1 files changed, 63 insertions, 0 deletions
diff --git a/ui/events/x/device_list_cache_x.h b/ui/events/x/device_list_cache_x.h
new file mode 100644
index 0000000..f68803a
--- /dev/null
+++ b/ui/events/x/device_list_cache_x.h
@@ -0,0 +1,63 @@
+// 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 UI_EVENTS_X_DEVICE_LIST_CACHE_X_H_
+#define UI_EVENTS_X_DEVICE_LIST_CACHE_X_H_
+
+#include <X11/extensions/XInput.h>
+#include <X11/extensions/XInput2.h>
+
+#include <map>
+
+#include "base/basictypes.h"
+#include "ui/events/events_export.h"
+
+template <typename T> struct DefaultSingletonTraits;
+
+typedef struct _XDisplay Display;
+
+template <typename T>
+struct DeviceList {
+  DeviceList() : devices(NULL), count(0) {
+  }
+  T& operator[] (int x) {
+    return devices[x];
+  }
+  T* devices;
+  int count;
+};
+
+typedef struct DeviceList<XDeviceInfo> XDeviceList;
+typedef struct DeviceList<XIDeviceInfo> XIDeviceList;
+
+namespace ui {
+
+// A class to cache the current XInput device list. This minimized the
+// round-trip time to the X server whenever such a device list is needed. The
+// update function will be called on each incoming XI_HierarchyChanged event.
+class EVENTS_EXPORT DeviceListCacheX {
+ public:
+  static DeviceListCacheX* GetInstance();
+
+  void UpdateDeviceList(Display* display);
+
+  const XDeviceList& GetXDeviceList(Display* display);
+  const XIDeviceList& GetXI2DeviceList(Display* display);
+
+ private:
+  friend struct DefaultSingletonTraits<DeviceListCacheX>;
+
+  DeviceListCacheX();
+  ~DeviceListCacheX();
+
+  std::map<Display*, XDeviceList> x_dev_list_map_;
+  std::map<Display*, XIDeviceList> xi_dev_list_map_;
+
+  DISALLOW_COPY_AND_ASSIGN(DeviceListCacheX);
+};
+
+}  // namespace ui
+
+#endif  // UI_EVENTS_X_DEVICE_LIST_CACHE_X_H_
+