--- media/audio/sndio/sndio_output.h.orig	2022-02-07 13:39:41 UTC
+++ media/audio/sndio/sndio_output.h
@@ -0,0 +1,88 @@
+// 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.
+
+#ifndef MEDIA_AUDIO_SNDIO_SNDIO_OUTPUT_H_
+#define MEDIA_AUDIO_SNDIO_SNDIO_OUTPUT_H_
+
+#include <pthread.h>
+#include <sndio.h>
+
+#include "base/time/tick_clock.h"
+#include "base/time/time.h"
+#include "media/audio/audio_io.h"
+
+namespace media {
+
+class AudioManagerBase;
+
+// Implementation of AudioOutputStream using sndio(7)
+class SndioAudioOutputStream : public AudioOutputStream {
+ public:
+  // The manager is creating this object
+  SndioAudioOutputStream(const AudioParameters& params,
+                         AudioManagerBase* manager);
+
+  SndioAudioOutputStream(const SndioAudioOutputStream&) = delete;
+  SndioAudioOutputStream& operator=(const SndioAudioOutputStream&) = delete;
+
+  virtual ~SndioAudioOutputStream();
+
+  // Implementation of AudioOutputStream.
+  bool Open() override;
+  void Close() override;
+  void Start(AudioSourceCallback* callback) override;
+  void Stop() override;
+  void SetVolume(double volume) override;
+  void GetVolume(double* volume) override;
+  void Flush() override;
+
+  friend void sndio_onmove(void *arg, int delta);
+  friend void sndio_onvol(void *arg, unsigned int vol);
+  friend void *sndio_threadstart(void *arg);
+
+ private:
+  enum StreamState {
+    kClosed,            // Not opened yet
+    kStopped,           // Device opened, but not started yet
+    kRunning,           // Started, device playing
+    kStopWait           // Stopping, waiting for the real-time thread to exit
+  };
+
+  // C-style call-backs
+  static void OnMoveCallback(void *arg, int delta);
+  static void OnVolCallback(void *arg, unsigned int vol);
+  static void* ThreadEntry(void *arg);
+
+  // Continuously moves data from the producer to the device
+  void ThreadLoop(void);
+
+  // Our creator, the audio manager needs to be notified when we close.
+  AudioManagerBase* manager;
+  // Parameters of the source
+  AudioParameters params;
+  // Source stores data here
+  std::unique_ptr<AudioBus> audio_bus;
+  // Call-back that produces data to play
+  AudioSourceCallback* source;
+  // Handle of the audio device
+  struct sio_hdl* hdl;
+  // Current state of the stream
+  enum StreamState state;
+  // High priority thread running ThreadLoop()
+  pthread_t thread;
+  // Protects vol, volpending and hw_delay
+  pthread_mutex_t mutex;
+  // Current volume in the 0..SIO_MAXVOL range
+  int vol;
+  // Set to 1 if volumes must be refreshed in the realtime thread
+  int volpending;
+  // Number of frames buffered in the hardware
+  int hw_delay;
+  // Temporary buffer where data is stored sndio-compatible format
+  char* buffer;
+};
+
+}  // namespace media
+
+#endif  // MEDIA_AUDIO_SNDIO_SNDIO_OUTPUT_H_