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1 // Copyright 2017 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 MOJO_PUBLIC_CPP_BINDINGS_LIB_DELETION_TRACKER_H_ | |
yzshen1
2017/03/03 00:03:50
Please make it consistent with the file name.
Ken Rockot(use gerrit already)
2017/03/03 00:37:05
N/A - delete this code and used WeakPtrs instead p
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6 #define MOJO_PUBLIC_CPP_BINDINGS_LIB_DELETION_TRACKER_H_ | |
7 | |
8 #include "base/macros.h" | |
9 | |
10 namespace mojo { | |
11 | |
12 // A helper which can be used to detect object deletion from within the object's | |
13 // own methods. | |
14 // | |
15 // To use this, a class should declare a DestructionTracker as a data member | |
16 // and guard any operation which might delete the owning object with a | |
17 // stack-local instance of DestructionTracker::Flag, like so: | |
18 // | |
19 // DestructionTracker::Flag was_destroyed(&destruction_tracker_); | |
20 // DoSomethingWhichMightDestroyThis(); | |
21 // if (was_destroyed) | |
22 // return; // Escape safely | |
23 // // Continue doing stuff to |this|. | |
24 // | |
25 // This mechanism supports multiple DestructionTracker::Flag instances nested | |
26 // within the call stack so that methods which use it can be reentrant. | |
27 class DestructionTracker { | |
28 public: | |
29 class Flag { | |
30 public: | |
31 explicit Flag(DestructionTracker* tracker); | |
32 ~Flag(); | |
33 | |
34 explicit operator bool() const { return was_destroyed_; } | |
yzshen1
2017/03/03 00:03:50
can we use !tracker_ to indicate destructed?
Ken Rockot(use gerrit already)
2017/03/03 00:37:05
N/A
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35 | |
36 private: | |
37 friend class DestructionTracker; | |
38 | |
39 void NotifyDestroyed(); | |
40 | |
41 DestructionTracker* tracker_; | |
42 Flag* const outer_flag_; | |
43 bool was_destroyed_ = false; | |
44 | |
45 DISALLOW_COPY_AND_ASSIGN(Flag); | |
46 }; | |
47 | |
48 DestructionTracker(); | |
49 ~DestructionTracker(); | |
50 | |
51 private: | |
52 void SetFlag(Flag* flag); | |
53 | |
54 Flag* flag_ = nullptr; | |
55 | |
56 DISALLOW_COPY_AND_ASSIGN(DestructionTracker); | |
57 }; | |
58 | |
59 } // namespace mojo | |
60 | |
61 #endif // MOJO_PUBLIC_CPP_BINDINGS_LIB_DELETION_TRACKER_H_ | |
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