Implement the gamepad API in the IPC proxy

content/browser/gamepad/gamepad_platform_data_fetcher_win.cc

+// 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.
+
+#include "content/browser/gamepad/gamepad_platform_data_fetcher_win.h"
+
+#include "base/debug/trace_event.h"
+#include "content/common/gamepad_messages.h"
+#include "content/common/gamepad_hardware_buffer.h"
+
+namespace content {
+
+using namespace WebKit;
+
+namespace {
+
+// See http://goo.gl/5VSJR. These are not available in all versions of the
+// header, but they can be returned from the driver, so we define our own
+// versions here.
+static const BYTE kDeviceSubTypeGamepad = 1;
+static const BYTE kDeviceSubTypeWheel = 2;
+static const BYTE kDeviceSubTypeArcadeStick = 3;
+static const BYTE kDeviceSubTypeFlightStick = 4;
+static const BYTE kDeviceSubTypeDancePad = 5;
+static const BYTE kDeviceSubTypeGuitar = 6;
+static const BYTE kDeviceSubTypeGuitarAlternate = 7;
+static const BYTE kDeviceSubTypeDrumKit = 8;
+static const BYTE kDeviceSubTypeGuitarBass = 11;
+static const BYTE kDeviceSubTypeArcadePad = 19;
+
+float NormalizeAxis(SHORT value) {
+  return ((value + 32768.f) / 32767.5f) - 1.f;
+}
+
+const WebUChar* const GamepadSubTypeName(BYTE sub_type) {
+  switch (sub_type) {
+    case kDeviceSubTypeGamepad: return L"GAMEPAD";
+    case kDeviceSubTypeWheel: return L"WHEEL";
+    case kDeviceSubTypeArcadeStick: return L"ARCADE_STICK";
+    case kDeviceSubTypeFlightStick: return L"FLIGHT_STICK";
+    case kDeviceSubTypeDancePad: return L"DANCE_PAD";
+    case kDeviceSubTypeGuitar: return L"GUITAR";
+    case kDeviceSubTypeGuitarAlternate: return L"GUITAR_ALTERNATE";
+    case kDeviceSubTypeDrumKit: return L"DRUM_KIT";
+    case kDeviceSubTypeGuitarBass: return L"GUITAR_BASS";
+    case kDeviceSubTypeArcadePad: return L"ARCADE_PAD";
+    default: return L"<UNKNOWN>";
+  }
+}
+
+}  // namespace
+
+GamepadPlatformDataFetcherWin::GamepadPlatformDataFetcherWin()
+    : xinput_dll_(FilePath(FILE_PATH_LITERAL("xinput1_3.dll"))),
+      xinput_available_(GetXinputDllFunctions()) {
+}
+
+GamepadPlatformDataFetcherWin::~GamepadPlatformDataFetcherWin() {
+}
+
+void GamepadPlatformDataFetcherWin::GetGamepadData(WebGamepads* pads,
+                                        bool devices_changed_hint) {
+  TRACE_EVENT0("GAMEPAD", "GetGamepadData");
+
+  // If there's no XInput DLL on the system, early out so that we don't
+  // call any other XInput functions.
+  if (!xinput_available_) {
+    pads->length = 0;
+    return;
+  }
+
+  pads->length = WebGamepads::itemsLengthCap;
+
+  // If we got notification that system devices have been updated, then
+  // run GetCapabilities to update the connected status and the device
+  // identifier. It can be slow to do to both GetCapabilities and
+  // GetState on unconnected devices, so we want to avoid a 2-5ms pause
+  // here by only doing this when the devices are updated (despite
+  // documentation claiming it's OK to call it any time).
+  if (devices_changed_hint) {
+    for (unsigned i = 0; i < WebGamepads::itemsLengthCap; ++i) {
+      WebGamepad& pad = pads->items[i];
+      TRACE_EVENT1("GAMEPAD", "GetCapabilities", "id", i);
+      XINPUT_CAPABILITIES caps;
+      DWORD res = xinput_get_capabilities_(i, XINPUT_FLAG_GAMEPAD, &caps);
+      if (res == ERROR_DEVICE_NOT_CONNECTED) {
+        pad.connected = false;
+      } else {
+        pad.connected = true;
+        base::swprintf(pad.id,
+                       WebGamepad::idLengthCap,
+                       L"Xbox 360 Controller (XInput STANDARD %ls)",
+                       GamepadSubTypeName(caps.SubType));
+      }
+    }
+  }
+
+  // We've updated the connection state if necessary, now update the actual
+  // data for the devices that are connected.
+  for (unsigned i = 0; i < WebGamepads::itemsLengthCap; ++i) {
+    WebGamepad& pad = pads->items[i];
+
+    // We rely on device_changed and GetCapabilities to tell us that
+    // something's been connected, but we will mark as disconnected if
+    // GetState returns that we've lost the pad.
+    if (!pad.connected)
+      continue;
+
+    XINPUT_STATE state;
+    memset(&state, 0, sizeof(XINPUT_STATE));
+    TRACE_EVENT_BEGIN1("GAMEPAD", "XInputGetState", "id", i);
+    DWORD dwResult = xinput_get_state_(i, &state);
+    TRACE_EVENT_END1("GAMEPAD", "XInputGetState", "id", i);
+
+    if (dwResult == ERROR_SUCCESS) {
+      pad.timestamp = state.dwPacketNumber;
+      pad.buttonsLength = 0;
+#define ADD(b) pad.buttons[pad.buttonsLength++] = \
+    ((state.Gamepad.wButtons & (b)) ? 1.0 : 0.0);
+      ADD(XINPUT_GAMEPAD_A);
+      ADD(XINPUT_GAMEPAD_B);
+      ADD(XINPUT_GAMEPAD_X);
+      ADD(XINPUT_GAMEPAD_Y);
+      ADD(XINPUT_GAMEPAD_LEFT_SHOULDER);
+      ADD(XINPUT_GAMEPAD_RIGHT_SHOULDER);
+      pad.buttons[pad.buttonsLength++] = state.Gamepad.bLeftTrigger / 255.0;
+      pad.buttons[pad.buttonsLength++] = state.Gamepad.bRightTrigger / 255.0;
+      ADD(XINPUT_GAMEPAD_BACK);
+      ADD(XINPUT_GAMEPAD_START);
+      ADD(XINPUT_GAMEPAD_LEFT_THUMB);
+      ADD(XINPUT_GAMEPAD_RIGHT_THUMB);
+      ADD(XINPUT_GAMEPAD_DPAD_UP);
+      ADD(XINPUT_GAMEPAD_DPAD_DOWN);
+      ADD(XINPUT_GAMEPAD_DPAD_LEFT);
+      ADD(XINPUT_GAMEPAD_DPAD_RIGHT);
+#undef ADD
+      pad.axesLength = 0;
+      // XInput are +up/+right, -down/-left, we want -up/-left.
+      pad.axes[pad.axesLength++] = NormalizeAxis(state.Gamepad.sThumbLX);
+      pad.axes[pad.axesLength++] = -NormalizeAxis(state.Gamepad.sThumbLY);
+      pad.axes[pad.axesLength++] = NormalizeAxis(state.Gamepad.sThumbRX);
+      pad.axes[pad.axesLength++] = -NormalizeAxis(state.Gamepad.sThumbRY);
+    } else {
+      pad.connected = false;
+    }
+  }
+}
+
+bool GamepadPlatformDataFetcherWin::GetXinputDllFunctions() {
+  xinput_get_capabilities_ = NULL;
+  xinput_get_state_ = NULL;
+  xinput_enable_ = static_cast<XInputEnableFunc>(
+      xinput_dll_.GetFunctionPointer("XInputEnable"));
+  if (!xinput_enable_)
+    return false;
+  xinput_get_capabilities_ = static_cast<XInputGetCapabilitiesFunc>(
+      xinput_dll_.GetFunctionPointer("XInputGetCapabilities"));
+  if (!xinput_get_capabilities_)
+    return false;
+  xinput_get_state_ = static_cast<XInputGetStateFunc>(
+      xinput_dll_.GetFunctionPointer("XInputGetState"));
+  if (!xinput_get_state_)
+    return false;
+  xinput_enable_(true);
+  return true;
+}
+
+}  // namespace content