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 // Use precise timer for periodic events which want precision in ms. 39 bool UsePreciseTimer(); 40 41 // Register a read Event, so [callback] is called when [fd] can be read 42 // without blocking. If registered successfully, return the reference 43 // to control the Event, otherwise return nullptr. 44 IOEventRef AddReadEvent(int fd, const std::function<bool()>& callback); 45 46 // Register a write Event, so [callback] is called when [fd] can be written 47 // without blocking. 48 IOEventRef AddWriteEvent(int fd, const std::function<bool()>& callback); 49 50 // Register a signal Event, so [callback] is called each time signal [sig] 51 // happens. 52 bool AddSignalEvent(int sig, const std::function<bool()>& callback); 53 54 // Register a vector of signal Events. 55 bool AddSignalEvents(std::vector<int> sigs, 56 const std::function<bool()>& callback); 57 58 // Register a periodic Event, so [callback] is called periodically every 59 // [duration]. 60 bool AddPeriodicEvent(timeval duration, 61 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, short events, timeval* timeout, 81 const std::function<bool()>& callback); 82 static void EventCallbackFn(int, short, void*); 83 84 event_base* ebase_; 85 std::vector<std::unique_ptr<IOEvent>> events_; 86 bool has_error_; 87 bool use_precise_timer_; 88 }; 89 90 #endif // SIMPLE_PERF_IOEVENT_LOOP_H_ 91
