blob: 9f21d8e7d74c905c7a9edd16f86d83c72928dee6 [file] [log] [blame]
/*
* Copyright (C) 1999-2000 Harri Porten (porten@kde.org)
* Copyright (C) 2003-2019 Apple Inc. All rights reserved.
* Copyright (C) 2003 Peter Kelly (pmk@post.com)
* Copyright (C) 2006 Alexey Proskuryakov (ap@nypop.com)
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
*/
#include "config.h"
#include "JSArray.h"
#include "ArrayPrototype.h"
#include "ButterflyInlines.h"
#include "CodeBlock.h"
#include "Error.h"
#include "GetterSetter.h"
#include "IndexingHeaderInlines.h"
#include "JSArrayInlines.h"
#include "JSCInlines.h"
#include "PropertyNameArray.h"
#include "TypeError.h"
#include <wtf/Assertions.h>
namespace JSC {
const ASCIILiteral LengthExceededTheMaximumArrayLengthError { "Length exceeded the maximum array length"_s };
STATIC_ASSERT_IS_TRIVIALLY_DESTRUCTIBLE(JSArray);
const ClassInfo JSArray::s_info = {"Array", &JSNonFinalObject::s_info, nullptr, nullptr, CREATE_METHOD_TABLE(JSArray)};
JSArray* JSArray::tryCreateUninitializedRestricted(ObjectInitializationScope& scope, GCDeferralContext* deferralContext, Structure* structure, unsigned initialLength)
{
VM& vm = scope.vm();
if (UNLIKELY(initialLength > MAX_STORAGE_VECTOR_LENGTH))
return nullptr;
unsigned outOfLineStorage = structure->outOfLineCapacity();
Butterfly* butterfly;
IndexingType indexingType = structure->indexingType();
if (LIKELY(!hasAnyArrayStorage(indexingType))) {
ASSERT(
hasUndecided(indexingType)
|| hasInt32(indexingType)
|| hasDouble(indexingType)
|| hasContiguous(indexingType));
unsigned vectorLength = Butterfly::optimalContiguousVectorLength(structure, initialLength);
void* temp = vm.jsValueGigacageAuxiliarySpace.allocateNonVirtual(
vm,
Butterfly::totalSize(0, outOfLineStorage, true, vectorLength * sizeof(EncodedJSValue)),
deferralContext, AllocationFailureMode::ReturnNull);
if (UNLIKELY(!temp))
return nullptr;
butterfly = Butterfly::fromBase(temp, 0, outOfLineStorage);
butterfly->setVectorLength(vectorLength);
butterfly->setPublicLength(initialLength);
if (hasDouble(indexingType)) {
for (unsigned i = initialLength; i < vectorLength; ++i)
butterfly->contiguousDouble().atUnsafe(i) = PNaN;
} else {
for (unsigned i = initialLength; i < vectorLength; ++i)
butterfly->contiguous().atUnsafe(i).clear();
}
} else {
ASSERT(
indexingType == ArrayWithSlowPutArrayStorage
|| indexingType == ArrayWithArrayStorage);
static constexpr unsigned indexBias = 0;
unsigned vectorLength = ArrayStorage::optimalVectorLength(indexBias, structure, initialLength);
void* temp = vm.jsValueGigacageAuxiliarySpace.allocateNonVirtual(
vm,
Butterfly::totalSize(indexBias, outOfLineStorage, true, ArrayStorage::sizeFor(vectorLength)),
deferralContext, AllocationFailureMode::ReturnNull);
if (UNLIKELY(!temp))
return nullptr;
butterfly = Butterfly::fromBase(temp, indexBias, outOfLineStorage);
*butterfly->indexingHeader() = indexingHeaderForArrayStorage(initialLength, vectorLength);
ArrayStorage* storage = butterfly->arrayStorage();
storage->m_indexBias = indexBias;
storage->m_sparseMap.clear();
storage->m_numValuesInVector = initialLength;
for (unsigned i = initialLength; i < vectorLength; ++i)
storage->m_vector[i].clear();
}
JSArray* result = createWithButterfly(vm, deferralContext, structure, butterfly);
const bool createUninitialized = true;
scope.notifyAllocated(result, createUninitialized);
return result;
}
void JSArray::eagerlyInitializeButterfly(ObjectInitializationScope& scope, JSArray* array, unsigned initialLength)
{
Structure* structure = array->structure(scope.vm());
IndexingType indexingType = structure->indexingType();
Butterfly* butterfly = array->butterfly();
// This function only serves as a companion to tryCreateUninitializedRestricted()
// in the event that we really can't defer initialization of the butterfly after all.
// tryCreateUninitializedRestricted() already initialized the elements between
// initialLength and vector length. We just need to do 0 - initialLength.
// ObjectInitializationScope::notifyInitialized() will verify that all elements are
// initialized.
if (LIKELY(!hasAnyArrayStorage(indexingType))) {
if (hasDouble(indexingType)) {
for (unsigned i = 0; i < initialLength; ++i)
butterfly->contiguousDouble().atUnsafe(i) = PNaN;
} else {
for (unsigned i = 0; i < initialLength; ++i)
butterfly->contiguous().atUnsafe(i).clear();
}
} else {
ArrayStorage* storage = butterfly->arrayStorage();
for (unsigned i = 0; i < initialLength; ++i)
storage->m_vector[i].clear();
}
scope.notifyInitialized(array);
}
void JSArray::setLengthWritable(ExecState* exec, bool writable)
{
ASSERT(isLengthWritable() || !writable);
if (!isLengthWritable() || writable)
return;
enterDictionaryIndexingMode(exec->vm());
SparseArrayValueMap* map = arrayStorage()->m_sparseMap.get();
ASSERT(map);
map->setLengthIsReadOnly();
}
// Defined in ES5.1 15.4.5.1
bool JSArray::defineOwnProperty(JSObject* object, ExecState* exec, PropertyName propertyName, const PropertyDescriptor& descriptor, bool throwException)
{
VM& vm = exec->vm();
auto scope = DECLARE_THROW_SCOPE(vm);
JSArray* array = jsCast<JSArray*>(object);
// 3. If P is "length", then
if (propertyName == vm.propertyNames->length) {
// All paths through length definition call the default [[DefineOwnProperty]], hence:
// from ES5.1 8.12.9 7.a.
if (descriptor.configurablePresent() && descriptor.configurable())
return typeError(exec, scope, throwException, UnconfigurablePropertyChangeConfigurabilityError);
// from ES5.1 8.12.9 7.b.
if (descriptor.enumerablePresent() && descriptor.enumerable())
return typeError(exec, scope, throwException, UnconfigurablePropertyChangeEnumerabilityError);
// a. If the [[Value]] field of Desc is absent, then
// a.i. Return the result of calling the default [[DefineOwnProperty]] internal method (8.12.9) on A passing "length", Desc, and Throw as arguments.
if (descriptor.isAccessorDescriptor())
return typeError(exec, scope, throwException, UnconfigurablePropertyChangeAccessMechanismError);
// from ES5.1 8.12.9 10.a.
if (!array->isLengthWritable() && descriptor.writablePresent() && descriptor.writable())
return typeError(exec, scope, throwException, UnconfigurablePropertyChangeWritabilityError);
// This descriptor is either just making length read-only, or changing nothing!
if (!descriptor.value()) {
if (descriptor.writablePresent())
array->setLengthWritable(exec, descriptor.writable());
return true;
}
// b. Let newLenDesc be a copy of Desc.
// c. Let newLen be ToUint32(Desc.[[Value]]).
unsigned newLen = descriptor.value().toUInt32(exec);
RETURN_IF_EXCEPTION(scope, false);
// d. If newLen is not equal to ToNumber( Desc.[[Value]]), throw a RangeError exception.
double valueAsNumber = descriptor.value().toNumber(exec);
RETURN_IF_EXCEPTION(scope, false);
if (newLen != valueAsNumber) {
JSC::throwException(exec, scope, createRangeError(exec, "Invalid array length"_s));
return false;
}
// Based on SameValue check in 8.12.9, this is always okay.
// FIXME: Nothing prevents this from being called on a RuntimeArray, and the length function will always return 0 in that case.
if (newLen == array->length()) {
if (descriptor.writablePresent())
array->setLengthWritable(exec, descriptor.writable());
return true;
}
// e. Set newLenDesc.[[Value] to newLen.
// f. If newLen >= oldLen, then
// f.i. Return the result of calling the default [[DefineOwnProperty]] internal method (8.12.9) on A passing "length", newLenDesc, and Throw as arguments.
// g. Reject if oldLenDesc.[[Writable]] is false.
if (!array->isLengthWritable())
return typeError(exec, scope, throwException, ReadonlyPropertyChangeError);
// h. If newLenDesc.[[Writable]] is absent or has the value true, let newWritable be true.
// i. Else,
// i.i. Need to defer setting the [[Writable]] attribute to false in case any elements cannot be deleted.
// i.ii. Let newWritable be false.
// i.iii. Set newLenDesc.[[Writable] to true.
// j. Let succeeded be the result of calling the default [[DefineOwnProperty]] internal method (8.12.9) on A passing "length", newLenDesc, and Throw as arguments.
// k. If succeeded is false, return false.
// l. While newLen < oldLen repeat,
// l.i. Set oldLen to oldLen – 1.
// l.ii. Let deleteSucceeded be the result of calling the [[Delete]] internal method of A passing ToString(oldLen) and false as arguments.
// l.iii. If deleteSucceeded is false, then
bool success = array->setLength(exec, newLen, throwException);
EXCEPTION_ASSERT(!scope.exception() || !success);
if (!success) {
// 1. Set newLenDesc.[[Value] to oldLen+1.
// 2. If newWritable is false, set newLenDesc.[[Writable] to false.
// 3. Call the default [[DefineOwnProperty]] internal method (8.12.9) on A passing "length", newLenDesc, and false as arguments.
// 4. Reject.
if (descriptor.writablePresent())
array->setLengthWritable(exec, descriptor.writable());
return false;
}
// m. If newWritable is false, then
// i. Call the default [[DefineOwnProperty]] internal method (8.12.9) on A passing "length",
// Property Descriptor{[[Writable]]: false}, and false as arguments. This call will always
// return true.
if (descriptor.writablePresent())
array->setLengthWritable(exec, descriptor.writable());
// n. Return true.
return true;
}
// 4. Else if P is an array index (15.4), then
// a. Let index be ToUint32(P).
if (Optional<uint32_t> optionalIndex = parseIndex(propertyName)) {
// b. Reject if index >= oldLen and oldLenDesc.[[Writable]] is false.
uint32_t index = optionalIndex.value();
// FIXME: Nothing prevents this from being called on a RuntimeArray, and the length function will always return 0 in that case.
if (index >= array->length() && !array->isLengthWritable())
return typeError(exec, scope, throwException, "Attempting to define numeric property on array with non-writable length property."_s);
// c. Let succeeded be the result of calling the default [[DefineOwnProperty]] internal method (8.12.9) on A passing P, Desc, and false as arguments.
// d. Reject if succeeded is false.
// e. If index >= oldLen
// e.i. Set oldLenDesc.[[Value]] to index + 1.
// e.ii. Call the default [[DefineOwnProperty]] internal method (8.12.9) on A passing "length", oldLenDesc, and false as arguments. This call will always return true.
// f. Return true.
RELEASE_AND_RETURN(scope, array->defineOwnIndexedProperty(exec, index, descriptor, throwException));
}
RELEASE_AND_RETURN(scope, array->JSObject::defineOwnNonIndexProperty(exec, propertyName, descriptor, throwException));
}
bool JSArray::getOwnPropertySlot(JSObject* object, ExecState* exec, PropertyName propertyName, PropertySlot& slot)
{
VM& vm = exec->vm();
JSArray* thisObject = jsCast<JSArray*>(object);
if (propertyName == vm.propertyNames->length) {
unsigned attributes = thisObject->isLengthWritable() ? PropertyAttribute::DontDelete | PropertyAttribute::DontEnum : PropertyAttribute::DontDelete | PropertyAttribute::DontEnum | PropertyAttribute::ReadOnly;
slot.setValue(thisObject, attributes, jsNumber(thisObject->length()));
return true;
}
return JSObject::getOwnPropertySlot(thisObject, exec, propertyName, slot);
}
// ECMA 15.4.5.1
bool JSArray::put(JSCell* cell, ExecState* exec, PropertyName propertyName, JSValue value, PutPropertySlot& slot)
{
VM& vm = exec->vm();
auto scope = DECLARE_THROW_SCOPE(vm);
JSArray* thisObject = jsCast<JSArray*>(cell);
if (UNLIKELY(isThisValueAltered(slot, thisObject)))
RELEASE_AND_RETURN(scope, ordinarySetSlow(exec, thisObject, propertyName, value, slot.thisValue(), slot.isStrictMode()));
thisObject->ensureWritable(vm);
if (propertyName == vm.propertyNames->length) {
if (!thisObject->isLengthWritable()) {
if (slot.isStrictMode())
throwTypeError(exec, scope, "Array length is not writable"_s);
return false;
}
unsigned newLength = value.toUInt32(exec);
RETURN_IF_EXCEPTION(scope, false);
double valueAsNumber = value.toNumber(exec);
RETURN_IF_EXCEPTION(scope, false);
if (valueAsNumber != static_cast<double>(newLength)) {
throwException(exec, scope, createRangeError(exec, "Invalid array length"_s));
return false;
}
RELEASE_AND_RETURN(scope, thisObject->setLength(exec, newLength, slot.isStrictMode()));
}
RELEASE_AND_RETURN(scope, JSObject::put(thisObject, exec, propertyName, value, slot));
}
bool JSArray::deleteProperty(JSCell* cell, ExecState* exec, PropertyName propertyName)
{
VM& vm = exec->vm();
JSArray* thisObject = jsCast<JSArray*>(cell);
if (propertyName == vm.propertyNames->length)
return false;
return JSObject::deleteProperty(thisObject, exec, propertyName);
}
static int compareKeysForQSort(const void* a, const void* b)
{
unsigned da = *static_cast<const unsigned*>(a);
unsigned db = *static_cast<const unsigned*>(b);
return (da > db) - (da < db);
}
void JSArray::getOwnNonIndexPropertyNames(JSObject* object, ExecState* exec, PropertyNameArray& propertyNames, EnumerationMode mode)
{
VM& vm = exec->vm();
JSArray* thisObject = jsCast<JSArray*>(object);
if (mode.includeDontEnumProperties())
propertyNames.add(vm.propertyNames->length);
JSObject::getOwnNonIndexPropertyNames(thisObject, exec, propertyNames, mode);
}
// This method makes room in the vector, but leaves the new space for count slots uncleared.
bool JSArray::unshiftCountSlowCase(const AbstractLocker&, VM& vm, DeferGC&, bool addToFront, unsigned count)
{
ASSERT(cellLock().isLocked());
ArrayStorage* storage = ensureArrayStorage(vm);
Butterfly* butterfly = storage->butterfly();
Structure* structure = this->structure(vm);
unsigned propertyCapacity = structure->outOfLineCapacity();
unsigned propertySize = structure->outOfLineSize();
// If not, we should have handled this on the fast path.
ASSERT(!addToFront || count > storage->m_indexBias);
// Step 1:
// Gather 4 key metrics:
// * usedVectorLength - how many entries are currently in the vector (conservative estimate - fewer may be in use in sparse vectors).
// * requiredVectorLength - how many entries are will there be in the vector, after allocating space for 'count' more.
// * currentCapacity - what is the current size of the vector, including any pre-capacity.
// * desiredCapacity - how large should we like to grow the vector to - based on 2x requiredVectorLength.
unsigned length = storage->length();
unsigned oldVectorLength = storage->vectorLength();
unsigned usedVectorLength = std::min(oldVectorLength, length);
ASSERT(usedVectorLength <= MAX_STORAGE_VECTOR_LENGTH);
// Check that required vector length is possible, in an overflow-safe fashion.
if (count > MAX_STORAGE_VECTOR_LENGTH - usedVectorLength)
return false;
unsigned requiredVectorLength = usedVectorLength + count;
ASSERT(requiredVectorLength <= MAX_STORAGE_VECTOR_LENGTH);
// The sum of m_vectorLength and m_indexBias will never exceed MAX_STORAGE_VECTOR_LENGTH.
ASSERT(storage->vectorLength() <= MAX_STORAGE_VECTOR_LENGTH && (MAX_STORAGE_VECTOR_LENGTH - storage->vectorLength()) >= storage->m_indexBias);
unsigned currentCapacity = storage->vectorLength() + storage->m_indexBias;
// The calculation of desiredCapacity won't overflow, due to the range of MAX_STORAGE_VECTOR_LENGTH.
// FIXME: This code should be fixed to avoid internal fragmentation. It's not super high
// priority since increaseVectorLength() will "fix" any mistakes we make, but it would be cool
// to get this right eventually.
unsigned desiredCapacity = std::min(MAX_STORAGE_VECTOR_LENGTH, std::max(BASE_ARRAY_STORAGE_VECTOR_LEN, requiredVectorLength) << 1);
// Step 2:
// We're either going to choose to allocate a new ArrayStorage, or we're going to reuse the existing one.
void* newAllocBase = nullptr;
unsigned newStorageCapacity;
bool allocatedNewStorage;
// If the current storage array is sufficiently large (but not too large!) then just keep using it.
if (currentCapacity > desiredCapacity && isDenseEnoughForVector(currentCapacity, requiredVectorLength)) {
newAllocBase = butterfly->base(structure);
newStorageCapacity = currentCapacity;
allocatedNewStorage = false;
} else {
const unsigned preCapacity = 0;
Butterfly* newButterfly = Butterfly::tryCreateUninitialized(vm, this, preCapacity, propertyCapacity, true, ArrayStorage::sizeFor(desiredCapacity));
if (!newButterfly)
return false;
newAllocBase = newButterfly->base(preCapacity, propertyCapacity);
newStorageCapacity = desiredCapacity;
allocatedNewStorage = true;
}
// Step 3:
// Work out where we're going to move things to.
// Determine how much of the vector to use as pre-capacity, and how much as post-capacity.
// If we're adding to the end, we'll add all the new space to the end.
// If the vector had no free post-capacity (length >= m_vectorLength), don't give it any.
// If it did, we calculate the amount that will remain based on an atomic decay - leave the
// vector with half the post-capacity it had previously.
unsigned postCapacity = 0;
if (!addToFront)
postCapacity = newStorageCapacity - requiredVectorLength;
else if (length < storage->vectorLength()) {
// Atomic decay, + the post-capacity cannot be greater than what is available.
postCapacity = std::min((storage->vectorLength() - length) >> 1, newStorageCapacity - requiredVectorLength);
// If we're moving contents within the same allocation, the post-capacity is being reduced.
ASSERT(newAllocBase != butterfly->base(structure) || postCapacity < storage->vectorLength() - length);
}
unsigned newVectorLength = requiredVectorLength + postCapacity;
RELEASE_ASSERT(newVectorLength <= MAX_STORAGE_VECTOR_LENGTH);
unsigned preCapacity = newStorageCapacity - newVectorLength;
Butterfly* newButterfly = Butterfly::fromBase(newAllocBase, preCapacity, propertyCapacity);
if (addToFront) {
ASSERT(count + usedVectorLength <= newVectorLength);
memmove(newButterfly->arrayStorage()->m_vector + count, storage->m_vector, sizeof(JSValue) * usedVectorLength);
memmove(newButterfly->propertyStorage() - propertySize, butterfly->propertyStorage() - propertySize, sizeof(JSValue) * propertySize + sizeof(IndexingHeader) + ArrayStorage::sizeFor(0));
// We don't need to zero the pre-capacity for the concurrent GC because it is not available to use as property storage.
memset(newButterfly->base(0, propertyCapacity), 0, (propertyCapacity - propertySize) * sizeof(JSValue));
if (allocatedNewStorage) {
// We will set the vectorLength to newVectorLength. We populated requiredVectorLength
// (usedVectorLength + count), which is less. Clear the difference.
for (unsigned i = requiredVectorLength; i < newVectorLength; ++i)
newButterfly->arrayStorage()->m_vector[i].clear();
}
} else if ((newAllocBase != butterfly->base(structure)) || (preCapacity != storage->m_indexBias)) {
memmove(newButterfly->propertyStorage() - propertyCapacity, butterfly->propertyStorage() - propertyCapacity, sizeof(JSValue) * propertyCapacity + sizeof(IndexingHeader) + ArrayStorage::sizeFor(0));
memmove(newButterfly->arrayStorage()->m_vector, storage->m_vector, sizeof(JSValue) * usedVectorLength);
for (unsigned i = requiredVectorLength; i < newVectorLength; i++)
newButterfly->arrayStorage()->m_vector[i].clear();
}
newButterfly->arrayStorage()->setVectorLength(newVectorLength);
newButterfly->arrayStorage()->m_indexBias = preCapacity;
setButterfly(vm, newButterfly);
return true;
}
bool JSArray::setLengthWithArrayStorage(ExecState* exec, unsigned newLength, bool throwException, ArrayStorage* storage)
{
VM& vm = exec->vm();
auto scope = DECLARE_THROW_SCOPE(vm);
unsigned length = storage->length();
// If the length is read only then we enter sparse mode, so should enter the following 'if'.
ASSERT(isLengthWritable() || storage->m_sparseMap);
if (SparseArrayValueMap* map = storage->m_sparseMap.get()) {
// Fail if the length is not writable.
if (map->lengthIsReadOnly())
return typeError(exec, scope, throwException, ReadonlyPropertyWriteError);
if (newLength < length) {
// Copy any keys we might be interested in into a vector.
Vector<unsigned, 0, UnsafeVectorOverflow> keys;
keys.reserveInitialCapacity(std::min(map->size(), static_cast<size_t>(length - newLength)));
SparseArrayValueMap::const_iterator end = map->end();
for (SparseArrayValueMap::const_iterator it = map->begin(); it != end; ++it) {
unsigned index = static_cast<unsigned>(it->key);
if (index < length && index >= newLength)
keys.append(index);
}
// Check if the array is in sparse mode. If so there may be non-configurable
// properties, so we have to perform deletion with caution, if not we can
// delete values in any order.
if (map->sparseMode()) {
qsort(keys.begin(), keys.size(), sizeof(unsigned), compareKeysForQSort);
unsigned i = keys.size();
while (i) {
unsigned index = keys[--i];
SparseArrayValueMap::iterator it = map->find(index);
ASSERT(it != map->notFound());
if (it->value.attributes() & PropertyAttribute::DontDelete) {
storage->setLength(index + 1);
return typeError(exec, scope, throwException, UnableToDeletePropertyError);
}
map->remove(it);
}
} else {
for (unsigned i = 0; i < keys.size(); ++i)
map->remove(keys[i]);
if (map->isEmpty())
deallocateSparseIndexMap();
}
}
}
if (newLength < length) {
// Delete properties from the vector.
unsigned usedVectorLength = std::min(length, storage->vectorLength());
for (unsigned i = newLength; i < usedVectorLength; ++i) {
WriteBarrier<Unknown>& valueSlot = storage->m_vector[i];
bool hadValue = !!valueSlot;
valueSlot.clear();
storage->m_numValuesInVector -= hadValue;
}
}
storage->setLength(newLength);
return true;
}
bool JSArray::appendMemcpy(ExecState* exec, VM& vm, unsigned startIndex, JSC::JSArray* otherArray)
{
auto scope = DECLARE_THROW_SCOPE(vm);
if (!canFastCopy(vm, otherArray))
return false;
IndexingType type = indexingType();
IndexingType otherType = otherArray->indexingType();
IndexingType copyType = mergeIndexingTypeForCopying(otherType);
if (type == ArrayWithUndecided && copyType != NonArray) {
if (copyType == ArrayWithInt32)
convertUndecidedToInt32(vm);
else if (copyType == ArrayWithDouble)
convertUndecidedToDouble(vm);
else if (copyType == ArrayWithContiguous)
convertUndecidedToContiguous(vm);
else {
ASSERT(copyType == ArrayWithUndecided);
return true;
}
} else if (type != copyType)
return false;
unsigned otherLength = otherArray->length();
Checked<unsigned, RecordOverflow> checkedNewLength = startIndex;
checkedNewLength += otherLength;
unsigned newLength;
if (checkedNewLength.safeGet(newLength) == CheckedState::DidOverflow) {
throwException(exec, scope, createRangeError(exec, LengthExceededTheMaximumArrayLengthError));
return false;
}
if (newLength >= MIN_SPARSE_ARRAY_INDEX)
return false;
if (!ensureLength(vm, newLength)) {
throwOutOfMemoryError(exec, scope);
return false;
}
ASSERT(copyType == indexingType());
if (UNLIKELY(otherType == ArrayWithUndecided)) {
auto* butterfly = this->butterfly();
if (type == ArrayWithDouble) {
for (unsigned i = startIndex; i < newLength; ++i)
butterfly->contiguousDouble().at(this, i) = PNaN;
} else {
for (unsigned i = startIndex; i < newLength; ++i)
butterfly->contiguousInt32().at(this, i).setWithoutWriteBarrier(JSValue());
}
} else if (type == ArrayWithDouble)
memcpy(butterfly()->contiguousDouble().data() + startIndex, otherArray->butterfly()->contiguousDouble().data(), sizeof(JSValue) * otherLength);
else {
memcpy(butterfly()->contiguous().data() + startIndex, otherArray->butterfly()->contiguous().data(), sizeof(JSValue) * otherLength);
vm.heap.writeBarrier(this);
}
return true;
}
bool JSArray::setLength(ExecState* exec, unsigned newLength, bool throwException)
{
VM& vm = exec->vm();
auto scope = DECLARE_THROW_SCOPE(vm);
Butterfly* butterfly = this->butterfly();
switch (indexingMode()) {
case ArrayClass:
if (!newLength)
return true;
if (newLength >= MIN_SPARSE_ARRAY_INDEX) {
RELEASE_AND_RETURN(scope, setLengthWithArrayStorage(
exec, newLength, throwException,
ensureArrayStorage(vm)));
}
createInitialUndecided(vm, newLength);
return true;
case CopyOnWriteArrayWithInt32:
case CopyOnWriteArrayWithDouble:
case CopyOnWriteArrayWithContiguous:
if (newLength == butterfly->publicLength())
return true;
convertFromCopyOnWrite(vm);
butterfly = this->butterfly();
FALLTHROUGH;
case ArrayWithUndecided:
case ArrayWithInt32:
case ArrayWithDouble:
case ArrayWithContiguous: {
if (newLength == butterfly->publicLength())
return true;
if (newLength > MAX_STORAGE_VECTOR_LENGTH // This check ensures that we can do fast push.
|| (newLength >= MIN_SPARSE_ARRAY_INDEX
&& !isDenseEnoughForVector(newLength, countElements()))) {
RELEASE_AND_RETURN(scope, setLengthWithArrayStorage(
exec, newLength, throwException,
ensureArrayStorage(vm)));
}
if (newLength > butterfly->publicLength()) {
if (!ensureLength(vm, newLength)) {
throwOutOfMemoryError(exec, scope);
return false;
}
return true;
}
unsigned lengthToClear = butterfly->publicLength() - newLength;
unsigned costToAllocateNewButterfly = 64; // a heuristic.
if (lengthToClear > newLength && lengthToClear > costToAllocateNewButterfly) {
reallocateAndShrinkButterfly(vm, newLength);
return true;
}
if (indexingType() == ArrayWithDouble) {
for (unsigned i = butterfly->publicLength(); i-- > newLength;)
butterfly->contiguousDouble().at(this, i) = PNaN;
} else {
for (unsigned i = butterfly->publicLength(); i-- > newLength;)
butterfly->contiguous().at(this, i).clear();
}
butterfly->setPublicLength(newLength);
return true;
}
case ArrayWithArrayStorage:
case ArrayWithSlowPutArrayStorage:
RELEASE_AND_RETURN(scope, setLengthWithArrayStorage(exec, newLength, throwException, arrayStorage()));
default:
CRASH();
return false;
}
}
JSValue JSArray::pop(ExecState* exec)
{
VM& vm = exec->vm();
auto scope = DECLARE_THROW_SCOPE(vm);
ensureWritable(vm);
Butterfly* butterfly = this->butterfly();
switch (indexingType()) {
case ArrayClass:
return jsUndefined();
case ArrayWithUndecided:
if (!butterfly->publicLength())
return jsUndefined();
// We have nothing but holes. So, drop down to the slow version.
break;
case ArrayWithInt32:
case ArrayWithContiguous: {
unsigned length = butterfly->publicLength();
if (!length--)
return jsUndefined();
RELEASE_ASSERT(length < butterfly->vectorLength());
JSValue value = butterfly->contiguous().at(this, length).get();
if (value) {
butterfly->contiguous().at(this, length).clear();
butterfly->setPublicLength(length);
return value;
}
break;
}
case ArrayWithDouble: {
unsigned length = butterfly->publicLength();
if (!length--)
return jsUndefined();
RELEASE_ASSERT(length < butterfly->vectorLength());
double value = butterfly->contiguousDouble().at(this, length);
if (value == value) {
butterfly->contiguousDouble().at(this, length) = PNaN;
butterfly->setPublicLength(length);
return JSValue(JSValue::EncodeAsDouble, value);
}
break;
}
case ARRAY_WITH_ARRAY_STORAGE_INDEXING_TYPES: {
ArrayStorage* storage = butterfly->arrayStorage();
unsigned length = storage->length();
if (!length) {
if (!isLengthWritable())
throwTypeError(exec, scope, ReadonlyPropertyWriteError);
return jsUndefined();
}
unsigned index = length - 1;
if (index < storage->vectorLength()) {
WriteBarrier<Unknown>& valueSlot = storage->m_vector[index];
if (valueSlot) {
--storage->m_numValuesInVector;
JSValue element = valueSlot.get();
valueSlot.clear();
RELEASE_ASSERT(isLengthWritable());
storage->setLength(index);
return element;
}
}
break;
}
default:
CRASH();
return JSValue();
}
unsigned index = getArrayLength() - 1;
// Let element be the result of calling the [[Get]] internal method of O with argument indx.
JSValue element = get(exec, index);
RETURN_IF_EXCEPTION(scope, JSValue());
// Call the [[Delete]] internal method of O with arguments indx and true.
bool success = deletePropertyByIndex(this, exec, index);
RETURN_IF_EXCEPTION(scope, JSValue());
if (!success) {
throwTypeError(exec, scope, UnableToDeletePropertyError);
return jsUndefined();
}
// Call the [[Put]] internal method of O with arguments "length", indx, and true.
scope.release();
setLength(exec, index, true);
// Return element.
return element;
}
// Push & putIndex are almost identical, with two small differences.
// - we always are writing beyond the current array bounds, so it is always necessary to update m_length & m_numValuesInVector.
// - pushing to an array of length 2^32-1 stores the property, but throws a range error.
NEVER_INLINE void JSArray::push(ExecState* exec, JSValue value)
{
pushInline(exec, value);
}
JSArray* JSArray::fastSlice(ExecState& exec, unsigned startIndex, unsigned count)
{
VM& vm = exec.vm();
ensureWritable(vm);
auto arrayType = indexingMode();
switch (arrayType) {
case ArrayWithDouble:
case ArrayWithInt32:
case ArrayWithContiguous: {
if (count >= MIN_SPARSE_ARRAY_INDEX || structure(vm)->holesMustForwardToPrototype(vm, this))
return nullptr;
JSGlobalObject* lexicalGlobalObject = exec.lexicalGlobalObject();
Structure* resultStructure = lexicalGlobalObject->arrayStructureForIndexingTypeDuringAllocation(arrayType);
if (UNLIKELY(hasAnyArrayStorage(resultStructure->indexingType())))
return nullptr;
ASSERT(!lexicalGlobalObject->isHavingABadTime());
ObjectInitializationScope scope(vm);
JSArray* resultArray = JSArray::tryCreateUninitializedRestricted(scope, resultStructure, count);
if (UNLIKELY(!resultArray))
return nullptr;
auto& resultButterfly = *resultArray->butterfly();
if (arrayType == ArrayWithDouble)
memcpy(resultButterfly.contiguousDouble().data(), butterfly()->contiguousDouble().data() + startIndex, sizeof(JSValue) * count);
else
memcpy(resultButterfly.contiguous().data(), butterfly()->contiguous().data() + startIndex, sizeof(JSValue) * count);
resultButterfly.setPublicLength(count);
return resultArray;
}
default:
return nullptr;
}
}
bool JSArray::shiftCountWithArrayStorage(VM& vm, unsigned startIndex, unsigned count, ArrayStorage* storage)
{
unsigned oldLength = storage->length();
RELEASE_ASSERT(count <= oldLength);
// If the array contains holes or is otherwise in an abnormal state,
// use the generic algorithm in ArrayPrototype.
if (storage->hasHoles()
|| hasSparseMap()
|| shouldUseSlowPut(indexingType())) {
return false;
}
if (!oldLength)
return true;
unsigned length = oldLength - count;
storage->m_numValuesInVector -= count;
storage->setLength(length);
unsigned vectorLength = storage->vectorLength();
if (!vectorLength)
return true;
if (startIndex >= vectorLength)
return true;
DisallowGC disallowGC;
auto locker = holdLock(cellLock());
if (startIndex + count > vectorLength)
count = vectorLength - startIndex;
unsigned usedVectorLength = std::min(vectorLength, oldLength);
unsigned numElementsBeforeShiftRegion = startIndex;
unsigned firstIndexAfterShiftRegion = startIndex + count;
unsigned numElementsAfterShiftRegion = usedVectorLength - firstIndexAfterShiftRegion;
ASSERT(numElementsBeforeShiftRegion + count + numElementsAfterShiftRegion == usedVectorLength);
// The point of this comparison seems to be to minimize the amount of elements that have to
// be moved during a shift operation.
if (numElementsBeforeShiftRegion < numElementsAfterShiftRegion) {
// The number of elements before the shift region is less than the number of elements
// after the shift region, so we move the elements before to the right.
if (numElementsBeforeShiftRegion) {
RELEASE_ASSERT(count + startIndex <= vectorLength);
memmove(storage->m_vector + count,
storage->m_vector,
sizeof(JSValue) * startIndex);
}
// Adjust the Butterfly and the index bias. We only need to do this here because we're changing
// the start of the Butterfly, which needs to point at the first indexed property in the used
// portion of the vector.
Butterfly* butterfly = this->butterfly()->shift(structure(vm), count);
storage = butterfly->arrayStorage();
storage->m_indexBias += count;
// Since we're consuming part of the vector by moving its beginning to the left,
// we need to modify the vector length appropriately.
storage->setVectorLength(vectorLength - count);
setButterfly(vm, butterfly);
} else {
// The number of elements before the shift region is greater than or equal to the number
// of elements after the shift region, so we move the elements after the shift region to the left.
memmove(storage->m_vector + startIndex,
storage->m_vector + firstIndexAfterShiftRegion,
sizeof(JSValue) * numElementsAfterShiftRegion);
// Clear the slots of the elements we just moved.
unsigned startOfEmptyVectorTail = usedVectorLength - count;
for (unsigned i = startOfEmptyVectorTail; i < usedVectorLength; ++i)
storage->m_vector[i].clear();
// We don't modify the index bias or the Butterfly pointer in this case because we're not changing
// the start of the Butterfly, which needs to point at the first indexed property in the used
// portion of the vector. We also don't modify the vector length because we're not actually changing
// its length; we're just using less of it.
}
return true;
}
bool JSArray::shiftCountWithAnyIndexingType(ExecState* exec, unsigned& startIndex, unsigned count)
{
VM& vm = exec->vm();
RELEASE_ASSERT(count > 0);
ensureWritable(vm);
Butterfly* butterfly = this->butterfly();
switch (indexingType()) {
case ArrayClass:
return true;
case ArrayWithUndecided:
// Don't handle this because it's confusing and it shouldn't come up.
return false;
case ArrayWithInt32:
case ArrayWithContiguous: {
unsigned oldLength = butterfly->publicLength();
RELEASE_ASSERT(count <= oldLength);
// We may have to walk the entire array to do the shift. We're willing to do
// so only if it's not horribly slow.
if (oldLength - (startIndex + count) >= MIN_SPARSE_ARRAY_INDEX)
return shiftCountWithArrayStorage(vm, startIndex, count, ensureArrayStorage(vm));
// Storing to a hole is fine since we're still having a good time. But reading from a hole
// is totally not fine, since we might have to read from the proto chain.
// We have to check for holes before we start moving things around so that we don't get halfway
// through shifting and then realize we should have been in ArrayStorage mode.
unsigned end = oldLength - count;
if (this->structure(vm)->holesMustForwardToPrototype(vm, this)) {
for (unsigned i = startIndex; i < end; ++i) {
JSValue v = butterfly->contiguous().at(this, i + count).get();
if (UNLIKELY(!v)) {
startIndex = i;
return shiftCountWithArrayStorage(vm, startIndex, count, ensureArrayStorage(vm));
}
butterfly->contiguous().at(this, i).setWithoutWriteBarrier(v);
}
} else {
memmove(butterfly->contiguous().data() + startIndex,
butterfly->contiguous().data() + startIndex + count,
sizeof(JSValue) * (end - startIndex));
}
for (unsigned i = end; i < oldLength; ++i)
butterfly->contiguous().at(this, i).clear();
butterfly->setPublicLength(oldLength - count);
// Our memmoving of values around in the array could have concealed some of them from
// the collector. Let's make sure that the collector scans this object again.
vm.heap.writeBarrier(this);
return true;
}
case ArrayWithDouble: {
unsigned oldLength = butterfly->publicLength();
RELEASE_ASSERT(count <= oldLength);
// We may have to walk the entire array to do the shift. We're willing to do
// so only if it's not horribly slow.
if (oldLength - (startIndex + count) >= MIN_SPARSE_ARRAY_INDEX)
return shiftCountWithArrayStorage(vm, startIndex, count, ensureArrayStorage(vm));
// Storing to a hole is fine since we're still having a good time. But reading from a hole
// is totally not fine, since we might have to read from the proto chain.
// We have to check for holes before we start moving things around so that we don't get halfway
// through shifting and then realize we should have been in ArrayStorage mode.
unsigned end = oldLength - count;
if (this->structure(vm)->holesMustForwardToPrototype(vm, this)) {
for (unsigned i = startIndex; i < end; ++i) {
double v = butterfly->contiguousDouble().at(this, i + count);
if (UNLIKELY(v != v)) {
startIndex = i;
return shiftCountWithArrayStorage(vm, startIndex, count, ensureArrayStorage(vm));
}
butterfly->contiguousDouble().at(this, i) = v;
}
} else {
memmove(butterfly->contiguousDouble().data() + startIndex,
butterfly->contiguousDouble().data() + startIndex + count,
sizeof(JSValue) * (end - startIndex));
}
for (unsigned i = end; i < oldLength; ++i)
butterfly->contiguousDouble().at(this, i) = PNaN;
butterfly->setPublicLength(oldLength - count);
return true;
}
case ArrayWithArrayStorage:
case ArrayWithSlowPutArrayStorage:
return shiftCountWithArrayStorage(vm, startIndex, count, arrayStorage());
default:
CRASH();
return false;
}
}
// Returns true if the unshift can be handled, false to fallback.
bool JSArray::unshiftCountWithArrayStorage(ExecState* exec, unsigned startIndex, unsigned count, ArrayStorage* storage)
{
VM& vm = exec->vm();
auto scope = DECLARE_THROW_SCOPE(vm);
unsigned length = storage->length();
RELEASE_ASSERT(startIndex <= length);
// If the array contains holes or is otherwise in an abnormal state,
// use the generic algorithm in ArrayPrototype.
if (storage->hasHoles() || storage->inSparseMode() || shouldUseSlowPut(indexingType()))
return false;
bool moveFront = !startIndex || startIndex < length / 2;
unsigned vectorLength = storage->vectorLength();
// Need to have GC deferred around the unshiftCountSlowCase(), since that leaves the butterfly in
// a weird state: some parts of it will be left uninitialized, which we will fill in here.
DeferGC deferGC(vm.heap);
auto locker = holdLock(cellLock());
if (moveFront && storage->m_indexBias >= count) {
Butterfly* newButterfly = storage->butterfly()->unshift(structure(vm), count);
storage = newButterfly->arrayStorage();
storage->m_indexBias -= count;
storage->setVectorLength(vectorLength + count);
setButterfly(vm, newButterfly);
} else if (!moveFront && vectorLength - length >= count)
storage = storage->butterfly()->arrayStorage();
else if (unshiftCountSlowCase(locker, vm, deferGC, moveFront, count))
storage = arrayStorage();
else {
throwOutOfMemoryError(exec, scope);
return true;
}
WriteBarrier<Unknown>* vector = storage->m_vector;
if (startIndex) {
if (moveFront)
memmove(vector, vector + count, startIndex * sizeof(JSValue));
else if (length - startIndex)
memmove(vector + startIndex + count, vector + startIndex, (length - startIndex) * sizeof(JSValue));
}
for (unsigned i = 0; i < count; i++)
vector[i + startIndex].clear();
return true;
}
bool JSArray::unshiftCountWithAnyIndexingType(ExecState* exec, unsigned startIndex, unsigned count)
{
VM& vm = exec->vm();
auto scope = DECLARE_THROW_SCOPE(vm);
ensureWritable(vm);
Butterfly* butterfly = this->butterfly();
switch (indexingType()) {
case ArrayClass:
case ArrayWithUndecided:
// We could handle this. But it shouldn't ever come up, so we won't.
return false;
case ArrayWithInt32:
case ArrayWithContiguous: {
unsigned oldLength = butterfly->publicLength();
// We may have to walk the entire array to do the unshift. We're willing to do so
// only if it's not horribly slow.
if (oldLength - startIndex >= MIN_SPARSE_ARRAY_INDEX)
RELEASE_AND_RETURN(scope, unshiftCountWithArrayStorage(exec, startIndex, count, ensureArrayStorage(vm)));
Checked<unsigned, RecordOverflow> checkedLength(oldLength);
checkedLength += count;
unsigned newLength;
if (CheckedState::DidOverflow == checkedLength.safeGet(newLength)) {
throwOutOfMemoryError(exec, scope);
return true;
}
if (newLength > MAX_STORAGE_VECTOR_LENGTH)
return false;
if (!ensureLength(vm, newLength)) {
throwOutOfMemoryError(exec, scope);
return true;
}
butterfly = this->butterfly();
// We have to check for holes before we start moving things around so that we don't get halfway
// through shifting and then realize we should have been in ArrayStorage mode.
for (unsigned i = oldLength; i-- > startIndex;) {
JSValue v = butterfly->contiguous().at(this, i).get();
if (UNLIKELY(!v))
RELEASE_AND_RETURN(scope, unshiftCountWithArrayStorage(exec, startIndex, count, ensureArrayStorage(vm)));
}
for (unsigned i = oldLength; i-- > startIndex;) {
JSValue v = butterfly->contiguous().at(this, i).get();
ASSERT(v);
butterfly->contiguous().at(this, i + count).setWithoutWriteBarrier(v);
}
// Our memmoving of values around in the array could have concealed some of them from
// the collector. Let's make sure that the collector scans this object again.
vm.heap.writeBarrier(this);
// NOTE: we're leaving being garbage in the part of the array that we shifted out
// of. This is fine because the caller is required to store over that area, and
// in contiguous mode storing into a hole is guaranteed to behave exactly the same
// as storing over an existing element.
return true;
}
case ArrayWithDouble: {
unsigned oldLength = butterfly->publicLength();
// We may have to walk the entire array to do the unshift. We're willing to do so
// only if it's not horribly slow.
if (oldLength - startIndex >= MIN_SPARSE_ARRAY_INDEX)
RELEASE_AND_RETURN(scope, unshiftCountWithArrayStorage(exec, startIndex, count, ensureArrayStorage(vm)));
Checked<unsigned, RecordOverflow> checkedLength(oldLength);
checkedLength += count;
unsigned newLength;
if (CheckedState::DidOverflow == checkedLength.safeGet(newLength)) {
throwOutOfMemoryError(exec, scope);
return true;
}
if (newLength > MAX_STORAGE_VECTOR_LENGTH)
return false;
if (!ensureLength(vm, newLength)) {
throwOutOfMemoryError(exec, scope);
return true;
}
butterfly = this->butterfly();
// We have to check for holes before we start moving things around so that we don't get halfway
// through shifting and then realize we should have been in ArrayStorage mode.
for (unsigned i = oldLength; i-- > startIndex;) {
double v = butterfly->contiguousDouble().at(this, i);
if (UNLIKELY(v != v))
RELEASE_AND_RETURN(scope, unshiftCountWithArrayStorage(exec, startIndex, count, ensureArrayStorage(vm)));
}
for (unsigned i = oldLength; i-- > startIndex;) {
double v = butterfly->contiguousDouble().at(this, i);
ASSERT(v == v);
butterfly->contiguousDouble().at(this, i + count) = v;
}
// NOTE: we're leaving being garbage in the part of the array that we shifted out
// of. This is fine because the caller is required to store over that area, and
// in contiguous mode storing into a hole is guaranteed to behave exactly the same
// as storing over an existing element.
return true;
}
case ArrayWithArrayStorage:
case ArrayWithSlowPutArrayStorage:
RELEASE_AND_RETURN(scope, unshiftCountWithArrayStorage(exec, startIndex, count, arrayStorage()));
default:
CRASH();
return false;
}
}
void JSArray::fillArgList(ExecState* exec, MarkedArgumentBuffer& args)
{
unsigned i = 0;
unsigned vectorEnd;
WriteBarrier<Unknown>* vector;
Butterfly* butterfly = this->butterfly();
switch (indexingType()) {
case ArrayClass:
return;
case ArrayWithUndecided: {
vector = 0;
vectorEnd = 0;
break;
}
case ArrayWithInt32:
case ArrayWithContiguous: {
vectorEnd = butterfly->publicLength();
vector = butterfly->contiguous().data();
break;
}
case ArrayWithDouble: {
vector = 0;
vectorEnd = 0;
for (; i < butterfly->publicLength(); ++i) {
double v = butterfly->contiguousDouble().at(this, i);
if (v != v)
break;
args.append(JSValue(JSValue::EncodeAsDouble, v));
}
break;
}
case ARRAY_WITH_ARRAY_STORAGE_INDEXING_TYPES: {
ArrayStorage* storage = butterfly->arrayStorage();
vector = storage->m_vector;
vectorEnd = std::min(storage->length(), storage->vectorLength());
break;
}
default:
CRASH();
#if COMPILER_QUIRK(CONSIDERS_UNREACHABLE_CODE)
vector = 0;
vectorEnd = 0;
break;
#endif
}
for (; i < vectorEnd; ++i) {
WriteBarrier<Unknown>& v = vector[i];
if (!v)
break;
args.append(v.get());
}
// FIXME: What prevents this from being called with a RuntimeArray? The length function will always return 0 in that case.
for (; i < length(); ++i)
args.append(get(exec, i));
}
void JSArray::copyToArguments(ExecState* exec, VirtualRegister firstElementDest, unsigned offset, unsigned length)
{
VM& vm = exec->vm();
auto scope = DECLARE_THROW_SCOPE(vm);
unsigned i = offset;
WriteBarrier<Unknown>* vector;
unsigned vectorEnd;
length += offset; // We like to think of the length as being our length, rather than the output length.
// FIXME: What prevents this from being called with a RuntimeArray? The length function will always return 0 in that case.
ASSERT(length == this->length());
Butterfly* butterfly = this->butterfly();
switch (indexingType()) {
case ArrayClass:
return;
case ArrayWithUndecided: {
vector = 0;
vectorEnd = 0;
break;
}
case ArrayWithInt32:
case ArrayWithContiguous: {
vector = butterfly->contiguous().data();
vectorEnd = butterfly->publicLength();
break;
}
case ArrayWithDouble: {
vector = 0;
vectorEnd = 0;
for (; i < butterfly->publicLength(); ++i) {
ASSERT(i < butterfly->vectorLength());
double v = butterfly->contiguousDouble().at(this, i);
if (v != v)
break;
exec->r(firstElementDest + i - offset) = JSValue(JSValue::EncodeAsDouble, v);
}
break;
}
case ARRAY_WITH_ARRAY_STORAGE_INDEXING_TYPES: {
ArrayStorage* storage = butterfly->arrayStorage();
vector = storage->m_vector;
vectorEnd = std::min(length, storage->vectorLength());
break;
}
default:
CRASH();
#if COMPILER_QUIRK(CONSIDERS_UNREACHABLE_CODE)
vector = 0;
vectorEnd = 0;
break;
#endif
}
for (; i < vectorEnd; ++i) {
WriteBarrier<Unknown>& v = vector[i];
if (!v)
break;
exec->r(firstElementDest + i - offset) = v.get();
}
for (; i < length; ++i) {
exec->r(firstElementDest + i - offset) = get(exec, i);
RETURN_IF_EXCEPTION(scope, void());
}
}
bool JSArray::isIteratorProtocolFastAndNonObservable()
{
JSGlobalObject* globalObject = this->globalObject();
if (!globalObject->isArrayPrototypeIteratorProtocolFastAndNonObservable())
return false;
VM& vm = globalObject->vm();
Structure* structure = this->structure(vm);
// This is the fast case. Many arrays will be an original array.
if (globalObject->isOriginalArrayStructure(structure))
return true;
if (structure->mayInterceptIndexedAccesses())
return false;
if (getPrototypeDirect(vm) != globalObject->arrayPrototype())
return false;
if (getDirectOffset(vm, vm.propertyNames->iteratorSymbol) != invalidOffset)
return false;
return true;
}
inline JSArray* constructArray(ObjectInitializationScope& scope, Structure* arrayStructure, unsigned length)
{
JSArray* array = JSArray::tryCreateUninitializedRestricted(scope, arrayStructure, length);
// FIXME: we should probably throw an out of memory error here, but
// when making this change we should check that all clients of this
// function will correctly handle an exception being thrown from here.
// https://bugs.webkit.org/show_bug.cgi?id=169786
RELEASE_ASSERT(array);
// FIXME: We only need this for subclasses of Array because we might need to allocate a new structure to change
// indexing types while initializing. If this triggered a GC then we might scan our currently uninitialized
// array and crash. https://bugs.webkit.org/show_bug.cgi?id=186811
if (!arrayStructure->globalObject()->isOriginalArrayStructure(arrayStructure))
JSArray::eagerlyInitializeButterfly(scope, array, length);
return array;
}
JSArray* constructArray(ExecState* exec, Structure* arrayStructure, const ArgList& values)
{
VM& vm = exec->vm();
unsigned length = values.size();
ObjectInitializationScope scope(vm);
JSArray* array = constructArray(scope, arrayStructure, length);
for (unsigned i = 0; i < length; ++i)
array->initializeIndex(scope, i, values.at(i));
return array;
}
JSArray* constructArray(ExecState* exec, Structure* arrayStructure, const JSValue* values, unsigned length)
{
VM& vm = exec->vm();
ObjectInitializationScope scope(vm);
JSArray* array = constructArray(scope, arrayStructure, length);
for (unsigned i = 0; i < length; ++i)
array->initializeIndex(scope, i, values[i]);
return array;
}
JSArray* constructArrayNegativeIndexed(ExecState* exec, Structure* arrayStructure, const JSValue* values, unsigned length)
{
VM& vm = exec->vm();
ObjectInitializationScope scope(vm);
JSArray* array = constructArray(scope, arrayStructure, length);
for (int i = 0; i < static_cast<int>(length); ++i)
array->initializeIndex(scope, i, values[-i]);
return array;
}
} // namespace JSC