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sr: session: Keep a global pollfd array 

Currently we keep a file descriptor for each source and construct a pollfd array
from these during each loop iteration in sr_session_run(). This patch modifies
the code to keep a global pollfd array which is only modified when a source is
added or removed. On one hand this gets rid of the constant constructing and
subsequent freeing of the pollfd array in sr_session_run(), on the other hand it
will allow us to implement support for non-fd based pollfds.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
This commit is contained in:
Lars-Peter Clausen 2012-06-30 20:54:43 +02:00 committed by Uwe Hermann
parent 2bccd322bc
commit 0687dfcde9
1 changed files with 40 additions and 36 deletions
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76
session.c
View File

@ -29,8 +29,6 @@
extern SR_PRIV GIOChannel channels[2];
struct source {
int fd;
int events;
int timeout;
sr_receive_data_callback_t cb;
void *cb_data;
@ -41,7 +39,13 @@ struct source {
struct sr_session *session;
static int num_sources = 0;
/* Both "sources" and "pollfds" are of the same size and contain pairs of
* descriptor and callback function. We can not embed the GPollFD into the
* source struct since we want to be able to pass the array of all poll
* descriptors to g_poll.
*/
static struct source *sources = NULL;
static GPollFD *pollfds;
static int source_timeout = -1;
/**
@ -207,49 +211,25 @@ SR_API int sr_session_datafeed_callback_add(sr_datafeed_callback_t cb)
*/
static int sr_session_run_poll(void)
{
GPollFD *fds, my_gpollfd;
int ret, i;
fds = NULL;
while (session->running) {
/* TODO: Add comment. */
g_free(fds);
/* Construct g_poll()'s array. */
if (!(fds = g_try_malloc(sizeof(GPollFD) * num_sources))) {
/* Not enough memory, or num_sources was 0. */
sr_err("session: %s: fds malloc failed "
"(num_sources was %d).", __func__, num_sources);
return SR_ERR_MALLOC;
}
for (i = 0; i < num_sources; i++) {
#ifdef _WIN32
g_io_channel_win32_make_pollfd(&channels[0],
sources[i].events, &my_gpollfd);
#else
my_gpollfd.fd = sources[i].fd;
my_gpollfd.events = sources[i].events;
fds[i] = my_gpollfd;
#endif
}
ret = g_poll(fds, num_sources, source_timeout);
ret = g_poll(pollfds, num_sources, source_timeout);
for (i = 0; i < num_sources; i++) {
if (fds[i].revents > 0 || (ret == 0
if (pollfds[i].revents > 0 || (ret == 0
&& source_timeout == sources[i].timeout)) {
/*
* Invoke the source's callback on an event,
* or if the poll timeout out and this source
* asked for that timeout.
*/
if (!sources[i].cb(fds[i].fd, fds[i].revents,
if (!sources[i].cb(pollfds[i].fd, pollfds[i].revents,
sources[i].cb_data))
sr_session_source_remove(sources[i].fd);
sr_session_source_remove(pollfds[i].fd);
}
}
}
g_free(fds);
return SR_OK;
}
@ -326,7 +306,7 @@ SR_API int sr_session_run(void)
session->running = TRUE;
/* Do we have real sources? */
if (num_sources == 1 && sources[0].fd == -1) {
if (num_sources == 1 && pollfds[0].fd == -1) {
/* Dummy source, freewheel over it. */
while (session->running)
sources[0].cb(-1, 0, sources[0].cb_data);
@ -497,6 +477,7 @@ SR_API int sr_session_source_add(int fd, int events, int timeout,
sr_receive_data_callback_t cb, void *cb_data)
{
struct source *new_sources, *s;
GPollFD *new_pollfds, *p;
if (!cb) {
sr_err("session: %s: cb was NULL", __func__);
@ -505,18 +486,31 @@ SR_API int sr_session_source_add(int fd, int events, int timeout,
/* Note: cb_data can be NULL, that's not a bug. */
new_pollfds = g_try_realloc(pollfds, sizeof(GPollFD) * (num_sources + 1));
if (!new_pollfds) {
sr_err("session: %s: new_sources malloc failed", __func__);
return SR_ERR_MALLOC;
}
new_sources = g_try_realloc(sources, sizeof(struct source) * (num_sources + 1));
if (!new_sources) {
sr_err("session: %s: new_sources malloc failed", __func__);
return SR_ERR_MALLOC;
}
p = &new_pollfds[num_sources];
s = &new_sources[num_sources++];
s->fd = fd;
s->events = events;
#ifdef _WIN32
g_io_channel_win32_make_pollfd(&channels[0],
events, p);
#else
p->fd = fd;
p->events = events;
#endif
s->timeout = timeout;
s->cb = cb;
s->cb_data = cb_data;
pollfds = new_pollfds;
sources = new_sources;
if (timeout != source_timeout && timeout > 0
@ -540,7 +534,8 @@ SR_API int sr_session_source_add(int fd, int events, int timeout,
SR_API int sr_session_source_remove(int fd)
{
struct source *new_sources;
int old, new;
GPollFD *new_pollfds;
int old;
if (!sources) {
sr_err("session: %s: sources was NULL", __func__);
@ -548,7 +543,7 @@ SR_API int sr_session_source_remove(int fd)
}
for (old = 0; old < num_sources; old++) {
if (sources[old].fd == fd)
if (pollfds[old].fd == fd)
break;
}
@ -559,16 +554,25 @@ SR_API int sr_session_source_remove(int fd)
num_sources -= 1;
if (old != num_sources) {
memmove(&pollfds[old], &pollfds[old+1],
(num_sources - old) * sizeof(GPollFD));
memmove(&sources[old], &sources[old+1],
(num_sources - old) * sizeof(struct source));
}
new_sources = g_try_realloc(sources, sizeof(struct source) * (num_sources - 1));
new_pollfds = g_try_realloc(sources, sizeof(GPollFD) * num_sources);
if (!new_pollfds && num_sources > 0) {
sr_err("session: %s: new_sources malloc failed", __func__);
return SR_ERR_MALLOC;
}
new_sources = g_try_realloc(sources, sizeof(struct source) * num_sources);
if (!new_sources && num_sources > 0) {
sr_err("session: %s: new_sources malloc failed", __func__);
return SR_ERR_MALLOC;
}
pollfds = new_pollfds;
sources = new_sources;
return SR_OK;