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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <Block.h>
#include "base/bind.h"
#include "base/callback_forward.h"
#include "base/mac/scoped_block.h"
// BindBlock builds a callback from an Objective-C block. Example usages:
// Closure closure = BindBlock(^{DoSomething();});
// Callback<int(void)> callback = BindBlock(^{return 42;});
// Callback<void(const std::string&, const std::string&)> callback =
// BindBlock(^(const std::string& arg0, const std::string& arg1) {
// ...
// });
namespace base {
namespace internal {
// Helper functions to run the block contained in the parameter.
template<typename R>
R RunBlock(base::mac::ScopedBlock<R(^)()> block) {
R(^extracted_block)() = block.get();
return extracted_block();
template<typename R, typename A1>
R RunBlock(base::mac::ScopedBlock<R(^)(A1)> block, A1 a) {
R(^extracted_block)(A1) = block.get();
return extracted_block(a);
template<typename R, typename A1, typename A2>
R RunBlock(base::mac::ScopedBlock<R(^)(A1, A2)> block, A1 a, A2 b) {
R(^extracted_block)(A1, A2) = block.get();
return extracted_block(a, b);
} // namespace internal
// Construct a callback with no argument from an objective-C block.
template<typename R>
base::Callback<R(void)> BindBlock(R(^block)()) {
return base::Bind(&base::internal::RunBlock<R>,
// Construct a callback with one argument from an objective-C block.
template<typename R, typename A1>
base::Callback<R(A1)> BindBlock(R(^block)(A1)) {
return base::Bind(&base::internal::RunBlock<R, A1>,
// Construct a callback with two arguments from an objective-C block.
template<typename R, typename A1, typename A2>
base::Callback<R(A1, A2)> BindBlock(R(^block)(A1, A2)) {
return base::Bind(&base::internal::RunBlock<R, A1, A2>,
base::mac::ScopedBlock<R(^)(A1, A2)>(Block_copy(block)));
} // namespace base