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/*
* Copyright (C) 2016 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 "JSGlobalObject.h"
#include "JSObject.h"
namespace JSC {
class JSFixedArray : public JSCell {
typedef JSCell Base;
public:
static const unsigned StructureFlags = Base::StructureFlags | StructureIsImmortal;
DECLARE_INFO;
static Structure* createStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype)
{
return Structure::create(vm, globalObject, prototype, TypeInfo(JSFixedArrayType, StructureFlags), info());
}
ALWAYS_INLINE static JSFixedArray* createFromArray(ExecState* exec, VM& vm, JSArray* array)
{
IndexingType indexingType = array->indexingType() & IndexingShapeMask;
unsigned length = array->length();
JSFixedArray* result = JSFixedArray::create(vm, vm.fixedArrayStructure.get(), length);
if (!length)
return result;
if (indexingType == ContiguousShape || indexingType == Int32Shape) {
for (unsigned i = 0; i < length; i++) {
JSValue value = array->butterfly()->contiguous()[i].get();
value = !!value ? value : jsUndefined();
result->buffer()[i].set(vm, result, value);
}
return result;
}
if (indexingType == DoubleShape) {
for (unsigned i = 0; i < length; i++) {
double d = array->butterfly()->contiguousDouble()[i];
JSValue value = std::isnan(d) ? jsUndefined() : JSValue(JSValue::EncodeAsDouble, d);
result->buffer()[i].set(vm, result, value);
}
return result;
}
auto throwScope = DECLARE_THROW_SCOPE(vm);
for (unsigned i = 0; i < length; i++) {
JSValue value = array->getDirectIndex(exec, i);
if (!value) {
// When we see a hole, we assume that it's safe to assume the get would have returned undefined.
// We may still call into this function when !globalObject->isArrayIteratorProtocolFastAndNonObservable(),
// however, if we do that, we ensure we're calling in with an array with all self properties between
// [0, length).
//
// We may also call into this during OSR exit to materialize a phantom fixed array.
// We may be creating a fixed array during OSR exit even after the iterator protocol changed.
// But, when the phantom would have logically been created, the protocol hadn't been
// changed. Therefore, it is sound to assume empty indices are jsUndefined().
value = jsUndefined();
}
RETURN_IF_EXCEPTION(throwScope, nullptr);
result->buffer()[i].set(vm, result, value);
}
return result;
}
ALWAYS_INLINE JSValue get(unsigned index)
{
ASSERT(index < m_size);
return buffer()[index].get();
}
ALWAYS_INLINE WriteBarrier<Unknown>* buffer() { return bitwise_cast<WriteBarrier<Unknown>*>(bitwise_cast<char*>(this) + offsetOfData()); }
static void visitChildren(JSCell*, SlotVisitor&);
unsigned size() const { return m_size; }
static size_t offsetOfSize() { return OBJECT_OFFSETOF(JSFixedArray, m_size); }
static size_t offsetOfData()
{
return WTF::roundUpToMultipleOf<sizeof(WriteBarrier<Unknown>)>(sizeof(JSFixedArray));
}
private:
unsigned m_size;
ALWAYS_INLINE static JSFixedArray* create(VM& vm, Structure* structure, unsigned size)
{
JSFixedArray* result = new (NotNull, allocateCell<JSFixedArray>(vm.heap, allocationSize(size))) JSFixedArray(vm, structure, size);
result->finishCreation(vm);
return result;
}
JSFixedArray(VM& vm, Structure* structure, unsigned size)
: Base(vm, structure)
, m_size(size)
{
for (unsigned i = 0; i < m_size; i++)
buffer()[i].setStartingValue(JSValue());
}
static size_t allocationSize(unsigned numItems)
{
return offsetOfData() + numItems * sizeof(WriteBarrier<Unknown>);
}
};
} // namespace JSC
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