| // Copyright (c) 2010 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef CHROME_BROWSER_HANG_MONITOR_HUNG_WINDOW_DETECTOR_H__ |
| #define CHROME_BROWSER_HANG_MONITOR_HUNG_WINDOW_DETECTOR_H__ |
| |
| #include "base/macros.h" |
| #include "base/synchronization/lock.h" |
| #include "chrome/common/worker_thread_ticker.h" |
| |
| // This class provides the following functionality: |
| // Given a top-level window handle, it enumerates all descendant windows |
| // of that window and, on finding a window that belongs to a different |
| // thread from that of the top-level window, it tests to see if that window |
| // is responding to messages. It does this test by first calling the |
| // IsHungAppWindow API and, additionally (since the IsHungAppWindow API |
| // does not deal correctly with suspended threads), send a dummy message |
| // (WM_NULL) to the window and verifies that the call does not timeout. |
| // This class is typically used in conjunction with the WorkerThreadTicker |
| // class so that the checking can happen on a periodic basis. |
| // If a hung window is detected it calls back the specified implementation of |
| // the HungWindowNotification interface. Currently this class only supports |
| // a single callback but it can be extended later to support multiple |
| // callbacks. |
| class HungWindowDetector : public WorkerThreadTicker::Callback { |
| public: |
| // This property specifies the message timeout for a child window. |
| static const wchar_t kHungChildWindowTimeout[]; |
| // This is the notification callback interface that is used to notify |
| // callers about a non-responsive window |
| class HungWindowNotification { |
| public: |
| enum ActionOnHungWindow { |
| HUNG_WINDOW_IGNORE, |
| HUNG_WINDOW_TERMINATE_PROCESS, |
| }; |
| |
| // This callback method is invoked when a hung window is detected. |
| // A return value of false indicates that we should stop enumerating the |
| // child windows of the browser window to check if they are hung. |
| virtual bool OnHungWindowDetected(HWND hung_window, HWND top_level_window, |
| ActionOnHungWindow* action) = 0; |
| }; |
| |
| // The notification object is not owned by this class. It is assumed that |
| // this pointer will be valid throughout the lifetime of this class. |
| // Ownership of this pointer is not transferred to this class. |
| // Note that the Initialize method needs to be called to initiate monitoring |
| // of hung windows. |
| explicit HungWindowDetector(HungWindowNotification* notification); |
| ~HungWindowDetector() override; |
| |
| // This method initialized the monitoring of hung windows. All descendant |
| // windows of the passed-in top-level window which belong to a thread |
| // different from that of the top-level window are monitored. The |
| // message_response_timeout parameter indicates how long this class must |
| // wait for a window to respond to a sent message before it is considered |
| // to be non-responsive. |
| // Initialize can be called multiple times to change the actual window to |
| // be monitored as well as the message response timeout |
| bool Initialize(HWND top_level_window, |
| int message_response_timeout); |
| |
| // Implementation of the WorkerThreadTicker::Callback interface |
| void OnTick() override; |
| |
| private: |
| // Helper function that checks whether the specified child window is hung. |
| // If so, it invokes the HungWindowNotification interface implementation |
| bool CheckChildWindow(HWND child_window); |
| |
| static BOOL CALLBACK ChildWndEnumProc(HWND child_window, LPARAM param); |
| |
| // Pointer to the HungWindowNotification callback interface. This class does |
| // not RefCount this pointer and it is assumed that the pointer will be valid |
| // throughout the lifetime of this class. |
| HungWindowNotification* notification_; |
| HWND top_level_window_; |
| |
| // How long do we wait before we consider a window hung (in ms) |
| int message_response_timeout_; |
| base::Lock hang_detection_lock_; |
| // Indicates if this object is currently enumerating hung windows |
| bool enumerating_; |
| |
| DISALLOW_COPY_AND_ASSIGN(HungWindowDetector); |
| }; |
| |
| |
| #endif // CHROME_BROWSER_HANG_MONITOR_HUNG_WINDOW_DETECTOR_H__ |