chrome_frame/ns_isupports_impl.h

   1 // Copyright (c) 2009 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 CHROME_FRAME_NS_ISUPPORTS_IMPL_H_
   6 #define CHROME_FRAME_NS_ISUPPORTS_IMPL_H_
   7
   8 #include "base/basictypes.h"
   9 #include "base/logging.h"
  10 #include "base/platform_thread.h"
  11 #include "chrome_frame/utils.h"
  12 #include "third_party/xulrunner-sdk/win/include/xpcom/nscore.h"
  13 #include "third_party/xulrunner-sdk/win/include/xpcom/nsid.h"
  14 #include "third_party/xulrunner-sdk/win/include/xpcom/nsISupportsBase.h"
  15
  16 // A simple single-threaded implementation of methods needed to support
  17 // nsISupports. Must be inherited by classes that also inherit from nsISupports.
  18 template<class Derived>
  19 class NsISupportsImplBase {
  20  public:
  21   NsISupportsImplBase() : nsiimpl_ref_count_(0) {
  22     nsiimpl_thread_id_ = PlatformThread::CurrentId();
  23   }
  24
  25   virtual ~NsISupportsImplBase() {
  26     DCHECK(nsiimpl_thread_id_ == PlatformThread::CurrentId());
  27   }
  28
  29   NS_IMETHOD QueryInterface(REFNSIID iid, void** ptr) {
  30     DCHECK(nsiimpl_thread_id_ == PlatformThread::CurrentId());
  31     nsresult res = NS_NOINTERFACE;
  32
  33     if (memcmp(&iid, &__uuidof(nsISupports), sizeof(nsIID)) == 0) {
  34       *ptr = static_cast<nsISupports*>(static_cast<typename Derived*>(this));
  35       AddRef();
  36       res = NS_OK;
  37     }
  38
  39     return res;
  40   }
  41
  42   NS_IMETHOD_(nsrefcnt) AddRef() {
  43     DCHECK(nsiimpl_thread_id_ == PlatformThread::CurrentId());
  44     nsiimpl_ref_count_++;
  45     return nsiimpl_ref_count_;
  46   }
  47
  48   NS_IMETHOD_(nsrefcnt) Release() {
  49     DCHECK(nsiimpl_thread_id_ == PlatformThread::CurrentId());
  50     nsiimpl_ref_count_--;
  51
  52     if (!nsiimpl_ref_count_) {
  53       Derived* me = static_cast<Derived*>(this);
  54       delete me;
  55       return 0;
  56     }
  57
  58     return nsiimpl_ref_count_;
  59   }
  60
  61  protected:
  62   nsrefcnt nsiimpl_ref_count_;
  63   AddRefModule nsiimpl_module_ref_;
  64   // used to DCHECK on expected single-threaded usage
  65   uint64 nsiimpl_thread_id_;
  66 };
  67
  68 #endif  // CHROME_FRAME_NS_ISUPPORTS_IMPL_H_