| // Copyright 2013 The Flutter 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 FLUTTER_FML_CLOSURE_H_ |
| #define FLUTTER_FML_CLOSURE_H_ |
| |
| #include <functional> |
| |
| #include "flutter/fml/macros.h" |
| |
| namespace fml { |
| |
| using closure = std::function<void()>; |
| |
| //------------------------------------------------------------------------------ |
| /// @brief Wraps a closure that is invoked in the destructor unless |
| /// released by the caller. |
| /// |
| /// This is especially useful in dealing with APIs that return a |
| /// resource by accepting ownership of a sub-resource and a closure |
| /// that releases that resource. When such APIs are chained, each |
| /// link in the chain must check that the next member in the chain |
| /// has accepted the resource. If not, it must invoke the closure |
| /// eagerly. Not doing this results in a resource leak in the |
| /// erroneous case. Using this wrapper, the closure can be released |
| /// once the next call in the chain has successfully accepted |
| /// ownership of the resource. If not, the closure gets invoked |
| /// automatically at the end of the scope. This covers the cases |
| /// where there are early returns as well. |
| /// |
| class ScopedCleanupClosure { |
| public: |
| ScopedCleanupClosure() = default; |
| |
| explicit ScopedCleanupClosure(const fml::closure& closure) |
| : closure_(closure) {} |
| |
| ~ScopedCleanupClosure() { |
| if (closure_) { |
| closure_(); |
| } |
| } |
| |
| fml::closure SetClosure(const fml::closure& closure) { |
| auto old_closure = closure_; |
| closure_ = closure; |
| return old_closure; |
| } |
| |
| fml::closure Release() { |
| fml::closure closure = closure_; |
| closure_ = nullptr; |
| return closure; |
| } |
| |
| private: |
| fml::closure closure_; |
| |
| FML_DISALLOW_COPY_AND_ASSIGN(ScopedCleanupClosure); |
| }; |
| |
| } // namespace fml |
| |
| #endif // FLUTTER_FML_CLOSURE_H_ |