Add gamepad data fetcher for Linux

content/browser/gamepad/platform_data_fetcher_linux.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_BROWSER_GAMEPAD_DATA_FETCHER_LINUX_H_
+#define CONTENT_BROWSER_GAMEPAD_DATA_FETCHER_LINUX_H_
+
+#include <string>
+
+#include "base/compiler_specific.h"
+#include "base/message_pump_libevent.h"
+#include "build/build_config.h"
+#include "content/browser/gamepad/data_fetcher.h"
+#include "content/browser/gamepad/gamepad_standard_mappings_linux.h"
+#include "content/common/gamepad_hardware_buffer.h"
+
+extern "C" {
+struct udev;
+struct udev_device;
+struct udev_monitor;
+}
+
+namespace content {
+
+class GamepadPlatformDataFetcherLinux :
+    public GamepadDataFetcher,
+    public base::MessagePumpLibevent::Watcher {
+ public:
+  GamepadPlatformDataFetcherLinux();
+  virtual ~GamepadPlatformDataFetcherLinux();
+
+  // GamepadDataFetcher:
+  virtual void GetGamepadData(WebKit::WebGamepads* pads,
+                              bool devices_changed_hint) OVERRIDE;
+
+  // base::MessagePump:Libevent::Watcher:
+  virtual void OnFileCanReadWithoutBlocking(int fd) OVERRIDE;
+  virtual void OnFileCanWriteWithoutBlocking(int fd) OVERRIDE;
+
+ private:
+  bool IsGamepad(udev_device* dev, int& index, std::string& path);
+  void RefreshDevice(udev_device* dev);
+  void EnumerateDevices();
+  void ReadDeviceData(size_t index);
+
+  // libudev-related items, the main context, and the monitoring context to be
+  // notified about changes to device states.
+  udev* udev_;
+  udev_monitor* monitor_;
+  int monitor_fd_;
+  base::MessagePumpLibevent::FileDescriptorWatcher monitor_watcher_;
+
+  // File descriptors for the /dev/input/js* devices. -1 if not in use.
+  int device_fds_[WebKit::WebGamepads::itemsLengthCap];
+
+  // Functions to map from device data to standard layout, if available. May
+  // be null if no mapping is available.
+  GamepadStandardMappingFunction mappers_[WebKit::WebGamepads::itemsLengthCap];
+
+  // Data that's returned to the consumer.
+  WebKit::WebGamepads data_;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_GAMEPAD_DATA_FETCHER_LINUX_H_