Adds the UserInputMonitor implementation for Windows.

media/base/user_input_monitor_linux.cc

 // Copyright 2013 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.
 
 #include "media/base/user_input_monitor.h"
 
 #include <sys/select.h>
 #include <unistd.h>
 #define XK_MISCELLANY
 #include <X11/keysymdef.h>
 
 #include "base/basictypes.h"
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/compiler_specific.h"
 #include "base/location.h"
 #include "base/logging.h"
+#include "base/memory/weak_ptr.h"
 #include "base/message_loop/message_loop.h"
 #include "base/message_loop/message_pump_libevent.h"
+#include "base/observer_list_threadsafe.h"
 #include "base/posix/eintr_wrapper.h"
 #include "base/single_thread_task_runner.h"
+#include "base/synchronization/lock.h"
 #include "media/base/keyboard_event_counter.h"
 #include "third_party/skia/include/core/SkPoint.h"
 #include "ui/base/keycodes/keyboard_code_conversion_x.h"
 
 // These includes need to be later than dictated by the style guide due to
 // Xlib header pollution, specifically the min, max, and Status macros.
 #include <X11/XKBlib.h>
 #include <X11/Xlibint.h>
 #include <X11/extensions/record.h>
 
 namespace media {
 namespace {
 
-class UserInputMonitorLinux : public UserInputMonitor ,
-                              public base::MessagePumpLibevent::Watcher {
+class UserInputMonitorLinux : public UserInputMonitor {
  public:
   explicit UserInputMonitorLinux(
       const scoped_refptr<base::SingleThreadTaskRunner>& io_task_runner);
   virtual ~UserInputMonitorLinux();
 
+  // Public interface of UserInputMonitor.
+  virtual void AddMouseListener(MouseEventListener* listener) OVERRIDE;
+  virtual void RemoveMouseListener(MouseEventListener* listener) OVERRIDE;
   virtual size_t GetKeyPressCount() const OVERRIDE;
 
  private:
+  // Private interface of UserInputMonitor.
+  virtual void StartKeyboardMonitoring() OVERRIDE;
+  virtual void StopKeyboardMonitoring() OVERRIDE;
+
+  class Core;
+  Core* core_;
+
+  DISALLOW_COPY_AND_ASSIGN(UserInputMonitorLinux);
+};
+
+// This is the actual implementation of event monitoring. It's separated from
+// UserInputMonitorLinux since it needs to be deleted on the IO thread.
+class UserInputMonitorLinux::Core : public base::MessagePumpLibevent::Watcher {
+ public:
+  explicit Core(
+      const scoped_refptr<base::SingleThreadTaskRunner>& io_task_runner);
+  virtual ~Core();
+
+  void AddMouseListener(MouseEventListener* listener);
+  void RemoveMouseListener(MouseEventListener* listener);
+  size_t GetKeyPressCount() const;
+  void StartKeyboardMonitoring();
+  void StopKeyboardMonitoring();
+  scoped_refptr<base::SingleThreadTaskRunner> io_task_runner() {
+    return io_task_runner_;
+  }
+
+ private:
   enum EventType {
     MOUSE_EVENT,
     KEYBOARD_EVENT
   };
 
-  virtual void StartMouseMonitoring() OVERRIDE;
-  virtual void StopMouseMonitoring() OVERRIDE;
-  virtual void StartKeyboardMonitoring() OVERRIDE;
-  virtual void StopKeyboardMonitoring() OVERRIDE;
-
-  //
-  // The following methods must be called on the IO thread.
-  //
   void StartMonitor(EventType type);
   void StopMonitor(EventType type);
 
   // base::MessagePumpLibevent::Watcher interface.
   virtual void OnFileCanReadWithoutBlocking(int fd) OVERRIDE;
   virtual void OnFileCanWriteWithoutBlocking(int fd) OVERRIDE;
 
   // Processes key and mouse events.
   void ProcessXEvent(xEvent* event);
   static void ProcessReply(XPointer self, XRecordInterceptData* data);
 
-  // Task runner on which X Window events are received.
+  base::Lock lock_;
   scoped_refptr<base::SingleThreadTaskRunner> io_task_runner_;
+  scoped_refptr<ObserverListThreadSafe<MouseEventListener> > mouse_listeners_;
+  size_t mouse_listeners_count_;
 
   //
   // The following members should only be accessed on the IO thread.
   //
   base::MessagePumpLibevent::FileDescriptorWatcher controller_;
   Display* display_;
   Display* x_record_display_;
   XRecordRange* x_record_range_[2];
   XRecordContext x_record_context_;
   KeyboardEventCounter counter_;
+  base::WeakPtrFactory<Core> weak_factory_;
 
-  DISALLOW_COPY_AND_ASSIGN(UserInputMonitorLinux);
+  DISALLOW_COPY_AND_ASSIGN(Core);
 };
 
-UserInputMonitorLinux::UserInputMonitorLinux(
+UserInputMonitorLinux::Core::Core(
     const scoped_refptr<base::SingleThreadTaskRunner>& io_task_runner)
     : io_task_runner_(io_task_runner),
+      mouse_listeners_(new ObserverListThreadSafe<MouseEventListener>()),
+      mouse_listeners_count_(0),
       display_(NULL),
       x_record_display_(NULL),
-      x_record_context_(0) {
+      x_record_context_(0),
+      weak_factory_(this) {
   x_record_range_[0] = NULL;
   x_record_range_[1] = NULL;
 }
 
-UserInputMonitorLinux::~UserInputMonitorLinux() {
+UserInputMonitorLinux::Core::~Core() {
+  DCHECK_EQ(0u, mouse_listeners_count_);
   DCHECK(!display_);
   DCHECK(!x_record_display_);
   DCHECK(!x_record_range_[0]);
   DCHECK(!x_record_range_[1]);
   DCHECK(!x_record_context_);
 }
 
-size_t UserInputMonitorLinux::GetKeyPressCount() const {
+void UserInputMonitorLinux::Core::AddMouseListener(
+    MouseEventListener* listener) {
+  mouse_listeners_->AddObserver(listener);
+  {
+    base::AutoLock auto_lock(lock_);
+    mouse_listeners_count_++;
+    if (mouse_listeners_count_ == 1) {
+      StartMonitor(MOUSE_EVENT);
+      DVLOG(2) << "Started mouse monitoring.";
+    }
+  }
+}
+
+void UserInputMonitorLinux::Core::RemoveMouseListener(
+    MouseEventListener* listener) {
+  mouse_listeners_->RemoveObserver(listener);
+  {
+    base::AutoLock auto_lock(lock_);
+    mouse_listeners_count_--;
+    if (mouse_listeners_count_ == 0) {
+      StopMonitor(MOUSE_EVENT);
+      DVLOG(2) << "Stopped mouse monitoring.";
+    }
+  }
+}
+
+size_t UserInputMonitorLinux::Core::GetKeyPressCount() const {
   return counter_.GetKeyPressCount();
 }
 
-void UserInputMonitorLinux::StartMouseMonitoring() {
+void UserInputMonitorLinux::Core::StartKeyboardMonitoring() {
+  StartMonitor(KEYBOARD_EVENT);
+}
+
+void UserInputMonitorLinux::Core::StopKeyboardMonitoring() {
+  StopMonitor(KEYBOARD_EVENT);
+}
+
+void UserInputMonitorLinux::Core::StartMonitor(EventType type) {
   if (!io_task_runner_->BelongsToCurrentThread()) {

[Sergey Ulanov, 2013/09/07 20:19:41]

There is still the problem that I pointed before: If some thread calls
StartMonitor() and then IO thread calls StopMonitor() immediately after that
then StopMonitor() will be executed before StartMonitor() is called on the IO
thread. This should be easy to fix. Just add DoStartMonitor() and always post a
task from StartMonitor().

StartMonitoring() and StopMonitoring() are always called with the lock held, so
there is definite order in which these methods are called. The code that
starts/stops monitoring on the IO thread should be always executed in the same
order, but that's not guaranteed if you don't always post a task here.

[jiayl, 2013/09/10 16:31:00]

Done.

     io_task_runner_->PostTask(
         FROM_HERE,
-        base::Bind(&UserInputMonitorLinux::StartMonitor,
-                   base::Unretained(this),
-                   MOUSE_EVENT));
+        base::Bind(&Core::StartMonitor, weak_factory_.GetWeakPtr(), type));
     return;
   }
-  StartMonitor(MOUSE_EVENT);
-}
-
-void UserInputMonitorLinux::StopMouseMonitoring() {
-  if (!io_task_runner_->BelongsToCurrentThread()) {
-    io_task_runner_->PostTask(
-        FROM_HERE,
-        base::Bind(&UserInputMonitorLinux::StopMonitor,
-                   base::Unretained(this),
-                   MOUSE_EVENT));
-    return;
-  }
-  StopMonitor(MOUSE_EVENT);
-}
-
-void UserInputMonitorLinux::StartKeyboardMonitoring() {
-  if (!io_task_runner_->BelongsToCurrentThread()) {
-    io_task_runner_->PostTask(
-        FROM_HERE,
-        base::Bind(&UserInputMonitorLinux::StartMonitor,
-                   base::Unretained(this),
-                   KEYBOARD_EVENT));
-    return;
-  }
-  StartMonitor(KEYBOARD_EVENT);
-}
-
-void UserInputMonitorLinux::StopKeyboardMonitoring() {
-  if (!io_task_runner_->BelongsToCurrentThread()) {
-    io_task_runner_->PostTask(
-        FROM_HERE,
-        base::Bind(&UserInputMonitorLinux::StopMonitor,
-                   base::Unretained(this),
-                   KEYBOARD_EVENT));
-    return;
-  }
-  StopMonitor(KEYBOARD_EVENT);
-}
-
-void UserInputMonitorLinux::StartMonitor(EventType type) {
-  DCHECK(io_task_runner_->BelongsToCurrentThread());
 
   if (type == KEYBOARD_EVENT)
     counter_.Reset();
 
   // TODO(jamiewalch): We should pass the display in. At that point, since
   // XRecord needs a private connection to the X Server for its data channel
   // and both channels are used from a separate thread, we'll need to duplicate
   // them with something like the following:
   //   XOpenDisplay(DisplayString(display));
   if (!display_)
@@ skipping 48 matching lines @@
                                            1,
                                            record_range_to_use,
                                            number_of_ranges);
   if (!x_record_context_) {
     LOG(ERROR) << "XRecordCreateContext failed.";
     return;
   }
 
   if (!XRecordEnableContextAsync(x_record_display_,
                                  x_record_context_,
-                                 &UserInputMonitorLinux::ProcessReply,
+                                 &Core::ProcessReply,
                                  reinterpret_cast<XPointer>(this))) {
     LOG(ERROR) << "XRecordEnableContextAsync failed.";
     return;
   }
 
   if (!x_record_range_[0] || !x_record_range_[1]) {
     // Register OnFileCanReadWithoutBlocking() to be called every time there is
     // something to read from |x_record_display_|.
     base::MessageLoopForIO* message_loop = base::MessageLoopForIO::current();
     int result =
         message_loop->WatchFileDescriptor(ConnectionNumber(x_record_display_),
                                           true,
                                           base::MessageLoopForIO::WATCH_READ,
                                           &controller_,
                                           this);
     if (!result) {
       LOG(ERROR) << "Failed to create X record task.";
       return;
     }
   }
 
   // Fetch pending events if any.
   OnFileCanReadWithoutBlocking(ConnectionNumber(x_record_display_));
 }
 
-void UserInputMonitorLinux::StopMonitor(EventType type) {
-  DCHECK(io_task_runner_->BelongsToCurrentThread());
+void UserInputMonitorLinux::Core::StopMonitor(EventType type) {
+  if (!io_task_runner_->BelongsToCurrentThread()) {
+    io_task_runner_->PostTask(
+        FROM_HERE,
+        base::Bind(&Core::StopMonitor, weak_factory_.GetWeakPtr(), type));
+    return;
+  }
 
   if (x_record_range_[type]) {
     XFree(x_record_range_[type]);
     x_record_range_[type] = NULL;
   }
   if (x_record_range_[0] || x_record_range_[1])
     return;
 
   // Context must be disabled via the control channel because we can't send
   // any X protocol traffic over the data channel while it's recording.
   if (x_record_context_) {
     XRecordDisableContext(display_, x_record_context_);
     XFlush(display_);
     XRecordFreeContext(x_record_display_, x_record_context_);
     x_record_context_ = 0;
 
     controller_.StopWatchingFileDescriptor();
     if (x_record_display_) {
       XCloseDisplay(x_record_display_);
       x_record_display_ = NULL;
     }
     if (display_) {
       XCloseDisplay(display_);
       display_ = NULL;
     }
   }
 }
 
-void UserInputMonitorLinux::OnFileCanReadWithoutBlocking(int fd) {
+void UserInputMonitorLinux::Core::OnFileCanReadWithoutBlocking(int fd) {
   DCHECK(io_task_runner_->BelongsToCurrentThread());
   XEvent event;
   // Fetch pending events if any.
   while (XPending(x_record_display_)) {
     XNextEvent(x_record_display_, &event);
   }
 }
 
-void UserInputMonitorLinux::OnFileCanWriteWithoutBlocking(int fd) {
+void UserInputMonitorLinux::Core::OnFileCanWriteWithoutBlocking(int fd) {
   NOTREACHED();
 }
 
-void UserInputMonitorLinux::ProcessXEvent(xEvent* event) {
+void UserInputMonitorLinux::Core::ProcessXEvent(xEvent* event) {
   DCHECK(io_task_runner_->BelongsToCurrentThread());
   if (event->u.u.type == MotionNotify) {
     SkIPoint position(SkIPoint::Make(event->u.keyButtonPointer.rootX,
                                      event->u.keyButtonPointer.rootY));
-    OnMouseEvent(position);
+    mouse_listeners_->Notify(&MouseEventListener::OnMouseMoved, position);
   } else {
     ui::EventType type;
     if (event->u.u.type == KeyPress) {
       type = ui::ET_KEY_PRESSED;
     } else if (event->u.u.type == KeyRelease) {
       type = ui::ET_KEY_RELEASED;
     } else {
       NOTREACHED();
       return;
     }
 
     KeySym key_sym = XkbKeycodeToKeysym(display_, event->u.u.detail, 0, 0);
     ui::KeyboardCode key_code = ui::KeyboardCodeFromXKeysym(key_sym);
     counter_.OnKeyboardEvent(type, key_code);
   }
 }
 
 // static
-void UserInputMonitorLinux::ProcessReply(XPointer self,
-                                         XRecordInterceptData* data) {
+void UserInputMonitorLinux::Core::ProcessReply(XPointer self,
+                                               XRecordInterceptData* data) {
   if (data->category == XRecordFromServer) {
     xEvent* event = reinterpret_cast<xEvent*>(data->data);
-    reinterpret_cast<UserInputMonitorLinux*>(self)->ProcessXEvent(event);
+    reinterpret_cast<Core*>(self)->ProcessXEvent(event);
   }
   XRecordFreeData(data);
 }
 
+//
+// Implementation of UserInputMonitorLinux.
+//
+
+UserInputMonitorLinux::UserInputMonitorLinux(
+    const scoped_refptr<base::SingleThreadTaskRunner>& io_task_runner)
+    : core_(new Core(io_task_runner)) {}
+
+UserInputMonitorLinux::~UserInputMonitorLinux() {
+  if (!core_->io_task_runner()->DeleteSoon(FROM_HERE, core_))
+    delete core_;
+}
+
+void UserInputMonitorLinux::AddMouseListener(MouseEventListener* listener) {
+  core_->AddMouseListener(listener);
+}
+
+void UserInputMonitorLinux::RemoveMouseListener(MouseEventListener* listener) {
+  core_->RemoveMouseListener(listener);
+}
+
+size_t UserInputMonitorLinux::GetKeyPressCount() const {
+  return core_->GetKeyPressCount();
+}
+
+void UserInputMonitorLinux::StartKeyboardMonitoring() {
+  core_->StartKeyboardMonitoring();
+}
+
+void UserInputMonitorLinux::StopKeyboardMonitoring() {
+  core_->StopKeyboardMonitoring();
+}
+
 }  // namespace
 
 scoped_ptr<UserInputMonitor> UserInputMonitor::Create(
     const scoped_refptr<base::SingleThreadTaskRunner>& io_task_runner,
     const scoped_refptr<base::SingleThreadTaskRunner>& ui_task_runner) {
   return scoped_ptr<UserInputMonitor>(
       new UserInputMonitorLinux(io_task_runner));
 }
 
 }  // namespace media