1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
3 /* This Source Code Form is subject to the terms of the Mozilla Public
4  * License, v. 2.0. If a copy of the MPL was not distributed with this
5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
6 
7 #ifndef SELF_REF_H
8 #define SELF_REF_H
9 
10 #include "mozilla/Attributes.h"
11 
12 namespace mozilla {
13 
14 template <class T>
15 class SelfReference {
16  public:
SelfReference()17   SelfReference() : mHeld(false) {}
~SelfReference()18   ~SelfReference() {
19     NS_ASSERTION(!mHeld, "Forgot to drop the self reference?");
20   }
21 
Take(T * t)22   void Take(T* t) {
23     if (!mHeld) {
24       mHeld = true;
25       t->AddRef();
26     }
27   }
Drop(T * t)28   void Drop(T* t) {
29     if (mHeld) {
30       mHeld = false;
31       t->Release();
32     }
33   }
34 
35   MOZ_IMPLICIT operator bool() const { return mHeld; }
36 
37   SelfReference(const SelfReference& aOther) = delete;
38   void operator=(const SelfReference& aOther) = delete;
39 
40  private:
41   bool mHeld;
42 };
43 
44 }  // namespace mozilla
45 
46 #endif  // SELF_REF_H
47