Add generic mapping for gamepad

ui/events/ozone/gamepad/generic_gamepad_mapping.cc

Index: ui/events/ozone/gamepad/generic_gamepad_mapping.cc
diff --git a/ui/events/ozone/gamepad/generic_gamepad_mapping.cc b/ui/events/ozone/gamepad/generic_gamepad_mapping.cc
new file mode 100644
index 0000000000000000000000000000000000000000..343b2a98c40a1f14d67df83a0a1c45522c4440ad
--- /dev/null
+++ b/ui/events/ozone/gamepad/generic_gamepad_mapping.cc
@@ -0,0 +1,250 @@
+// 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.
+
+#include <linux/input.h>
+#include <algorithm>
+#include <bitset>
+#include <cstdint>
+#include <list>
+#include <set>
+#include <vector>
+
+#include "base/macros.h"
+#include "base/memory/ptr_util.h"
+#include "ui/events/ozone/evdev/event_device_info.h"
+#include "ui/events/ozone/gamepad/generic_gamepad_mapping.h"
+#include "ui/events/ozone/gamepad/webgamepad_constants.h"
+
+namespace {
+using ui::GamepadEventType;
+
+class GenericGamepadMapper : public ui::GamepadMapper {
+ public:
+  GenericGamepadMapper(std::vector<ui::AbsMapEntry> axis_mapping,
+                       std::vector<ui::KeyMapEntry> button_mapping) {
+    axis_mapping.swap(axis_mapping_);
+    button_mapping.swap(button_mapping_);
+  }
+
+  bool Map(uint16_t type,
+           uint16_t code,
+           ui::GamepadEventType* mapped_type,
+           uint16_t* mapped_code) const override {
+    if (type == EV_KEY) {
+      for (auto entry : button_mapping_) {
+        if (entry.evdev_code == code) {
+          *mapped_type = ui::GamepadEventType::BUTTON;
+          *mapped_code = entry.mapped_code;
+          return true;
+        }
+      }
+      return false;
+    }
+
+    if (type == EV_ABS) {
+      for (auto entry : axis_mapping_) {
+        if (entry.evdev_code == code) {
+          *mapped_type = entry.mapped_type;
+          *mapped_code = entry.mapped_code;
+          return true;
+        }
+      }
+      return false;
+    }
+    return false;
+  }
+
+  ~GenericGamepadMapper() override {}
+
+ private:
+  std::vector<ui::AbsMapEntry> axis_mapping_;
+  std::vector<ui::KeyMapEntry> button_mapping_;
+};
+
+// This helper class will be used to build generic mapping.
+class GamepadMapperBuilder {
+ public:
+  explicit GamepadMapperBuilder(const ui::EventDeviceInfo& devinfo)
+      : devinfo_(devinfo) {}
+
+  std::unique_ptr<ui::GamepadMapper> ToGamepadMapper() {
+    return base::MakeUnique<GenericGamepadMapper>(std::move(axis_mapping_),
+                                                  std::move(button_mapping_));
+  }
+
+  void MapButton(uint16_t from_button, uint16_t mapped_button) {
+    if (!devinfo_.HasKeyEvent(from_button)) {
+      return;
+    }
+    DCHECK(!IfEvdevButtonMappedFrom(from_button));
+    DCHECK(!IfWebgamepadButtonMappedTo(mapped_button));
+
+    button_mapping_.push_back({from_button, mapped_button});
+    evdev_buttons_.set(from_button);
+    webgamepad_buttons_.set(mapped_button);
+  }
+
+  void MapAxisToButton(uint16_t from_axis, uint16_t mapped_button) {
+    if (!devinfo_.HasAbsEvent(from_axis)) {
+      return;
+    }
+    DCHECK(!IfEvdevAxisMappedFrom(from_axis));
+    evdev_axes_.set(from_axis);
+    axis_mapping_.push_back(TO_BTN(from_axis, mapped_button));
+
+    if (mapped_button == ui::kHAT_X) {
+      DCHECK(!IfWebgamepadButtonMappedTo(ui::WG_BUTTON_DPAD_LEFT));
+      DCHECK(!IfWebgamepadButtonMappedTo(ui::WG_BUTTON_DPAD_RIGHT));
+
+      webgamepad_buttons_.set(ui::WG_BUTTON_DPAD_LEFT);
+      webgamepad_buttons_.set(ui::WG_BUTTON_DPAD_RIGHT);
+    } else if (mapped_button == ui::kHAT_Y) {
+      DCHECK(!IfWebgamepadButtonMappedTo(ui::WG_BUTTON_DPAD_UP));
+      DCHECK(!IfWebgamepadButtonMappedTo(ui::WG_BUTTON_DPAD_DOWN));
+
+      webgamepad_buttons_.set(ui::WG_BUTTON_DPAD_UP);
+      webgamepad_buttons_.set(ui::WG_BUTTON_DPAD_DOWN);
+    } else {
+      DCHECK(!IfWebgamepadButtonMappedTo(mapped_button));
+      webgamepad_buttons_.set(mapped_button);
+    }
+  }
+
+  void MapAxisToAxis(uint16_t from_axis, uint16_t mapped_axis) {
+    if (!devinfo_.HasAbsEvent(from_axis)) {
+      return;
+    }
+    DCHECK(!IfEvdevAxisMappedFrom(from_axis));
+    DCHECK(!IfWebgamepadAxisMappedTo(mapped_axis));
+
+    axis_mapping_.push_back(TO_ABS(from_axis, mapped_axis));
+    evdev_axes_.set(from_axis);
+    webgamepad_axes_.set(mapped_axis);
+  }
+
+  void MapButtonLikeJoydev() {
+    uint16_t next_unmapped_button = 0;
+    // In linux kernel, joydev.c map evdev events in the same way.
+    for (int i = BTN_JOYSTICK - BTN_MISC; i < KEY_MAX - BTN_MISC + 1; i++) {
+      int code = i + BTN_MISC;
+      if (devinfo_.HasKeyEvent(code) && !IfEvdevButtonMappedFrom(code) &&
+          FindNextUnmappedCode(webgamepad_buttons_, &next_unmapped_button)) {
+        MapButton(code, next_unmapped_button);
+      }
+    }
+
+    for (int i = 0; i < BTN_JOYSTICK - BTN_MISC; i++) {
+      int code = i + BTN_MISC;
+      if (devinfo_.HasKeyEvent(code) && !IfEvdevButtonMappedFrom(code) &&
+          FindNextUnmappedCode(webgamepad_buttons_, &next_unmapped_button)) {
+        MapButton(code, next_unmapped_button);
+      }
+    }
+  }
+
+  void MapAxisLikeJoydev() {
+    uint16_t next_unmapped_axis = 0;
+    for (int code = 0; code < ABS_CNT; ++code) {
+      if (devinfo_.HasAbsEvent(code) && !IfEvdevAxisMappedFrom(code) &&
+          FindNextUnmappedCode(webgamepad_axes_, &next_unmapped_axis)) {
+        MapAxisToAxis(code, next_unmapped_axis);
+      }
+    }
+  }
+
+ private:
+  // This function helps to find the next unmapped button or axis. Code is the
+  // last unmapped code and will be the next unmapped code when the function
+  // returns.
+  template <typename T>
+  bool FindNextUnmappedCode(const T& bitset, uint16_t* code) {
+    for (uint16_t i = *code; i < bitset.size(); ++i) {
+      if (!bitset.test(i)) {
+        *code = i;
+        return true;
+      }
+    }
+    return false;
+  }
+
+  bool IfEvdevButtonMappedFrom(uint16_t code) {
+    DCHECK_LT(code, KEY_CNT);
+    return evdev_buttons_.test(code);
+  }
+
+  bool IfEvdevAxisMappedFrom(uint16_t code) {
+    DCHECK_LT(code, ABS_CNT);
+    return evdev_axes_.test(code);
+  }
+
+  bool IfWebgamepadButtonMappedTo(uint16_t code) {
+    DCHECK_LT(code, ui::WG_BUTTON_COUNT);
+    return webgamepad_buttons_.test(code);
+  }
+
+  bool IfWebgamepadAxisMappedTo(uint16_t code) {
+    DCHECK_LT(code, ui::WG_ABS_COUNT);
+    return webgamepad_axes_.test(code);
+  }
+
+  const ui::EventDeviceInfo& devinfo_;
+
+  // Mapped webgamepad buttons and axes will be marked as true.
+  std::bitset<ui::WG_BUTTON_COUNT> webgamepad_buttons_;
+  std::bitset<ui::WG_ABS_COUNT> webgamepad_axes_;
+  // Evdev buttons and axes that are already mapped will be marked as true.
+  std::bitset<KEY_CNT> evdev_buttons_;
+  std::bitset<ABS_CNT> evdev_axes_;
+
+  // Generated Mapping.
+  std::vector<ui::AbsMapEntry> axis_mapping_;
+  std::vector<ui::KeyMapEntry> button_mapping_;
+};
+
+void MapSpecialButtons(GamepadMapperBuilder* builder) {
+  // Map mode seperately.
+  builder->MapButton(BTN_MODE, ui::WG_BUTTON_MODE);
+  // Take care of ADT style back and start.
+  builder->MapButton(KEY_BACK, ui::WG_BUTTON_SELECT);
+  builder->MapButton(KEY_HOMEPAGE, ui::WG_BUTTON_START);
+}
+
+void MapSpecialAxes(const ui::EventDeviceInfo& devinfo,
+                    GamepadMapperBuilder* builder) {
+  // HAT0X and HAT0Y always map to DPAD.
+  builder->MapAxisToButton(ABS_HAT0X, ui::kHAT_X);
+  builder->MapAxisToButton(ABS_HAT0Y, ui::kHAT_Y);
+
+  // When ABS_BRAKE and ABS_GAS supported at the same time, they are mapped to
+  // l-trigger and r-trigger.
+  // Otherwise, when x,y,z,rx,ry,rz are all supported, z and rz are mapped to
+  // triggers (As XInput gamepad mapper).
+  if (devinfo.HasAbsEvent(ABS_BRAKE) && devinfo.HasAbsEvent(ABS_GAS)) {
+    builder->MapAxisToButton(ABS_BRAKE, ui::WG_BUTTON_LT);
+    builder->MapAxisToButton(ABS_GAS, ui::WG_BUTTON_RT);
+  } else if (devinfo.HasAbsEvent(ABS_X) && devinfo.HasAbsEvent(ABS_Y) &&
+             devinfo.HasAbsEvent(ABS_Z) && devinfo.HasAbsEvent(ABS_RX) &&
+             devinfo.HasAbsEvent(ABS_RY) && devinfo.HasAbsEvent(ABS_RZ)) {
+    builder->MapAxisToButton(ABS_Z, ui::WG_BUTTON_LT);
+    builder->MapAxisToButton(ABS_RZ, ui::WG_BUTTON_RT);
+  }
+}
+}  // namespace
+
+namespace ui {
+std::unique_ptr<GamepadMapper> BuildGenericGamepadMapper(
+    const EventDeviceInfo& info) {
+  GamepadMapperBuilder builder(info);
+  // Must map axes first as axis might be mapped to button and occupy some
+  // webgamepad button slots.
+  MapSpecialAxes(info, &builder);
+  builder.MapAxisLikeJoydev();
+
+  MapSpecialButtons(&builder);
+  builder.MapButtonLikeJoydev();
+
+  return builder.ToGamepadMapper();
+}
+
+}  // namespace ui