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 <sys/time.h> 22 #include <time.h> 23 24 #include <functional> 25 #include <memory> 26 #include <vector> 27 28 struct event_base; 29 30 namespace simpleperf { 31 32 struct IOEvent; 33 typedef IOEvent* IOEventRef; 34 35 enum IOEventPriority { 36 // Lower value means higher priority. 37 IOEventHighPriority = 0, 38 IOEventLowPriority = 1, 39 }; 40 41 // IOEventLoop is a class wrapper of libevent, it monitors events happened, 42 // and calls the corresponding callbacks. Possible events are: file ready to 43 // read, file ready to write, signal happens, periodic timer timeout. 44 class IOEventLoop { 45 public: 46 IOEventLoop(); 47 ~IOEventLoop(); 48 49 // Use precise timer for periodic events which want precision in ms. 50 bool UsePreciseTimer(); 51 52 // Register a read Event, so [callback] is called when [fd] can be read 53 // without blocking. If registered successfully, return the reference 54 // to control the Event, otherwise return nullptr. 55 IOEventRef AddReadEvent(int fd, const std::function<bool()>& callback, 56 IOEventPriority priority = IOEventLowPriority); 57 58 // Register a write Event, so [callback] is called when [fd] can be written 59 // without blocking. 60 IOEventRef AddWriteEvent(int fd, const std::function<bool()>& callback, 61 IOEventPriority priority = IOEventLowPriority); 62 63 // Register a signal Event, so [callback] is called each time signal [sig] 64 // happens. 65 bool AddSignalEvent(int sig, const std::function<bool()>& callback, 66 IOEventPriority priority = IOEventLowPriority); 67 68 // Register a vector of signal Events. 69 bool AddSignalEvents(std::vector<int> sigs, const std::function<bool()>& callback, 70 IOEventPriority priority = IOEventLowPriority); 71 72 // Register a periodic Event, so [callback] is called periodically every 73 // [duration]. 74 IOEventRef AddPeriodicEvent(timeval duration, const std::function<bool()>& callback, 75 IOEventPriority priority = IOEventLowPriority); 76 77 // Run a loop polling for Events. It only exits when ExitLoop() is called 78 // in a callback function of registered Events. 79 bool RunLoop(); 80 81 // Exit the loop started by RunLoop(). 82 bool ExitLoop(); 83 84 // Disable an Event, which can be enabled later. 85 static bool DisableEvent(IOEventRef ref); 86 // Enable a disabled Event. 87 static bool EnableEvent(IOEventRef ref); 88 89 // Unregister an Event. 90 static bool DelEvent(IOEventRef ref); 91 92 private: 93 bool EnsureInit(); 94 IOEventRef AddEvent(int fd_or_sig, int16_t events, timeval* timeout, 95 const std::function<bool()>& callback, 96 IOEventPriority priority = IOEventLowPriority); 97 static void EventCallbackFn(int, int16_t, void*); 98 99 event_base* ebase_; 100 std::vector<std::unique_ptr<IOEvent>> events_; 101 bool has_error_; 102 bool use_precise_timer_; 103 bool in_loop_; 104 }; 105 106 } // namespace simpleperf 107 108 #endif // SIMPLE_PERF_IOEVENT_LOOP_H_ 109