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 <stdint.h> 21 #include <time.h> 22 23 #include <functional> 24 #include <memory> 25 #include <vector> 26 27 struct IOEvent; 28 typedef IOEvent* IOEventRef; 29 struct event_base; 30 31 // IOEventLoop is a class wrapper of libevent, it monitors events happened, 32 // and calls the corresponding callbacks. Possible events are: file ready to 33 // read, file ready to write, signal happens, periodic timer timeout. 34 class IOEventLoop { 35 public: 36 IOEventLoop(); 37 ~IOEventLoop(); 38 39 // Use precise timer for periodic events which want precision in ms. 40 bool UsePreciseTimer(); 41 42 // Register a read Event, so [callback] is called when [fd] can be read 43 // without blocking. If registered successfully, return the reference 44 // to control the Event, otherwise return nullptr. 45 IOEventRef AddReadEvent(int fd, const std::function<bool()>& callback); 46 47 // Register a write Event, so [callback] is called when [fd] can be written 48 // without blocking. 49 IOEventRef AddWriteEvent(int fd, const std::function<bool()>& callback); 50 51 // Register a signal Event, so [callback] is called each time signal [sig] 52 // happens. 53 bool AddSignalEvent(int sig, const std::function<bool()>& callback); 54 55 // Register a vector of signal Events. 56 bool AddSignalEvents(std::vector<int> sigs, 57 const std::function<bool()>& callback); 58 59 // Register a periodic Event, so [callback] is called periodically every 60 // [duration]. 61 IOEventRef AddPeriodicEvent(timeval duration, const std::function<bool()>& callback); 62 63 // Run a loop polling for Events. It only exits when ExitLoop() is called 64 // in a callback function of registered Events. 65 bool RunLoop(); 66 67 // Exit the loop started by RunLoop(). 68 bool ExitLoop(); 69 70 // Disable an Event, which can be enabled later. 71 static bool DisableEvent(IOEventRef ref); 72 // Enable a disabled Event. 73 static bool EnableEvent(IOEventRef ref); 74 75 // Unregister an Event. 76 static bool DelEvent(IOEventRef ref); 77 78 private: 79 bool EnsureInit(); 80 IOEventRef AddEvent(int fd_or_sig, int16_t events, timeval* timeout, 81 const std::function<bool()>& callback); 82 static void EventCallbackFn(int, int16_t, void*); 83 84 event_base* ebase_; 85 std::vector<std::unique_ptr<IOEvent>> events_; 86 bool has_error_; 87 bool use_precise_timer_; 88 bool in_loop_; 89 }; 90 91 #endif // SIMPLE_PERF_IOEVENT_LOOP_H_ 92