session: Unify handling of I/O and timer sources
Handle I/O sources and timer ("dummy") sources within the same
polling loop, so that both may be used together. Slightly change
the API to improve consistency: a timeout value of -1 now disables
the timeout, and 0 makes the source always time out immediately.
The "dummy" sources already behaved that way, although it wasn't
documented as such.
Make sure that I/O events are processed preferentially: Skip any
timeout callbacks if an I/O event occurred within the same poll
iteration. This applies to both timer/idle sources and timeouts
of I/O sources.
Do not create dummy GPollFDs for timer/idle sources. Instead,
split the sources array into an I/O section and a timer section,
and create corresponding GPollFDs only for the I/O section. Use
GArray to simplify the handling of the dynamic arrays.
This commit is contained in:
Daniel Elstner
parent
62d7945f80
commit
faa5d7d997
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@ -721,16 +721,15 @@ struct sr_session {
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gboolean running;
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unsigned int num_sources;
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/*
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* Both "sources" and "pollfds" are of the same size and contain pairs
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* of descriptor and callback function. We can not embed the GPollFD
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* into the source struct since we want to be able to pass the array
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* of all poll descriptors to g_poll().
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* Each I/O source has an entry with the same index in both "sources"
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* and "pollfds". The "sources" array may be larger than "pollfds",
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* in which case the excess sources are pure timer sources.
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* We can not embed the GPollFD into the source struct since we want
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* to be able to pass the array of all poll descriptors to g_poll().
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*/
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struct source *sources;
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GPollFD *pollfds;
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GArray *sources;
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GArray *pollfds;
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/*
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* These are our synchronization primitives for stopping the session in
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236
src/session.c
236
src/session.c
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@ -45,7 +45,8 @@
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*/
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struct source {
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int64_t due;
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int64_t timeout; /* microseconds */
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int64_t due; /* microseconds */
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sr_receive_data_callback cb;
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void *cb_data;
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@ -54,8 +55,8 @@ struct source {
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*/
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gintptr poll_object;
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int timeout;
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gboolean is_usb;
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gboolean triggered;
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};
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struct datafeed_callback {
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@ -87,8 +88,10 @@ SR_API int sr_session_new(struct sr_context *ctx,
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session = g_malloc0(sizeof(struct sr_session));
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session->ctx = ctx;
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session->running = FALSE;
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session->abort_session = FALSE;
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session->sources = g_array_new(FALSE, FALSE, sizeof(struct source));
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session->pollfds = g_array_new(FALSE, FALSE, sizeof(GPollFD));
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g_mutex_init(&session->stop_mutex);
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*new_session = session;
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@ -121,6 +124,9 @@ SR_API int sr_session_destroy(struct sr_session *session)
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g_slist_free_full(session->owned_devs, (GDestroyNotify)sr_dev_inst_free);
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g_array_unref(session->pollfds);
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g_array_unref(session->sources);
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g_free(session);
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return SR_OK;
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@ -377,12 +383,10 @@ static gboolean sr_session_check_aborted(struct sr_session *session)
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return stop;
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}
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static int _sr_session_source_remove(struct sr_session *session, gintptr poll_object);
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/**
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* Call every device in the current session's callback.
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*
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* For sessions not driven by select loops such as sr_session_run(),
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* but driven by another scheduler, this can be used to poll the devices
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* from within that scheduler.
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* Poll the session's event sources.
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*
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* @param session The session to use. Must not be NULL.
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* @retval SR_OK Success.
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@ -390,15 +394,13 @@ static gboolean sr_session_check_aborted(struct sr_session *session)
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*/
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static int sr_session_iteration(struct sr_session *session)
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{
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int64_t start_time;
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int64_t stop_time;
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int64_t min_due;
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int64_t due;
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int64_t start_time, stop_time, min_due, due;
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int timeout_ms;
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unsigned int i;
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int ret, timeout;
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int ret;
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int fd;
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int revents;
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gboolean stop_checked;
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gboolean stopped;
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gboolean triggered, stopped;
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struct source *source;
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GPollFD *pollfd;
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gintptr poll_object;
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@ -406,16 +408,18 @@ static int sr_session_iteration(struct sr_session *session)
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int64_t usb_due;
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struct timeval tv;
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#endif
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if (session->num_sources <= 0) {
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if (session->sources->len == 0) {
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sr_session_check_aborted(session);
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return SR_OK;
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}
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start_time = g_get_monotonic_time();
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min_due = INT64_MAX;
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for (i = 0; i < session->num_sources; ++i) {
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if (session->sources[i].due < min_due)
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min_due = session->sources[i].due;
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for (i = 0; i < session->sources->len; ++i) {
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source = &g_array_index(session->sources, struct source, i);
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if (source->due < min_due)
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min_due = source->due;
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source->triggered = FALSE;
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}
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#ifdef HAVE_LIBUSB_1_0
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usb_due = INT64_MAX;
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@ -433,13 +437,15 @@ static int sr_session_iteration(struct sr_session *session)
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}
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}
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#endif
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if (min_due > start_time)
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timeout = (min_due == INT64_MAX) ? -1
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: MIN((min_due - start_time + 999) / 1000, INT_MAX);
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if (min_due == INT64_MAX)
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timeout_ms = -1;
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else if (min_due > start_time)
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timeout_ms = MIN((min_due - start_time + 999) / 1000, INT_MAX);
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else
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timeout = 0;
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timeout_ms = 0;
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ret = g_poll(session->pollfds, session->num_sources, timeout);
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ret = g_poll((GPollFD *)session->pollfds->data,
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session->pollfds->len, timeout_ms);
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#ifdef G_OS_UNIX
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if (ret < 0 && errno != EINTR) {
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sr_err("Error in poll: %s", g_strerror(errno));
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@ -452,13 +458,27 @@ static int sr_session_iteration(struct sr_session *session)
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}
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#endif
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stop_time = g_get_monotonic_time();
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stop_checked = FALSE;
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triggered = FALSE;
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stopped = FALSE;
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for (i = 0; i < session->num_sources; i++) {
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source = &session->sources[i];
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pollfd = &session->pollfds[i];
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revents = (ret > 0) ? pollfd->revents : 0;
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for (i = 0; i < session->sources->len; ++i) {
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source = &g_array_index(session->sources, struct source, i);
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if (source->triggered)
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continue; /* already handled */
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poll_object = source->poll_object;
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fd = (int)poll_object;
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revents = 0;
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if (i < session->pollfds->len) {
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pollfd = &g_array_index(session->pollfds, GPollFD, i);
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fd = pollfd->fd;
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if (ret > 0)
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revents = pollfd->revents;
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}
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if (ret > 0 && revents == 0)
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continue; /* skip timeouts if any I/O event occurred */
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due = source->due;
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#ifdef HAVE_LIBUSB_1_0
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if (source->is_usb && usb_due < due)
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@ -470,29 +490,30 @@ static int sr_session_iteration(struct sr_session *session)
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* The source may be gone after the callback returns,
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* so access any data now that needs accessing.
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*/
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poll_object = source->poll_object;
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if (source->timeout > 0)
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source->due = stop_time + INT64_C(1000) * source->timeout;
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pollfd->revents = 0;
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if (source->timeout >= 0)
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source->due = stop_time + source->timeout;
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source->triggered = TRUE;
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triggered = TRUE;
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/*
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* Invoke the source's callback on an event or timeout.
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*/
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if (!source->cb(pollfd->fd, revents, source->cb_data))
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sr_session_source_remove(session, poll_object);
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if (!source->cb(fd, revents, source->cb_data))
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_sr_session_source_remove(session, poll_object);
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/*
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* We want to take as little time as possible to stop
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* the session if we have been told to do so. Therefore,
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* we check the flag after processing every source, not
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* just once per main event loop.
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*/
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if (!stopped) {
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if (!stopped)
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stopped = sr_session_check_aborted(session);
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stop_checked = TRUE;
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}
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/* Restart loop as the sources list may have changed. */
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i = 0;
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}
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if (!stop_checked)
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/* Check for abort at least once per iteration. */
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if (!triggered)
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sr_session_check_aborted(session);
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return SR_OK;
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@ -609,11 +630,14 @@ SR_API int sr_session_start(struct sr_session *session)
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*
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* @retval SR_OK Success.
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* @retval SR_ERR_ARG Invalid session passed.
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* @retval SR_ERR Error during event processing.
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*
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* @since 0.4.0
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*/
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SR_API int sr_session_run(struct sr_session *session)
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{
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int ret;
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if (!session) {
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sr_err("%s: session was NULL", __func__);
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return SR_ERR_ARG;
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@ -629,17 +653,12 @@ SR_API int sr_session_run(struct sr_session *session)
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sr_info("Running.");
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/* Do we have real sources? */
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if (session->num_sources == 1 && session->pollfds[0].fd == -1) {
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/* Dummy source, freewheel over it. */
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while (session->num_sources)
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session->sources[0].cb(-1, 0, session->sources[0].cb_data);
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} else {
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/* Real sources, use g_poll() main loop. */
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while (session->num_sources)
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sr_session_iteration(session);
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/* Poll event sources until none are left. */
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while (session->sources->len > 0) {
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ret = sr_session_iteration(session);
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if (ret != SR_OK)
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return ret;
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}
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return SR_OK;
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}
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@ -854,8 +873,8 @@ SR_PRIV int sr_session_send(const struct sr_dev_inst *sdi,
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*
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* @param session The session to use. Must not be NULL.
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* @param pollfd The GPollFD.
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* @param[in] timeout Max time to wait before the callback is called,
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* ignored if 0.
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* @param[in] timeout Max time in ms to wait before the callback is called,
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* or -1 to wait indefinitely.
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* @param cb Callback function to add. Must not be NULL.
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* @param cb_data Data for the callback function. Can be NULL.
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* @param poll_object Handle by which the source is identified
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@ -868,34 +887,36 @@ SR_PRIV int sr_session_source_add_internal(struct sr_session *session,
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GPollFD *pollfd, int timeout, sr_receive_data_callback cb,
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void *cb_data, gintptr poll_object, gboolean is_usb)
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{
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struct source *new_sources, *s;
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GPollFD *new_pollfds;
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struct source src;
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if (!cb) {
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sr_err("%s: cb was NULL", __func__);
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return SR_ERR_ARG;
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}
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/* Note: cb_data can be NULL, that's not a bug. */
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new_pollfds = g_realloc(session->pollfds,
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sizeof(GPollFD) * (session->num_sources + 1));
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new_sources = g_realloc(session->sources, sizeof(struct source) *
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(session->num_sources + 1));
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src.cb = cb;
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src.cb_data = cb_data;
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src.poll_object = poll_object;
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src.is_usb = is_usb;
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src.triggered = FALSE;
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new_pollfds[session->num_sources] = *pollfd;
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s = &new_sources[session->num_sources++];
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if (timeout > 0)
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s->due = g_get_monotonic_time() + INT64_C(1000) * timeout;
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else
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s->due = INT64_MAX;
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s->cb = cb;
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s->cb_data = cb_data;
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s->poll_object = poll_object;
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s->timeout = timeout;
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s->is_usb = is_usb;
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session->pollfds = new_pollfds;
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session->sources = new_sources;
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if (timeout >= 0) {
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src.timeout = INT64_C(1000) * timeout;
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src.due = g_get_monotonic_time() + src.timeout;
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} else {
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src.timeout = -1;
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src.due = INT64_MAX;
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}
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if (pollfd) {
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/* I/O source */
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g_array_insert_val(session->sources, session->pollfds->len, src);
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g_array_append_vals(session->pollfds, pollfd, 1);
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} else {
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/* Timer source */
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g_array_append_val(session->sources, src);
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}
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return SR_OK;
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}
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@ -906,7 +927,8 @@ SR_PRIV int sr_session_source_add_internal(struct sr_session *session,
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* @param session The session to use. Must not be NULL.
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* @param fd The file descriptor.
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* @param events Events to check for.
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* @param timeout Max time to wait before the callback is called, ignored if 0.
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* @param timeout Max time in ms to wait before the callback is called,
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* or -1 to wait indefinitely.
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* @param cb Callback function to add. Must not be NULL.
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* @param cb_data Data for the callback function. Can be NULL.
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*
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@ -920,20 +942,25 @@ SR_API int sr_session_source_add(struct sr_session *session, int fd,
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{
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GPollFD p;
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if (fd < 0 && timeout < 0) {
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sr_err("Timer source without timeout would block indefinitely");
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return SR_ERR_ARG;
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}
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p.fd = fd;
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p.events = events;
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p.revents = 0;
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return sr_session_source_add_internal(session, &p, timeout,
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cb, cb_data, fd, FALSE);
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return sr_session_source_add_internal(session,
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(fd < 0) ? NULL : &p, timeout, cb, cb_data, fd, FALSE);
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}
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/**
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* Add an event source for a GPollFD.
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*
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* @param session The session to use. Must not be NULL.
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* @param pollfd The GPollFD.
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* @param timeout Max time to wait before the callback is called, ignored if 0.
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* @param pollfd The GPollFD. Must not be NULL.
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* @param timeout Max time in ms to wait before the callback is called,
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* or -1 to wait indefinitely.
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* @param cb Callback function to add. Must not be NULL.
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* @param cb_data Data for the callback function. Can be NULL.
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*
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@ -946,6 +973,10 @@ SR_API int sr_session_source_add_pollfd(struct sr_session *session,
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GPollFD *pollfd, int timeout, sr_receive_data_callback cb,
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void *cb_data)
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{
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if (!pollfd) {
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sr_err("%s: pollfd was NULL", __func__);
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return SR_ERR_ARG;
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}
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return sr_session_source_add_internal(session, pollfd, timeout,
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cb, cb_data, (gintptr)pollfd, FALSE);
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}
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@ -956,7 +987,8 @@ SR_API int sr_session_source_add_pollfd(struct sr_session *session,
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* @param session The session to use. Must not be NULL.
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* @param channel The GIOChannel.
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* @param events Events to poll on.
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* @param timeout Max time to wait before the callback is called, ignored if 0.
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* @param timeout Max time in ms to wait before the callback is called,
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* or -1 to wait indefinitely.
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* @param cb Callback function to add. Must not be NULL.
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* @param cb_data Data for the callback function. Can be NULL.
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*
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@ -971,7 +1003,7 @@ SR_API int sr_session_source_add_channel(struct sr_session *session,
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{
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GPollFD p;
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#ifdef _WIN32
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#ifdef G_OS_WIN32
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g_io_channel_win32_make_pollfd(channel, events, &p);
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#else
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p.fd = g_io_channel_unix_get_fd(channel);
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@ -994,34 +1026,18 @@ SR_API int sr_session_source_add_channel(struct sr_session *session,
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*/
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static int _sr_session_source_remove(struct sr_session *session, gintptr poll_object)
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{
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unsigned int old;
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unsigned int i;
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if (!session->sources || !session->num_sources) {
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sr_err("%s: sources was NULL", __func__);
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return SR_ERR_BUG;
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}
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for (i = 0; i < session->sources->len; ++i) {
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if (g_array_index(session->sources, struct source, i)
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.poll_object == poll_object) {
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for (old = 0; old < session->num_sources; old++) {
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if (session->sources[old].poll_object == poll_object)
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g_array_remove_index(session->sources, i);
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if (i < session->pollfds->len)
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g_array_remove_index(session->pollfds, i);
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break;
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}
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}
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/* fd not found, nothing to do */
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if (old == session->num_sources)
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return SR_OK;
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session->num_sources--;
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if (old != session->num_sources) {
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memmove(&session->pollfds[old], &session->pollfds[old + 1],
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(session->num_sources - old) * sizeof(GPollFD));
|
||||
memmove(&session->sources[old], &session->sources[old + 1],
|
||||
(session->num_sources - old) * sizeof(struct source));
|
||||
}
|
||||
|
||||
session->pollfds = g_realloc(session->pollfds, sizeof(GPollFD) * session->num_sources);
|
||||
session->sources = g_realloc(session->sources, sizeof(struct source) * session->num_sources);
|
||||
|
||||
return SR_OK;
|
||||
}
|
||||
|
||||
|
|
@ -1039,7 +1055,7 @@ static int _sr_session_source_remove(struct sr_session *session, gintptr poll_ob
|
|||
*/
|
||||
SR_API int sr_session_source_remove(struct sr_session *session, int fd)
|
||||
{
|
||||
return _sr_session_source_remove(session, (gintptr)fd);
|
||||
return _sr_session_source_remove(session, fd);
|
||||
}
|
||||
|
||||
/**
|
||||
|
|
@ -1047,7 +1063,7 @@ SR_API int sr_session_source_remove(struct sr_session *session, int fd)
|
|||
*
|
||||
* @param session The session to use. Must not be NULL.
|
||||
* @param pollfd The poll descriptor for which the source should be removed.
|
||||
*
|
||||
* Must not be NULL.
|
||||
* @return SR_OK upon success, SR_ERR_ARG upon invalid arguments, or
|
||||
* SR_ERR_MALLOC upon memory allocation errors, SR_ERR_BUG upon
|
||||
* internal errors.
|
||||
|
|
@ -1057,6 +1073,10 @@ SR_API int sr_session_source_remove(struct sr_session *session, int fd)
|
|||
SR_API int sr_session_source_remove_pollfd(struct sr_session *session,
|
||||
GPollFD *pollfd)
|
||||
{
|
||||
if (!pollfd) {
|
||||
sr_err("%s: pollfd was NULL", __func__);
|
||||
return SR_ERR_ARG;
|
||||
}
|
||||
return _sr_session_source_remove(session, (gintptr)pollfd);
|
||||
}
|
||||
|
||||
|
|
@ -1065,7 +1085,7 @@ SR_API int sr_session_source_remove_pollfd(struct sr_session *session,
|
|||
*
|
||||
* @param session The session to use. Must not be NULL.
|
||||
* @param channel The channel for which the source should be removed.
|
||||
*
|
||||
* Must not be NULL.
|
||||
* @retval SR_OK Success.
|
||||
* @retval SR_ERR_ARG Invalid argument.
|
||||
* @return SR_ERR_BUG Internal error.
|
||||
|
|
@ -1075,6 +1095,10 @@ SR_API int sr_session_source_remove_pollfd(struct sr_session *session,
|
|||
SR_API int sr_session_source_remove_channel(struct sr_session *session,
|
||||
GIOChannel *channel)
|
||||
{
|
||||
if (!channel) {
|
||||
sr_err("%s: channel was NULL", __func__);
|
||||
return SR_ERR_ARG;
|
||||
}
|
||||
return _sr_session_source_remove(session, (gintptr)channel);
|
||||
}
|
||||
|
||||
|
|
|
|||
Loading…
Reference in New Issue