refactoring mouse lock to support pepper and WebKit

content/renderer/mouse_lock_dispatcher.cc

Index: content/renderer/mouse_lock_dispatcher.cc
diff --git a/content/renderer/mouse_lock_dispatcher.cc b/content/renderer/mouse_lock_dispatcher.cc
new file mode 100644
index 0000000000000000000000000000000000000000..885150fd83234a4074d58c7dbc592b59fb5404e4
--- /dev/null
+++ b/content/renderer/mouse_lock_dispatcher.cc
@@ -0,0 +1,157 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.

[yzshen1, 2012/01/16 07:50:35]

2012. :)

[scheib, 2012/01/17 22:05:36]

Done.

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "content/renderer/mouse_lock_dispatcher.h"
+
+#include "content/common/view_messages.h"
+#include "content/renderer/render_view_impl.h"
+#include "third_party/WebKit/Source/WebKit/chromium/public/WebWidget.h"
+#include "third_party/WebKit/Source/WebKit/chromium/public/WebInputEvent.h"

[yzshen1, 2012/01/16 07:50:35]

Alphabetically, please.

[scheib, 2012/01/17 22:05:36]

Done.

+
+MouseLockDispatcher::MouseLockDispatcher(RenderViewImpl* render_view_impl)
+    : content::RenderViewObserver(render_view_impl),
+      render_view_impl_(render_view_impl),
+      mouse_locked_(false),
+      pending_lock_request_(false),
+      pending_unlock_request_(false),
+      mouse_lock_webwidget_owner_(NULL),
+      mouse_lock_pinstance_owner_(NULL) {
+}
+
+MouseLockDispatcher::~MouseLockDispatcher() {
+}
+
+bool MouseLockDispatcher::LockMouse(WebKit::WebWidget* webwidget,
+               webkit::ppapi::PluginInstance* pinstance) {

[yzshen1, 2012/01/16 07:50:35]

Wrong indent.

[scheib, 2012/01/17 22:05:36]

Done.

+  DCHECK(!(webwidget && pinstance)); // Only one mouse lock target at a time.
+
+  if (MouseLockedOrPendingAction())
+    return false;
+
+  pending_lock_request_ = true;
+  DCHECK(!mouse_lock_webwidget_owner_ && !mouse_lock_pinstance_owner_);
+  mouse_lock_webwidget_owner_ = webwidget;
+  mouse_lock_pinstance_owner_ = pinstance;
+
+  Send(new ViewHostMsg_LockMouse(routing_id()));
+  return true;
+}
+
+void MouseLockDispatcher::UnlockMouse(WebKit::WebWidget* webwidget,
+                 webkit::ppapi::PluginInstance* pinstance) {

[yzshen1, 2012/01/16 07:50:35]

Wrong indent.

[scheib, 2012/01/17 22:05:36]

Done.

+  if (!MouseLockedOrPendingAction() || pending_unlock_request_)
+    return;
+
+  // Ignore unless the unlock request is for the current lock holder.
+  if (webwidget == mouse_lock_webwidget_owner_ ||
+      pinstance == mouse_lock_pinstance_owner_) {
+    pending_unlock_request_ = true;
+    Send(new ViewHostMsg_UnlockMouse(routing_id()));
+  }
+}
+
+bool MouseLockDispatcher::IsPointerLockedTo(WebKit::WebWidget* webwidget) {
+  return mouse_locked_ && mouse_lock_webwidget_owner_ == webwidget;
+}
+
+bool MouseLockDispatcher::IsMouseLockedTo(
+    webkit::ppapi::PluginInstance* pinstance) {
+  return mouse_locked_ && mouse_lock_pinstance_owner_ == pinstance;
+}
+
+bool MouseLockDispatcher::WillHandleMouseEvent(
+    const WebKit::WebMouseEvent& event) {
+  if (mouse_locked_ && mouse_lock_pinstance_owner_) {
+    DCHECK(!mouse_lock_webwidget_owner_);
+    if (mouse_lock_pinstance_owner_)

[yzshen1, 2012/01/16 07:50:35]

you don't need this check, right?

[scheib, 2012/01/17 22:05:36]

Done.

+      mouse_lock_pinstance_owner_->HandleMouseLockedInputEvent(event);
+
+    // mouse_lock_webwidget_owner_ handles mouse lock in handleInputEvent().
+
+    // If the mouse is locked, only the current owner of the mouse lock can
+    // process mouse events.
+    return true;
+  }
+  return false;
+}

[yzshen1, 2012/01/16 07:50:35]

Empty line after it, please.

[scheib, 2012/01/17 22:05:36]

Done.

+bool MouseLockDispatcher::OnMessageReceived(const IPC::Message& message) {
+  bool handled = true;
+  IPC_BEGIN_MESSAGE_MAP(MouseLockDispatcher, message)
+    IPC_MESSAGE_HANDLER(ViewMsg_LockMouse_ACK, OnLockMouseACK)
+    IPC_MESSAGE_HANDLER(ViewMsg_MouseLockLost, OnMouseLockLost)
+    IPC_MESSAGE_UNHANDLED(handled = false)
+  IPC_END_MESSAGE_MAP()
+  return handled;
+}
+
+void MouseLockDispatcher::OnLockMouseACK(bool succeeded) {
+  // Mouse Lock removes the system cursor and provides all mouse motion as
+  // .movementX/Y values on events all sent to a fixed target. This requires
+  // content to specifically request the mode to be entered.
+  // Mouse Capture is implicitly given for the duration of a drag event, and
+  // sends all mouse events to the initial target of the drag.
+  // If Lock is entered it supercedes any in progress Capture.
+  if (succeeded && render_view_impl_->webwidget())
+      render_view_impl_->webwidget()->mouseCaptureLost();
+
+  DCHECK(!mouse_locked_ && pending_lock_request_);
+
+  mouse_locked_ = succeeded;
+  pending_lock_request_ = false;
+  if (pending_unlock_request_ && !succeeded) {
+    // We have sent an unlock request after the lock request. However, since
+    // the lock request has failed, the unlock request will be ignored by the
+    // browser side and there won't be any response to it.
+    pending_unlock_request_ = false;
+  }
+
+  if (mouse_lock_webwidget_owner_ || mouse_lock_pinstance_owner_) {
+    WebKit::WebWidget* last_webwidget_owner = mouse_lock_webwidget_owner_;

[yzshen1, 2012/01/16 07:50:35]

[Just want to double check.]
Is it possible that mouse_lock_webwidget_owner_ dies before MouseLockDispatcher?
If yes, have you notified this object?

[scheib, 2012/01/17 22:05:36]

It is not possible, the render view impl will call close() on the widget, which
will unlock. I discussed this with Darin for increased confidence.

+    webkit::ppapi::PluginInstance* last_pinstance_owner =
+        mouse_lock_pinstance_owner_;
+
+    if (!succeeded) {
+      // Reset mouse lock owner to NULL before calling OnLockMouseACK(), so
+      // that if OnLockMouseACK() results in calls to any mouse lock method
+      // (e.g., LockMouse()), the method will see consistent internal state.
+      mouse_lock_webwidget_owner_ = NULL;
+      mouse_lock_pinstance_owner_ = NULL;
+    }
+
+    DCHECK(!mouse_lock_webwidget_owner_ || !mouse_lock_pinstance_owner_);
+    if (last_webwidget_owner) {
+      if (succeeded)
+        last_webwidget_owner->didCompletePointerLock();
+      else
+        last_webwidget_owner->didNotCompletePointerLock();
+    }
+    if (last_pinstance_owner)
+      last_pinstance_owner->OnLockMouseACK(succeeded);
+  }
+}
+
+void MouseLockDispatcher::OnMouseLockLost() {
+  DCHECK(mouse_locked_ && !pending_lock_request_);
+
+  mouse_locked_ = false;
+  pending_unlock_request_ = false;
+  if (mouse_lock_webwidget_owner_ || mouse_lock_pinstance_owner_) {
+    WebKit::WebWidget* last_webwidget_owner = mouse_lock_webwidget_owner_;
+    webkit::ppapi::PluginInstance* last_pinstance_owner =
+        mouse_lock_pinstance_owner_;
+
+    // Reset mouse lock owner to NULL before calling OnLockMouseACK(), so

[yzshen1, 2012/01/16 07:50:35]

OnLockMouseACK -> OnMouseLockLost. (And the same for the next line.)

[scheib, 2012/01/17 22:05:36]

Done.

+    // that if OnLockMouseACK() results in calls to any mouse lock method
+    // (e.g., LockMouse()), the method will see consistent internal state.
+    mouse_lock_webwidget_owner_ = NULL;
+    mouse_lock_pinstance_owner_ = NULL;
+
+    DCHECK(!mouse_lock_webwidget_owner_ || !mouse_lock_pinstance_owner_);
+    if (last_webwidget_owner)
+      last_webwidget_owner->didLosePointerLock();
+    if (last_pinstance_owner)
+      last_pinstance_owner->OnMouseLockLost();
+  }
+}
+