| /* |
| * Copyright (C) 2018 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #ifndef INCLUDE_PERFETTO_EXT_BASE_EVENT_FD_H_ |
| #define INCLUDE_PERFETTO_EXT_BASE_EVENT_FD_H_ |
| |
| #include "perfetto/base/build_config.h" |
| #include "perfetto/base/platform_handle.h" |
| #include "perfetto/ext/base/scoped_file.h" |
| |
| namespace perfetto { |
| namespace base { |
| |
| // A waitable event that can be used with poll/select. |
| // This is really a wrapper around eventfd_create with a pipe-based fallback |
| // for other platforms where eventfd is not supported. |
| class EventFd { |
| public: |
| EventFd(); |
| ~EventFd(); |
| EventFd(EventFd&&) noexcept = default; |
| EventFd& operator=(EventFd&&) = default; |
| |
| // The non-blocking file descriptor that can be polled to wait for the event. |
| PlatformHandle fd() const { return event_handle_.get(); } |
| |
| // Can be called from any thread. |
| void Notify(); |
| |
| // Can be called from any thread. If more Notify() are queued a Clear() call |
| // can clear all of them (up to 16 per call). |
| void Clear(); |
| |
| private: |
| // The eventfd, when eventfd is supported, otherwise this is the read end of |
| // the pipe for fallback mode. |
| ScopedPlatformHandle event_handle_; |
| |
| #if !PERFETTO_BUILDFLAG(PERFETTO_OS_LINUX) && \ |
| !PERFETTO_BUILDFLAG(PERFETTO_OS_ANDROID) && \ |
| !PERFETTO_BUILDFLAG(PERFETTO_OS_WIN) |
| // On Mac and other non-Linux UNIX platforms a pipe-based fallback is used. |
| // The write end of the wakeup pipe. |
| ScopedFile write_fd_; |
| #endif |
| }; |
| |
| } // namespace base |
| } // namespace perfetto |
| |
| #endif // INCLUDE_PERFETTO_EXT_BASE_EVENT_FD_H_ |