15821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Copyright (c) 2012 The Chromium Authors. All rights reserved. 25821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Use of this source code is governed by a BSD-style license that can be 35821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// found in the LICENSE file. 45821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 55821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#ifndef CHROME_COMMON_WORKER_THREAD_TICKER_H_ 65821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#define CHROME_COMMON_WORKER_THREAD_TICKER_H_ 75821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 85821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include <vector> 95821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 105821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/synchronization/lock.h" 115821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/threading/thread.h" 125821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 135821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// This class provides the following functionality: 145821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// It invokes a set of registered handlers at periodic intervals in 155821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// the context of an arbitrary worker thread. 165821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// The timer runs on a separate thread, so it will run even if the current 175821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// thread is hung. Similarly, the callbacks will be called on a separate 185821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// thread so they won't block the main thread. 195821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)class WorkerThreadTicker { 205821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) public: 215821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // This callback interface to be implemented by clients of this 225821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // class 235821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) class Callback { 245821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) public: 255821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Gets invoked when the timer period is up 265821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) virtual void OnTick() = 0; 275821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 285821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) protected: 295821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) virtual ~Callback() {} 305821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) }; 315821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 325821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // tick_interval is the periodic interval in which to invoke the 335821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // registered handlers (in milliseconds) 345821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) explicit WorkerThreadTicker(int tick_interval); 355821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 365821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) ~WorkerThreadTicker(); 375821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 385821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Registers a callback handler interface 395821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // tick_handler is the handler interface to register. The ownership of this 405821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // object is not transferred to this class. 415821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) bool RegisterTickHandler(Callback *tick_handler); 425821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 435821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Unregisters a callback handler interface 445821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // tick_handler is the handler interface to unregister 455821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) bool UnregisterTickHandler(Callback *tick_handler); 465821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 475821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Starts the ticker. Returns false if the ticker is already running 485821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // or if the Start fails. 495821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) bool Start(); 505821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Stops the ticker and waits for all callbacks. to be done. This method 515821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // does not provide a way to stop without waiting for the callbacks to be 525821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // done because this is inherently risky. 535821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Returns false is the ticker is not running 545821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) bool Stop(); 555821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) bool IsRunning() const { 565821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return is_running_; 575821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 585821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 595821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) void set_tick_interval(int tick_interval) { 605821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) tick_interval_ = base::TimeDelta::FromMilliseconds(tick_interval); 615821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 625821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 635821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) int tick_interval() const { 645821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return tick_interval_.InMilliseconds(); 655821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 665821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 675821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) private: 685821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) void ScheduleTimerTask(); 695821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 705821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) void TimerTask(); 715821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 725821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // A list type that holds all registered callback interfaces 735821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) typedef std::vector<Callback*> TickHandlerListType; 745821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 755821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Lock to protect is_running_ and tick_handler_list_ 765821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) base::Lock lock_; 775821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 785821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) base::Thread timer_thread_; 795821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) bool is_running_; 805821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 815821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // The interval at which the callbacks are to be invoked 825821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) base::TimeDelta tick_interval_; 835821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 845821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // A list that holds all registered callback interfaces 855821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) TickHandlerListType tick_handler_list_; 865821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 875821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) DISALLOW_COPY_AND_ASSIGN(WorkerThreadTicker); 885821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)}; 895821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 905821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#endif // CHROME_COMMON_WORKER_THREAD_TICKER_H_ 91