1 /* 2 * Copyright (C) 2016 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef SIMPLE_PERF_IOEVENT_LOOP_H_ 18 #define SIMPLE_PERF_IOEVENT_LOOP_H_ 19 20 #include <time.h> 21 22 #include <functional> 23 #include <memory> 24 #include <vector> 25 26 struct IOEvent; 27 typedef IOEvent* IOEventRef; 28 struct event_base; 29 30 // IOEventLoop is a class wrapper of libevent, it monitors events happened, 31 // and calls the corresponding callbacks. Possible events are: file ready to 32 // read, file ready to write, signal happens, periodic timer timeout. 33 class IOEventLoop { 34 public: 35 IOEventLoop(); 36 ~IOEventLoop(); 37 38 // Register a read Event, so [callback] is called when [fd] can be read 39 // without blocking. If registered successfully, return the reference 40 // to control the Event, otherwise return nullptr. 41 IOEventRef AddReadEvent(int fd, const std::function<bool()>& callback); 42 43 // Register a write Event, so [callback] is called when [fd] can be written 44 // without blocking. 45 IOEventRef AddWriteEvent(int fd, const std::function<bool()>& callback); 46 47 // Register a signal Event, so [callback] is called each time signal [sig] 48 // happens. 49 bool AddSignalEvent(int sig, const std::function<bool()>& callback); 50 51 // Register a vector of signal Events. 52 bool AddSignalEvents(std::vector<int> sigs, 53 const std::function<bool()>& callback); 54 55 // Register a periodic Event, so [callback] is called periodically every 56 // [duration]. 57 bool AddPeriodicEvent(timeval duration, 58 const std::function<bool()>& callback); 59 60 // Run a loop polling for Events. It only exits when ExitLoop() is called 61 // in a callback function of registered Events. 62 bool RunLoop(); 63 64 // Exit the loop started by RunLoop(). 65 bool ExitLoop(); 66 67 // Disable an Event, which can be enabled later. 68 static bool DisableEvent(IOEventRef ref); 69 // Enable a disabled Event. 70 static bool EnableEvent(IOEventRef ref); 71 72 // Unregister an Event. 73 static bool DelEvent(IOEventRef ref); 74 75 private: 76 bool EnsureInit(); 77 IOEventRef AddEvent(int fd_or_sig, short events, timeval* timeout, 78 const std::function<bool()>& callback); 79 static void EventCallbackFn(int, short, void*); 80 81 event_base* ebase_; 82 std::vector<std::unique_ptr<IOEvent>> events_; 83 bool has_error_; 84 }; 85 86 #endif // SIMPLE_PERF_IOEVENT_LOOP_H_ 87