widget/windows/AudioSession.cpp

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
   2  *
   3  * This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include <atomic>
   8 #include <audiopolicy.h>
   9 #include <windows.h>
  10 #include <mmdeviceapi.h>
  11
  12 #include "mozilla/ClearOnShutdown.h"
  13 #include "mozilla/RefPtr.h"
  14 #include "mozilla/ScopeExit.h"
  15 #include "mozilla/StaticPtr.h"
  16 #include "nsIStringBundle.h"
  17
  18 #include "nsCOMPtr.h"
  19 #include "nsID.h"
  20 #include "nsServiceManagerUtils.h"
  21 #include "nsString.h"
  22 #include "nsThreadUtils.h"
  23 #include "nsXULAppAPI.h"
  24 #include "mozilla/Attributes.h"
  25 #include "mozilla/mscom/AgileReference.h"
  26 #include "mozilla/mscom/Utils.h"
  27 #include "mozilla/Mutex.h"
  28 #include "mozilla/WindowsVersion.h"
  29
  30 namespace mozilla {
  31 namespace widget {
  32
  33 /*
  34  * To take advantage of what Vista+ have to offer with respect to audio,
  35  * we need to maintain an audio session.  This class wraps IAudioSessionControl
  36  * and implements IAudioSessionEvents (for callbacks from Windows)
  37  */
  38 class AudioSession final : public IAudioSessionEvents {
  39  public:
  40   AudioSession();
  41
  42   static AudioSession* GetSingleton();
  43
  44   // COM IUnknown
  45   STDMETHODIMP_(ULONG) AddRef();
  46   STDMETHODIMP QueryInterface(REFIID, void**);
  47   STDMETHODIMP_(ULONG) Release();
  48
  49   // IAudioSessionEvents
  50   STDMETHODIMP OnChannelVolumeChanged(DWORD aChannelCount,
  51                                       float aChannelVolumeArray[],
  52                                       DWORD aChangedChannel, LPCGUID aContext);
  53   STDMETHODIMP OnDisplayNameChanged(LPCWSTR aDisplayName, LPCGUID aContext);
  54   STDMETHODIMP OnGroupingParamChanged(LPCGUID aGroupingParam, LPCGUID aContext);
  55   STDMETHODIMP OnIconPathChanged(LPCWSTR aIconPath, LPCGUID aContext);
  56   STDMETHODIMP OnSessionDisconnected(AudioSessionDisconnectReason aReason);
  57   STDMETHODIMP OnSimpleVolumeChanged(float aVolume, BOOL aMute,
  58                                      LPCGUID aContext);
  59   STDMETHODIMP OnStateChanged(AudioSessionState aState);
  60
  61   void Start();
  62   void Stop(bool shouldRestart = false);
  63
  64   nsresult GetSessionData(nsID& aID, nsString& aSessionName,
  65                           nsString& aIconPath);
  66   nsresult SetSessionData(const nsID& aID, const nsString& aSessionName,
  67                           const nsString& aIconPath);
  68
  69  private:
  70   ~AudioSession() = default;
  71
  72   void StopInternal(const MutexAutoLock& aProofOfLock,
  73                     bool shouldRestart = false);
  74
  75  protected:
  76   RefPtr<IAudioSessionControl> mAudioSessionControl;
  77   nsString mDisplayName;
  78   nsString mIconPath;
  79   nsID mSessionGroupingParameter;
  80   // Guards the IAudioSessionControl
  81   mozilla::Mutex mMutex MOZ_UNANNOTATED;
  82
  83   ThreadSafeAutoRefCnt mRefCnt;
  84   NS_DECL_OWNINGTHREAD
  85 };
  86
  87 StaticRefPtr<AudioSession> sService;
  88
  89 void StartAudioSession() {
  90   MOZ_ASSERT(NS_IsMainThread());
  91   MOZ_ASSERT(!sService);
  92   sService = new AudioSession();
  93
  94   // Destroy AudioSession only after any background task threads have been
  95   // stopped or abandoned.
  96   ClearOnShutdown(&sService, ShutdownPhase::XPCOMShutdownFinal);
  97
  98   NS_DispatchBackgroundTask(
  99       NS_NewCancelableRunnableFunction("StartAudioSession", []() -> void {
 100         MOZ_ASSERT(AudioSession::GetSingleton(),
 101                    "AudioSession should outlive background threads");
 102         AudioSession::GetSingleton()->Start();
 103       }));
 104 }
 105
 106 void StopAudioSession() {
 107   MOZ_ASSERT(NS_IsMainThread());
 108   MOZ_ASSERT(sService);
 109   NS_DispatchBackgroundTask(
 110       NS_NewRunnableFunction("StopAudioSession", []() -> void {
 111         MOZ_ASSERT(AudioSession::GetSingleton(),
 112                    "AudioSession should outlive background threads");
 113         AudioSession::GetSingleton()->Stop();
 114       }));
 115 }
 116
 117 AudioSession* AudioSession::GetSingleton() {
 118   MOZ_ASSERT(mscom::IsCurrentThreadMTA());
 119   return sService;
 120 }
 121
 122 // It appears Windows will use us on a background thread ...
 123 NS_IMPL_ADDREF(AudioSession)
 124 NS_IMPL_RELEASE(AudioSession)
 125
 126 STDMETHODIMP
 127 AudioSession::QueryInterface(REFIID iid, void** ppv) {
 128   const IID IID_IAudioSessionEvents = __uuidof(IAudioSessionEvents);
 129   if ((IID_IUnknown == iid) || (IID_IAudioSessionEvents == iid)) {
 130     *ppv = static_cast<IAudioSessionEvents*>(this);
 131     AddRef();
 132     return S_OK;
 133   }
 134
 135   return E_NOINTERFACE;
 136 }
 137
 138 AudioSession::AudioSession() : mMutex("AudioSessionControl") {
 139   // This func must be run on the main thread as
 140   // nsStringBundle is not thread safe otherwise
 141   MOZ_ASSERT(NS_IsMainThread());
 142
 143   MOZ_ASSERT(XRE_IsParentProcess(),
 144              "Should only get here in a chrome process!");
 145
 146   nsCOMPtr<nsIStringBundleService> bundleService =
 147       do_GetService(NS_STRINGBUNDLE_CONTRACTID);
 148   MOZ_ASSERT(bundleService);
 149
 150   nsCOMPtr<nsIStringBundle> bundle;
 151   bundleService->CreateBundle("chrome://branding/locale/brand.properties",
 152                               getter_AddRefs(bundle));
 153   MOZ_ASSERT(bundle);
 154   bundle->GetStringFromName("brandFullName", mDisplayName);
 155
 156   wchar_t* buffer;
 157   mIconPath.GetMutableData(&buffer, MAX_PATH);
 158   ::GetModuleFileNameW(nullptr, buffer, MAX_PATH);
 159
 160   [[maybe_unused]] nsresult rv =
 161       nsID::GenerateUUIDInPlace(mSessionGroupingParameter);
 162   MOZ_ASSERT(rv == NS_OK);
 163 }
 164
 165 // Once we are started Windows will hold a reference to us through our
 166 // IAudioSessionEvents interface that will keep us alive until the appshell
 167 // calls Stop.
 168 void AudioSession::Start() {
 169   MOZ_ASSERT(mscom::IsCurrentThreadMTA());
 170
 171   const CLSID CLSID_MMDeviceEnumerator = __uuidof(MMDeviceEnumerator);
 172   const IID IID_IMMDeviceEnumerator = __uuidof(IMMDeviceEnumerator);
 173   const IID IID_IAudioSessionManager = __uuidof(IAudioSessionManager);
 174
 175   MutexAutoLock lock(mMutex);
 176   MOZ_ASSERT(!mAudioSessionControl);
 177   MOZ_ASSERT(!mDisplayName.IsEmpty() || !mIconPath.IsEmpty(),
 178              "Should never happen ...");
 179
 180   auto scopeExit = MakeScopeExit([&] { StopInternal(lock); });
 181
 182   RefPtr<IMMDeviceEnumerator> enumerator;
 183   HRESULT hr =
 184       ::CoCreateInstance(CLSID_MMDeviceEnumerator, nullptr, CLSCTX_ALL,
 185                          IID_IMMDeviceEnumerator, getter_AddRefs(enumerator));
 186   if (FAILED(hr)) {
 187     return;
 188   }
 189
 190   RefPtr<IMMDevice> device;
 191   hr = enumerator->GetDefaultAudioEndpoint(
 192       EDataFlow::eRender, ERole::eMultimedia, getter_AddRefs(device));
 193   if (FAILED(hr)) {
 194     return;
 195   }
 196
 197   RefPtr<IAudioSessionManager> manager;
 198   hr = device->Activate(IID_IAudioSessionManager, CLSCTX_ALL, nullptr,
 199                         getter_AddRefs(manager));
 200   if (FAILED(hr)) {
 201     return;
 202   }
 203
 204   hr = manager->GetAudioSessionControl(&GUID_NULL, 0,
 205                                        getter_AddRefs(mAudioSessionControl));
 206
 207   if (FAILED(hr) || !mAudioSessionControl) {
 208     return;
 209   }
 210
 211   // Increments refcount of 'this'.
 212   hr = mAudioSessionControl->RegisterAudioSessionNotification(this);
 213   if (FAILED(hr)) {
 214     return;
 215   }
 216
 217   hr = mAudioSessionControl->SetGroupingParam(
 218       (LPGUID) & (mSessionGroupingParameter), nullptr);
 219   if (FAILED(hr)) {
 220     return;
 221   }
 222
 223   hr = mAudioSessionControl->SetDisplayName(mDisplayName.get(), nullptr);
 224   if (FAILED(hr)) {
 225     return;
 226   }
 227
 228   hr = mAudioSessionControl->SetIconPath(mIconPath.get(), nullptr);
 229   if (FAILED(hr)) {
 230     return;
 231   }
 232
 233   scopeExit.release();
 234 }
 235
 236 void AudioSession::Stop(bool shouldRestart) {
 237   MOZ_ASSERT(mscom::IsCurrentThreadMTA());
 238
 239   MutexAutoLock lock(mMutex);
 240   StopInternal(lock, shouldRestart);
 241 }
 242
 243 void AudioSession::StopInternal(const MutexAutoLock& aProofOfLock,
 244                                 bool shouldRestart) {
 245   if (!mAudioSessionControl) {
 246     return;
 247   }
 248
 249   // Decrement refcount of 'this'
 250   mAudioSessionControl->UnregisterAudioSessionNotification(this);
 251
 252   // Deleting the IAudioSessionControl COM object requires the STA/main thread.
 253   // Audio code may concurrently be running on the main thread and it may
 254   // block waiting for this to complete, creating deadlock.  So we destroy the
 255   // IAudioSessionControl on the main thread instead.  In order to do that, we
 256   // need to marshall the object to the main thread's apartment with an
 257   // AgileReference.
 258   mscom::AgileReference agileAsc(mAudioSessionControl);
 259   mAudioSessionControl = nullptr;
 260   NS_DispatchToMainThread(NS_NewRunnableFunction(
 261       "FreeAudioSession",
 262       [agileAsc = std::move(agileAsc), shouldRestart]() mutable {
 263         // Now release the AgileReference which holds our only reference to the
 264         // IAudioSessionControl, then maybe restart.
 265         agileAsc = nullptr;
 266         if (shouldRestart) {
 267           NS_DispatchBackgroundTask(
 268               NS_NewCancelableRunnableFunction("RestartAudioSession", [] {
 269                 AudioSession* as = AudioSession::GetSingleton();
 270                 MOZ_ASSERT(as);
 271                 as->Start();
 272               }));
 273         }
 274       }));
 275 }
 276
 277 void CopynsID(nsID& lhs, const nsID& rhs) {
 278   lhs.m0 = rhs.m0;
 279   lhs.m1 = rhs.m1;
 280   lhs.m2 = rhs.m2;
 281   for (int i = 0; i < 8; i++) {
 282     lhs.m3[i] = rhs.m3[i];
 283   }
 284 }
 285
 286 nsresult AudioSession::GetSessionData(nsID& aID, nsString& aSessionName,
 287                                       nsString& aIconPath) {
 288   CopynsID(aID, mSessionGroupingParameter);
 289   aSessionName = mDisplayName;
 290   aIconPath = mIconPath;
 291
 292   return NS_OK;
 293 }
 294
 295 nsresult AudioSession::SetSessionData(const nsID& aID,
 296                                       const nsString& aSessionName,
 297                                       const nsString& aIconPath) {
 298   MOZ_ASSERT(!XRE_IsParentProcess(),
 299              "Should never get here in a chrome process!");
 300   CopynsID(mSessionGroupingParameter, aID);
 301   mDisplayName = aSessionName;
 302   mIconPath = aIconPath;
 303   return NS_OK;
 304 }
 305
 306 STDMETHODIMP
 307 AudioSession::OnChannelVolumeChanged(DWORD aChannelCount,
 308                                      float aChannelVolumeArray[],
 309                                      DWORD aChangedChannel, LPCGUID aContext) {
 310   return S_OK;  // NOOP
 311 }
 312
 313 STDMETHODIMP
 314 AudioSession::OnDisplayNameChanged(LPCWSTR aDisplayName, LPCGUID aContext) {
 315   return S_OK;  // NOOP
 316 }
 317
 318 STDMETHODIMP
 319 AudioSession::OnGroupingParamChanged(LPCGUID aGroupingParam, LPCGUID aContext) {
 320   return S_OK;  // NOOP
 321 }
 322
 323 STDMETHODIMP
 324 AudioSession::OnIconPathChanged(LPCWSTR aIconPath, LPCGUID aContext) {
 325   return S_OK;  // NOOP
 326 }
 327
 328 STDMETHODIMP
 329 AudioSession::OnSessionDisconnected(AudioSessionDisconnectReason aReason) {
 330   Stop(true /* shouldRestart */);
 331   return S_OK;
 332 }
 333
 334 STDMETHODIMP
 335 AudioSession::OnSimpleVolumeChanged(float aVolume, BOOL aMute,
 336                                     LPCGUID aContext) {
 337   return S_OK;  // NOOP
 338 }
 339
 340 STDMETHODIMP
 341 AudioSession::OnStateChanged(AudioSessionState aState) {
 342   return S_OK;  // NOOP
 343 }
 344
 345 }  // namespace widget
 346 }  // namespace mozilla