use Loadlibrary/GetProcAddress for XInput, rather than /DELAYLOAD

content/browser/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/platform_data_fetcher_win.h"
 
 #include "base/debug/trace_event.h"
 #include "content/common/gamepad_messages.h"
 #include "content/common/gamepad_hardware_buffer.h"
 
-#if defined(_WIN32_WINNT_WIN8)
-// The Windows 8 SDK defines FACILITY_VISUALCPP in winerror.h.
-#undef FACILITY_VISUALCPP
-#endif
-#include <delayimp.h>
-
-#pragma comment(lib, "delayimp.lib")
-#pragma comment(lib, "xinput.lib")
-
 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;
@@ skipping 20 matching lines @@
     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>";
   }
 }
 
-// Trap only the exceptions that DELAYLOAD can throw, otherwise rethrow.
-// See http://msdn.microsoft.com/en-us/library/1c9e046h(v=VS.90).aspx.
-LONG WINAPI DelayLoadDllExceptionFilter(PEXCEPTION_POINTERS pExcPointers) {
-  LONG disposition = EXCEPTION_EXECUTE_HANDLER;
-  switch (pExcPointers->ExceptionRecord->ExceptionCode) {
-    case VcppException(ERROR_SEVERITY_ERROR, ERROR_MOD_NOT_FOUND):
-    case VcppException(ERROR_SEVERITY_ERROR, ERROR_PROC_NOT_FOUND):
-      break;
-    default:
-      // Exception is not related to delay loading.
-      disposition = EXCEPTION_CONTINUE_SEARCH;
-      break;
-  }
-  return disposition;
-}
-
-bool EnableXInput() {
-  // We have specified DELAYLOAD for xinput1_3.dll. If the DLL is not
-  // installed (XP w/o DirectX redist installed), we disable functionality.
-  __try {
-    XInputEnable(true);
-  } __except(DelayLoadDllExceptionFilter(GetExceptionInformation())) {
-    return false;
-  }
-  return true;
-}
-
 }  // namespace
 
-GamepadPlatformDataFetcherWin::GamepadPlatformDataFetcherWin()
-    : xinput_available_(EnableXInput()) {
+GamepadPlatformDataFetcherWin::GamepadPlatformDataFetcherWin() :
+    xinput_dll_(FilePath(L"xinput1_3.dll")),

[cpu_(ooo_6.6-7.5), 2012/07/17 19:30:46]

FILE_PATH_LITERAL("...")

+    xinput_available_(GetXinputDllFunctions()) {
 }
 
 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 = XInputGetCapabilities(i, XINPUT_FLAG_GAMEPAD, &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 = XInputGetState(i, &state);
+    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);
@@ skipping 16 matching lines @@
       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_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