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rework the logic of pa_asyncq

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git-svn-id: file:///home/lennart/svn/public/pulseaudio/branches/lennart@1496 fefdeb5f-60dc-0310-8127-8f9354f1896f
This commit is contained in:
Lennart Poettering 2007-06-24 16:15:56 +00:00
parent 77ebe70443
commit d873731810
1 changed files with 126 additions and 101 deletions
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217
src/pulsecore/asyncq.c
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@ -52,9 +52,10 @@ struct pa_asyncq {
unsigned size; unsigned size;
unsigned read_idx; unsigned read_idx;
unsigned write_idx; unsigned write_idx;
pa_atomic_t read_waiting, n_read; pa_atomic_t read_waiting; /* a bool */
pa_atomic_t write_waiting, n_written; pa_atomic_t write_waiting; /* a bool */
int read_fds[2], write_fds[2]; int read_fds[2], write_fds[2];
pa_atomic_t in_read_fifo, in_write_fifo;
}; };
#define PA_ASYNCQ_CELLS(x) ((pa_atomic_ptr_t*) ((uint8_t*) (x) + PA_ALIGN(sizeof(struct pa_asyncq)))) #define PA_ASYNCQ_CELLS(x) ((pa_atomic_ptr_t*) ((uint8_t*) (x) + PA_ALIGN(sizeof(struct pa_asyncq))))
@ -80,8 +81,8 @@ pa_asyncq *pa_asyncq_new(unsigned size) {
l->size = size; l->size = size;
pa_atomic_store(&l->read_waiting, 0); pa_atomic_store(&l->read_waiting, 0);
pa_atomic_store(&l->write_waiting, 0); pa_atomic_store(&l->write_waiting, 0);
pa_atomic_store(&l->n_written, 0); pa_atomic_store(&l->in_read_fifo, 0);
pa_atomic_store(&l->n_read, 0); pa_atomic_store(&l->in_write_fifo, 0);
if (pipe(l->read_fds) < 0) { if (pipe(l->read_fds) < 0) {
pa_xfree(l); pa_xfree(l);
@ -133,68 +134,79 @@ int pa_asyncq_push(pa_asyncq*l, void *p, int wait) {
if (!pa_atomic_ptr_cmpxchg(&cells[idx], NULL, p)) { if (!pa_atomic_ptr_cmpxchg(&cells[idx], NULL, p)) {
if (!wait) { /* Let's empty the FIFO from old notifications, before we return */
/* Let's empty the FIFO from old notifications, before we return */
while (pa_atomic_load(&l->n_read) > 0) { while (pa_atomic_load(&l->in_write_fifo) > 0) {
ssize_t r;
int x[20];
errno = 0;
if ((r = read(l->write_fds[0], x, sizeof(x))) < 0 && errno != EINTR)
return -1;
pa_assert(r != 0);
if (r > 0)
if (pa_atomic_sub(&l->n_read, r) <= r)
break;
}
return -1;
}
/* First try failed. Let's wait for changes. */
_Y;
pa_atomic_inc(&l->write_waiting);
for (;;) {
char x[20];
ssize_t r; ssize_t r;
int x[20];
_Y; if ((r = read(l->write_fds[0], x, sizeof(x))) < 0) {
if (pa_atomic_ptr_cmpxchg(&cells[idx], NULL, p)) if (errno == EINTR)
break; continue;
_Y;
if ((r = read(l->write_fds[0], x, sizeof(x))) < 0 && errno != EINTR) {
pa_atomic_dec(&l->write_waiting);
return -1; return -1;
} }
pa_assert(r != 0); pa_assert(r > 0);
if (pa_atomic_sub(&l->in_write_fifo, r) <= r)
break;
if (r > 0)
pa_atomic_sub(&l->n_read, r);
} }
_Y; /* Now let's make sure that we didn't lose any events */
if (!pa_atomic_ptr_cmpxchg(&cells[idx], NULL, p)) {
pa_atomic_dec(&l->write_waiting); if (!wait)
return -1;
/* Let's wait for changes. */
_Y;
pa_assert_se(pa_atomic_cmpxchg(&l->write_waiting, 0, 1));
for (;;) {
char x[20];
ssize_t r;
_Y;
if (pa_atomic_ptr_cmpxchg(&cells[idx], NULL, p))
break;
_Y;
if ((r = read(l->write_fds[0], x, sizeof(x))) < 0) {
if (errno == EINTR)
continue;
pa_assert_se(pa_atomic_cmpxchg(&l->write_waiting, 1, 0));
return -1;
}
pa_assert(r > 0);
pa_atomic_sub(&l->in_write_fifo, r);
}
_Y;
pa_assert_se(pa_atomic_cmpxchg(&l->write_waiting, 1, 0));
}
} }
_Y; _Y;
l->write_idx++; l->write_idx++;
if (pa_atomic_load(&l->read_waiting)) { if (pa_atomic_load(&l->read_waiting) > 0) {
char x = 'x'; char x = 'x';
_Y; _Y;
if (write(l->read_fds[1], &x, sizeof(x)) > 0) if (write(l->read_fds[1], &x, sizeof(x)) > 0) {
pa_atomic_inc(&l->n_written); pa_atomic_inc(&l->in_read_fifo);
/* pa_log("increasing %p by 1", l); */
}
} }
return 0; return 0;
@ -214,71 +226,86 @@ void* pa_asyncq_pop(pa_asyncq*l, int wait) {
if (!(ret = pa_atomic_ptr_load(&cells[idx]))) { if (!(ret = pa_atomic_ptr_load(&cells[idx]))) {
/* First try failed. Let's wait for changes. */ /* pa_log("pop failed wait=%i", wait); */
if (!wait) { /* Hmm, nothing, here, so let's drop all queued events. */
/* Let's empty the FIFO from old notifications, before we return */ while (pa_atomic_load(&l->in_read_fifo) > 0) {
while (pa_atomic_load(&l->n_written) > 0) {
ssize_t r;
int x[20];
errno = 0;
if ((r = read(l->read_fds[0], x, sizeof(x))) < 0 && errno != EINTR)
return NULL;
pa_assert(r != 0);
if (r > 0)
if (pa_atomic_sub(&l->n_written, r) <= r)
break;
}
return NULL;
}
_Y;
pa_atomic_inc(&l->read_waiting);
for (;;) {
char x[20];
ssize_t r; ssize_t r;
int x[20];
_Y; if ((r = read(l->read_fds[0], x, sizeof(x))) < 0) {
if ((ret = pa_atomic_ptr_load(&cells[idx]))) if (errno == EINTR)
break; continue;
_Y;
if ((r = read(l->read_fds[0], x, sizeof(x))) < 0 && errno != EINTR) {
pa_atomic_dec(&l->read_waiting);
return NULL; return NULL;
} }
pa_assert(r != 0); pa_assert(r > 0);
if (r > 0) /* pa_log("decreasing %p by %i", l, r); */
pa_atomic_sub(&l->n_written, r);
if (pa_atomic_sub(&l->in_read_fifo, r) <= r)
break;
} }
_Y; /* Now let's make sure that we didn't lose any events */
if (!(ret = pa_atomic_ptr_load(&cells[idx]))) {
pa_atomic_dec(&l->read_waiting); if (!wait)
return NULL;
/* Let's wait for changes. */
_Y;
pa_assert_se(pa_atomic_cmpxchg(&l->read_waiting, 0, 1));
for (;;) {
char x[20];
ssize_t r;
_Y;
if ((ret = pa_atomic_ptr_load(&cells[idx])))
break;
_Y;
if ((r = read(l->read_fds[0], x, sizeof(x))) < 0) {
if (errno == EINTR)
continue;
pa_assert_se(pa_atomic_cmpxchg(&l->read_waiting, 1, 0));
return NULL;
}
/* pa_log("decreasing %p by %i", l, r); */
pa_assert(r > 0);
pa_atomic_sub(&l->in_read_fifo, r);
}
_Y;
pa_assert_se(pa_atomic_cmpxchg(&l->read_waiting, 1, 0));
}
} }
pa_assert(ret);
/* Guaranteed if we only have a single reader */ /* Guaranteed if we only have a single reader */
pa_assert_se(pa_atomic_ptr_cmpxchg(&cells[idx], ret, NULL)); pa_assert_se(pa_atomic_ptr_cmpxchg(&cells[idx], ret, NULL));
_Y; _Y;
l->read_idx++; l->read_idx++;
if (pa_atomic_load(&l->write_waiting)) { if (pa_atomic_load(&l->write_waiting) > 0) {
char x = 'x'; char x = 'x';
_Y; _Y;
if (write(l->write_fds[1], &x, sizeof(x)) >= 0) if (write(l->write_fds[1], &x, sizeof(x)) >= 0)
pa_atomic_inc(&l->n_read); pa_atomic_inc(&l->in_write_fifo);
} }
return ret; return ret;
@ -301,13 +328,13 @@ int pa_asyncq_before_poll(pa_asyncq *l) {
_Y; _Y;
idx = reduce(l, l->read_idx); idx = reduce(l, l->read_idx);
if (pa_atomic_ptr_load(&cells[idx])) if (pa_atomic_ptr_load(&cells[idx]) || pa_atomic_load(&l->in_read_fifo) > 0)
return -1; return -1;
pa_atomic_inc(&l->read_waiting); pa_assert_se(pa_atomic_cmpxchg(&l->read_waiting, 0, 1));
if (pa_atomic_ptr_load(&cells[idx])) { if (pa_atomic_ptr_load(&cells[idx]) || pa_atomic_load(&l->in_read_fifo) > 0) {
pa_atomic_dec(&l->read_waiting); pa_assert_se(pa_atomic_cmpxchg(&l->read_waiting, 1, 0));
return -1; return -1;
} }
@ -317,7 +344,5 @@ int pa_asyncq_before_poll(pa_asyncq *l) {
void pa_asyncq_after_poll(pa_asyncq *l) { void pa_asyncq_after_poll(pa_asyncq *l) {
pa_assert(l); pa_assert(l);
pa_assert(pa_atomic_load(&l->read_waiting) > 0); pa_assert_se(pa_atomic_cmpxchg(&l->read_waiting, 1, 0));
pa_atomic_dec(&l->read_waiting);
} }