// Copyright (c) 2012 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 BASE_TASK_SEQUENCED_TASK_RUNNER_HELPERS_H_ #define BASE_TASK_SEQUENCED_TASK_RUNNER_HELPERS_H_ #include namespace base { class SequencedTaskRunner; // Template helpers which use function indirection to erase T from the // function signature while still remembering it so we can call the // correct destructor/release function. // // We use this trick so we don't need to include bind.h in a header // file like sequenced_task_runner.h. We also wrap the helpers in a // templated class to make it easier for users of DeleteSoon to // declare the helper as a friend. template class DeleteHelper { private: static void DoDelete(const void* object) { delete static_cast(object); } friend class SequencedTaskRunner; }; template class DeleteUniquePtrHelper { private: static void DoDelete(const void* object) { // Carefully unwrap `object`. T could have originally been const-qualified // or not, and it is important to ensure that the constness matches in order // to use the right specialization of std::default_delete... std::unique_ptr destroyer(const_cast(static_cast(object))); } friend class SequencedTaskRunner; }; template class ReleaseHelper { private: static void DoRelease(const void* object) { static_cast(object)->Release(); } friend class SequencedTaskRunner; }; } // namespace base #endif // BASE_TASK_SEQUENCED_TASK_RUNNER_HELPERS_H_