* obvious way. If the callback finds itself required to play when there is no
* playing track it returns dead air.
*
+ * To implement gapless playback, the server is notified that a track has
+ * finished slightly early. @ref SM_PLAY is therefore allowed to arrive while
+ * the previous track is still playing provided an early @ref SM_FINISHED has
+ * been sent for it.
+ *
* @b Encodings. The encodings supported depend entirely on the uaudio backend
* chosen. See @ref uaudio.h, etc.
*
#include <sys/un.h>
#include <sys/stat.h>
#include <pthread.h>
+#include <sys/resource.h>
+#include <gcrypt.h>
#include "configuration.h"
#include "syscalls.h"
/** @brief Maximum number of FDs to poll for */
#define NFDS 1024
+/** @brief Number of bytes before end of track to send SM_FINISHED
+ *
+ * Generally set to 1 second.
+ */
+static size_t early_finish;
+
/** @brief Track structure
*
* Known tracks are kept in a linked list. Usually there will be at most two
* out life not playable.
*/
int playable;
+
+ /** @brief Set when finished
+ *
+ * This is set when we've notified the server that the track is finished.
+ * Once this has happened (typically very late in the track's lifetime) the
+ * track cannot be paused or cancelled.
+ */
+ int finished;
/** @brief Input buffer
*
/** @brief Lock protecting data structures
*
* This lock protects values shared between the main thread and the callback.
- * It is needed e.g. if changing @ref playing or if modifying buffer pointers.
- * It is not needed to add a new track, to read values only modified in the
- * same thread, etc.
+ *
+ * It is held 'all' the time by the main thread, the exceptions being when
+ * called activate/deactivate callbacks and when calling (potentially) slow
+ * system calls (in particular poll(), where in fact the main thread will spend
+ * most of its time blocked).
+ *
+ * The callback holds it when it's running.
*/
static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
/** @brief Playing track, or NULL
*
- * This means the DESIRED playing track. It does not reflect any other state
- * (e.g. activation of uaudio backend).
+ * This means the track the speaker process intends to play. It does not
+ * reflect any other state (e.g. activation of uaudio backend).
*/
static struct track *playing;
+/** @brief Pending playing track, or NULL
+ *
+ * This means the track the server wants the speaker to play.
+ */
+static struct track *pending_playing;
+
/** @brief Array of file descriptors for poll() */
static struct pollfd fds[NFDS];
t->id, t->eof, t->used));
if(t->eof)
return -1;
- pthread_mutex_lock(&lock);
if(t->used < sizeof t->buffer) {
/* there is room left in the buffer */
where = (t->start + t->used) % sizeof t->buffer;
rc = 0;
}
}
- pthread_mutex_unlock(&lock);
return rc;
}
*
* We want to play audio if there is a current track; and it is not paused; and
* it is playable according to the rules for @ref track::playable.
+ *
+ * We don't allow tracks to be paused if we've already told the server we've
+ * finished them; that would cause such tracks to survive much longer than the
+ * few samples they're supposed to, with report() remaining silent for the
+ * duration.
*/
static int playable(void) {
return playing
- && !paused
+ && (!paused || playing->finished)
&& playing->playable;
}
struct speaker_message sm;
if(playing) {
+ /* Had better not send a report for a track that the server thinks has
+ * finished, that would be confusing. */
+ if(playing->finished)
+ return;
memset(&sm, 0, sizeof sm);
sm.type = paused ? SM_PAUSED : SM_PLAYING;
strcpy(sm.id, playing->id);
- pthread_mutex_lock(&lock);
sm.data = playing->played / (uaudio_rate * uaudio_channels);
- pthread_mutex_unlock(&lock);
speaker_send(1, &sm);
+ xtime(&last_report);
}
- time(&last_report);
}
/** @brief Add a file descriptor to the set to poll() for
if(playing->start == sizeof playing->buffer)
playing->start = 0;
/* See if we've reached the end of the track */
- if(playing->used == 0 && playing->eof)
- write(sigpipe[1], "", 1);
+ if(playing->used == 0 && playing->eof) {
+ int ignored = write(sigpipe[1], "", 1);
+ (void) ignored;
+ }
provided_samples = bytes / uaudio_sample_size;
playing->played += provided_samples;
}
if(!provided_samples) {
memset(buffer, 0, max_bytes);
provided_samples = max_samples;
+ if(playing)
+ info("%zu samples silence, playing->used=%zu", provided_samples, playing->used);
+ else
+ info("%zu samples silence, playing=NULL", provided_samples);
}
pthread_mutex_unlock(&lock);
return provided_samples;
int n, fd, stdin_slot, timeout, listen_slot, sigpipe_slot;
/* Keep going while our parent process is alive */
+ pthread_mutex_lock(&lock);
while(getppid() != 1) {
int force_report = 0;
fdno = 0;
- /* By default we will wait up to a second before thinking about current
- * state. */
- timeout = 1000;
+ /* By default we will wait up to half a second before thinking about
+ * current state. */
+ timeout = 500;
/* Always ready for commands from the main server. */
stdin_slot = addfd(0, POLLIN);
/* Also always ready for inbound connections */
} else
t->slot = -1;
}
- sigpipe_slot = addfd(sigpipe[1], POLLIN);
+ sigpipe_slot = addfd(sigpipe[0], POLLIN);
/* Wait for something interesting to happen */
+ pthread_mutex_unlock(&lock);
n = poll(fds, fdno, timeout);
+ pthread_mutex_lock(&lock);
if(n < 0) {
if(errno == EINTR) continue;
fatal(errno, "error calling poll");
* this won't be the case, so we don't bother looping around to pick them
* all up. */
n = speaker_recv(0, &sm);
- /* TODO */
if(n > 0)
+ /* As a rule we don't send success replies to most commands - we just
+ * force the regular status update to be sent immediately rather than
+ * on schedule. */
switch(sm.type) {
case SM_PLAY:
- if(playing)
- fatal(0, "got SM_PLAY but already playing something");
+ /* SM_PLAY is only allowed if the server reasonably believes that
+ * nothing is playing */
+ if(playing) {
+ /* If finished isn't set then the server can't believe that this
+ * track has finished */
+ if(!playing->finished)
+ fatal(0, "got SM_PLAY but already playing something");
+ /* If pending_playing is set then the server must believe that that
+ * is playing */
+ if(pending_playing)
+ fatal(0, "got SM_PLAY but have a pending playing track");
+ }
t = findtrack(sm.id, 1);
D(("SM_PLAY %s fd %d", t->id, t->fd));
if(t->fd == -1)
error(0, "cannot play track because no connection arrived");
- playing = t;
- force_report = 1;
+ /* TODO as things stand we often report this error message but then
+ * appear to proceed successfully. Understanding why requires a look
+ * at play.c: we call prepare() which makes the connection in a child
+ * process, and then sends the SM_PLAY in the parent process. The
+ * latter may well be faster. As it happens this is harmless; we'll
+ * just sit around sending silence until the decoder connects and
+ * starts sending some sample data. But is is annoying and ought to
+ * be fixed. */
+ pending_playing = t;
+ /* If nothing is currently playing then we'll switch to the pending
+ * track below so there's no point distinguishing the situations
+ * here. */
break;
case SM_PAUSE:
D(("SM_PAUSE"));
D(("SM_CANCEL %s", sm.id));
t = removetrack(sm.id);
if(t) {
- pthread_mutex_lock(&lock);
- if(t == playing) {
- /* scratching the playing track */
+ if(t == playing || t == pending_playing) {
+ /* Scratching the track that the server believes is playing,
+ * which might either be the actual playing track or a pending
+ * playing track */
sm.type = SM_FINISHED;
- playing = 0;
+ if(t == playing)
+ playing = 0;
+ else
+ pending_playing = 0;
} else {
/* Could be scratching the playing track before it's quite got
* going, or could be just removing a track from the queue. We
}
strcpy(sm.id, t->id);
destroy(t);
- pthread_mutex_unlock(&lock);
} else {
/* Probably scratching the playing track well before it's got
* going, but could indicate a bug, so we log this as an error. */
break;
case SM_RELOAD:
D(("SM_RELOAD"));
- if(config_read(1))
+ if(config_read(1, NULL))
error(0, "cannot read configuration");
info("reloaded configuration");
break;
* interrupted poll(). */
if(fds[sigpipe_slot].revents & POLLIN) {
char buffer[64];
+ int ignored; (void)ignored;
- read(sigpipe[0], buffer, sizeof buffer);
+ ignored = read(sigpipe[0], buffer, sizeof buffer);
}
- if(playing && playing->used == 0 && playing->eof) {
- /* The playing track is done. Tell the server, and destroy it. */
+ /* Send SM_FINISHED when we're near the end of the track.
+ *
+ * This is how we implement gapless play; we hope that the SM_PLAY from the
+ * server arrives before the remaining bytes of the track play out.
+ */
+ if(playing
+ && playing->eof
+ && !playing->finished
+ && playing->used <= early_finish) {
memset(&sm, 0, sizeof sm);
sm.type = SM_FINISHED;
strcpy(sm.id, playing->id);
speaker_send(1, &sm);
+ playing->finished = 1;
+ }
+ /* When the track is actually finished, deconfigure it */
+ if(playing && playing->eof && !playing->used) {
removetrack(playing->id);
- pthread_mutex_lock(&lock);
destroy(playing);
playing = 0;
- pthread_mutex_unlock(&lock);
- /* The server will presumalby send as an SM_PLAY by return */
+ }
+ /* Act on the pending SM_PLAY */
+ if(!playing && pending_playing) {
+ playing = pending_playing;
+ pending_playing = 0;
+ force_report = 1;
}
/* Impose any state change required by the above */
if(playable()) {
if(!activated) {
activated = 1;
+ pthread_mutex_unlock(&lock);
backend->activate();
+ pthread_mutex_lock(&lock);
}
} else {
if(activated) {
activated = 0;
+ pthread_mutex_unlock(&lock);
backend->deactivate();
+ pthread_mutex_lock(&lock);
}
}
/* If we've not reported our state for a second do so now. */
- if(force_report || time(0) > last_report)
+ if(force_report || xtime(0) > last_report)
report();
}
}
log_default = &log_syslog;
}
config_uaudio_apis = uaudio_apis;
- if(config_read(1)) fatal(0, "cannot read configuration");
+ if(config_read(1, NULL)) fatal(0, "cannot read configuration");
/* ignore SIGPIPE */
signal(SIGPIPE, SIG_IGN);
/* set nice value */
info("set RLIM_NOFILE to %lu", (unsigned long)rl->rlim_cur);
} else
info("RLIM_NOFILE is %lu", (unsigned long)rl->rlim_cur);
+ /* gcrypt initialization */
+ if(!gcry_check_version(NULL))
+ disorder_fatal(0, "gcry_check_version failed");
+ gcry_control(GCRYCTL_INIT_SECMEM, 0);
+ gcry_control (GCRYCTL_INITIALIZATION_FINISHED, 0);
/* create a pipe between the backend callback and the poll() loop */
xpipe(sigpipe);
nonblock(sigpipe[0]);
config->sample_format.channels,
config->sample_format.bits,
config->sample_format.bits != 8);
+ early_finish = uaudio_sample_size * uaudio_channels * uaudio_rate;
/* TODO other parameters! */
backend = uaudio_find(config->api);
/* backend-specific initialization */
+ if(backend->configure)
+ backend->configure();
backend->start(speaker_callback, NULL);
/* create the socket directory */
byte_xasprintf(&dir, "%s/speaker", config->home);
~mdw / disorder / blobdiff