summaryrefslogtreecommitdiffstats
path: root/widget/windows/AudioSession.cpp
blob: c14278f56c63090d064cb5f7a715587853693f07 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include <atomic>
#include <audiopolicy.h>
#include <windows.h>
#include <mmdeviceapi.h>

#include "mozilla/ClearOnShutdown.h"
#include "mozilla/RefPtr.h"
#include "mozilla/ScopeExit.h"
#include "mozilla/StaticPtr.h"
#include "nsIStringBundle.h"

#include "nsCOMPtr.h"
#include "nsID.h"
#include "nsServiceManagerUtils.h"
#include "nsString.h"
#include "nsThreadUtils.h"
#include "nsXULAppAPI.h"
#include "mozilla/Attributes.h"
#include "mozilla/mscom/AgileReference.h"
#include "mozilla/mscom/Utils.h"
#include "mozilla/Mutex.h"
#include "mozilla/WindowsVersion.h"

namespace mozilla {
namespace widget {

/*
 * To take advantage of what Vista+ have to offer with respect to audio,
 * we need to maintain an audio session.  This class wraps IAudioSessionControl
 * and implements IAudioSessionEvents (for callbacks from Windows)
 */
class AudioSession final : public IAudioSessionEvents {
 public:
  AudioSession();

  static AudioSession* GetSingleton();

  // COM IUnknown
  STDMETHODIMP_(ULONG) AddRef();
  STDMETHODIMP QueryInterface(REFIID, void**);
  STDMETHODIMP_(ULONG) Release();

  // IAudioSessionEvents
  STDMETHODIMP OnChannelVolumeChanged(DWORD aChannelCount,
                                      float aChannelVolumeArray[],
                                      DWORD aChangedChannel, LPCGUID aContext);
  STDMETHODIMP OnDisplayNameChanged(LPCWSTR aDisplayName, LPCGUID aContext);
  STDMETHODIMP OnGroupingParamChanged(LPCGUID aGroupingParam, LPCGUID aContext);
  STDMETHODIMP OnIconPathChanged(LPCWSTR aIconPath, LPCGUID aContext);
  STDMETHODIMP OnSessionDisconnected(AudioSessionDisconnectReason aReason);
  STDMETHODIMP OnSimpleVolumeChanged(float aVolume, BOOL aMute,
                                     LPCGUID aContext);
  STDMETHODIMP OnStateChanged(AudioSessionState aState);

  void Start();
  void Stop(bool shouldRestart = false);

  nsresult GetSessionData(nsID& aID, nsString& aSessionName,
                          nsString& aIconPath);
  nsresult SetSessionData(const nsID& aID, const nsString& aSessionName,
                          const nsString& aIconPath);

 private:
  ~AudioSession() = default;

  void StopInternal(const MutexAutoLock& aProofOfLock,
                    bool shouldRestart = false);

 protected:
  RefPtr<IAudioSessionControl> mAudioSessionControl;
  nsString mDisplayName;
  nsString mIconPath;
  nsID mSessionGroupingParameter;
  // Guards the IAudioSessionControl
  mozilla::Mutex mMutex MOZ_UNANNOTATED;

  ThreadSafeAutoRefCnt mRefCnt;
  NS_DECL_OWNINGTHREAD
};

StaticRefPtr<AudioSession> sService;

void StartAudioSession() {
  MOZ_ASSERT(NS_IsMainThread());
  MOZ_ASSERT(!sService);
  sService = new AudioSession();

  // Destroy AudioSession only after any background task threads have been
  // stopped or abandoned.
  ClearOnShutdown(&sService, ShutdownPhase::XPCOMShutdownFinal);

  NS_DispatchBackgroundTask(
      NS_NewCancelableRunnableFunction("StartAudioSession", []() -> void {
        MOZ_ASSERT(AudioSession::GetSingleton(),
                   "AudioSession should outlive background threads");
        AudioSession::GetSingleton()->Start();
      }));
}

void StopAudioSession() {
  MOZ_ASSERT(NS_IsMainThread());
  MOZ_ASSERT(sService);
  NS_DispatchBackgroundTask(
      NS_NewRunnableFunction("StopAudioSession", []() -> void {
        MOZ_ASSERT(AudioSession::GetSingleton(),
                   "AudioSession should outlive background threads");
        AudioSession::GetSingleton()->Stop();
      }));
}

AudioSession* AudioSession::GetSingleton() {
  MOZ_ASSERT(mscom::IsCurrentThreadMTA());
  return sService;
}

// It appears Windows will use us on a background thread ...
NS_IMPL_ADDREF(AudioSession)
NS_IMPL_RELEASE(AudioSession)

STDMETHODIMP
AudioSession::QueryInterface(REFIID iid, void** ppv) {
  const IID IID_IAudioSessionEvents = __uuidof(IAudioSessionEvents);
  if ((IID_IUnknown == iid) || (IID_IAudioSessionEvents == iid)) {
    *ppv = static_cast<IAudioSessionEvents*>(this);
    AddRef();
    return S_OK;
  }

  return E_NOINTERFACE;
}

AudioSession::AudioSession() : mMutex("AudioSessionControl") {
  // This func must be run on the main thread as
  // nsStringBundle is not thread safe otherwise
  MOZ_ASSERT(NS_IsMainThread());

  MOZ_ASSERT(XRE_IsParentProcess(),
             "Should only get here in a chrome process!");

  nsCOMPtr<nsIStringBundleService> bundleService =
      do_GetService(NS_STRINGBUNDLE_CONTRACTID);
  MOZ_ASSERT(bundleService);

  nsCOMPtr<nsIStringBundle> bundle;
  bundleService->CreateBundle("chrome://branding/locale/brand.properties",
                              getter_AddRefs(bundle));
  MOZ_ASSERT(bundle);
  bundle->GetStringFromName("brandFullName", mDisplayName);

  wchar_t* buffer;
  mIconPath.GetMutableData(&buffer, MAX_PATH);
  ::GetModuleFileNameW(nullptr, buffer, MAX_PATH);

  [[maybe_unused]] nsresult rv =
      nsID::GenerateUUIDInPlace(mSessionGroupingParameter);
  MOZ_ASSERT(rv == NS_OK);
}

// Once we are started Windows will hold a reference to us through our
// IAudioSessionEvents interface that will keep us alive until the appshell
// calls Stop.
void AudioSession::Start() {
  MOZ_ASSERT(mscom::IsCurrentThreadMTA());

  const CLSID CLSID_MMDeviceEnumerator = __uuidof(MMDeviceEnumerator);
  const IID IID_IMMDeviceEnumerator = __uuidof(IMMDeviceEnumerator);
  const IID IID_IAudioSessionManager = __uuidof(IAudioSessionManager);

  MutexAutoLock lock(mMutex);
  MOZ_ASSERT(!mAudioSessionControl);
  MOZ_ASSERT(!mDisplayName.IsEmpty() || !mIconPath.IsEmpty(),
             "Should never happen ...");

  auto scopeExit = MakeScopeExit([&] { StopInternal(lock); });

  RefPtr<IMMDeviceEnumerator> enumerator;
  HRESULT hr =
      ::CoCreateInstance(CLSID_MMDeviceEnumerator, nullptr, CLSCTX_ALL,
                         IID_IMMDeviceEnumerator, getter_AddRefs(enumerator));
  if (FAILED(hr)) {
    return;
  }

  RefPtr<IMMDevice> device;
  hr = enumerator->GetDefaultAudioEndpoint(
      EDataFlow::eRender, ERole::eMultimedia, getter_AddRefs(device));
  if (FAILED(hr)) {
    return;
  }

  RefPtr<IAudioSessionManager> manager;
  hr = device->Activate(IID_IAudioSessionManager, CLSCTX_ALL, nullptr,
                        getter_AddRefs(manager));
  if (FAILED(hr)) {
    return;
  }

  hr = manager->GetAudioSessionControl(&GUID_NULL, 0,
                                       getter_AddRefs(mAudioSessionControl));

  if (FAILED(hr) || !mAudioSessionControl) {
    return;
  }

  // Increments refcount of 'this'.
  hr = mAudioSessionControl->RegisterAudioSessionNotification(this);
  if (FAILED(hr)) {
    return;
  }

  hr = mAudioSessionControl->SetGroupingParam(
      (LPGUID) & (mSessionGroupingParameter), nullptr);
  if (FAILED(hr)) {
    return;
  }

  hr = mAudioSessionControl->SetDisplayName(mDisplayName.get(), nullptr);
  if (FAILED(hr)) {
    return;
  }

  hr = mAudioSessionControl->SetIconPath(mIconPath.get(), nullptr);
  if (FAILED(hr)) {
    return;
  }

  scopeExit.release();
}

void AudioSession::Stop(bool shouldRestart) {
  MOZ_ASSERT(mscom::IsCurrentThreadMTA());

  MutexAutoLock lock(mMutex);
  StopInternal(lock, shouldRestart);
}

void AudioSession::StopInternal(const MutexAutoLock& aProofOfLock,
                                bool shouldRestart) {
  if (!mAudioSessionControl) {
    return;
  }

  // Decrement refcount of 'this'
  mAudioSessionControl->UnregisterAudioSessionNotification(this);

  // Deleting the IAudioSessionControl COM object requires the STA/main thread.
  // Audio code may concurrently be running on the main thread and it may
  // block waiting for this to complete, creating deadlock.  So we destroy the
  // IAudioSessionControl on the main thread instead.  In order to do that, we
  // need to marshall the object to the main thread's apartment with an
  // AgileReference.
  mscom::AgileReference agileAsc(mAudioSessionControl);
  mAudioSessionControl = nullptr;
  NS_DispatchToMainThread(NS_NewRunnableFunction(
      "FreeAudioSession",
      [agileAsc = std::move(agileAsc), shouldRestart]() mutable {
        // Now release the AgileReference which holds our only reference to the
        // IAudioSessionControl, then maybe restart.
        agileAsc = nullptr;
        if (shouldRestart) {
          NS_DispatchBackgroundTask(
              NS_NewCancelableRunnableFunction("RestartAudioSession", [] {
                AudioSession* as = AudioSession::GetSingleton();
                MOZ_ASSERT(as);
                as->Start();
              }));
        }
      }));
}

void CopynsID(nsID& lhs, const nsID& rhs) {
  lhs.m0 = rhs.m0;
  lhs.m1 = rhs.m1;
  lhs.m2 = rhs.m2;
  for (int i = 0; i < 8; i++) {
    lhs.m3[i] = rhs.m3[i];
  }
}

nsresult AudioSession::GetSessionData(nsID& aID, nsString& aSessionName,
                                      nsString& aIconPath) {
  CopynsID(aID, mSessionGroupingParameter);
  aSessionName = mDisplayName;
  aIconPath = mIconPath;

  return NS_OK;
}

nsresult AudioSession::SetSessionData(const nsID& aID,
                                      const nsString& aSessionName,
                                      const nsString& aIconPath) {
  MOZ_ASSERT(!XRE_IsParentProcess(),
             "Should never get here in a chrome process!");
  CopynsID(mSessionGroupingParameter, aID);
  mDisplayName = aSessionName;
  mIconPath = aIconPath;
  return NS_OK;
}

STDMETHODIMP
AudioSession::OnChannelVolumeChanged(DWORD aChannelCount,
                                     float aChannelVolumeArray[],
                                     DWORD aChangedChannel, LPCGUID aContext) {
  return S_OK;  // NOOP
}

STDMETHODIMP
AudioSession::OnDisplayNameChanged(LPCWSTR aDisplayName, LPCGUID aContext) {
  return S_OK;  // NOOP
}

STDMETHODIMP
AudioSession::OnGroupingParamChanged(LPCGUID aGroupingParam, LPCGUID aContext) {
  return S_OK;  // NOOP
}

STDMETHODIMP
AudioSession::OnIconPathChanged(LPCWSTR aIconPath, LPCGUID aContext) {
  return S_OK;  // NOOP
}

STDMETHODIMP
AudioSession::OnSessionDisconnected(AudioSessionDisconnectReason aReason) {
  Stop(true /* shouldRestart */);
  return S_OK;
}

STDMETHODIMP
AudioSession::OnSimpleVolumeChanged(float aVolume, BOOL aMute,
                                    LPCGUID aContext) {
  return S_OK;  // NOOP
}

STDMETHODIMP
AudioSession::OnStateChanged(AudioSessionState aState) {
  return S_OK;  // NOOP
}

}  // namespace widget
}  // namespace mozilla