1 /* 2 * Copyright (C) 2006 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef ANDROID_USB_API_ADBWINUSBAPI_H__ 18 #define ANDROID_USB_API_ADBWINUSBAPI_H__ 19 20 /** \file 21 Contains declarations required to link AdbWinApi and AdbWinUsbApi DLLs. 22 */ 23 24 /** \brief Function prototype for InstantiateWinUsbInterface routine exported 25 from AdbWinUsbApi.dll 26 27 In order to provide backward compatibility with the systems that still run 28 legacy (custom) USB drivers, and have not installed WINUSB.DLL we need to 29 split functionality of our ADB API on Windows between two DLLs: AdbWinApi, 30 and AdbWinUsbApi. AdbWinApi is fully capable of working on top of the legacy 31 driver, but has no traces to WinUsb. AdbWinUsbApi is capable of working on 32 top of WinUsb API. We are forced to do this split, because we can have 33 dependency on WINUSB.DLL in the DLL that implements legacy API. The problem 34 is that customers may have a legacy driver that they don't want to upgrade 35 to WinUsb, so they may not have WINUSB.DLL installed on their machines, but 36 they still must be able to use ADB. So, the idea behind the split is as 37 such. When AdbWinApi.dll is loaded into a process, it will check WINUSB.DLL 38 installation (by checking existance of C:\Windows\System32\winusb.dll). If 39 WINUSB.DLL is installed, AdbWinApi will also load AdbWinUsbApi.dll (by 40 calling LoadLibrary), and will extract address of InstantiateWinUsbInterface 41 routine exported from AdbWinUsbApi.dll. Then this routine will be used to 42 instantiate AdbInterfaceObject instance on condition that it is confirmed 43 that USB driver underneath us is in deed WinUsb. 44 */ 45 typedef class AdbInterfaceObject* \ 46 (__cdecl *PFN_INSTWINUSBINTERFACE)(const wchar_t*); 47 48 #endif // ANDROID_USB_API_ADBWINUSBAPI_H__ 49