base/mac/scoped_cffiledescriptorref.h

   1 // Copyright 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_SCOPED_CFFILEDESCRIPTORREF_H_
   6 #define BASE_MAC_SCOPED_CFFILEDESCRIPTORREF_H_
   7
   8 #include <CoreFoundation/CoreFoundation.h>
   9
  10 #include "base/basictypes.h"
  11 #include "base/compiler_specific.h"
  12
  13 namespace base {
  14 namespace mac {
  15
  16 // ScopedCFFileDescriptorRef is designed after ScopedCFTypeRef<>. On
  17 // destruction, it will invalidate the file descriptor.
  18 // ScopedCFFileDescriptorRef (unlike ScopedCFTypeRef<>) does not support RETAIN
  19 // semantics, copying, or assignment, as doing so would increase the chances
  20 // that a file descriptor is invalidated while still in use.
  21 class ScopedCFFileDescriptorRef {
  22  public:
  23   explicit ScopedCFFileDescriptorRef(CFFileDescriptorRef fdref = NULL)
  24       : fdref_(fdref) {
  25   }
  26
  27   ~ScopedCFFileDescriptorRef() {
  28     if (fdref_) {
  29       CFFileDescriptorInvalidate(fdref_);
  30       CFRelease(fdref_);
  31     }
  32   }
  33
  34   void reset(CFFileDescriptorRef fdref = NULL) {
  35     if (fdref_ == fdref)
  36       return;
  37     if (fdref_) {
  38       CFFileDescriptorInvalidate(fdref_);
  39       CFRelease(fdref_);
  40     }
  41     fdref_ = fdref;
  42   }
  43
  44   bool operator==(CFFileDescriptorRef that) const {
  45     return fdref_ == that;
  46   }
  47
  48   bool operator!=(CFFileDescriptorRef that) const {
  49     return fdref_ != that;
  50   }
  51
  52   operator CFFileDescriptorRef() const {
  53     return fdref_;
  54   }
  55
  56   CFFileDescriptorRef get() const {
  57     return fdref_;
  58   }
  59
  60   CFFileDescriptorRef release() WARN_UNUSED_RESULT {
  61     CFFileDescriptorRef temp = fdref_;
  62     fdref_ = NULL;
  63     return temp;
  64   }
  65
  66  private:
  67   CFFileDescriptorRef fdref_;
  68
  69   DISALLOW_COPY_AND_ASSIGN(ScopedCFFileDescriptorRef);
  70 };
  71
  72 }  // namespace mac
  73 }  // namespace base
  74
  75 #endif  // BASE_MAC_SCOPED_CFFILEDESCRIPTORREF_H_