Source/JavaScriptCore/wasm/js/JSWebAssemblyMemory.cpp

/*
 * 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
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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "config.h"
#include "JSWebAssemblyMemory.h"

#if ENABLE(WEBASSEMBLY)

#include "JSCInlines.h"

#include "JSArrayBuffer.h"
#include "ArrayBuffer.h"

namespace JSC {

const ClassInfo JSWebAssemblyMemory::s_info = { "WebAssembly.Memory", &Base::s_info, 0, CREATE_METHOD_TABLE(JSWebAssemblyMemory) };

JSWebAssemblyMemory* JSWebAssemblyMemory::create(VM& vm, Structure* structure, std::unique_ptr<Wasm::Memory>&& memory)
{
    auto* instance = new (NotNull, allocateCell<JSWebAssemblyMemory>(vm.heap)) JSWebAssemblyMemory(vm, structure, WTFMove(memory));
    instance->finishCreation(vm);
    return instance;
}

Structure* JSWebAssemblyMemory::createStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype)
{
    return Structure::create(vm, globalObject, prototype, TypeInfo(ObjectType, StructureFlags), info());
}

JSWebAssemblyMemory::JSWebAssemblyMemory(VM& vm, Structure* structure, std::unique_ptr<Wasm::Memory>&& memory)
    : Base(vm, structure)
    , m_memory(WTFMove(memory))
{
}

JSArrayBuffer* JSWebAssemblyMemory::buffer(VM& vm, JSGlobalObject* globalObject)
{
    if (m_bufferWrapper)
        return m_bufferWrapper.get();

    auto destructor = [] (void*) {
        // We don't need to do anything here to destroy the memory.
        // The ArrayBuffer backing the JSArrayBuffer is only owned by us,
        // so we guarantee its lifecylce.
    };
    m_buffer = ArrayBuffer::createFromBytes(memory()->memory(), memory()->size(), WTFMove(destructor));
    m_bufferWrapper.set(vm, this, JSArrayBuffer::create(vm, globalObject->m_arrayBufferStructure.get(), m_buffer.get()));
    RELEASE_ASSERT(m_bufferWrapper);
    return m_bufferWrapper.get();
}

void JSWebAssemblyMemory::finishCreation(VM& vm)
{
    Base::finishCreation(vm);
    ASSERT(inherits(info()));
}

void JSWebAssemblyMemory::destroy(JSCell* cell)
{
    static_cast<JSWebAssemblyMemory*>(cell)->JSWebAssemblyMemory::~JSWebAssemblyMemory();
}

void JSWebAssemblyMemory::visitChildren(JSCell* cell, SlotVisitor& visitor)
{
    auto* thisObject = jsCast<JSWebAssemblyMemory*>(cell);
    ASSERT_GC_OBJECT_INHERITS(thisObject, info());

    Base::visitChildren(thisObject, visitor);
    visitor.append(&thisObject->m_bufferWrapper);
}

} // namespace JSC

#endif // ENABLE(WEBASSEMBLY)