Index: mojo/public/cpp/bindings/lib/destruction_tracker.h |
diff --git a/mojo/public/cpp/bindings/lib/destruction_tracker.h b/mojo/public/cpp/bindings/lib/destruction_tracker.h |
new file mode 100644 |
index 0000000000000000000000000000000000000000..7508487faf005dddfdb4e92d4eba2af58d9bb8ac |
--- /dev/null |
+++ b/mojo/public/cpp/bindings/lib/destruction_tracker.h |
@@ -0,0 +1,61 @@ |
+// Copyright 2017 The Chromium Authors. All rights reserved. |
+// Use of this source code is governed by a BSD-style license that can be |
+// found in the LICENSE file. |
+ |
+#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
|
+#define MOJO_PUBLIC_CPP_BINDINGS_LIB_DELETION_TRACKER_H_ |
+ |
+#include "base/macros.h" |
+ |
+namespace mojo { |
+ |
+// A helper which can be used to detect object deletion from within the object's |
+// own methods. |
+// |
+// To use this, a class should declare a DestructionTracker as a data member |
+// and guard any operation which might delete the owning object with a |
+// stack-local instance of DestructionTracker::Flag, like so: |
+// |
+// DestructionTracker::Flag was_destroyed(&destruction_tracker_); |
+// DoSomethingWhichMightDestroyThis(); |
+// if (was_destroyed) |
+// return; // Escape safely |
+// // Continue doing stuff to |this|. |
+// |
+// This mechanism supports multiple DestructionTracker::Flag instances nested |
+// within the call stack so that methods which use it can be reentrant. |
+class DestructionTracker { |
+ public: |
+ class Flag { |
+ public: |
+ explicit Flag(DestructionTracker* tracker); |
+ ~Flag(); |
+ |
+ 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
|
+ |
+ private: |
+ friend class DestructionTracker; |
+ |
+ void NotifyDestroyed(); |
+ |
+ DestructionTracker* tracker_; |
+ Flag* const outer_flag_; |
+ bool was_destroyed_ = false; |
+ |
+ DISALLOW_COPY_AND_ASSIGN(Flag); |
+ }; |
+ |
+ DestructionTracker(); |
+ ~DestructionTracker(); |
+ |
+ private: |
+ void SetFlag(Flag* flag); |
+ |
+ Flag* flag_ = nullptr; |
+ |
+ DISALLOW_COPY_AND_ASSIGN(DestructionTracker); |
+}; |
+ |
+} // namespace mojo |
+ |
+#endif // MOJO_PUBLIC_CPP_BINDINGS_LIB_DELETION_TRACKER_H_ |