1// Copyright (c) 2012 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 BASE_MAC_BIND_OBJC_BLOCK_H_
6#define BASE_MAC_BIND_OBJC_BLOCK_H_
7
8#include <Block.h>
9
10#include "base/bind.h"
11#include "base/callback_forward.h"
12#include "base/mac/scoped_block.h"
13
14// BindBlock builds a callback from an Objective-C block. Example usages:
15//
16// Closure closure = BindBlock(^{DoSomething();});
17//
18// Callback<int(void)> callback = BindBlock(^{return 42;});
19//
20// Callback<void(const std::string&, const std::string&)> callback =
21//     BindBlock(^(const std::string& arg0, const std::string& arg1) {
22//         ...
23//     });
24
25namespace base {
26
27namespace internal {
28
29// Helper functions to run the block contained in the parameter.
30template<typename R>
31R RunBlock(base::mac::ScopedBlock<R(^)()> block) {
32  R(^extracted_block)() = block.get();
33  return extracted_block();
34}
35
36template<typename R, typename A1>
37R RunBlock(base::mac::ScopedBlock<R(^)(A1)> block, A1 a) {
38  R(^extracted_block)(A1) = block.get();
39  return extracted_block(a);
40}
41
42template<typename R, typename A1, typename A2>
43R RunBlock(base::mac::ScopedBlock<R(^)(A1, A2)> block, A1 a, A2 b) {
44  R(^extracted_block)(A1, A2) = block.get();
45  return extracted_block(a, b);
46}
47
48}  // namespace internal
49
50// Construct a callback with no argument from an objective-C block.
51template<typename R>
52base::Callback<R(void)> BindBlock(R(^block)()) {
53  return base::Bind(&base::internal::RunBlock<R>,
54                    base::mac::ScopedBlock<R(^)()>(Block_copy(block)));
55}
56
57// Construct a callback with one argument from an objective-C block.
58template<typename R, typename A1>
59base::Callback<R(A1)> BindBlock(R(^block)(A1)) {
60  return base::Bind(&base::internal::RunBlock<R, A1>,
61                    base::mac::ScopedBlock<R(^)(A1)>(Block_copy(block)));
62}
63
64// Construct a callback with two arguments from an objective-C block.
65template<typename R, typename A1, typename A2>
66base::Callback<R(A1, A2)> BindBlock(R(^block)(A1, A2)) {
67  return base::Bind(&base::internal::RunBlock<R, A1, A2>,
68                    base::mac::ScopedBlock<R(^)(A1, A2)>(Block_copy(block)));
69}
70
71}  // namespace base
72
73#endif  // BASE_MAC_BIND_OBJC_BLOCK_H_
74