base/mac/bind_objc_block.h

   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 // Callback<int(void)> callback = BindBlock(^{return 42;});
  18
  19 namespace base {
  20
  21 namespace internal {
  22
  23 // Helper functions to run the block contained in the parameter.
  24 template<typename R>
  25 R RunBlock(base::mac::ScopedBlock<R(^)()> block) {
  26   R(^extracted_block)() = block.get();
  27   return extracted_block();
  28 }
  29
  30 template<typename R, typename A1>
  31 R RunBlock(base::mac::ScopedBlock<R(^)(A1)> block, A1 a) {
  32   R(^extracted_block)(A1) = block.get();
  33   return extracted_block(a);
  34 }
  35
  36 }  // namespace internal
  37
  38 // Construct a callback with no argument from an objective-C block.
  39 template<typename R>
  40 base::Callback<R(void)> BindBlock(R(^block)()) {
  41   return base::Bind(&base::internal::RunBlock<R>,
  42                     base::mac::ScopedBlock<R(^)()>(Block_copy(block)));
  43 }
  44
  45 // Construct a callback with one argument from an objective-C block.
  46 template<typename R, typename A1>
  47 base::Callback<R(A1)> BindBlock(R(^block)(A1)) {
  48   return base::Bind(&base::internal::RunBlock<R, A1>,
  49                     base::mac::ScopedBlock<R(^)(A1)>(Block_copy(block)));
  50 }
  51
  52 }  // namespace base
  53
  54 #endif  // BASE_MAC_BIND_OBJC_BLOCK_H_