ozone: evdev: Add gamepad support

ui/events/ozone/evdev/gamepad_event_converter_evdev.h

+// Copyright 2017 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_OZONE_GAMEPAD_EVENT_CONVERTER_EVDEV_H_
+#define UI_EVENTS_OZONE_GAMEPAD_EVENT_CONVERTER_EVDEV_H_
+
+#include <vector>
+
+#include "base/files/file_path.h"
+#include "base/macros.h"
+#include "ui/events/devices/input_device.h"
+#include "ui/events/event.h"
+#include "ui/events/ozone/evdev/event_converter_evdev.h"
+#include "ui/events/ozone/evdev/event_device_info.h"
+#include "ui/events/ozone/evdev/events_ozone_evdev_export.h"
+#include "ui/events/ozone/evdev/scoped_input_device.h"
+#include "ui/events/ozone/gamepad/gamepad_mapping.h"
+#include "ui/events/ozone/gamepad/webgamepad_constants.h"
+
+struct input_event;
+
+namespace ui {
+
+class DeviceEventDispatcherEvdev;
+
+class EVENTS_OZONE_EVDEV_EXPORT GamepadEventConverterEvdev
+    : public EventConverterEvdev {
+ public:
+  GamepadEventConverterEvdev(ScopedInputDevice fd,
+                             base::FilePath path,
+                             int id,
+                             const EventDeviceInfo& info,
+                             DeviceEventDispatcherEvdev* dispatcher);
+
+  ~GamepadEventConverterEvdev() override;
+
+  // EventConverterEvdev:
+  void OnFileCanReadWithoutBlocking(int fd) override;
+  bool HasGamepad() const override;
+  void OnDisabled() override;
+
+  // This function processes one input_event from evdev.
+  void ProcessEvent(const struct input_event& input);
+
+ private:
+  // This function processes EV_KEY event from gamepad device.
+  void ProcessEvdevKey(uint16_t code,
+                       uint16_t value,
+                       const base::TimeTicks& timestamp);
+
+  // This function processes EV_ABS event from gamepad device.
+  void ProcessEvdevAbs(uint16_t code,
+                       uint16_t value,
+                       const base::TimeTicks& timestamp);
+
+  // This function releases all the keys and resets all the axises.
+  void ResetGamepad();
+
+  // This function reads current gamepad status and resyncs the gamepad.
+  void ResyncGamepad();
+
+  void OnButtonChange(unsigned int code,
+                      double value,
+                      const base::TimeTicks& timestamp);
+  void OnAbsChange(unsigned int code,
+                   double value,
+                   const base::TimeTicks& timestamp);
+  void OnSync(const base::TimeTicks& timestamp);
+
+  // Sometimes, we want to drop abs values, when we do so, we no longer want to
+  // send gamepad frame event when we see next sync. This flag is set to false
+  // when each frame is sent. It is set to true when Btn or Abs event is sent.
+  bool will_send_frame_;
+
+  // Internal representation of axis information.
+
+  class Axis {
+   public:
+    Axis();
+    Axis(const input_absinfo& abs_info,
+         GamepadEventType mapped_type,
+         uint16_t mapped_code);
+
+    bool MapValue(uint16_t value, double* mapped_value);
+
+    GamepadEventType mapped_type();
+
+    uint16_t mapped_code();
+
+   private:
+    bool ValueChangeSignificantly(double new_value);
+    double last_value_;
+    double scale_;
+    double offset_;
+    double scaled_fuzz_;
+    double scaled_flat_;
+    GamepadEventType mapped_type_;
+    uint16_t mapped_code_;
+  };
+
+  Axis axes_[ABS_CNT];
+
+  // These values keeps the state of previous hat.
+  bool last_hat_left_press_;
+  bool last_hat_right_press_;
+  bool last_hat_up_press_;
+  bool last_hat_down_press_;
+
+  GamepadMapper mapper_;
+
+  // Input device file descriptor.
+  ScopedInputDevice input_device_fd_;
+
+  // Callbacks for dispatching events.
+  DeviceEventDispatcherEvdev* dispatcher_;
+
+  DISALLOW_COPY_AND_ASSIGN(GamepadEventConverterEvdev);
+};
+
+}  // namespace ui
+
+#endif  // UI_EVENTS_OZONE_GAMEPAD_EVENT_CONVERTER_EVDEV_H_