Create iOS Audio Manager implementation.

media/audio/ios/audio_manager_ios.mm

+// Copyright 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/ios/audio_manager_ios.h"
+
+#import <AudioToolbox/AudioToolbox.h>
+
+#include "base/sys_info.h"
+#include "media/audio/fake_audio_input_stream.h"
+#include "media/audio/mac/audio_input_mac.h"
+#include "media/base/limits.h"
+
+namespace media {
+
+enum {

[DaleCurtis, 2012/09/07 12:55:58]

nit: We generally place this all on one line for a single value.

[blundell, 2012/09/07 13:03:21]

Done.

+  kMaxInputChannels = 2,
+};
+
+AudioManagerIOS::AudioManagerIOS() {
+}
+
+AudioManagerIOS::~AudioManagerIOS() {
+  Shutdown();
+}
+
+bool AudioManagerIOS::HasAudioOutputDevices() {
+  return false;
+}
+
+bool AudioManagerIOS::HasAudioInputDevices() {
+  if (!InitAudioSession())
+    return false;
+  // Note that the |kAudioSessionProperty_AudioInputAvailable| property is a
+  // 32-bit integer, not a boolean (http://developer.apple.com/library/ios/#documentation/AudioToolbox/Reference/AudioSessionServicesReference/Reference/reference.html).

[stuartmorgan, 2012/09/07 12:47:34]

Remove this link; Apple's docs are notorious for changing the URL without
redirecting.

[blundell, 2012/09/07 12:53:06]

Done.

+  UInt32 property_size;
+  OSStatus error =
+      AudioSessionGetPropertySize(kAudioSessionProperty_AudioInputAvailable,
+                                  &property_size);
+  if (error != kAudioSessionNoError)
+    return false;
+  UInt32 audio_input_is_available = false;
+  DCHECK(property_size == sizeof(audio_input_is_available));
+  error = AudioSessionGetProperty(kAudioSessionProperty_AudioInputAvailable,
+                                  &property_size,
+                                  &audio_input_is_available);
+  return error == kAudioSessionNoError ? audio_input_is_available : false;
+}
+
+AudioOutputStream* AudioManagerIOS::MakeAudioOutputStream(
+    const AudioParameters& params) {
+  NOTIMPLEMENTED();  // Only input is supported on iOS.
+  return NULL;
+}
+
+AudioInputStream* AudioManagerIOS::MakeAudioInputStream(
+    const AudioParameters& params, const std::string& device_id) {
+  // Current line of iOS devices has only one audio input.
+  // Ignore the device_id (unittest uses a test value in it).
+  if (!params.IsValid() || (params.channels() > kMaxInputChannels))
+    return NULL;
+
+  if (params.format() == AudioParameters::AUDIO_MOCK)
+    return FakeAudioInputStream::MakeFakeStream(this, params);
+  else if (params.format() == AudioParameters::AUDIO_PCM_LINEAR)
+    return new PCMQueueInAudioInputStream(this, params);
+  return NULL;
+}
+
+AudioOutputStream* AudioManagerIOS::MakeLinearOutputStream(
+      const AudioParameters& params) {
+  NOTIMPLEMENTED();  // Only input is supported on iOS.
+  return NULL;
+}
+
+AudioOutputStream* AudioManagerIOS::MakeLowLatencyOutputStream(
+      const AudioParameters& params) {
+  NOTIMPLEMENTED();  // Only input is supported on iOS.
+  return NULL;
+}
+
+AudioInputStream* AudioManagerIOS::MakeLinearInputStream(
+      const AudioParameters& params, const std::string& device_id) {
+  return MakeAudioInputStream(params, device_id);
+}
+
+AudioInputStream* AudioManagerIOS::MakeLowLatencyInputStream(
+      const AudioParameters& params, const std::string& device_id) {
+  NOTIMPLEMENTED();  // Only linear audio input is supported on iOS.
+  return MakeAudioInputStream(params, device_id);
+}
+
+// Called by the stream when it has been released by calling Close().
+void AudioManagerIOS::ReleaseOutputStream(AudioOutputStream* stream) {
+  NOTIMPLEMENTED();  // Only input is supported on iOS.
+}
+
+// Called by the stream when it has been released by calling Close().
+void AudioManagerIOS::ReleaseInputStream(AudioInputStream* stream) {
+  delete stream;
+}
+
+// Initializes the audio session, returning a bool indicating whether
+// initialization was successful. Should only be called once.
+static bool InitAudioSessionInternal() {

[DaleCurtis, 2012/09/07 12:55:58]

nit: static functions at the top of the file.

[blundell, 2012/09/07 13:03:21]

Done.

+  OSStatus error = AudioSessionInitialize(NULL, NULL, NULL, NULL);
+  DCHECK(error != kAudioSessionAlreadyInitialized);
+  return error == kAudioSessionNoError;
+}
+
+bool AudioManagerIOS::InitAudioSession() {
+  static const bool kSessionInitialized = InitAudioSessionInternal();
+  return kSessionInitialized;
+}
+
+// static
+AudioManager* CreateAudioManager() {
+  return new AudioManagerIOS();
+}
+
+}  // namespace media