The Tor Browser: media/libcubeb/src/cubeb_audiotrack.c@b8a032363ba2 (annotated)

media/libcubeb/src/cubeb_audiotrack.c@b8a032363ba2 (annotated)

media/libcubeb/src/cubeb_audiotrack.c

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /*
  * Copyright © 2013 Mozilla Foundation
  *
  * This program is made available under an ISC-style license.  See the
  * accompanying file LICENSE for details.
  */
 #if !defined(NDEBUG)
 #define NDEBUG
 #endif
 #include <assert.h>
 #include <pthread.h>
 #include <stdlib.h>
 #include <time.h>
 #include <dlfcn.h>
 #include "android/log.h"
 #include "cubeb/cubeb.h"
 #include "cubeb-internal.h"
 #include "android/audiotrack_definitions.h"
 #ifndef ALOG
 #if defined(DEBUG) || defined(FORCE_ALOG)
 #define ALOG(args...)  __android_log_print(ANDROID_LOG_INFO, "Gecko - Cubeb" , ## args)
 #else
 #define ALOG(args...)
 #endif
 #endif
 /**
  * A lot of bytes for safety. It should be possible to bring this down a bit. */
 #define SIZE_AUDIOTRACK_INSTANCE 256
 /**
  * call dlsym to get the symbol |mangled_name|, handle the error and store the
  * pointer in |pointer|. Because depending on Android version, we want different
  * symbols, not finding a symbol is not an error. */
 #define DLSYM_DLERROR(mangled_name, pointer, lib)                        \
   do {                                                                   \
     pointer = dlsym(lib, mangled_name);                                  \
     if (!pointer) {                                                      \
       ALOG("error while loading %stm: %stm\n", mangled_name, dlerror()); \
     } else {                                                             \
       ALOG("%stm: OK", mangled_name);                                    \
     }                                                                    \
   } while(0);
 static struct cubeb_ops const audiotrack_ops;
 void audiotrack_destroy(cubeb * context);
 void audiotrack_stream_destroy(cubeb_stream * stream);
 struct AudioTrack {
                /* only available on ICS and later. The second int paramter is in fact of type audio_stream_type_t. */
   /* static */ status_t (*get_min_frame_count)(int* frame_count, int stream_type, uint32_t rate);
               /* if we have a recent ctor, but can't find the above symbol, we
                * can get the minimum frame count with this signature, and we are
                * running gingerbread. */
   /* static */ status_t (*get_min_frame_count_gingerbread)(int* frame_count, int stream_type, uint32_t rate);
                /* if this symbol is not availble, and the next one is, we know
                 * we are on a Froyo (Android 2.2) device. */
                void* (*ctor)(void* instance, int, unsigned int, int, int, int, unsigned int, void (*)(int, void*, void*), void*, int, int);
                void* (*ctor_froyo)(void* instance, int, unsigned int, int, int, int, unsigned int, void (*)(int, void*, void*), void*, int);
                void* (*dtor)(void* instance);
                void (*start)(void* instance);
                void (*pause)(void* instance);
                uint32_t (*latency)(void* instance);
                status_t (*check)(void* instance);
                status_t (*get_position)(void* instance, uint32_t* position);
               /* only used on froyo. */
   /* static */ int (*get_output_frame_count)(int* frame_count, int stream);
   /* static */ int (*get_output_latency)(uint32_t* latency, int stream);
   /* static */ int (*get_output_samplingrate)(int* samplerate, int stream);
                status_t (*set_marker_position)(void* instance, unsigned int);
 };
 struct cubeb {
   struct cubeb_ops const * ops;
   void * library;
   struct AudioTrack klass;
 };
 struct cubeb_stream {
   cubeb * context;
   cubeb_stream_params params;
   cubeb_data_callback data_callback;
   cubeb_state_callback state_callback;
   void * instance;
   void * user_ptr;
   /* Number of frames that have been passed to the AudioTrack callback */
   long unsigned written;
   int draining;
 };
 static void
 audiotrack_refill(int event, void* user, void* info)
 {
   cubeb_stream * stream = user;
   switch (event) {
     case EVENT_MORE_DATA: {
       long got = 0;
       struct Buffer * b = (struct Buffer*)info;
       if (stream->draining) {
         return;
       }
       got = stream->data_callback(stream, stream->user_ptr, b->raw, b->frameCount);
       stream->written += got;
       if (got != (long)b->frameCount) {
         uint32_t p;
         stream->draining = 1;
         /* set a marker so we are notified when the are done draining, that is,
          * when every frame has been played by android. */
         stream->context->klass.set_marker_position(stream->instance, stream->written);
       }
       break;
     }
     case EVENT_UNDERRUN:
       ALOG("underrun in cubeb backend.");
       break;
     case EVENT_LOOP_END:
       assert(0 && "We don't support the loop feature of audiotrack.");
       break;
     case EVENT_MARKER:
       assert(stream->draining);
       stream->state_callback(stream, stream->user_ptr, CUBEB_STATE_DRAINED);
       break;
     case EVENT_NEW_POS:
       assert(0 && "We don't support the setPositionUpdatePeriod feature of audiotrack.");
       break;
     case EVENT_BUFFER_END:
       assert(0 && "Should not happen.");
       break;
   }
 }
 /* We are running on froyo if we found the right AudioTrack constructor */
 static int
 audiotrack_version_is_froyo(cubeb * ctx)
 {
   return ctx->klass.ctor_froyo != NULL;
 }
 /* We are running on gingerbread if we found the gingerbread signature for
  * getMinFrameCount */
 static int
 audiotrack_version_is_gingerbread(cubeb * ctx)
 {
   return ctx->klass.get_min_frame_count_gingerbread != NULL;
 }
 int
 audiotrack_get_min_frame_count(cubeb * ctx, cubeb_stream_params * params, int * min_frame_count)
 {
   status_t status;
   /* Recent Android have a getMinFrameCount method. On Froyo, we have to compute it by hand. */
   if (audiotrack_version_is_froyo(ctx)) {
     int samplerate, frame_count, latency, min_buffer_count;
     status = ctx->klass.get_output_frame_count(&frame_count, params->stream_type);
     if (status) {
       ALOG("error getting the output frame count.");
       return CUBEB_ERROR;
     }
     status = ctx->klass.get_output_latency((uint32_t*)&latency, params->stream_type);
     if (status) {
       ALOG("error getting the output frame count.");
       return CUBEB_ERROR;
     }
     status = ctx->klass.get_output_samplingrate(&samplerate, params->stream_type);
     if (status) {
       ALOG("error getting the output frame count.");
       return CUBEB_ERROR;
     }
     /* Those numbers were found reading the Android source. It is the minimum
      * numbers that will be accepted by the AudioTrack class, hence yielding the
      * best latency possible.
      * See https://android.googlesource.com/platform/frameworks/base/+/android-2.2.3_r2.1/media/libmedia/AudioTrack.cpp
      * around line 181 for Android 2.2 */
     min_buffer_count = latency / ((1000 * frame_count) / samplerate);
     min_buffer_count = min_buffer_count < 2 ? min_buffer_count : 2;
     *min_frame_count = (frame_count * params->rate * min_buffer_count) / samplerate;
     return CUBEB_OK;
   }
   /* Recent Android have a getMinFrameCount method. */
   if (!audiotrack_version_is_gingerbread(ctx)) {
     status = ctx->klass.get_min_frame_count(min_frame_count, params->stream_type, params->rate);
   } else {
     status = ctx->klass.get_min_frame_count_gingerbread(min_frame_count, params->stream_type, params->rate);
   }
   if (status != 0) {
     ALOG("error getting the min frame count");
     return CUBEB_ERROR;
   }
   return CUBEB_OK;
 }
 int
 audiotrack_init(cubeb ** context, char const * context_name)
 {
   cubeb * ctx;
   struct AudioTrack* c;
   assert(context);
   *context = NULL;
   ctx = calloc(1, sizeof(*ctx));
   assert(ctx);
   /* If we use an absolute path here ("/system/lib/libmedia.so"), and on Android
    * 2.2, the dlopen succeeds, all the dlsym succeed, but a segfault happens on
    * the first call to a dlsym'ed function. Somehow this does not happen when
    * using only the name of the library. */
   ctx->library = dlopen("libmedia.so", RTLD_LAZY);
   if (!ctx->library) {
     ALOG("dlopen error: %s.", dlerror());
     free(ctx);
     return CUBEB_ERROR;
   }
   /* Recent Android first, then Froyo. */
   DLSYM_DLERROR("_ZN7android10AudioTrackC1EijiiijPFviPvS1_ES1_ii", ctx->klass.ctor, ctx->library);
   if (!ctx->klass.ctor) {
     DLSYM_DLERROR("_ZN7android10AudioTrackC1EijiiijPFviPvS1_ES1_i", ctx->klass.ctor_froyo, ctx->library);
     assert(ctx->klass.ctor_froyo);
   }
   DLSYM_DLERROR("_ZN7android10AudioTrackD1Ev", ctx->klass.dtor, ctx->library);
   DLSYM_DLERROR("_ZNK7android10AudioTrack7latencyEv", ctx->klass.latency, ctx->library);
   DLSYM_DLERROR("_ZNK7android10AudioTrack9initCheckEv", ctx->klass.check, ctx->library);
   DLSYM_DLERROR("_ZN7android11AudioSystem21getOutputSamplingRateEPii", ctx->klass.get_output_samplingrate, ctx->library);
   /* |getMinFrameCount| is not available on Froyo, and is available on
    * gingerbread and ICS with a different signature. */
   if (audiotrack_version_is_froyo(ctx)) {
     DLSYM_DLERROR("_ZN7android11AudioSystem19getOutputFrameCountEPii", ctx->klass.get_output_frame_count, ctx->library);
     DLSYM_DLERROR("_ZN7android11AudioSystem16getOutputLatencyEPji", ctx->klass.get_output_latency, ctx->library);
   } else {
     DLSYM_DLERROR("_ZN7android10AudioTrack16getMinFrameCountEPi19audio_stream_type_tj", ctx->klass.get_min_frame_count, ctx->library);
     if (!ctx->klass.get_min_frame_count) {
       DLSYM_DLERROR("_ZN7android10AudioTrack16getMinFrameCountEPiij", ctx->klass.get_min_frame_count_gingerbread, ctx->library);
     }
   }
   DLSYM_DLERROR("_ZN7android10AudioTrack5startEv", ctx->klass.start, ctx->library);
   DLSYM_DLERROR("_ZN7android10AudioTrack5pauseEv", ctx->klass.pause, ctx->library);
   DLSYM_DLERROR("_ZN7android10AudioTrack11getPositionEPj", ctx->klass.get_position, ctx->library);
   DLSYM_DLERROR("_ZN7android10AudioTrack17setMarkerPositionEj", ctx->klass.set_marker_position, ctx->library);
   /* check that we have a combination of symbol that makes sense */
   c = &ctx->klass;
   if(!((c->ctor || c->ctor_froyo) && /* at least on ctor. */
      c->dtor && c->latency && c->check &&
      /* at least one way to get the minimum frame count to request. */
      ((c->get_output_frame_count && c->get_output_latency && c->get_output_samplingrate) ||
       c->get_min_frame_count ||
       c->get_min_frame_count_gingerbread) &&
      c->start && c->pause && c->get_position && c->set_marker_position)) {
     ALOG("Could not find all the symbols we need.");
     audiotrack_destroy(ctx);
     return CUBEB_ERROR;
   }
   ctx->ops = &audiotrack_ops;
   *context = ctx;
   return CUBEB_OK;
 }
 char const *
 audiotrack_get_backend_id(cubeb * context)
 {
   return "audiotrack";
 }
 static int
 audiotrack_get_max_channel_count(cubeb * ctx, uint32_t * max_channels)
 {
   assert(ctx && max_channels);
   /* The android mixer handles up to two channels, see
   http://androidxref.com/4.2.2_r1/xref/frameworks/av/services/audioflinger/AudioFlinger.h#67 */
   *max_channels = 2;
   return CUBEB_OK;
 }
 static int
 audiotrack_get_min_latency(cubeb * ctx, cubeb_stream_params params, uint32_t * latency_ms)
 {
   /* We always use the lowest latency possible when using this backend (see
    * audiotrack_stream_init), so this value is not going to be used. */
   int rv;
   rv = audiotrack_get_min_frame_count(ctx, &params, (int *)latency_ms);
   if (rv != CUBEB_OK) {
     return CUBEB_ERROR;
   }
   /* Convert to milliseconds. */
   *latency_ms = *latency_ms * 1000 / params.rate;
   return CUBEB_OK;
 }
 static int
 audiotrack_get_preferred_sample_rate(cubeb * ctx, uint32_t * rate)
 {
   status_t rv;
   rv = ctx->klass.get_output_samplingrate((int32_t *)rate, 3 /* MUSIC */);
   return rv == 0 ? CUBEB_OK : CUBEB_ERROR;
 }
 void
 audiotrack_destroy(cubeb * context)
 {
   assert(context);
   dlclose(context->library);
   free(context);
 }
 int
 audiotrack_stream_init(cubeb * ctx, cubeb_stream ** stream, char const * stream_name,
                        cubeb_stream_params stream_params, unsigned int latency,
                        cubeb_data_callback data_callback,
                        cubeb_state_callback state_callback,
                        void * user_ptr)
 {
   cubeb_stream * stm;
   int32_t channels;
   uint32_t min_frame_count;
   assert(ctx && stream);
   if (stream_params.format == CUBEB_SAMPLE_FLOAT32LE ||
       stream_params.format == CUBEB_SAMPLE_FLOAT32BE) {
     return CUBEB_ERROR_INVALID_FORMAT;
   }
   if (audiotrack_get_min_frame_count(ctx, &stream_params, (int *)&min_frame_count)) {
     return CUBEB_ERROR;
   }
   stm = calloc(1, sizeof(*stm));
   assert(stm);
   stm->context = ctx;
   stm->data_callback = data_callback;
   stm->state_callback = state_callback;
   stm->user_ptr = user_ptr;
   stm->params = stream_params;
   stm->instance = calloc(SIZE_AUDIOTRACK_INSTANCE, 1);
   (*(uint32_t*)((intptr_t)stm->instance + SIZE_AUDIOTRACK_INSTANCE - 4)) = 0xbaadbaad;
   assert(stm->instance && "cubeb: EOM");
   /* gingerbread uses old channel layout enum */
   if (audiotrack_version_is_froyo(ctx) || audiotrack_version_is_gingerbread(ctx)) {
     channels = stm->params.channels == 2 ? AUDIO_CHANNEL_OUT_STEREO_Legacy : AUDIO_CHANNEL_OUT_MONO_Legacy;
   } else {
     channels = stm->params.channels == 2 ? AUDIO_CHANNEL_OUT_STEREO_ICS : AUDIO_CHANNEL_OUT_MONO_ICS;
   }
   if (audiotrack_version_is_froyo(ctx)) {
     ctx->klass.ctor_froyo(stm->instance,
                           stm->params.stream_type,
                           stm->params.rate,
                           AUDIO_FORMAT_PCM_16_BIT,
                           channels,
                           min_frame_count,
 ,
                           audiotrack_refill,
                           stm,
 );
   } else {
     ctx->klass.ctor(stm->instance,
                     stm->params.stream_type,
                     stm->params.rate,
                     AUDIO_FORMAT_PCM_16_BIT,
                     channels,
                     min_frame_count,
 ,
                     audiotrack_refill,
                     stm,
 ,
 );
   }
   assert((*(uint32_t*)((intptr_t)stm->instance + SIZE_AUDIOTRACK_INSTANCE - 4)) == 0xbaadbaad);
   if (ctx->klass.check(stm->instance)) {
     ALOG("stream not initialized properly.");
     audiotrack_stream_destroy(stm);
     return CUBEB_ERROR;
   }
   *stream = stm;
   return CUBEB_OK;
 }
 void
 audiotrack_stream_destroy(cubeb_stream * stream)
 {
   assert(stream->context);
   stream->context->klass.dtor(stream->instance);
   free(stream->instance);
   stream->instance = NULL;
   free(stream);
 }
 int
 audiotrack_stream_start(cubeb_stream * stream)
 {
   assert(stream->instance);
   stream->context->klass.start(stream->instance);
   stream->state_callback(stream, stream->user_ptr, CUBEB_STATE_STARTED);
   return CUBEB_OK;
 }
 int
 audiotrack_stream_stop(cubeb_stream * stream)
 {
   assert(stream->instance);
   stream->context->klass.pause(stream->instance);
   stream->state_callback(stream, stream->user_ptr, CUBEB_STATE_STOPPED);
   return CUBEB_OK;
 }
 int
 audiotrack_stream_get_position(cubeb_stream * stream, uint64_t * position)
 {
   uint32_t p;
   assert(stream->instance && position);
   stream->context->klass.get_position(stream->instance, &p);
   *position = p;
   return CUBEB_OK;
 }
 int
 audiotrack_stream_get_latency(cubeb_stream * stream, uint32_t * latency)
 {
   assert(stream->instance && latency);
   /* Android returns the latency in ms, we want it in frames. */
   *latency = stream->context->klass.latency(stream->instance);
   /* with rate <= 96000, we won't overflow until 44.739 seconds of latency */
   *latency = (*latency * stream->params.rate) / 1000;
   return 0;
 }
 static struct cubeb_ops const audiotrack_ops = {
   .init = audiotrack_init,
   .get_backend_id = audiotrack_get_backend_id,
   .get_max_channel_count = audiotrack_get_max_channel_count,
   .get_min_latency = audiotrack_get_min_latency,
   .get_preferred_sample_rate = audiotrack_get_preferred_sample_rate,
   .destroy = audiotrack_destroy,
   .stream_init = audiotrack_stream_init,
   .stream_destroy = audiotrack_stream_destroy,
   .stream_start = audiotrack_stream_start,
   .stream_stop = audiotrack_stream_stop,
   .stream_get_position = audiotrack_stream_get_position,
   .stream_get_latency = audiotrack_stream_get_latency
 };

The Tor Browser / annotate

media/libcubeb/src/cubeb_audiotrack.c@b8a032363ba2 (annotated)

media/libcubeb/src/cubeb_audiotrack.c