base/mac/scoped_ioplugininterface.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_SCOPED_IOPLUGININTERFACE_H_
   6 #define BASE_MAC_SCOPED_IOPLUGININTERFACE_H_
   7
   8 #include <IOKit/IOKitLib.h>
   9
  10 #include "base/basictypes.h"
  11 #include "base/compiler_specific.h"
  12
  13 namespace base {
  14 namespace mac {
  15
  16 // Just like ScopedCFTypeRef but for IOCFPlugInInterface and friends
  17 // (IOUSBInterfaceStruct and IOUSBDeviceStruct320 in particular).
  18 template<typename T>
  19 class ScopedIOPluginInterface {
  20  public:
  21   typedef T** InterfaceT;
  22   typedef InterfaceT element_type;
  23
  24   explicit ScopedIOPluginInterface(InterfaceT object = NULL)
  25       : object_(object) {
  26   }
  27
  28   ~ScopedIOPluginInterface() {
  29     if (object_)
  30       (*object_)->Release(object_);
  31   }
  32
  33   void reset(InterfaceT object = NULL) {
  34     if (object_)
  35       (*object_)->Release(object_);
  36     object_ = object;
  37   }
  38
  39   bool operator==(InterfaceT that) const {
  40     return object_ == that;
  41   }
  42
  43   bool operator!=(InterfaceT that) const {
  44     return object_ != that;
  45   }
  46
  47   operator InterfaceT() const {
  48     return object_;
  49   }
  50
  51   InterfaceT get() const {
  52     return object_;
  53   }
  54
  55   void swap(ScopedIOPluginInterface& that) {
  56     InterfaceT temp = that.object_;
  57     that.object_ = object_;
  58     object_ = temp;
  59   }
  60
  61   InterfaceT release() WARN_UNUSED_RESULT {
  62     InterfaceT temp = object_;
  63     object_ = NULL;
  64     return temp;
  65   }
  66
  67  private:
  68   InterfaceT object_;
  69
  70   DISALLOW_COPY_AND_ASSIGN(ScopedIOPluginInterface);
  71 };
  72
  73 }  // namespace mac
  74 }  // namespace base
  75
  76 #endif  // BASE_MAC_SCOPED_IOPLUGININTERFACE_H_