Only block internal touchpad and allow external mice to continue working in maximize mode.

ash/wm/maximize_mode/maximize_mode_event_blocker.cc

 // Copyright 2014 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 "ash/wm/maximize_mode/maximize_mode_event_blocker.h"
 
 #include "ash/shell.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/strings/string_util.h"
 #include "ui/aura/client/cursor_client.h"
+#include "ui/aura/window_event_dispatcher.h"
+#include "ui/aura/window_tree_host.h"
 #include "ui/events/event_targeter.h"
+#include "ui/gfx/point.h"
+
+#if defined(USE_X11)
+#include <X11/extensions/XInput2.h>
+#include <X11/Xlib.h>
+
+#include "ui/events/x/device_data_manager.h"
+#include "ui/events/x/device_list_cache_x.h"
+#include "ui/gfx/x/x11_types.h"
+#endif
 
 namespace ash {
 
 namespace {
 
+#if defined(USE_X11)
+// The name of the xinput device corresponding to the internal touchpad.
+const char kInternalTouchpadName[] = "Elan Touchpad";
+#endif
+
 // Event targeter to prevent delivery of mouse and touchpad events while
 // maximize mode is active. Other events such as touch are passed on to the
 // default targeter.
-// TODO(flackr): This should only stop events from the internal keyboard and
-// touchpad.
 class BlockKeyboardAndTouchpadTargeter : public ui::EventTargeter {
  public:
-  BlockKeyboardAndTouchpadTargeter();
+  BlockKeyboardAndTouchpadTargeter(aura::Window* root_window,
+                                   std::set<int>* internal_device_ids);
   virtual ~BlockKeyboardAndTouchpadTargeter();
 
   // Sets the default targeter to use when the event is not being blocked.
   void SetDefaultTargeter(EventTargeter* default_targeter);
 
   // Overridden from ui::EventTargeter:
   virtual ui::EventTarget* FindTargetForEvent(ui::EventTarget* root,
                                               ui::Event* event) OVERRIDE;
 
  private:
+  // A weak pointer to the root window on which this targeter will be set.
+  aura::Window* root_window_;

[sadrul, 2014/05/07 13:59:23]

We expect that the root-window will outlive this targeter, right?

[flackr, 2014/05/14 16:46:56]

Yes, commented.

+
+  // A weak pointer to the set of device ids to block.
+  std::set<int>* internal_device_ids_;
+
   // A weak pointer to the targeter this targeter is wrapping. The
   // default_targeter is owned by the ScopedWindowTargeter which will be valid
   // as long as this targeter is alive.
   ui::EventTargeter* default_targeter_;
 
+  // The last known mouse location to lock the cursor in place to when events
+  // come from the internal touchpad.
+  gfx::Point last_mouse_location_;
+
   DISALLOW_COPY_AND_ASSIGN(BlockKeyboardAndTouchpadTargeter);
 };
 
-BlockKeyboardAndTouchpadTargeter::BlockKeyboardAndTouchpadTargeter()
-    : default_targeter_(NULL) {
+BlockKeyboardAndTouchpadTargeter::BlockKeyboardAndTouchpadTargeter(
+    aura::Window* root_window,
+    std::set<int>* internal_device_ids)
+    : root_window_(root_window),
+      internal_device_ids_(internal_device_ids),
+      default_targeter_(NULL),
+      last_mouse_location_(root_window->GetHost()->dispatcher()->
+          GetLastMouseLocationInRoot()) {
 }
 
 BlockKeyboardAndTouchpadTargeter::~BlockKeyboardAndTouchpadTargeter() {
 }
 
 void BlockKeyboardAndTouchpadTargeter::SetDefaultTargeter(
     ui::EventTargeter* default_targeter) {
   default_targeter_ = default_targeter;
 }
 
 ui::EventTarget* BlockKeyboardAndTouchpadTargeter::FindTargetForEvent(
     ui::EventTarget* root,
     ui::Event* event) {
-  if (event->HasNativeEvent() && (event->IsMouseEvent() || event->IsKeyEvent()))
-    return NULL;
+  if (event->HasNativeEvent()) {
+    if (event->IsMouseEvent()) {
+#if defined(USE_X11)
+      XIDeviceEvent* xiev = static_cast<XIDeviceEvent*>(
+          event->native_event()->xcookie.data);
+      if (internal_device_ids_->find(xiev->sourceid) !=
+              internal_device_ids_->end()) {
+        root_window_->GetHost()->MoveCursorToHostLocation(
+            last_mouse_location_);

[sadrul, 2014/05/07 13:59:23]

Add a comment here about why we are doing this (it isn't immediately clear that
we don't want the cursor to move in this mode).

[flackr, 2014/05/14 16:46:56]

Done.

+        return NULL;
+      } else {
+        // Track the last location seen from an external mouse event.
+        last_mouse_location_ = static_cast<ui::MouseEvent*>(event)->location();
+        root_window_->GetHost()->GetRootTransform().TransformPoint(
+            &last_mouse_location_);

[sadrul, 2014/05/07 13:59:23]

Use WindowTreeHost::ConvertPointToHost on the event's root_location() instead?

[flackr, 2014/05/14 16:46:56]

Done.

+      }
+#else
+      return NULL;
+#endif
+    } else if (event->IsKeyEvent()) {
+      // TODO(flackr): Disable events only from the internal keyboard device
+      // when we begin using XI2 events for keyboard events
+      // (http://crbug.com/368750) and can tell which device the event is
+      // coming from, http://crbug.com/362881.
+      return NULL;
+    }
+  }
   return default_targeter_->FindTargetForEvent(root, event);
 }
 
 }  // namespace
 
 MaximizeModeEventBlocker::MaximizeModeEventBlocker() {
   Shell::GetInstance()->AddShellObserver(this);
 
+#if defined(USE_X11)
+  if (ui::DeviceDataManager::GetInstance()->IsXInput2Available()) {
+    XIDeviceList xi_dev_list = ui::DeviceListCacheX::GetInstance()->
+        GetXI2DeviceList(gfx::GetXDisplay());
+    for (int i = 0; i < xi_dev_list.count; ++i) {
+      std::string device_name(xi_dev_list[i].name);
+      base::TrimWhitespaceASCII(device_name, base::TRIM_TRAILING, &device_name);

[sadrul, 2014/05/07 13:59:23]

How safe is it to assume that the name is ASCII?

[flackr, 2014/05/14 16:46:56]

It should be safe, TrimWhitespaceASCII uses std::string::find_last_not_of
basically ignoring encoding. Afaik at worst trimming a UTF8 string would give an
invalid UTF8 string but since we don't use the string as anything but ASCII it
wouldn't matter.

+      if (device_name == kInternalTouchpadName)
+        internal_device_ids_.insert(xi_dev_list[i].deviceid);
+    }
+  }
+#endif
+
   // Hide the cursor as mouse events will be blocked.
   aura::client::CursorClient* cursor_client_ =
       aura::client::GetCursorClient(Shell::GetTargetRootWindow());
   if (cursor_client_)
     cursor_client_->HideCursor();
 
   // Block keyboard and mouse events on all existing and new root windows for
   // the lifetime of this class.
   aura::Window::Windows root_windows(Shell::GetAllRootWindows());
   for (aura::Window::Windows::iterator iter = root_windows.begin();
        iter != root_windows.end(); ++iter) {
     AddEventTargeterOn(*iter);
   }
 }
 
 MaximizeModeEventBlocker::~MaximizeModeEventBlocker() {
   Shell::GetInstance()->RemoveShellObserver(this);
 }
 
 void MaximizeModeEventBlocker::OnRootWindowAdded(aura::Window* root_window) {
   AddEventTargeterOn(root_window);
 }
 
 void MaximizeModeEventBlocker::AddEventTargeterOn(
     aura::Window* root_window) {
   BlockKeyboardAndTouchpadTargeter* targeter =
-      new BlockKeyboardAndTouchpadTargeter();
+      new BlockKeyboardAndTouchpadTargeter(root_window,
+                                           &internal_device_ids_);
   aura::ScopedWindowTargeter* scoped_targeter = new aura::ScopedWindowTargeter(
       root_window, scoped_ptr<ui::EventTargeter>(targeter));
   targeter->SetDefaultTargeter(scoped_targeter->old_targeter());
   targeters_.push_back(scoped_targeter);
 }
 
 }  // namespace ash