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)// The Watchdog class creates a second thread that can Alarm if a specific 65821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// duration of time passes without proper attention. The duration of time is 75821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// specified at construction time. The Watchdog may be used many times by 85821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// simply calling Arm() (to start timing) and Disarm() (to reset the timer). 95821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// The Watchdog is typically used under a debugger, where the stack traces on 105821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// other threads can be examined if/when the Watchdog alarms. 115821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 125821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Some watchdogs will be enabled or disabled via command line switches. To 135821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// facilitate such code, an "enabled" argument for the constuctor can be used 145821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// to permanently disable the watchdog. Disabled watchdogs don't even spawn 155821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// a second thread, and their methods call (Arm() and Disarm()) return very 165821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// quickly. 175821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 185821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#ifndef BASE_THREADING_WATCHDOG_H_ 195821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#define BASE_THREADING_WATCHDOG_H_ 205821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 215821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include <string> 225821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 235821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/base_export.h" 245821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/compiler_specific.h" 255821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/synchronization/condition_variable.h" 265821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/synchronization/lock.h" 275821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/threading/platform_thread.h" 28eb525c5499e34cc9c4b825d6d9e75bb07cc06aceBen Murdoch#include "base/time/time.h" 295821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 305821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)namespace base { 315821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 325821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)class BASE_EXPORT Watchdog { 335821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) public: 345821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Constructor specifies how long the Watchdog will wait before alarming. 355821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) Watchdog(const TimeDelta& duration, 365821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) const std::string& thread_watched_name, 375821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) bool enabled); 385821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) virtual ~Watchdog(); 395821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 405821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Notify watchdog thread to finish up. Sets the state_ to SHUTDOWN. 415821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) void Cleanup(); 425821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 435821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Returns true if we state_ is JOINABLE (which indicates that Watchdog has 445821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // exited). 455821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) bool IsJoinable(); 465821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 475821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Start timing, and alarm when time expires (unless we're disarm()ed.) 485821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) void Arm(); // Arm starting now. 495821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) void ArmSomeTimeDeltaAgo(const TimeDelta& time_delta); 505821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) void ArmAtStartTime(const TimeTicks start_time); 515821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 525821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Reset time, and do not set off the alarm. 535821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) void Disarm(); 545821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 555821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Alarm is called if the time expires after an Arm() without someone calling 565821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Disarm(). This method can be overridden to create testable classes. 575821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) virtual void Alarm(); 585821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 595821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Reset static data to initial state. Useful for tests, to ensure 605821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // they are independent. 615821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) static void ResetStaticData(); 625821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 635821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) private: 645821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) class ThreadDelegate : public PlatformThread::Delegate { 655821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) public: 665821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) explicit ThreadDelegate(Watchdog* watchdog) : watchdog_(watchdog) { 675821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 685821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) virtual void ThreadMain() OVERRIDE; 695821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) private: 705821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) void SetThreadName() const; 715821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 725821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) Watchdog* watchdog_; 735821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) }; 745821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 755821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) enum State {ARMED, DISARMED, SHUTDOWN, JOINABLE }; 765821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 775821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) bool enabled_; 785821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 795821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) Lock lock_; // Mutex for state_. 805821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) ConditionVariable condition_variable_; 815821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) State state_; 825821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) const TimeDelta duration_; // How long after start_time_ do we alarm? 835821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) const std::string thread_watched_name_; 845821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) PlatformThreadHandle handle_; 855821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) ThreadDelegate delegate_; // Store it, because it must outlive the thread. 865821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 875821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) TimeTicks start_time_; // Start of epoch, and alarm after duration_. 885821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 895821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) DISALLOW_COPY_AND_ASSIGN(Watchdog); 905821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)}; 915821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 925821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} // namespace base 935821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 945821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#endif // BASE_THREADING_WATCHDOG_H_ 95