Remove libao sound backend

A single person uses it[0], and it sometimes messes up the Linux
buildbots ("ninja: error: 'ao', needed by 'Binaries/dolphin-emu', missing
and no known rule to make it").

[0]: https://analytics.dolphin-emu.org/stats/popular-audio-backends.txt

CMake/FindAO.cmake

@@ -1,42 +0,0 @@
-# - Find AO library
-# This module defines
-#  AO_INCLUDE_DIR
-#  AO_LIBRARIES
-#  AO_FOUND
-#
-# vim: expandtab sw=4 ts=4 sts=4:
-
-include(FindPkgConfig)
-pkg_check_modules (AO_PKG QUIET ao)
-
-find_path(AO_INCLUDE_DIR NAMES ao/ao.h
-  PATHS
-  ${AO_PKG_INCLUDE_DIRS}
-  /usr/include/ao
-  /usr/include
-  /usr/local/include/ao
-  /usr/local/include
-)
-
-find_library(AO_LIBRARIES NAMES ao
-  PATHS
-  ${AO_PKG_LIBRARY_DIRS}
-  /usr/lib
-  /usr/local/lib
-)
-
-include(FindPackageHandleStandardArgs)
-find_package_handle_standard_args(AO
-                                  REQUIRED_VARS AO_LIBRARIES AO_INCLUDE_DIR)
-
-if(AO_FOUND)
-  if(NOT TARGET AO::AO)
-    add_library(AO::AO UNKNOWN IMPORTED)
-    set_target_properties(AO::AO PROPERTIES
-      IMPORTED_LOCATION ${AO_LIBRARIES}
-      INTERFACE_INCLUDE_DIRECTORIES ${AO_INCLUDE_DIR}
-    )
-  endif()
-endif()
-
-mark_as_advanced(AO_INCLUDE_DIR AO_LIBRARIES)

CMakeLists.txt

@@ -21,7 +21,6 @@ option(ENABLE_LTO "Enables Link Time Optimization" OFF)
 option(ENABLE_GENERIC "Enables generic build that should run on any little-endian host" OFF)
 option(ENABLE_HEADLESS "Enables running Dolphin as a headless variant" OFF)
 option(ENABLE_ALSA "Enables ALSA sound backend" ON)
-option(ENABLE_AO "Enables libao sound backend" ON)
 option(ENABLE_PULSEAUDIO "Enables PulseAudio sound backend" ON)
 option(ENABLE_OPENAL "Enables OpenAL sound backend" ON)
 option(ENABLE_LLVM "Enables LLVM support, for disassembly" ON)

Source/Core/AudioCommon/AOSoundStream.cpp

@@ -1,82 +0,0 @@
-// Copyright 2008 Dolphin Emulator Project
-// Licensed under GPLv2+
-// Refer to the license.txt file included.
-
-#include <cstring>
-
-#include "AudioCommon/AOSoundStream.h"
-#include "AudioCommon/Mixer.h"
-#include "Common/Logging/Log.h"
-#include "Common/MsgHandler.h"
-
-#if defined(HAVE_AO) && HAVE_AO
-
-void AOSound::SoundLoop()
-{
-  Common::SetCurrentThreadName("Audio thread - ao");
-
-  uint_32 numBytesToRender = 256;
-  ao_initialize();
-  default_driver = ao_default_driver_id();
-  format.bits = 16;
-  format.channels = 2;
-  format.rate = m_mixer->GetSampleRate();
-  format.byte_format = AO_FMT_LITTLE;
-
-  device = ao_open_live(default_driver, &format, nullptr /* no options */);
-  if (!device)
-  {
-    PanicAlertT("AudioCommon: Error opening AO device.\n");
-    ao_shutdown();
-    Stop();
-    return;
-  }
-
-  buf_size = format.bits / 8 * format.channels * format.rate;
-
-  while (m_run_thread.IsSet())
-  {
-    m_mixer->Mix(realtimeBuffer, numBytesToRender >> 2);
-
-    {
-      std::lock_guard<std::mutex> lk(soundCriticalSection);
-      ao_play(device, (char*)realtimeBuffer, numBytesToRender);
-    }
-
-    soundSyncEvent.Wait();
-  }
-}
-
-bool AOSound::Start()
-{
-  m_run_thread.Set();
-  memset(realtimeBuffer, 0, sizeof(realtimeBuffer));
-
-  thread = std::thread(&AOSound::SoundLoop, this);
-  return true;
-}
-
-void AOSound::Update()
-{
-  soundSyncEvent.Set();
-}
-
-void AOSound::Stop()
-{
-  m_run_thread.Clear();
-  soundSyncEvent.Set();
-
-  {
-    std::lock_guard<std::mutex> lk(soundCriticalSection);
-    thread.join();
-
-    if (device)
-      ao_close(device);
-
-    ao_shutdown();
-
-    device = nullptr;
-  }
-}
-
-#endif

Source/Core/AudioCommon/AOSoundStream.h

@@ -1,42 +0,0 @@
-// Copyright 2008 Dolphin Emulator Project
-// Licensed under GPLv2+
-// Refer to the license.txt file included.
-
-#pragma once
-
-#include <mutex>
-#include <thread>
-
-#include "AudioCommon/SoundStream.h"
-#include "Common/Event.h"
-#include "Common/Thread.h"
-
-#if defined(HAVE_AO) && HAVE_AO
-#include <ao/ao.h>
-#endif
-
-class AOSound final : public SoundStream
-{
-#if defined(HAVE_AO) && HAVE_AO
-  std::thread thread;
-  Common::Flag m_run_thread;
-  std::mutex soundCriticalSection;
-  Common::Event soundSyncEvent;
-
-  int buf_size;
-
-  ao_device* device;
-  ao_sample_format format;
-  int default_driver;
-
-  short realtimeBuffer[1024 * 1024];
-
-public:
-  bool Start() override;
-  void SoundLoop() override;
-  void Stop() override;
-  void Update() override;
-
-  static bool isValid() { return true; }
-#endif
-};

Source/Core/AudioCommon/AudioCommon.cpp

@@ -3,7 +3,6 @@
 // Refer to the license.txt file included.
 
 #include "AudioCommon/AudioCommon.h"
-#include "AudioCommon/AOSoundStream.h"
 #include "AudioCommon/AlsaSoundStream.h"
 #include "AudioCommon/CoreAudioSoundStream.h"
 #include "AudioCommon/Mixer.h"
@@ -42,8 +41,6 @@ void InitSoundStream()
     else if (XAudio2_7::isValid())
       g_sound_stream = std::make_unique<XAudio2_7>();
   }
-  else if (backend == BACKEND_AOSOUND && AOSound::isValid())
-    g_sound_stream = std::make_unique<AOSound>();
   else if (backend == BACKEND_ALSA && AlsaSound::isValid())
     g_sound_stream = std::make_unique<AlsaSound>();
   else if (backend == BACKEND_COREAUDIO && CoreAudioSound::isValid())
@@ -115,8 +112,6 @@ std::vector<std::string> GetSoundBackends()
   backends.push_back(BACKEND_NULLSOUND);
   if (XAudio2_7::isValid() || XAudio2::isValid())
     backends.push_back(BACKEND_XAUDIO2);
-  if (AOSound::isValid())
-    backends.push_back(BACKEND_AOSOUND);
   if (AlsaSound::isValid())
     backends.push_back(BACKEND_ALSA);
   if (CoreAudioSound::isValid())

Source/Core/AudioCommon/AudioCommon.vcxproj

@@ -50,7 +50,6 @@
   <ItemGroup>
     <ClInclude Include="aldlist.h" />
     <ClInclude Include="AlsaSoundStream.h" />
-    <ClInclude Include="AOSoundStream.h" />
     <ClInclude Include="AudioCommon.h" />
     <ClInclude Include="CoreAudioSoundStream.h" />
     <ClInclude Include="DPL2Decoder.h" />
@@ -78,4 +77,4 @@
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
   <ImportGroup Label="ExtensionTargets">
   </ImportGroup>
-</Project>
+</Project>

Source/Core/AudioCommon/AudioCommon.vcxproj.filters

@@ -30,9 +30,6 @@
     <ClInclude Include="DPL2Decoder.h" />
     <ClInclude Include="Mixer.h" />
     <ClInclude Include="WaveFile.h" />
-    <ClInclude Include="AOSoundStream.h">
-      <Filter>SoundStreams</Filter>
-    </ClInclude>
     <ClInclude Include="NullSoundStream.h">
       <Filter>SoundStreams</Filter>
     </ClInclude>
@@ -64,4 +61,4 @@
   <ItemGroup>
     <Text Include="CMakeLists.txt" />
   </ItemGroup>
-</Project>
+</Project>

Source/Core/AudioCommon/CMakeLists.txt

@@ -29,20 +29,6 @@ else()
   message(STATUS "ALSA explicitly disabled, disabling ALSA sound backend")
 endif()
 
-if(ENABLE_AO)
-  find_package(AO)
-  if(AO_FOUND)
-    message(STATUS "ao found, enabling ao sound backend")
-    target_sources(audiocommon PRIVATE AOSoundStream.cpp)
-    target_link_libraries(audiocommon PRIVATE AO::AO)
-    target_compile_definitions(audiocommon PRIVATE HAVE_AO=1)
-  else()
-    message(STATUS "ao NOT found, disabling ao sound backend")
-  endif()
-else()
-  message(STATUS "ao explicitly disabled, disabling ao sound backend")
-endif()
-
 if(ENABLE_OPENAL)
   if(WIN32)
     set(ENV{OPENALDIR} ${PROJECT_SOURCE_DIR}/Externals/OpenAL)

Source/Core/Core/ConfigManager.h

@@ -32,7 +32,6 @@ class TMDReader;
 // DSP Backend Types
 #define BACKEND_NULLSOUND _trans("No audio output")
 #define BACKEND_ALSA "ALSA"
-#define BACKEND_AOSOUND "AOSound"
 #define BACKEND_COREAUDIO "CoreAudio"
 #define BACKEND_OPENAL "OpenAL"
 #define BACKEND_PULSEAUDIO "Pulse"