| // Copyright 2016 The Fuchsia 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 LIB_FXL_MEMORY_WEAK_PTR_INTERNAL_H_ |
| #define LIB_FXL_MEMORY_WEAK_PTR_INTERNAL_H_ |
| |
| #include "src/lib/fxl/macros.h" |
| #include "src/lib/fxl/memory/ref_counted.h" |
| |
| namespace fxl { |
| namespace internal { |
| |
| // |WeakPtr<T>|s have a reference to a |WeakPtrFlag| to determine whether they |
| // are valid (non-null) or not. We do not store a |T*| in this object since |
| // there may also be |WeakPtr<U>|s to the same object, where |U| is a superclass |
| // of |T|. |
| // |
| // This class in not thread-safe, though references may be released on any |
| // thread (allowing weak pointers to be destroyed/reset/reassigned on any |
| // thread). |
| class WeakPtrFlag : public RefCountedThreadSafe<WeakPtrFlag> { |
| public: |
| WeakPtrFlag(); |
| ~WeakPtrFlag(); |
| |
| bool is_valid() const { return is_valid_; } |
| |
| void Invalidate(); |
| |
| private: |
| bool is_valid_; |
| |
| FXL_DISALLOW_COPY_AND_ASSIGN(WeakPtrFlag); |
| }; |
| |
| } // namespace internal |
| } // namespace fxl |
| |
| #endif // LIB_FXL_MEMORY_WEAK_PTR_INTERNAL_H_ |