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1 // Copyright 2014 The Chromium Authors. All rights reserved. | |
2 // Use of this source code is governed by a BSD-style license that can be | |
3 // found in the LICENSE file. | |
4 | |
5 #ifndef MOJO_PUBLIC_CPP_BINDINGS_LIB_CALLBACK_INTERNAL_H_ | |
6 #define MOJO_PUBLIC_CPP_BINDINGS_LIB_CALLBACK_INTERNAL_H_ | |
7 | |
8 #include "mojo/public/cpp/bindings/lib/template_util.h" | |
9 | |
10 namespace mojo { | |
11 class String; | |
12 | |
13 namespace internal { | |
14 | |
15 template <typename T> | |
16 struct Callback_ParamTraits { | |
17 typedef T ForwardType; | |
18 }; | |
19 | |
20 template <> | |
21 struct Callback_ParamTraits<String> { | |
22 typedef const String& ForwardType; | |
23 }; | |
24 | |
25 template <typename T, typename... Args> | |
26 struct HasCompatibleCallOperator { | |
27 // This template's second parameter is the signature of the operator() | |
28 // overload we want to try to detect: | |
29 // void operator()(Args...) const; | |
30 template <typename U, | |
31 void (U::*)( | |
32 typename internal::Callback_ParamTraits<Args>::ForwardType...) | |
33 const> | |
34 struct TestType {}; | |
35 | |
36 // This matches type U if it has a call operator with the | |
37 // expected signature. | |
38 template <typename U> | |
39 static YesType Test(TestType<U, &U::operator()>*); | |
40 | |
41 // This matches anything else. | |
42 template <typename U> | |
43 static NoType Test(...); | |
44 | |
45 // HasCompatibleCallOperator<T, Args...>::value will be true if T has a | |
46 // compatible call operator. | |
47 enum { value = (sizeof(Test<T>(nullptr)) == sizeof(YesType)) }; | |
48 }; | |
49 | |
50 } // namespace internal | |
51 } // namespace mojo | |
52 | |
53 #endif // MOJO_PUBLIC_CPP_BINDINGS_LIB_CALLBACK_INTERNAL_H_ | |
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