2, std::span { characters }.first(length), stackLimit);
WTF::HashTranslatorCharBuffer<Latin1Character> buffer { std::span { characters }.first(length) };
return vm.keyAtomStringCache.make(vm, buffer, createFromRope);
}
std::array<char16_t, KeyAtomStringCache::maxStringLengthForCache> characters;
JSRopeString::resolveToBuffer(fiber0, fiber1, fiber2, std::span { characters }.first(length), stackLimit);
WTF::HashTranslatorCharBuffer<char16_t> buffer { std::span { characters }.first(length) };
return vm.keyAtomStringCache.make(vm, buffer, createFromRope);
}
auto view = StringView { ropeString->substringBase()->valueInternal() }.substring(ropeString->substringOffset(), length);
if (view.is8Bit()) {
WTF::HashTranslatorCharBuffer<Latin1Character> buffer { view.span8() };
return vm.keyAtomStringCache.make(vm, buffer, createFromRope);
}
WTF::HashTranslatorCharBuffer<char16_t> buffer { view.span16() };
return vm.keyAtomStringCache.make(vm, buffer, createFromRope);
}
inline JSString* jsAtomString(JSGlobalObject* globalObject, VM& vm, JSString* s1, JSString* s2)
{
auto scope = DECLARE_THROW_SCOPE(vm);
unsigned length1 = s1->length();
if (!length1)
RELEASE_AND_RETURN(scope, jsAtomString(globalObject, vm, s2));
unsigned length2 = s2->length();
if (!length2)
RELEASE_AND_RETURN(scope, jsAtomString(globalObject, vm, s1));
static_assert(JSString::MaxLength == std::numeric_limits<int32_t>::max());
if (sumOverflows<int32_t>(length1, length2)) {
throwOutOfMemoryError(globalObject, scope);
return nullptr;
}
unsigned length = length1 + length2;
if (length > KeyAtomStringCache::maxStringLengthForCache) {
auto* ropeString = jsString(globalObject, s1, s2);
RETURN_IF_EXCEPTION(scope, nullptr);
ropeString->toIdentifier(globalObject);
RETURN_IF_EXCEPTION(scope, nullptr);
return ropeString;
}
auto createFromFibers = [&](VM& vm, auto& buffer) {
return jsString(vm, String { AtomStringImpl::add(buffer) });
};
// This is quite unfortunate, but duplicating this part here is the key of performance improvement in JetStream2/WSL,
// which stress this jsAtomString significantly.
auto resolveWith2Fibers = [&](JSString* fiber0, JSString* fiber1, auto buffer) {
uint8_t* stackLimit = std::bit_cast<uint8_t*>(vm.softStackLimit());
if (fiber0->isRope()) {
if (fiber1->isRope())
return JSRopeString::resolveToBufferSlow(fiber0, fiber1, nullptr, buffer, stackLimit);
auto* rope0 = static_cast<const JSRopeString*>(fiber0);
StringView view1 = fiber1->valueInternal().impl();
view1.getCharacters(buffer.subspan(rope0->length()));
if (rope0->isSubstring()) {
StringView view0 = *rope0->substringBase()->valueInternal().impl();
unsigned offset = rope0->substringOffset();
view0.substring(offset, rope0->length()).getCharacters(buffer);
return;
}
return JSRopeString::resolveToBuffer(rope0->fiber0(), rope0->fiber1(), rope0->fiber2(), buffer.first(rope0->length()), stackLimit);
}
if (fiber1->isRope()) {
StringView view0 = fiber0->valueInternal().impl();
view0.getCharacters(buffer);
auto* rope1 = static_cast<const JSRopeString*>(fiber1);
if (rope1->isSubstring()) {
StringView view1 = *rope1->substringBase()->valueInternal().impl();
unsigned offset = rope1->substringOffset();
view1.substring(offset, rope1->length()).getCharacters(buffer.subspan(view0.length()));
return;
}
return JSRopeString::resolveToBuffer(rope1->fiber0(), rope1->fiber1(), rope1->fiber2(), buffer.subspan(view0.length(), rope1->length()), stackLimit);
}
StringView view0 = fiber0->valueInternal().impl();
view0.getCharacters(buffer);
StringView view1 = fiber1->valueInternal().impl();
view1.getCharacters(buffer.subspan(view0.length()));
};
if (s1->is8Bit() && s2->is8Bit()) {
Latin1Character characters[KeyAtomStringCache::maxStringLengthForCache];
resolveWith2Fibers(s1, s2, std::span { characters }.first(length));
WTF::HashTranslatorCharBuffer<Latin1Character> buffer { std::span(characters).first(length) };
return vm.keyAtomStringCache.make(vm, buffer, createFromFibers);
}
char16_t characters[KeyAtomStringCache::maxStringLengthForCache];
resolveWith2Fibers(s1, s2, std::span(characters).first(length));
WTF::HashTranslatorCharBuffer<char16_t> buffer { std::span(characters).first(length) };
return vm.keyAtomStringCache.make(vm, buffer, createFromFibers);
}
inline JSString* jsAtomString(JSGlobalObject* globalObject, VM& vm, JSString* s1, JSString* s2, JSString* s3)
{
auto scope = DECLARE_THROW_SCOPE(vm);
unsigned length1 = s1->length();
if (!length1)
RELEASE_AND_RETURN(scope, jsAtomString(globalObject, vm, s2, s3));
unsigned length2 = s2->length();
if (!length2)
RELEASE_AND_RETURN(scope, jsAtomString(globalObject, vm, s1, s3));
unsigned length3 = s3->length();
if (!length3)
RELEASE_AND_RETURN(scope, jsAtomString(globalObject, vm, s1, s2));
static_assert(JSString::MaxLength == std::numeric_limits<int32_t>::max());
if (sumOverflows<int32_t>(length1, length2, length3)) {
throwOutOfMemoryError(globalObject, scope);
return nullptr;
}
unsigned length = length1 + length2 + length3;
if (length > KeyAtomStringCache::maxStringLengthForCache) {
auto* ropeString = jsString(globalObject, s1, s2, s3);
RETURN_IF_EXCEPTION(scope, nullptr);
ropeString->toIdentifier(globalObject);
RETURN_IF_EXCEPTION(scope, nullptr);
return ropeString;
}
auto createFromFibers = [&](VM& vm, auto& buffer) {
return jsString(vm, String { AtomStringImpl::add(buffer) });
};
auto resolveWith3Fibers = [&](JSString* fiber0, JSString* fiber1, JSString* fiber2, auto buffer) {
if (fiber0->isRope() || fiber1->isRope() || fiber2->isRope())
return JSRopeString::resolveToBufferSlow(fiber0, fiber1, fiber2, buffer, std::bit_cast<uint8_t*>(vm.softStackLimit()));
StringView view0 = fiber0->valueInternal().impl();
view0.getCharacters(buffer);
StringView view1 = fiber1->valueInternal().impl();
view1.getCharacters(buffer.subspan(view0.length()));
StringView view2 = fiber2->valueInternal().impl();
view2.getCharacters(buffer.subspan(view0.length() + view1.length()));
};
if (s1->is8Bit() && s2->is8Bit() && s3->is8Bit()) {
Latin1Character characters[KeyAtomStringCache::maxStringLengthForCache];
resolveWith3Fibers(s1, s2, s3, std::span { characters }.first(length));
WTF::HashTranslatorCharBuffer<Latin1Character> buffer { std::span { characters }.first(length) };
return vm.keyAtomStringCache.make(vm, buffer, createFromFibers);
}
char16_t characters[KeyAtomStringCache::maxStringLengthForCache];
resolveWith3Fibers(s1, s2, s3, std::span { characters }.first(length));
WTF::HashTranslatorCharBuffer<char16_t> buffer { std::span { characters }.first(length) };
return vm.keyAtomStringCache.make(vm, buffer, createFromFibers);
}
inline JSString* jsSubstringOfResolved(VM& vm, GCDeferralContext* deferralContext, JSString* s, unsigned offset, unsigned length)
{
ASSERT(offset <= s->length());
ASSERT(length <= s->length());
ASSERT(offset + length <= s->length());
if (!length)
return vm.smallStrings.emptyString();
if (s->isSubstring()) {
JSRopeString* baseRope = jsCast<JSRopeString*>(s);
ASSERT(!baseRope->substringBase()->isRope());
s = baseRope->substringBase();
offset += baseRope->substringOffset();
}
ASSERT(!s->isRope());
auto& base = s->valueInternal();
if (!offset && length == base.length())
return s;
if (length == 1) {
if (auto c = base.characterAt(offset); c <= maxSingleCharacterString)
return vm.smallStrings.singleCharacterString(c);
} else if (length == 2) {
char16_t first = base.characterAt(offset);
char16_t second = base.characterAt(offset + 1);
if ((first | second) < 0x80) {
auto createFromSubstring = [&](VM& vm, auto& buffer) {
auto impl = AtomStringImpl::add(buffer);
return JSString::create(vm, deferralContext, impl.releaseNonNull());
};
Latin1Character buf[] = { static_cast<Latin1Character>(first), static_cast<Latin1Character>(second) };
WTF::HashTranslatorCharBuffer<Latin1Character> buffer { unsafeMakeSpan(buf, length) };
return vm.keyAtomStringCache.make(vm, buffer, createFromSubstring);
}
}
return JSRopeString::createSubstringOfResolved(vm, deferralContext, s, offset, length, base.is8Bit());
}
template<typename CharacterType>
void JSString::resolveToBuffer(std::span<CharacterType> destination)
{
if (isRope()) {
auto* rope = jsCast<JSRopeString*>(this);
if (rope->isSubstring()) {
StringView view = *rope->substringBase()->valueInternal().impl();
unsigned offset = rope->substringOffset();
view.substring(offset, rope->length()).getCharacters(destination);
return;
}
uint8_t* stackLimit = std::bit_cast<uint8_t*>(vm().softStackLimit());
return JSRopeString::resolveToBuffer(rope->fiber0(), rope->fiber1(), rope->fiber2(), destination, stackLimit);
}
StringView(valueInternal().impl()).getCharacters(destination);
}
} // namespace JSC