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Duckstation/dep/cubeb/src/cubeb_alsa.c
Connor McLaughlin 3ba98e6ef8 dep: Add cubeb
2020-01-11 13:50:04 +10:00

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/*
* Copyright © 2011 Mozilla Foundation
*
* This program is made available under an ISC-style license. See the
* accompanying file LICENSE for details.
*/
#undef NDEBUG
#define _DEFAULT_SOURCE
#define _BSD_SOURCE
#define _XOPEN_SOURCE 500
#include <pthread.h>
#include <sys/time.h>
#include <assert.h>
#include <limits.h>
#include <poll.h>
#include <unistd.h>
#include <dlfcn.h>
#include <alsa/asoundlib.h>
#include "cubeb/cubeb.h"
#include "cubeb-internal.h"
#ifdef DISABLE_LIBASOUND_DLOPEN
#define WRAP(x) x
#else
#define WRAP(x) cubeb_##x
#define LIBASOUND_API_VISIT(X) \
X(snd_config) \
X(snd_config_add) \
X(snd_config_copy) \
X(snd_config_delete) \
X(snd_config_get_id) \
X(snd_config_get_string) \
X(snd_config_imake_integer) \
X(snd_config_search) \
X(snd_config_search_definition) \
X(snd_lib_error_set_handler) \
X(snd_pcm_avail_update) \
X(snd_pcm_close) \
X(snd_pcm_delay) \
X(snd_pcm_drain) \
X(snd_pcm_frames_to_bytes) \
X(snd_pcm_get_params) \
X(snd_pcm_hw_params_any) \
X(snd_pcm_hw_params_get_channels_max) \
X(snd_pcm_hw_params_get_rate) \
X(snd_pcm_hw_params_set_rate_near) \
X(snd_pcm_hw_params_sizeof) \
X(snd_pcm_nonblock) \
X(snd_pcm_open) \
X(snd_pcm_open_lconf) \
X(snd_pcm_pause) \
X(snd_pcm_poll_descriptors) \
X(snd_pcm_poll_descriptors_count) \
X(snd_pcm_poll_descriptors_revents) \
X(snd_pcm_readi) \
X(snd_pcm_recover) \
X(snd_pcm_set_params) \
X(snd_pcm_start) \
X(snd_pcm_state) \
X(snd_pcm_writei) \
#define MAKE_TYPEDEF(x) static typeof(x) * cubeb_##x;
LIBASOUND_API_VISIT(MAKE_TYPEDEF);
#undef MAKE_TYPEDEF
/* snd_pcm_hw_params_alloca is actually a macro */
#define snd_pcm_hw_params_sizeof cubeb_snd_pcm_hw_params_sizeof
#endif
#define CUBEB_STREAM_MAX 16
#define CUBEB_WATCHDOG_MS 10000
#define CUBEB_ALSA_PCM_NAME "default"
#define ALSA_PA_PLUGIN "ALSA <-> PulseAudio PCM I/O Plugin"
/* ALSA is not thread-safe. snd_pcm_t instances are individually protected
by the owning cubeb_stream's mutex. snd_pcm_t creation and destruction
is not thread-safe until ALSA 1.0.24 (see alsa-lib.git commit 91c9c8f1),
so those calls must be wrapped in the following mutex. */
static pthread_mutex_t cubeb_alsa_mutex = PTHREAD_MUTEX_INITIALIZER;
static int cubeb_alsa_error_handler_set = 0;
static struct cubeb_ops const alsa_ops;
struct cubeb {
struct cubeb_ops const * ops;
void * libasound;
pthread_t thread;
/* Mutex for streams array, must not be held while blocked in poll(2). */
pthread_mutex_t mutex;
/* Sparse array of streams managed by this context. */
cubeb_stream * streams[CUBEB_STREAM_MAX];
/* fds and nfds are only updated by alsa_run when rebuild is set. */
struct pollfd * fds;
nfds_t nfds;
int rebuild;
int shutdown;
/* Control pipe for forcing poll to wake and rebuild fds or recalculate the timeout. */
int control_fd_read;
int control_fd_write;
/* Track number of active streams. This is limited to CUBEB_STREAM_MAX
due to resource contraints. */
unsigned int active_streams;
/* Local configuration with handle_underrun workaround set for PulseAudio
ALSA plugin. Will be NULL if the PA ALSA plugin is not in use or the
workaround is not required. */
snd_config_t * local_config;
int is_pa;
};
enum stream_state {
INACTIVE,
RUNNING,
DRAINING,
PROCESSING,
ERROR
};
struct cubeb_stream {
/* Note: Must match cubeb_stream layout in cubeb.c. */
cubeb * context;
void * user_ptr;
/**/
pthread_mutex_t mutex;
snd_pcm_t * pcm;
cubeb_data_callback data_callback;
cubeb_state_callback state_callback;
snd_pcm_uframes_t stream_position;
snd_pcm_uframes_t last_position;
snd_pcm_uframes_t buffer_size;
cubeb_stream_params params;
/* Every member after this comment is protected by the owning context's
mutex rather than the stream's mutex, or is only used on the context's
run thread. */
pthread_cond_t cond; /* Signaled when the stream's state is changed. */
enum stream_state state;
struct pollfd * saved_fds; /* A copy of the pollfds passed in at init time. */
struct pollfd * fds; /* Pointer to this waitable's pollfds within struct cubeb's fds. */
nfds_t nfds;
struct timeval drain_timeout;
/* XXX: Horrible hack -- if an active stream has been idle for
CUBEB_WATCHDOG_MS it will be disabled and the error callback will be
called. This works around a bug seen with older versions of ALSA and
PulseAudio where streams would stop requesting new data despite still
being logically active and playing. */
struct timeval last_activity;
float volume;
char * buffer;
snd_pcm_uframes_t bufframes;
snd_pcm_stream_t stream_type;
struct cubeb_stream * other_stream;
};
static int
any_revents(struct pollfd * fds, nfds_t nfds)
{
nfds_t i;
for (i = 0; i < nfds; ++i) {
if (fds[i].revents) {
return 1;
}
}
return 0;
}
static int
cmp_timeval(struct timeval * a, struct timeval * b)
{
if (a->tv_sec == b->tv_sec) {
if (a->tv_usec == b->tv_usec) {
return 0;
}
return a->tv_usec > b->tv_usec ? 1 : -1;
}
return a->tv_sec > b->tv_sec ? 1 : -1;
}
static int
timeval_to_relative_ms(struct timeval * tv)
{
struct timeval now;
struct timeval dt;
long long t;
int r;
gettimeofday(&now, NULL);
r = cmp_timeval(tv, &now);
if (r >= 0) {
timersub(tv, &now, &dt);
} else {
timersub(&now, tv, &dt);
}
t = dt.tv_sec;
t *= 1000;
t += (dt.tv_usec + 500) / 1000;
if (t > INT_MAX) {
t = INT_MAX;
} else if (t < INT_MIN) {
t = INT_MIN;
}
return r >= 0 ? t : -t;
}
static int
ms_until(struct timeval * tv)
{
return timeval_to_relative_ms(tv);
}
static int
ms_since(struct timeval * tv)
{
return -timeval_to_relative_ms(tv);
}
static void
rebuild(cubeb * ctx)
{
nfds_t nfds;
int i;
nfds_t j;
cubeb_stream * stm;
assert(ctx->rebuild);
/* Always count context's control pipe fd. */
nfds = 1;
for (i = 0; i < CUBEB_STREAM_MAX; ++i) {
stm = ctx->streams[i];
if (stm) {
stm->fds = NULL;
if (stm->state == RUNNING) {
nfds += stm->nfds;
}
}
}
free(ctx->fds);
ctx->fds = calloc(nfds, sizeof(struct pollfd));
assert(ctx->fds);
ctx->nfds = nfds;
/* Include context's control pipe fd. */
ctx->fds[0].fd = ctx->control_fd_read;
ctx->fds[0].events = POLLIN | POLLERR;
for (i = 0, j = 1; i < CUBEB_STREAM_MAX; ++i) {
stm = ctx->streams[i];
if (stm && stm->state == RUNNING) {
memcpy(&ctx->fds[j], stm->saved_fds, stm->nfds * sizeof(struct pollfd));
stm->fds = &ctx->fds[j];
j += stm->nfds;
}
}
ctx->rebuild = 0;
}
static void
poll_wake(cubeb * ctx)
{
if (write(ctx->control_fd_write, "x", 1) < 0) {
/* ignore write error */
}
}
static void
set_timeout(struct timeval * timeout, unsigned int ms)
{
gettimeofday(timeout, NULL);
timeout->tv_sec += ms / 1000;
timeout->tv_usec += (ms % 1000) * 1000;
}
static void
stream_buffer_decrement(cubeb_stream * stm, long count)
{
char * bufremains = stm->buffer + WRAP(snd_pcm_frames_to_bytes)(stm->pcm, count);
memmove(stm->buffer, bufremains, WRAP(snd_pcm_frames_to_bytes)(stm->pcm, stm->bufframes - count));
stm->bufframes -= count;
}
static void
alsa_set_stream_state(cubeb_stream * stm, enum stream_state state)
{
cubeb * ctx;
int r;
ctx = stm->context;
stm->state = state;
r = pthread_cond_broadcast(&stm->cond);
assert(r == 0);
ctx->rebuild = 1;
poll_wake(ctx);
}
static enum stream_state
alsa_process_stream(cubeb_stream * stm)
{
unsigned short revents;
snd_pcm_sframes_t avail;
int draining;
draining = 0;
pthread_mutex_lock(&stm->mutex);
/* Call _poll_descriptors_revents() even if we don't use it
to let underlying plugins clear null events. Otherwise poll()
may wake up again and again, producing unnecessary CPU usage. */
WRAP(snd_pcm_poll_descriptors_revents)(stm->pcm, stm->fds, stm->nfds, &revents);
avail = WRAP(snd_pcm_avail_update)(stm->pcm);
/* Got null event? Bail and wait for another wakeup. */
if (avail == 0) {
pthread_mutex_unlock(&stm->mutex);
return RUNNING;
}
/* This could happen if we were suspended with SIGSTOP/Ctrl+Z for a long time. */
if ((unsigned int) avail > stm->buffer_size) {
avail = stm->buffer_size;
}
/* Capture: Read available frames */
if (stm->stream_type == SND_PCM_STREAM_CAPTURE && avail > 0) {
snd_pcm_sframes_t got;
if (avail + stm->bufframes > stm->buffer_size) {
/* Buffer overflow. Skip and overwrite with new data. */
stm->bufframes = 0;
// TODO: should it be marked as DRAINING?
}
got = WRAP(snd_pcm_readi)(stm->pcm, stm->buffer+stm->bufframes, avail);
if (got < 0) {
avail = got; // the error handler below will recover us
} else {
stm->bufframes += got;
stm->stream_position += got;
gettimeofday(&stm->last_activity, NULL);
}
}
/* Capture: Pass read frames to callback function */
if (stm->stream_type == SND_PCM_STREAM_CAPTURE && stm->bufframes > 0 &&
(!stm->other_stream || stm->other_stream->bufframes < stm->other_stream->buffer_size)) {
snd_pcm_sframes_t wrote = stm->bufframes;
struct cubeb_stream * mainstm = stm->other_stream ? stm->other_stream : stm;
void * other_buffer = stm->other_stream ? stm->other_stream->buffer + stm->other_stream->bufframes : NULL;
/* Correct write size to the other stream available space */
if (stm->other_stream && wrote > (snd_pcm_sframes_t) (stm->other_stream->buffer_size - stm->other_stream->bufframes)) {
wrote = stm->other_stream->buffer_size - stm->other_stream->bufframes;
}
pthread_mutex_unlock(&stm->mutex);
wrote = stm->data_callback(mainstm, stm->user_ptr, stm->buffer, other_buffer, wrote);
pthread_mutex_lock(&stm->mutex);
if (wrote < 0) {
avail = wrote; // the error handler below will recover us
} else {
stream_buffer_decrement(stm, wrote);
if (stm->other_stream) {
stm->other_stream->bufframes += wrote;
}
}
}
/* Playback: Don't have enough data? Let's ask for more. */
if (stm->stream_type == SND_PCM_STREAM_PLAYBACK && avail > (snd_pcm_sframes_t) stm->bufframes &&
(!stm->other_stream || stm->other_stream->bufframes > 0)) {
long got = avail - stm->bufframes;
void * other_buffer = stm->other_stream ? stm->other_stream->buffer : NULL;
char * buftail = stm->buffer + WRAP(snd_pcm_frames_to_bytes)(stm->pcm, stm->bufframes);
/* Correct read size to the other stream available frames */
if (stm->other_stream && got > (snd_pcm_sframes_t) stm->other_stream->bufframes) {
got = stm->other_stream->bufframes;
}
pthread_mutex_unlock(&stm->mutex);
got = stm->data_callback(stm, stm->user_ptr, other_buffer, buftail, got);
pthread_mutex_lock(&stm->mutex);
if (got < 0) {
avail = got; // the error handler below will recover us
} else {
stm->bufframes += got;
if (stm->other_stream) {
stream_buffer_decrement(stm->other_stream, got);
}
}
}
/* Playback: Still don't have enough data? Add some silence. */
if (stm->stream_type == SND_PCM_STREAM_PLAYBACK && avail > (snd_pcm_sframes_t) stm->bufframes) {
long drain_frames = avail - stm->bufframes;
double drain_time = (double) drain_frames / stm->params.rate;
char * buftail = stm->buffer + WRAP(snd_pcm_frames_to_bytes)(stm->pcm, stm->bufframes);
memset(buftail, 0, WRAP(snd_pcm_frames_to_bytes)(stm->pcm, drain_frames));
stm->bufframes = avail;
/* Mark as draining, unless we're waiting for capture */
if (!stm->other_stream || stm->other_stream->bufframes > 0) {
set_timeout(&stm->drain_timeout, drain_time * 1000);
draining = 1;
}
}
/* Playback: Have enough data and no errors. Let's write it out. */
if (stm->stream_type == SND_PCM_STREAM_PLAYBACK && avail > 0) {
snd_pcm_sframes_t wrote;
if (stm->params.format == CUBEB_SAMPLE_FLOAT32NE) {
float * b = (float *) stm->buffer;
for (uint32_t i = 0; i < avail * stm->params.channels; i++) {
b[i] *= stm->volume;
}
} else {
short * b = (short *) stm->buffer;
for (uint32_t i = 0; i < avail * stm->params.channels; i++) {
b[i] *= stm->volume;
}
}
wrote = WRAP(snd_pcm_writei)(stm->pcm, stm->buffer, avail);
if (wrote < 0) {
avail = wrote; // the error handler below will recover us
} else {
stream_buffer_decrement(stm, wrote);
stm->stream_position += wrote;
gettimeofday(&stm->last_activity, NULL);
}
}
/* Got some error? Let's try to recover the stream. */
if (avail < 0) {
avail = WRAP(snd_pcm_recover)(stm->pcm, avail, 0);
/* Capture pcm must be started after initial setup/recover */
if (avail >= 0 &&
stm->stream_type == SND_PCM_STREAM_CAPTURE &&
WRAP(snd_pcm_state)(stm->pcm) == SND_PCM_STATE_PREPARED) {
avail = WRAP(snd_pcm_start)(stm->pcm);
}
}
/* Failed to recover, this stream must be broken. */
if (avail < 0) {
pthread_mutex_unlock(&stm->mutex);
stm->state_callback(stm, stm->user_ptr, CUBEB_STATE_ERROR);
return ERROR;
}
pthread_mutex_unlock(&stm->mutex);
return draining ? DRAINING : RUNNING;
}
static int
alsa_run(cubeb * ctx)
{
int r;
int timeout;
int i;
char dummy;
cubeb_stream * stm;
enum stream_state state;
pthread_mutex_lock(&ctx->mutex);
if (ctx->rebuild) {
rebuild(ctx);
}
/* Wake up at least once per second for the watchdog. */
timeout = 1000;
for (i = 0; i < CUBEB_STREAM_MAX; ++i) {
stm = ctx->streams[i];
if (stm && stm->state == DRAINING) {
r = ms_until(&stm->drain_timeout);
if (r >= 0 && timeout > r) {
timeout = r;
}
}
}
pthread_mutex_unlock(&ctx->mutex);
r = poll(ctx->fds, ctx->nfds, timeout);
pthread_mutex_lock(&ctx->mutex);
if (r > 0) {
if (ctx->fds[0].revents & POLLIN) {
if (read(ctx->control_fd_read, &dummy, 1) < 0) {
/* ignore read error */
}
if (ctx->shutdown) {
pthread_mutex_unlock(&ctx->mutex);
return -1;
}
}
for (i = 0; i < CUBEB_STREAM_MAX; ++i) {
stm = ctx->streams[i];
/* We can't use snd_pcm_poll_descriptors_revents here because of
https://github.com/kinetiknz/cubeb/issues/135. */
if (stm && stm->state == RUNNING && stm->fds && any_revents(stm->fds, stm->nfds)) {
alsa_set_stream_state(stm, PROCESSING);
pthread_mutex_unlock(&ctx->mutex);
state = alsa_process_stream(stm);
pthread_mutex_lock(&ctx->mutex);
alsa_set_stream_state(stm, state);
}
}
} else if (r == 0) {
for (i = 0; i < CUBEB_STREAM_MAX; ++i) {
stm = ctx->streams[i];
if (stm) {
if (stm->state == DRAINING && ms_since(&stm->drain_timeout) >= 0) {
alsa_set_stream_state(stm, INACTIVE);
stm->state_callback(stm, stm->user_ptr, CUBEB_STATE_DRAINED);
} else if (stm->state == RUNNING && ms_since(&stm->last_activity) > CUBEB_WATCHDOG_MS) {
alsa_set_stream_state(stm, ERROR);
stm->state_callback(stm, stm->user_ptr, CUBEB_STATE_ERROR);
}
}
}
}
pthread_mutex_unlock(&ctx->mutex);
return 0;
}
static void *
alsa_run_thread(void * context)
{
cubeb * ctx = context;
int r;
do {
r = alsa_run(ctx);
} while (r >= 0);
return NULL;
}
static snd_config_t *
get_slave_pcm_node(snd_config_t * lconf, snd_config_t * root_pcm)
{
int r;
snd_config_t * slave_pcm;
snd_config_t * slave_def;
snd_config_t * pcm;
char const * string;
char node_name[64];
slave_def = NULL;
r = WRAP(snd_config_search)(root_pcm, "slave", &slave_pcm);
if (r < 0) {
return NULL;
}
r = WRAP(snd_config_get_string)(slave_pcm, &string);
if (r >= 0) {
r = WRAP(snd_config_search_definition)(lconf, "pcm_slave", string, &slave_def);
if (r < 0) {
return NULL;
}
}
do {
r = WRAP(snd_config_search)(slave_def ? slave_def : slave_pcm, "pcm", &pcm);
if (r < 0) {
break;
}
r = WRAP(snd_config_get_string)(slave_def ? slave_def : slave_pcm, &string);
if (r < 0) {
break;
}
r = snprintf(node_name, sizeof(node_name), "pcm.%s", string);
if (r < 0 || r > (int) sizeof(node_name)) {
break;
}
r = WRAP(snd_config_search)(lconf, node_name, &pcm);
if (r < 0) {
break;
}
return pcm;
} while (0);
if (slave_def) {
WRAP(snd_config_delete)(slave_def);
}
return NULL;
}
/* Work around PulseAudio ALSA plugin bug where the PA server forces a
higher than requested latency, but the plugin does not update its (and
ALSA's) internal state to reflect that, leading to an immediate underrun
situation. Inspired by WINE's make_handle_underrun_config.
Reference: http://mailman.alsa-project.org/pipermail/alsa-devel/2012-July/05 */
static snd_config_t *
init_local_config_with_workaround(char const * pcm_name)
{
int r;
snd_config_t * lconf;
snd_config_t * pcm_node;
snd_config_t * node;
char const * string;
char node_name[64];
lconf = NULL;
if (*WRAP(snd_config) == NULL) {
return NULL;
}
r = WRAP(snd_config_copy)(&lconf, *WRAP(snd_config));
if (r < 0) {
return NULL;
}
do {
r = WRAP(snd_config_search_definition)(lconf, "pcm", pcm_name, &pcm_node);
if (r < 0) {
break;
}
r = WRAP(snd_config_get_id)(pcm_node, &string);
if (r < 0) {
break;
}
r = snprintf(node_name, sizeof(node_name), "pcm.%s", string);
if (r < 0 || r > (int) sizeof(node_name)) {
break;
}
r = WRAP(snd_config_search)(lconf, node_name, &pcm_node);
if (r < 0) {
break;
}
/* If this PCM has a slave, walk the slave configurations until we reach the bottom. */
while ((node = get_slave_pcm_node(lconf, pcm_node)) != NULL) {
pcm_node = node;
}
/* Fetch the PCM node's type, and bail out if it's not the PulseAudio plugin. */
r = WRAP(snd_config_search)(pcm_node, "type", &node);
if (r < 0) {
break;
}
r = WRAP(snd_config_get_string)(node, &string);
if (r < 0) {
break;
}
if (strcmp(string, "pulse") != 0) {
break;
}
/* Don't clobber an explicit existing handle_underrun value, set it only
if it doesn't already exist. */
r = WRAP(snd_config_search)(pcm_node, "handle_underrun", &node);
if (r != -ENOENT) {
break;
}
/* Disable pcm_pulse's asynchronous underrun handling. */
r = WRAP(snd_config_imake_integer)(&node, "handle_underrun", 0);
if (r < 0) {
break;
}
r = WRAP(snd_config_add)(pcm_node, node);
if (r < 0) {
break;
}
return lconf;
} while (0);
WRAP(snd_config_delete)(lconf);
return NULL;
}
static int
alsa_locked_pcm_open(snd_pcm_t ** pcm, char const * pcm_name, snd_pcm_stream_t stream, snd_config_t * local_config)
{
int r;
pthread_mutex_lock(&cubeb_alsa_mutex);
if (local_config) {
r = WRAP(snd_pcm_open_lconf)(pcm, pcm_name, stream, SND_PCM_NONBLOCK, local_config);
} else {
r = WRAP(snd_pcm_open)(pcm, pcm_name, stream, SND_PCM_NONBLOCK);
}
pthread_mutex_unlock(&cubeb_alsa_mutex);
return r;
}
static int
alsa_locked_pcm_close(snd_pcm_t * pcm)
{
int r;
pthread_mutex_lock(&cubeb_alsa_mutex);
r = WRAP(snd_pcm_close)(pcm);
pthread_mutex_unlock(&cubeb_alsa_mutex);
return r;
}
static int
alsa_register_stream(cubeb * ctx, cubeb_stream * stm)
{
int i;
pthread_mutex_lock(&ctx->mutex);
for (i = 0; i < CUBEB_STREAM_MAX; ++i) {
if (!ctx->streams[i]) {
ctx->streams[i] = stm;
break;
}
}
pthread_mutex_unlock(&ctx->mutex);
return i == CUBEB_STREAM_MAX;
}
static void
alsa_unregister_stream(cubeb_stream * stm)
{
cubeb * ctx;
int i;
ctx = stm->context;
pthread_mutex_lock(&ctx->mutex);
for (i = 0; i < CUBEB_STREAM_MAX; ++i) {
if (ctx->streams[i] == stm) {
ctx->streams[i] = NULL;
break;
}
}
pthread_mutex_unlock(&ctx->mutex);
}
static void
silent_error_handler(char const * file, int line, char const * function,
int err, char const * fmt, ...)
{
(void)file;
(void)line;
(void)function;
(void)err;
(void)fmt;
}
/*static*/ int
alsa_init(cubeb ** context, char const * context_name)
{
(void)context_name;
void * libasound = NULL;
cubeb * ctx;
int r;
int i;
int fd[2];
pthread_attr_t attr;
snd_pcm_t * dummy;
assert(context);
*context = NULL;
#ifndef DISABLE_LIBASOUND_DLOPEN
libasound = dlopen("libasound.so.2", RTLD_LAZY);
if (!libasound) {
libasound = dlopen("libasound.so", RTLD_LAZY);
if (!libasound) {
return CUBEB_ERROR;
}
}
#define LOAD(x) { \
cubeb_##x = dlsym(libasound, #x); \
if (!cubeb_##x) { \
dlclose(libasound); \
return CUBEB_ERROR; \
} \
}
LIBASOUND_API_VISIT(LOAD);
#undef LOAD
#endif
pthread_mutex_lock(&cubeb_alsa_mutex);
if (!cubeb_alsa_error_handler_set) {
WRAP(snd_lib_error_set_handler)(silent_error_handler);
cubeb_alsa_error_handler_set = 1;
}
pthread_mutex_unlock(&cubeb_alsa_mutex);
ctx = calloc(1, sizeof(*ctx));
assert(ctx);
ctx->ops = &alsa_ops;
ctx->libasound = libasound;
r = pthread_mutex_init(&ctx->mutex, NULL);
assert(r == 0);
r = pipe(fd);
assert(r == 0);
for (i = 0; i < 2; ++i) {
fcntl(fd[i], F_SETFD, fcntl(fd[i], F_GETFD) | FD_CLOEXEC);
fcntl(fd[i], F_SETFL, fcntl(fd[i], F_GETFL) | O_NONBLOCK);
}
ctx->control_fd_read = fd[0];
ctx->control_fd_write = fd[1];
/* Force an early rebuild when alsa_run is first called to ensure fds and
nfds have been initialized. */
ctx->rebuild = 1;
r = pthread_attr_init(&attr);
assert(r == 0);
r = pthread_attr_setstacksize(&attr, 256 * 1024);
assert(r == 0);
r = pthread_create(&ctx->thread, &attr, alsa_run_thread, ctx);
assert(r == 0);
r = pthread_attr_destroy(&attr);
assert(r == 0);
/* Open a dummy PCM to force the configuration space to be evaluated so that
init_local_config_with_workaround can find and modify the default node. */
r = alsa_locked_pcm_open(&dummy, CUBEB_ALSA_PCM_NAME, SND_PCM_STREAM_PLAYBACK, NULL);
if (r >= 0) {
alsa_locked_pcm_close(dummy);
}
ctx->is_pa = 0;
pthread_mutex_lock(&cubeb_alsa_mutex);
ctx->local_config = init_local_config_with_workaround(CUBEB_ALSA_PCM_NAME);
pthread_mutex_unlock(&cubeb_alsa_mutex);
if (ctx->local_config) {
ctx->is_pa = 1;
r = alsa_locked_pcm_open(&dummy, CUBEB_ALSA_PCM_NAME, SND_PCM_STREAM_PLAYBACK, ctx->local_config);
/* If we got a local_config, we found a PA PCM. If opening a PCM with that
config fails with EINVAL, the PA PCM is too old for this workaround. */
if (r == -EINVAL) {
pthread_mutex_lock(&cubeb_alsa_mutex);
WRAP(snd_config_delete)(ctx->local_config);
pthread_mutex_unlock(&cubeb_alsa_mutex);
ctx->local_config = NULL;
} else if (r >= 0) {
alsa_locked_pcm_close(dummy);
}
}
*context = ctx;
return CUBEB_OK;
}
static char const *
alsa_get_backend_id(cubeb * ctx)
{
(void)ctx;
return "alsa";
}
static void
alsa_destroy(cubeb * ctx)
{
int r;
assert(ctx);
pthread_mutex_lock(&ctx->mutex);
ctx->shutdown = 1;
poll_wake(ctx);
pthread_mutex_unlock(&ctx->mutex);
r = pthread_join(ctx->thread, NULL);
assert(r == 0);
close(ctx->control_fd_read);
close(ctx->control_fd_write);
pthread_mutex_destroy(&ctx->mutex);
free(ctx->fds);
if (ctx->local_config) {
pthread_mutex_lock(&cubeb_alsa_mutex);
WRAP(snd_config_delete)(ctx->local_config);
pthread_mutex_unlock(&cubeb_alsa_mutex);
}
if (ctx->libasound) {
dlclose(ctx->libasound);
}
free(ctx);
}
static void alsa_stream_destroy(cubeb_stream * stm);
static int
alsa_stream_init_single(cubeb * ctx, cubeb_stream ** stream, char const * stream_name,
snd_pcm_stream_t stream_type,
cubeb_devid deviceid,
cubeb_stream_params * stream_params,
unsigned int latency_frames,
cubeb_data_callback data_callback,
cubeb_state_callback state_callback,
void * user_ptr)
{
(void)stream_name;
cubeb_stream * stm;
int r;
snd_pcm_format_t format;
snd_pcm_uframes_t period_size;
int latency_us = 0;
char const * pcm_name = deviceid ? (char const *) deviceid : CUBEB_ALSA_PCM_NAME;
assert(ctx && stream);
*stream = NULL;
if (stream_params->prefs & CUBEB_STREAM_PREF_LOOPBACK) {
return CUBEB_ERROR_NOT_SUPPORTED;
}
switch (stream_params->format) {
case CUBEB_SAMPLE_S16LE:
format = SND_PCM_FORMAT_S16_LE;
break;
case CUBEB_SAMPLE_S16BE:
format = SND_PCM_FORMAT_S16_BE;
break;
case CUBEB_SAMPLE_FLOAT32LE:
format = SND_PCM_FORMAT_FLOAT_LE;
break;
case CUBEB_SAMPLE_FLOAT32BE:
format = SND_PCM_FORMAT_FLOAT_BE;
break;
default:
return CUBEB_ERROR_INVALID_FORMAT;
}
pthread_mutex_lock(&ctx->mutex);
if (ctx->active_streams >= CUBEB_STREAM_MAX) {
pthread_mutex_unlock(&ctx->mutex);
return CUBEB_ERROR;
}
ctx->active_streams += 1;
pthread_mutex_unlock(&ctx->mutex);
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->state = INACTIVE;
stm->volume = 1.0;
stm->buffer = NULL;
stm->bufframes = 0;
stm->stream_type = stream_type;
stm->other_stream = NULL;
r = pthread_mutex_init(&stm->mutex, NULL);
assert(r == 0);
r = pthread_cond_init(&stm->cond, NULL);
assert(r == 0);
r = alsa_locked_pcm_open(&stm->pcm, pcm_name, stm->stream_type, ctx->local_config);
if (r < 0) {
alsa_stream_destroy(stm);
return CUBEB_ERROR;
}
r = WRAP(snd_pcm_nonblock)(stm->pcm, 1);
assert(r == 0);
latency_us = latency_frames * 1e6 / stm->params.rate;
/* Ugly hack: the PA ALSA plugin allows buffer configurations that can't
possibly work. See https://bugzilla.mozilla.org/show_bug.cgi?id=761274.
Only resort to this hack if the handle_underrun workaround failed. */
if (!ctx->local_config && ctx->is_pa) {
const int min_latency = 5e5;
latency_us = latency_us < min_latency ? min_latency: latency_us;
}
r = WRAP(snd_pcm_set_params)(stm->pcm, format, SND_PCM_ACCESS_RW_INTERLEAVED,
stm->params.channels, stm->params.rate, 1,
latency_us);
if (r < 0) {
alsa_stream_destroy(stm);
return CUBEB_ERROR_INVALID_FORMAT;
}
r = WRAP(snd_pcm_get_params)(stm->pcm, &stm->buffer_size, &period_size);
assert(r == 0);
/* Double internal buffer size to have enough space when waiting for the other side of duplex connection */
stm->buffer_size *= 2;
stm->buffer = calloc(1, WRAP(snd_pcm_frames_to_bytes)(stm->pcm, stm->buffer_size));
assert(stm->buffer);
stm->nfds = WRAP(snd_pcm_poll_descriptors_count)(stm->pcm);
assert(stm->nfds > 0);
stm->saved_fds = calloc(stm->nfds, sizeof(struct pollfd));
assert(stm->saved_fds);
r = WRAP(snd_pcm_poll_descriptors)(stm->pcm, stm->saved_fds, stm->nfds);
assert((nfds_t) r == stm->nfds);
if (alsa_register_stream(ctx, stm) != 0) {
alsa_stream_destroy(stm);
return CUBEB_ERROR;
}
*stream = stm;
return CUBEB_OK;
}
static int
alsa_stream_init(cubeb * ctx, cubeb_stream ** stream, char const * stream_name,
cubeb_devid input_device,
cubeb_stream_params * input_stream_params,
cubeb_devid output_device,
cubeb_stream_params * output_stream_params,
unsigned int latency_frames,
cubeb_data_callback data_callback, cubeb_state_callback state_callback,
void * user_ptr)
{
int result = CUBEB_OK;
cubeb_stream * instm = NULL, * outstm = NULL;
if (result == CUBEB_OK && input_stream_params) {
result = alsa_stream_init_single(ctx, &instm, stream_name, SND_PCM_STREAM_CAPTURE,
input_device, input_stream_params, latency_frames,
data_callback, state_callback, user_ptr);
}
if (result == CUBEB_OK && output_stream_params) {
result = alsa_stream_init_single(ctx, &outstm, stream_name, SND_PCM_STREAM_PLAYBACK,
output_device, output_stream_params, latency_frames,
data_callback, state_callback, user_ptr);
}
if (result == CUBEB_OK && input_stream_params && output_stream_params) {
instm->other_stream = outstm;
outstm->other_stream = instm;
}
if (result != CUBEB_OK && instm) {
alsa_stream_destroy(instm);
}
*stream = outstm ? outstm : instm;
return result;
}
static void
alsa_stream_destroy(cubeb_stream * stm)
{
int r;
cubeb * ctx;
assert(stm && (stm->state == INACTIVE ||
stm->state == ERROR ||
stm->state == DRAINING));
ctx = stm->context;
if (stm->other_stream) {
stm->other_stream->other_stream = NULL; // to stop infinite recursion
alsa_stream_destroy(stm->other_stream);
}
pthread_mutex_lock(&stm->mutex);
if (stm->pcm) {
if (stm->state == DRAINING) {
WRAP(snd_pcm_drain)(stm->pcm);
}
alsa_locked_pcm_close(stm->pcm);
stm->pcm = NULL;
}
free(stm->saved_fds);
pthread_mutex_unlock(&stm->mutex);
pthread_mutex_destroy(&stm->mutex);
r = pthread_cond_destroy(&stm->cond);
assert(r == 0);
alsa_unregister_stream(stm);
pthread_mutex_lock(&ctx->mutex);
assert(ctx->active_streams >= 1);
ctx->active_streams -= 1;
pthread_mutex_unlock(&ctx->mutex);
free(stm->buffer);
free(stm);
}
static int
alsa_get_max_channel_count(cubeb * ctx, uint32_t * max_channels)
{
int r;
cubeb_stream * stm;
snd_pcm_hw_params_t* hw_params;
cubeb_stream_params params;
params.rate = 44100;
params.format = CUBEB_SAMPLE_FLOAT32NE;
params.channels = 2;
snd_pcm_hw_params_alloca(&hw_params);
assert(ctx);
r = alsa_stream_init(ctx, &stm, "", NULL, NULL, NULL, &params, 100, NULL, NULL, NULL);
if (r != CUBEB_OK) {
return CUBEB_ERROR;
}
assert(stm);
r = WRAP(snd_pcm_hw_params_any)(stm->pcm, hw_params);
if (r < 0) {
return CUBEB_ERROR;
}
r = WRAP(snd_pcm_hw_params_get_channels_max)(hw_params, max_channels);
if (r < 0) {
return CUBEB_ERROR;
}
alsa_stream_destroy(stm);
return CUBEB_OK;
}
static int
alsa_get_preferred_sample_rate(cubeb * ctx, uint32_t * rate) {
(void)ctx;
int r, dir;
snd_pcm_t * pcm;
snd_pcm_hw_params_t * hw_params;
snd_pcm_hw_params_alloca(&hw_params);
/* get a pcm, disabling resampling, so we get a rate the
* hardware/dmix/pulse/etc. supports. */
r = WRAP(snd_pcm_open)(&pcm, CUBEB_ALSA_PCM_NAME, SND_PCM_STREAM_PLAYBACK, SND_PCM_NO_AUTO_RESAMPLE);
if (r < 0) {
return CUBEB_ERROR;
}
r = WRAP(snd_pcm_hw_params_any)(pcm, hw_params);
if (r < 0) {
WRAP(snd_pcm_close)(pcm);
return CUBEB_ERROR;
}
r = WRAP(snd_pcm_hw_params_get_rate)(hw_params, rate, &dir);
if (r >= 0) {
/* There is a default rate: use it. */
WRAP(snd_pcm_close)(pcm);
return CUBEB_OK;
}
/* Use a common rate, alsa may adjust it based on hw/etc. capabilities. */
*rate = 44100;
r = WRAP(snd_pcm_hw_params_set_rate_near)(pcm, hw_params, rate, NULL);
if (r < 0) {
WRAP(snd_pcm_close)(pcm);
return CUBEB_ERROR;
}
WRAP(snd_pcm_close)(pcm);
return CUBEB_OK;
}
static int
alsa_get_min_latency(cubeb * ctx, cubeb_stream_params params, uint32_t * latency_frames)
{
(void)ctx;
/* 40ms is found to be an acceptable minimum, even on a super low-end
* machine. */
*latency_frames = 40 * params.rate / 1000;
return CUBEB_OK;
}
static int
alsa_stream_start(cubeb_stream * stm)
{
cubeb * ctx;
assert(stm);
ctx = stm->context;
if (stm->stream_type == SND_PCM_STREAM_PLAYBACK && stm->other_stream) {
int r = alsa_stream_start(stm->other_stream);
if (r != CUBEB_OK)
return r;
}
pthread_mutex_lock(&stm->mutex);
/* Capture pcm must be started after initial setup/recover */
if (stm->stream_type == SND_PCM_STREAM_CAPTURE &&
WRAP(snd_pcm_state)(stm->pcm) == SND_PCM_STATE_PREPARED) {
WRAP(snd_pcm_start)(stm->pcm);
}
WRAP(snd_pcm_pause)(stm->pcm, 0);
gettimeofday(&stm->last_activity, NULL);
pthread_mutex_unlock(&stm->mutex);
pthread_mutex_lock(&ctx->mutex);
if (stm->state != INACTIVE) {
pthread_mutex_unlock(&ctx->mutex);
return CUBEB_ERROR;
}
alsa_set_stream_state(stm, RUNNING);
pthread_mutex_unlock(&ctx->mutex);
return CUBEB_OK;
}
static int
alsa_stream_stop(cubeb_stream * stm)
{
cubeb * ctx;
int r;
assert(stm);
ctx = stm->context;
if (stm->stream_type == SND_PCM_STREAM_PLAYBACK && stm->other_stream) {
int r = alsa_stream_stop(stm->other_stream);
if (r != CUBEB_OK)
return r;
}
pthread_mutex_lock(&ctx->mutex);
while (stm->state == PROCESSING) {
r = pthread_cond_wait(&stm->cond, &ctx->mutex);
assert(r == 0);
}
alsa_set_stream_state(stm, INACTIVE);
pthread_mutex_unlock(&ctx->mutex);
pthread_mutex_lock(&stm->mutex);
WRAP(snd_pcm_pause)(stm->pcm, 1);
pthread_mutex_unlock(&stm->mutex);
return CUBEB_OK;
}
static int
alsa_stream_get_position(cubeb_stream * stm, uint64_t * position)
{
snd_pcm_sframes_t delay;
assert(stm && position);
pthread_mutex_lock(&stm->mutex);
delay = -1;
if (WRAP(snd_pcm_state)(stm->pcm) != SND_PCM_STATE_RUNNING ||
WRAP(snd_pcm_delay)(stm->pcm, &delay) != 0) {
*position = stm->last_position;
pthread_mutex_unlock(&stm->mutex);
return CUBEB_OK;
}
assert(delay >= 0);
*position = 0;
if (stm->stream_position >= (snd_pcm_uframes_t) delay) {
*position = stm->stream_position - delay;
}
stm->last_position = *position;
pthread_mutex_unlock(&stm->mutex);
return CUBEB_OK;
}
static int
alsa_stream_get_latency(cubeb_stream * stm, uint32_t * latency)
{
snd_pcm_sframes_t delay;
/* This function returns the delay in frames until a frame written using
snd_pcm_writei is sent to the DAC. The DAC delay should be < 1ms anyways. */
if (WRAP(snd_pcm_delay)(stm->pcm, &delay)) {
return CUBEB_ERROR;
}
*latency = delay;
return CUBEB_OK;
}
static int
alsa_stream_set_volume(cubeb_stream * stm, float volume)
{
/* setting the volume using an API call does not seem very stable/supported */
pthread_mutex_lock(&stm->mutex);
stm->volume = volume;
pthread_mutex_unlock(&stm->mutex);
return CUBEB_OK;
}
static int
alsa_enumerate_devices(cubeb * context, cubeb_device_type type,
cubeb_device_collection * collection)
{
cubeb_device_info* device = NULL;
if (!context)
return CUBEB_ERROR;
uint32_t rate, max_channels;
int r;
r = alsa_get_preferred_sample_rate(context, &rate);
if (r != CUBEB_OK) {
return CUBEB_ERROR;
}
r = alsa_get_max_channel_count(context, &max_channels);
if (r != CUBEB_OK) {
return CUBEB_ERROR;
}
char const * a_name = "default";
device = (cubeb_device_info *) calloc(1, sizeof(cubeb_device_info));
assert(device);
if (!device)
return CUBEB_ERROR;
device->device_id = a_name;
device->devid = (cubeb_devid) device->device_id;
device->friendly_name = a_name;
device->group_id = a_name;
device->vendor_name = a_name;
device->type = type;
device->state = CUBEB_DEVICE_STATE_ENABLED;
device->preferred = CUBEB_DEVICE_PREF_ALL;
device->format = CUBEB_DEVICE_FMT_S16NE;
device->default_format = CUBEB_DEVICE_FMT_S16NE;
device->max_channels = max_channels;
device->min_rate = rate;
device->max_rate = rate;
device->default_rate = rate;
device->latency_lo = 0;
device->latency_hi = 0;
collection->device = device;
collection->count = 1;
return CUBEB_OK;
}
static int
alsa_device_collection_destroy(cubeb * context,
cubeb_device_collection * collection)
{
assert(collection->count == 1);
(void) context;
free(collection->device);
return CUBEB_OK;
}
static struct cubeb_ops const alsa_ops = {
.init = alsa_init,
.get_backend_id = alsa_get_backend_id,
.get_max_channel_count = alsa_get_max_channel_count,
.get_min_latency = alsa_get_min_latency,
.get_preferred_sample_rate = alsa_get_preferred_sample_rate,
.enumerate_devices = alsa_enumerate_devices,
.device_collection_destroy = alsa_device_collection_destroy,
.destroy = alsa_destroy,
.stream_init = alsa_stream_init,
.stream_destroy = alsa_stream_destroy,
.stream_start = alsa_stream_start,
.stream_stop = alsa_stream_stop,
.stream_reset_default_device = NULL,
.stream_get_position = alsa_stream_get_position,
.stream_get_latency = alsa_stream_get_latency,
.stream_set_volume = alsa_stream_set_volume,
.stream_get_current_device = NULL,
.stream_device_destroy = NULL,
.stream_register_device_changed_callback = NULL,
.register_device_collection_changed = NULL
};
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