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/*
* Copyright (C) 2009, 2010 Google 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:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * 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.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "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 THE COPYRIGHT
* OWNER 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.
*/
#ifndef THIRD_PARTY_BLINK_RENDERER_PLATFORM_WTF_CROSS_THREAD_COPIER_H_
#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_WTF_CROSS_THREAD_COPIER_H_
#include <type_traits>
#include "third_party/blink/renderer/platform/wtf/allocator/allocator.h"
#include "third_party/blink/renderer/platform/wtf/forward.h"
#include "third_party/blink/renderer/platform/wtf/wtf_size_t.h"
namespace WTF {
class SegmentedBuffer;
class String;
template <typename T>
struct CrossThreadCopierPassThrough {
STATIC_ONLY(CrossThreadCopierPassThrough);
typedef T Type;
static Type Copy(const T& parameter) { return parameter; }
};
template <typename T>
struct CrossThreadCopierByValuePassThrough {
STATIC_ONLY(CrossThreadCopierByValuePassThrough);
typedef T Type;
static Type Copy(T receiver) {
return receiver; // This is in fact a move.
}
};
template <typename T, bool isArithmeticOrEnum>
struct CrossThreadCopierBase;
// Arithmetic values (integers or floats) and enums can be safely copied.
template <typename T>
struct CrossThreadCopierBase<T, true> : public CrossThreadCopierPassThrough<T> {
STATIC_ONLY(CrossThreadCopierBase);
};
template <typename T>
struct CrossThreadCopier
: public CrossThreadCopierBase<T,
std::is_arithmetic<T>::value ||
std::is_enum<T>::value> {
STATIC_ONLY(CrossThreadCopier);
};
// To allow a type to be passed across threads using its copy constructor,
// provide a specialization of CrossThreadCopier<T>.
//
// * If the type is not defined in third_party/blink/
// ==> Choose one of the existing cross_thread_copier_*.h or add new one,
// and add a forward declaration and a CrossThreadCopier specialization
// for the type to the file.
// * If the type is defined in third_party/blink/public/
// ==> Add a forward declaration and a CrossThreadCopier specialization for
// the type to cross_thread_copier_public.h.
// * If the type is defined in third_party/blink/
// ==> Include cross_thread_copier.h from the header defining the type, and
// add a CrossThreadCopier specialization for the type to the header.
template <typename T, wtf_size_t inlineCapacity, typename Allocator>
struct CrossThreadCopier<Vector<T, inlineCapacity, Allocator>> {
STATIC_ONLY(CrossThreadCopier);
static_assert(std::is_enum<T>() || std::is_arithmetic<T>(),
"Vectors of this type are not known to be safe to pass to "
"another thread.");
using Type = Vector<T, inlineCapacity, Allocator>;
static Type Copy(Type value) { return value; }
};
template <wtf_size_t inlineCapacity, typename Allocator>
struct CrossThreadCopier<Vector<String, inlineCapacity, Allocator>>
: public CrossThreadCopierPassThrough<
Vector<String, inlineCapacity, Allocator>> {
STATIC_ONLY(CrossThreadCopier);
};
template <>
struct CrossThreadCopier<SegmentedBuffer>
: CrossThreadCopierByValuePassThrough<SegmentedBuffer> {
STATIC_ONLY(CrossThreadCopier);
};
template <>
struct CrossThreadCopier<AtomicString>
: public CrossThreadCopierPassThrough<AtomicString> {
STATIC_ONLY(CrossThreadCopier);
};
template <>
struct CrossThreadCopier<String> : public CrossThreadCopierPassThrough<String> {
STATIC_ONLY(CrossThreadCopier);
};
} // namespace WTF
#endif // THIRD_PARTY_BLINK_RENDERER_PLATFORM_WTF_CROSS_THREAD_COPIER_H_
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