refactoring mouse lock to support pepper and WebKit

content/renderer/mouse_lock_dispatcher.h

+// Copyright (c) 2012 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 CONTENT_RENDERER_MOUSE_LOCK_DISPATCHER_H_
+#define CONTENT_RENDERER_MOUSE_LOCK_DISPATCHER_H_
+#pragma once
+
+#include "base/basictypes.h"
+#include "content/public/renderer/render_view_observer.h"
+
+class RenderViewImpl;
+
+namespace WebKit {
+class WebMouseEvent;
+class WebWidget;
+}  // namespace WebKit
+
+namespace webkit{
+namespace ppapi {
+class PluginInstance;
+}  // namespace ppapi
+}  // namespace webkit
+
+// MouseLockDispatcher is owned by RenderViewImpl.
+class CONTENT_EXPORT MouseLockDispatcher : public content::RenderViewObserver {
+ public:
+  explicit MouseLockDispatcher(RenderViewImpl* render_view_impl);
+  virtual ~MouseLockDispatcher();
+
+  class LockTarget {
+   public:
+    virtual ~LockTarget() {}
+    // A mouse lock request was pending and this reports success or failure.
+    virtual void OnLockMouseACK(bool succeeded) = 0;
+    // A mouse lock was in place, but has been lost.
+    virtual void OnMouseLockLost() = 0;
+    // A mouse lock is enabled and mouse events are being delievered.
+    virtual bool HandleMouseLockedInputEvent(
+        const WebKit::WebMouseEvent& event) = 0;
+  };
+
+  // Locks the mouse to the |target|. If true is returned, an asynchronous
+  // response to target->OnLockMouseACK() will follow.
+  bool LockMouse(LockTarget* target);
+  // Request to unlock the mouse. An asynchronous response to
+  // target->OnMouseLockLost() will follow.
+  void UnlockMouse(LockTarget* target);
+  // Clears out the reference to the |target| because it has or is being
+  // destroyed. Unlocks if locked. The pointer will not be accessed.
+  void OnLockTargetDestroyed(LockTarget* target);
+  bool IsMouseLockedTo(LockTarget* target);
+
+  // Allow lock target to consumed a mouse event, if it does return true.
+  bool WillHandleMouseEvent(const WebKit::WebMouseEvent& event);
+
+ private:
+  // RenderView::Observer implementation.
+  virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
+
+  // IPC handlers.
+  void OnLockMouseACK(bool succeeded);
+  void OnMouseLockLost();
+
+  bool MouseLockedOrPendingAction() const {
+    return mouse_locked_ || pending_lock_request_ || pending_unlock_request_;
+  }
+
+  RenderViewImpl* render_view_impl_;
+
+  bool mouse_locked_;
+  // If both |pending_lock_request_| and |pending_unlock_request_| are true,
+  // it means a lock request was sent before an unlock request and we haven't
+  // received responses for them. The logic in LockMouse() makes sure that a
+  // lock request won't be sent when there is a pending unlock request.
+  bool pending_lock_request_;
+  bool pending_unlock_request_;
+
+  // |target_| is the pending or current owner of mouse lock. We retain a non
+  // owning reference here that must be cleared by |OnLockTargetDestroyed|
+  // when it is destroyed.
+  LockTarget* target_;
+
+  DISALLOW_COPY_AND_ASSIGN(MouseLockDispatcher);
+};
+
+#endif  // CONTENT_RENDERER_MOUSE_LOCK_DISPATCHER_H_