1 2 /** 3 * Copyright (C) 2018-present MongoDB, Inc. 4 * 5 * This program is free software: you can redistribute it and/or modify 6 * it under the terms of the Server Side Public License, version 1, 7 * as published by MongoDB, Inc. 8 * 9 * This program is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 * Server Side Public License for more details. 13 * 14 * You should have received a copy of the Server Side Public License 15 * along with this program. If not, see 16 * <http://www.mongodb.com/licensing/server-side-public-license>. 17 * 18 * As a special exception, the copyright holders give permission to link the 19 * code of portions of this program with the OpenSSL library under certain 20 * conditions as described in each individual source file and distribute 21 * linked combinations including the program with the OpenSSL library. You 22 * must comply with the Server Side Public License in all respects for 23 * all of the code used other than as permitted herein. If you modify file(s) 24 * with this exception, you may extend this exception to your version of the 25 * file(s), but you are not obligated to do so. If you do not wish to do so, 26 * delete this exception statement from your version. If you delete this 27 * exception statement from all source files in the program, then also delete 28 * it in the license file. 29 */ 30 31 #pragma once 32 33 #include "mongo/util/time_support.h" 34 35 namespace mongo { 36 37 class TickSource; 38 39 /** 40 * Time tracking object. 41 */ 42 class Timer { 43 public: 44 /** 45 * Creates a timer with the system default tick source. Should not be created before global 46 * initialization completes. 47 */ 48 Timer(); 49 50 /** 51 * Creates a timer using the specified tick source. Caller retains ownership of TickSource and 52 * must keep it in scope until Timer goes out of scope. 53 */ 54 explicit Timer(TickSource* tickSource); 55 micros()56 long long micros() const { 57 return static_cast<long long>((now() - _old) * _microsPerCount); 58 } millis()59 int millis() const { 60 return static_cast<int>(micros() / 1000); 61 } seconds()62 int seconds() const { 63 return static_cast<int>(micros() / 1000000); 64 } minutes()65 int minutes() const { 66 return seconds() / 60; 67 } 68 elapsed()69 Microseconds elapsed() const { 70 return Microseconds{micros()}; 71 } 72 reset()73 void reset() { 74 _old = now(); 75 } 76 77 private: 78 TickSource* const _tickSource; 79 80 // Derived value from _countsPerSecond. This represents the conversion ratio 81 // from clock ticks to microseconds. 82 const double _microsPerCount; 83 84 long long now() const; 85 86 long long _old; 87 }; 88 89 } // namespace mongo 90