1 // Copyright (c) 2010 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef CHROME_BROWSER_HANG_MONITOR_HUNG_WINDOW_DETECTOR_H__ 6 #define CHROME_BROWSER_HANG_MONITOR_HUNG_WINDOW_DETECTOR_H__ 7 8 #include "base/synchronization/lock.h" 9 #include "chrome/common/worker_thread_ticker.h" 10 11 // This class provides the following functionality: 12 // Given a top-level window handle, it enumerates all descendant windows 13 // of that window and, on finding a window that belongs to a different 14 // thread from that of the top-level window, it tests to see if that window 15 // is responding to messages. It does this test by first calling the 16 // IsHungAppWindow API and, additionally (since the IsHungAppWindow API 17 // does not deal correctly with suspended threads), send a dummy message 18 // (WM_NULL) to the window and verifies that the call does not timeout. 19 // This class is typically used in conjunction with the WorkerThreadTicker 20 // class so that the checking can happen on a periodic basis. 21 // If a hung window is detected it calls back the specified implementation of 22 // the HungWindowNotification interface. Currently this class only supports 23 // a single callback but it can be extended later to support multiple 24 // callbacks. 25 class HungWindowDetector : public WorkerThreadTicker::Callback { 26 public: 27 // This property specifies the message timeout for a child window. 28 static const wchar_t kHungChildWindowTimeout[]; 29 // This is the notification callback interface that is used to notify 30 // callers about a non-responsive window 31 class HungWindowNotification { 32 public: 33 enum ActionOnHungWindow { 34 HUNG_WINDOW_IGNORE, 35 HUNG_WINDOW_TERMINATE_PROCESS, 36 }; 37 38 // This callback method is invoked when a hung window is detected. 39 // A return value of false indicates that we should stop enumerating the 40 // child windows of the browser window to check if they are hung. 41 virtual bool OnHungWindowDetected(HWND hung_window, HWND top_level_window, 42 ActionOnHungWindow* action) = 0; 43 }; 44 45 // The notification object is not owned by this class. It is assumed that 46 // this pointer will be valid throughout the lifetime of this class. 47 // Ownership of this pointer is not transferred to this class. 48 // Note that the Initialize method needs to be called to initiate monitoring 49 // of hung windows. 50 explicit HungWindowDetector(HungWindowNotification* notification); 51 ~HungWindowDetector(); 52 53 // This method initialized the monitoring of hung windows. All descendant 54 // windows of the passed-in top-level window which belong to a thread 55 // different from that of the top-level window are monitored. The 56 // message_response_timeout parameter indicates how long this class must 57 // wait for a window to respond to a sent message before it is considered 58 // to be non-responsive. 59 // Initialize can be called multiple times to change the actual window to 60 // be monitored as well as the message response timeout 61 bool Initialize(HWND top_level_window, 62 int message_response_timeout); 63 64 // Implementation of the WorkerThreadTicker::Callback interface 65 virtual void OnTick(); 66 67 private: 68 // Helper function that checks whether the specified child window is hung. 69 // If so, it invokes the HungWindowNotification interface implementation 70 bool CheckChildWindow(HWND child_window); 71 72 static BOOL CALLBACK ChildWndEnumProc(HWND child_window, LPARAM param); 73 74 // Pointer to the HungWindowNotification callback interface. This class does 75 // not RefCount this pointer and it is assumed that the pointer will be valid 76 // throughout the lifetime of this class. 77 HungWindowNotification* notification_; 78 HWND top_level_window_; 79 80 // How long do we wait before we consider a window hung (in ms) 81 int message_response_timeout_; 82 base::Lock hang_detection_lock_; 83 // Indicates if this object is currently enumerating hung windows 84 bool enumerating_; 85 86 DISALLOW_COPY_AND_ASSIGN(HungWindowDetector); 87 }; 88 89 90 #endif // CHROME_BROWSER_HANG_MONITOR_HUNG_WINDOW_DETECTOR_H__ 91