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54 lines
1.5 KiB
C++
54 lines
1.5 KiB
C++
// Copyright 2014 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#ifndef MOJO_PUBLIC_CPP_BINDINGS_LIB_CALLBACK_INTERNAL_H_
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#define MOJO_PUBLIC_CPP_BINDINGS_LIB_CALLBACK_INTERNAL_H_
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#include "mojo/public/cpp/bindings/lib/template_util.h"
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namespace mojo {
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class String;
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namespace internal {
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template <typename T>
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struct Callback_ParamTraits {
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typedef T ForwardType;
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};
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template <>
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struct Callback_ParamTraits<String> {
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typedef const String& ForwardType;
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};
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template <typename T, typename... Args>
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struct HasCompatibleCallOperator {
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// This template's second parameter is the signature of the operator()
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// overload we want to try to detect:
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// void operator()(Args...) const;
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template <typename U,
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void (U::*)(
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typename internal::Callback_ParamTraits<Args>::ForwardType...)
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const>
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struct TestType {};
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// This matches type U if it has a call operator with the
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// expected signature.
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template <typename U>
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static YesType Test(TestType<U, &U::operator()>*);
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// This matches anything else.
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template <typename U>
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static NoType Test(...);
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// HasCompatibleCallOperator<T, Args...>::value will be true if T has a
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// compatible call operator.
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enum { value = (sizeof(Test<T>(nullptr)) == sizeof(YesType)) };
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};
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} // namespace internal
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} // namespace mojo
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#endif // MOJO_PUBLIC_CPP_BINDINGS_LIB_CALLBACK_INTERNAL_H_
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