touch: Allow grabbing/ungrabbing touch devices for XInput2.

views/touchui/touch_factory.h

+// Copyright (c) 2011 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 VIEWS_TOUCHUI_TOUCH_FACTORY_H_
+#define VIEWS_TOUCHUI_TOUCH_FACTORY_H_
+#pragma once
+
+#include <bitset>
+#include <vector>
+
+#include "base/singleton.h"
+
+typedef unsigned long Window;
+typedef struct _XDisplay Display;
+
+namespace views {
+
+// Functions related to determining touch devices.
+class TouchFactory {
+ public:
+  // Returns the TouchFactory singleton.
+  static TouchFactory* GetInstance();
+
+  // Keep a list of touch devices so that it is possible to determine if a
+  // pointer event is a touch-event or a mouse-event. The list is reset each
+  // time this is called.
+  void SetTouchDeviceList(const std::vector<unsigned int>& devices);
+
+  // Is the device a touch-device?
+  bool IsTouchDevice(unsigned int deviceid);
+
+  // Grab the touch devices for the specified window on the specified display.
+  // Returns if grab was successful for all touch devices.
+  bool GrabTouchDevices(Display* display, ::Window window);
+
+  // Ungrab the touch devices. Returns if ungrab was successful for all touch
+  // devices.
+  bool UngrabTouchDevices(Display* display);
+
+ private:
+  TouchFactory();
+
+  // Requirement for Signleton
+  friend struct DefaultSingletonTraits<TouchFactory>;
+
+  // NOTE: To keep track of touch devices, we currently maintain a lookup table
+  // to quickly decide if a device is a touch device or not. We also maintain a
+  // list of the touch devices. Ideally, there will be only one touch device,
+  // and instead of having the lookup table and the list, there will be a single
+  // identifier for the touch device. This can be completed after enough testing
+  // on real touch devices.
+
+  // A quick lookup table for determining if a device is a touch device.
+  std::bitset<128> touch_device_lookup_;
+
+  // The list of touch devices.
+  std::vector<int> touch_device_list_;
+
+  DISALLOW_COPY_AND_ASSIGN(TouchFactory);
+};
+
+}  // namespace views
+
+#endif  // VIEWS_TOUCHUI_TOUCH_FACTORY_H_