text: // 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 <MMDeviceAPI.h>
  #include <mmsystem.h>
  #include <Functiondiscoverykeys_devpkey.h>  // MMDeviceAPI.h must come first
  
  #include "media/audio/win/audio_manager_win.h"
  
  #include "base/logging.h"
  #include "base/utf_string_conversions.h"
  #include "base/win/scoped_co_mem.h"
  #include "base/win/scoped_comptr.h"
  
  using media::AudioDeviceNames;
  using base::win::ScopedComPtr;
  using base::win::ScopedCoMem;
  
  // Taken from Mmddk.h.
  #define DRV_RESERVED                      0x0800
  #define DRV_QUERYFUNCTIONINSTANCEID       (DRV_RESERVED + 17)
  #define DRV_QUERYFUNCTIONINSTANCEIDSIZE   (DRV_RESERVED + 18)
  
  namespace media {
  
  bool GetInputDeviceNamesWin(AudioDeviceNames* device_names) {
    // It is assumed that this method is called from a COM thread, i.e.,
    // CoInitializeEx() is not called here again to avoid STA/MTA conflicts.
    ScopedComPtr<IMMDeviceEnumerator> enumerator;
    HRESULT hr =  CoCreateInstance(__uuidof(MMDeviceEnumerator),
                                   NULL,
                                   CLSCTX_INPROC_SERVER,
                                   __uuidof(IMMDeviceEnumerator),
                                   enumerator.ReceiveVoid());
    if (FAILED(hr)) {
      LOG(WARNING) << "Failed to create IMMDeviceEnumerator: " << std::hex << hr;
      return false;
    }
  
    // Generate a collection of active audio capture endpoint devices.
    // This method will succeed even if all devices are disabled.
    ScopedComPtr<IMMDeviceCollection> collection;
    hr = enumerator->EnumAudioEndpoints(eCapture,
                                        DEVICE_STATE_ACTIVE,
                                        collection.Receive());
    if (FAILED(hr))
      return false;
  
    // Retrieve the number of active capture devices.
    UINT number_of_active_devices = 0;
    collection->GetCount(&number_of_active_devices);
    if (number_of_active_devices == 0)
      return true;
  
    media::AudioDeviceName device;
  
    // Loop over all active capture devices and add friendly name and
    // unique ID to the |device_names| list.
    for (UINT i = 0; i < number_of_active_devices; ++i) {
      // Retrieve unique name of endpoint device.
      // Example: "{0.0.1.00000000}.{8db6020f-18e3-4f25-b6f5-7726c9122574}".
      ScopedComPtr<IMMDevice> audio_device;
      ScopedCoMem<WCHAR> endpoint_device_id;
      hr = collection->Item(i, audio_device.Receive());
      if (FAILED(hr))
        continue;
      audio_device->GetId(&endpoint_device_id);
  
      // Store the unique name.
      device.unique_id = WideToUTF8(static_cast<WCHAR*>(endpoint_device_id));
  
      // Retrieve user-friendly name of endpoint device.
      // Example: "Microphone (Realtek High Definition Audio)".
      ScopedComPtr<IPropertyStore> properties;
      hr = audio_device->OpenPropertyStore(STGM_READ, properties.Receive());
      if (SUCCEEDED(hr)) {
        PROPVARIANT friendly_name;
        PropVariantInit(&friendly_name);
        hr = properties->GetValue(PKEY_Device_FriendlyName, &friendly_name);
  
        // Store the user-friendly name.
        if (SUCCEEDED(hr) &&
            friendly_name.vt == VT_LPWSTR && friendly_name.pwszVal) {
          device.device_name = WideToUTF8(friendly_name.pwszVal);
        }
        PropVariantClear(&friendly_name);
      }
  
      // Add combination of user-friendly and unique name to the output list.
      device_names->push_back(device);
    }
  
    return true;
  }
  
  bool GetInputDeviceNamesWinXP(AudioDeviceNames* device_names) {
    // Retrieve the number of active waveform input devices.
    UINT number_of_active_devices = waveInGetNumDevs();
    if (number_of_active_devices == 0)
      return true;
  
    media::AudioDeviceName device;
    WAVEINCAPS capabilities;
    MMRESULT err = MMSYSERR_NOERROR;
  
    // Loop over all active capture devices and add friendly name and
    // unique ID to the |device_names| list. Note that, for Wave on XP,
    // the "unique" name will simply be a copy of the friendly name since
    // there is no safe method to retrieve a unique device name on XP.
    for (UINT i = 0; i < number_of_active_devices; ++i) {
      // Retrieve the capabilities of the specified waveform-audio input device.
      err = waveInGetDevCaps(i,  &capabilities, sizeof(capabilities));
      if (err != MMSYSERR_NOERROR)
        continue;
  
      // Store the user-friendly name. Max length is MAXPNAMELEN(=32)
      // characters and the name cane be truncated on XP.
      // Example: "Microphone (Realtek High Defini".
      device.device_name = WideToUTF8(capabilities.szPname);
  
      // Store the "unique" name (we use same as friendly name on Windows XP).
      device.unique_id = WideToUTF8(capabilities.szPname);
  
      // Add combination of user-friendly and unique name to the output list.
      device_names->push_back(device);
    }
  
    return true;
  }
  
  std::string ConvertToWinXPDeviceId(const std::string& device_id) {
    UINT number_of_active_devices = waveInGetNumDevs();
    MMRESULT result = MMSYSERR_NOERROR;
  
    UINT i = 0;
    for (; i < number_of_active_devices; ++i) {
      size_t size = 0;
      // Get the size (including the terminating NULL) of the endpoint ID of the
      // waveIn device.
      result = waveInMessage(reinterpret_cast<HWAVEIN>(i),
                             DRV_QUERYFUNCTIONINSTANCEIDSIZE,
                             reinterpret_cast<DWORD_PTR>(&size), NULL);
      if (result != MMSYSERR_NOERROR)
        continue;
  
      ScopedCoMem<WCHAR> id;
      id.Reset(static_cast<WCHAR*>(CoTaskMemAlloc(size)));
      if (!id)
        continue;
  
      // Get the endpoint ID string for this waveIn device.
      result = waveInMessage(
          reinterpret_cast<HWAVEIN>(i), DRV_QUERYFUNCTIONINSTANCEID,
          reinterpret_cast<DWORD_PTR>(static_cast<WCHAR*>(id)), size);
      if (result != MMSYSERR_NOERROR)
        continue;
  
      std::string utf8_id = WideToUTF8(static_cast<WCHAR*>(id));
      // Check whether the endpoint ID string of this waveIn device matches that
      // of the audio endpoint device.
      if (device_id == utf8_id)
        break;
    }
  
    // If a matching waveIn device was found, convert the unique endpoint ID
    // string to a standard friendly name with max 32 characters.
    if (i < number_of_active_devices) {
      WAVEINCAPS capabilities;
  
      result = waveInGetDevCaps(i, &capabilities, sizeof(capabilities));
      if (result == MMSYSERR_NOERROR)
        return WideToUTF8(capabilities.szPname);
    }
  
    return std::string();
  }
  
  }  // namespace media
  