base/mac/scoped_block.h

   1 // Copyright (c) 2013 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_SCOPED_BLOCK_H_
   6 #define BASE_MAC_SCOPED_BLOCK_H_
   7
   8 #include <Block.h>
   9
  10 #include "base/basictypes.h"
  11 #include "base/compiler_specific.h"
  12 #include "base/memory/scoped_policy.h"
  13
  14 namespace base {
  15 namespace mac {
  16
  17 // ScopedBlock<> is patterned after ScopedCFTypeRef<>, but uses Block_copy() and
  18 // Block_release() instead of CFRetain() and CFRelease().
  19
  20 template<typename B>
  21 class ScopedBlock {
  22  public:
  23   explicit ScopedBlock(
  24       B block = NULL,
  25       base::scoped_policy::OwnershipPolicy policy = base::scoped_policy::ASSUME)
  26       : block_(block) {
  27     if (block_ && policy == base::scoped_policy::RETAIN)
  28       block_ = Block_copy(block);
  29   }
  30
  31   ScopedBlock(const ScopedBlock<B>& that)
  32       : block_(that.block_) {
  33     if (block_)
  34       block_ = Block_copy(block_);
  35   }
  36
  37   ~ScopedBlock() {
  38     if (block_)
  39       Block_release(block_);
  40   }
  41
  42   ScopedBlock& operator=(const ScopedBlock<B>& that) {
  43     reset(that.get(), base::scoped_policy::RETAIN);
  44     return *this;
  45   }
  46
  47   void reset(B block = NULL,
  48              base::scoped_policy::OwnershipPolicy policy =
  49                  base::scoped_policy::ASSUME) {
  50     if (block && policy == base::scoped_policy::RETAIN)
  51       block = Block_copy(block);
  52     if (block_)
  53       Block_release(block_);
  54     block_ = block;
  55   }
  56
  57   bool operator==(B that) const {
  58     return block_ == that;
  59   }
  60
  61   bool operator!=(B that) const {
  62     return block_ != that;
  63   }
  64
  65   operator B() const {
  66     return block_;
  67   }
  68
  69   B get() const {
  70     return block_;
  71   }
  72
  73   void swap(ScopedBlock& that) {
  74     B temp = that.block_;
  75     that.block_ = block_;
  76     block_ = temp;
  77   }
  78
  79   B release() WARN_UNUSED_RESULT {
  80     B temp = block_;
  81     block_ = NULL;
  82     return temp;
  83   }
  84
  85  private:
  86   B block_;
  87 };
  88
  89 }  // namespace mac
  90 }  // namespace base
  91
  92 #endif  // BASE_MAC_SCOPED_BLOCK_H_