Adds Core Audio Utility methods for Windows

media/audio/win/core_audio_util_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 "media/audio/win/core_audio_util_win.h"
+
+#include <Audioclient.h>
+#include <Functiondiscoverykeys_devpkey.h>
+
+#include "base/logging.h"
+#include "base/stringprintf.h"
+#include "base/utf_string_conversions.h"
+#include "base/win/scoped_co_mem.h"
+#include "base/win/windows_version.h"
+
+using base::win::ScopedCoMem;
+
+namespace media {
+
+// Scoped PROPVARIANT class for automatically freeing a COM PROPVARIANT
+// structure at the end of a scope.
+class ScopedPropertyVariant {
+ public:
+  ScopedPropertyVariant() {
+    PropVariantInit(&propvar_);
+  }
+  ~ScopedPropertyVariant() {
+    PropVariantClear(&propvar_);
+  }
+
+  // Retrieves the pointer address.
+  // Used to receive a PROPVARIANT as an out argument (and take ownership).
+  PROPVARIANT* Receive() {
+    return &propvar_;

[tommi (sloooow) - chröme, 2012/10/29 10:45:27]

Ideally you should have a DCHECK here to make sure that you don't already hold
something that might leak. (see ScopedVariant for an example).

An easy check (and more strict) would be to add this:
DCHECK_EQ(propvar_.vt, VT_EMPTY);

[henrika (OOO until Aug 14), 2012/10/29 12:10:17]

Thanks. I will make the easy fix ;-)

+  }
+
+  VARTYPE type() const {
+    return propvar_.vt;
+  }
+
+  LPWSTR wstring() const {

[tommi (sloooow) - chröme, 2012/10/29 10:45:27]

to avoid confusing this with std::wstring - which I'm sure will cause lint
errors - call this AsWideString(), as_wide_string() or something like that.

[henrika (OOO until Aug 14), 2012/10/29 12:10:17]

Done.

[henrika (OOO until Aug 14), 2012/10/29 12:10:17]

Done.

+    DCHECK(type() == VT_LPWSTR);

[tommi (sloooow) - chröme, 2012/10/29 10:45:27]

nit: DCHECK_EQ

[henrika (OOO until Aug 14), 2012/10/29 12:10:17]

Done.

+    return propvar_.pwszVal;
+  }
+
+ private:
+  PROPVARIANT propvar_;
+
+  DISALLOW_COPY_AND_ASSIGN(ScopedPropertyVariant);
+};
+
+bool CoreAudioUtil::IsSupported() {
+  // Microsoft does not plan to make the Core Audio APIs available for use
+  // with earlier versions of Windows, including Microsoft Windows Server 2003,
+  // Windows XP, Windows Millennium Edition, Windows 2000, and Windows 98.
+  return (base::win::GetVersion() >= base::win::VERSION_VISTA);
+}
+
+int CoreAudioUtil::NumberOfActiveDevices(EDataFlow data_flow) {
+  DCHECK(CoreAudioUtil::IsSupported());
+  // Create the IMMDeviceEnumerator interface.
+  ScopedComPtr<IMMDeviceEnumerator> device_enumerator =
+      CreateDeviceEnumerator();
+  if (!device_enumerator)
+    return 0;
+
+  // Generate a collection of active (present and not disabled) audio endpoint
+  // devices for the specified data-flow direction.
+  // This method will succeed even if all devices are disabled.
+  ScopedComPtr<IMMDeviceCollection> collection;
+  HRESULT hr = device_enumerator->EnumAudioEndpoints(data_flow,
+                                                     DEVICE_STATE_ACTIVE,
+                                                     collection.Receive());
+  if (FAILED(hr)) {
+    LOG(ERROR) << "IMMDeviceCollection::EnumAudioEndpoints: " << std::hex << hr;
+    return 0;
+  }
+
+  // Retrieve the number of active audio devices for the specified direction
+  UINT number_of_active_devices = 0;
+  collection->GetCount(&number_of_active_devices);
+  DVLOG(1) << ((data_flow == eCapture) ? "[in ] " : "[out] ")
+           << "number of devices: " << number_of_active_devices;
+  return static_cast<int>(number_of_active_devices);
+}
+
+ScopedComPtr<IMMDeviceEnumerator> CoreAudioUtil::CreateDeviceEnumerator() {
+  DCHECK(CoreAudioUtil::IsSupported());
+  ScopedComPtr<IMMDeviceEnumerator> device_enumerator;
+  HRESULT hr = CoCreateInstance(__uuidof(MMDeviceEnumerator),
+                                NULL,
+                                CLSCTX_INPROC_SERVER,
+                                __uuidof(IMMDeviceEnumerator),
+                                device_enumerator.ReceiveVoid());
+  // CO_E_NOTINITIALIZED is the most likely reason for failure and if that
+  // happens we might as well die here.
+  CHECK(SUCCEEDED(hr));
+  return device_enumerator;
+}
+
+ScopedComPtr<IMMDevice> CoreAudioUtil::CreateDefaultDevice(EDataFlow data_flow,
+                                                           ERole role) {
+  DCHECK(CoreAudioUtil::IsSupported());
+  ScopedComPtr<IMMDevice> endpoint_device;
+
+  // Create the IMMDeviceEnumerator interface.
+  ScopedComPtr<IMMDeviceEnumerator> device_enumerator =
+      CreateDeviceEnumerator();
+  if (!device_enumerator)
+    return endpoint_device;
+
+  // Retrieve the default audio endpoint for the specified data-flow
+  // direction and role.
+  HRESULT hr = device_enumerator->GetDefaultAudioEndpoint(
+      data_flow, role, endpoint_device.Receive());
+
+  if (FAILED(hr)) {
+    DVLOG(1) << "IMMDeviceEnumerator::GetDefaultAudioEndpoint: "
+             << std::hex << hr;
+    return endpoint_device;
+  }
+
+  // Verify that the audio endpoint device is active, i.e., that the audio
+  // adapter that connects to the endpoint device is present and enabled.
+  DWORD state = DEVICE_STATE_DISABLED;
+  hr = endpoint_device->GetState(&state);
+  if (SUCCEEDED(hr)) {
+    if (!(state & DEVICE_STATE_ACTIVE)) {
+      DVLOG(1) << "Selected endpoint device is not active";
+      endpoint_device.Release();
+    }
+  }
+  return endpoint_device;
+}
+
+ScopedComPtr<IMMDevice> CoreAudioUtil::CreateDevice(
+    const std::string& device_id) {
+  DCHECK(CoreAudioUtil::IsSupported());
+  ScopedComPtr<IMMDevice> endpoint_device;
+
+  // Create the IMMDeviceEnumerator interface.
+  ScopedComPtr<IMMDeviceEnumerator> device_enumerator =
+      CreateDeviceEnumerator();
+  if (!device_enumerator)
+    return endpoint_device;
+
+  // Retrieve an audio device specified by an endpoint device-identification
+  // string.
+  HRESULT hr = device_enumerator->GetDevice(UTF8ToUTF16(device_id).c_str(),
+                                            endpoint_device.Receive());
+  DVLOG_IF(1, FAILED(hr)) << "IMMDeviceEnumerator::GetDevice: "
+                          << std::hex << hr;
+  return endpoint_device;
+}
+
+HRESULT CoreAudioUtil::GetDeviceName(IMMDevice* device, AudioDeviceName* name) {
+  DCHECK(CoreAudioUtil::IsSupported());
+  DCHECK(device);
+  AudioDeviceName device_name;
+
+  // Retrieve unique name of endpoint device.
+  // Example: "{0.0.1.00000000}.{8db6020f-18e3-4f25-b6f5-7726c9122574}".
+  ScopedCoMem<WCHAR> endpoint_device_id;
+  HRESULT hr = device->GetId(&endpoint_device_id);
+  if (FAILED(hr))
+    return hr;
+  WideToUTF8(endpoint_device_id, wcslen(endpoint_device_id),
+             &device_name.unique_id);
+
+  // Retrieve user-friendly name of endpoint device.
+  // Example: "Microphone (Realtek High Definition Audio)".
+  ScopedComPtr<IPropertyStore> properties;
+  hr = device->OpenPropertyStore(STGM_READ, properties.Receive());
+  if (FAILED(hr))
+    return hr;
+  ScopedPropertyVariant friendly_name;
+  hr = properties->GetValue(PKEY_Device_FriendlyName, friendly_name.Receive());
+  if (FAILED(hr))
+    return hr;
+  if (friendly_name.wstring())
+    device_name.device_name = WideToUTF8(friendly_name.wstring());

[tommi (sloooow) - chröme, 2012/10/29 10:45:27]

here you're using the std::wstring version of WideToUTF8.
What's also confusing is that the wstring() method does not return a wstring,
see comment above.
Suggest switching to the other version of WideToUTF8 here as I recommended for
the other place and change the name of the wstring method.

[henrika (OOO until Aug 14), 2012/10/29 12:10:17]

Done.

+
+  *name = device_name;
+  DVLOG(1) << "friendly name: " << device_name.device_name;
+  DVLOG(1) << "unique id    : " << device_name.unique_id;
+  return hr;
+}
+
+std::string CoreAudioUtil::GetFriendlyName(const std::string& device_id) {
+  DCHECK(CoreAudioUtil::IsSupported());
+
+  ScopedComPtr<IMMDevice> audio_device = CreateDevice(device_id);
+  if (!audio_device)
+    return std::string();
+
+  AudioDeviceName device_name;
+  HRESULT hr = GetDeviceName(audio_device, &device_name);
+  if (FAILED(hr))
+    return std::string();
+
+  return device_name.device_name;
+}
+
+bool CoreAudioUtil::DeviceIsDefault(EDataFlow flow,
+                                    ERole role,
+                                    std::string device_id) {
+  DCHECK(CoreAudioUtil::IsSupported());
+  ScopedComPtr<IMMDevice> device = CreateDefaultDevice(flow, role);
+  if (!device)
+    return false;
+
+  ScopedCoMem<WCHAR> default_device_id;
+  HRESULT hr = device->GetId(&default_device_id);
+  if (FAILED(hr))
+    return false;
+
+  std::string str_default;
+  WideToUTF8(default_device_id, wcslen(default_device_id), &str_default);
+  if (device_id.compare(str_default) != 0)
+    return false;
+  return true;
+}
+
+EDataFlow CoreAudioUtil::GetDataFlow(IMMDevice* device) {
+  DCHECK(CoreAudioUtil::IsSupported());
+  DCHECK(device);
+
+  ScopedComPtr<IMMEndpoint> endpoint;
+  HRESULT hr = device->QueryInterface(endpoint.Receive());
+  if (FAILED(hr)) {
+    DVLOG(1) << "IMMDevice::QueryInterface: " << std::hex << hr;
+    return eAll;
+  }
+
+  EDataFlow data_flow;
+  hr = endpoint->GetDataFlow(&data_flow);
+  if (FAILED(hr)) {
+    DVLOG(1) << "IMMEndpoint::GetDataFlow: " << std::hex << hr;
+    return eAll;
+  }
+  return data_flow;
+}
+
+ScopedComPtr<IAudioClient> CoreAudioUtil::CreateClient(
+    IMMDevice* audio_device) {
+  DCHECK(CoreAudioUtil::IsSupported());
+  ScopedComPtr<IAudioClient> audio_client;
+
+  // Creates and activates an IAudioClient COM object given the selected
+  // endpoint device.
+  HRESULT hr = audio_device->Activate(__uuidof(IAudioClient),
+                                      CLSCTX_INPROC_SERVER,
+                                      NULL,
+                                      audio_client.ReceiveVoid());
+  DVLOG_IF(1, FAILED(hr)) << "IMMDevice::Activate: " << std::hex << hr;
+  return audio_client;
+}
+
+}  // namespace media