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- /* Copyright (c) 2001, Matej Pfajfar.
- * Copyright (c) 2001-2004, Roger Dingledine.
- * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
- * Copyright (c) 2007-2018, The Tor Project, Inc. */
- /* See LICENSE for licensing information */
- #include "orconfig.h"
- #include "src/core/or/or.h"
- #include "src/core/mainloop/mainloop.h"
- #include "src/core/mainloop/mainloop_pubsub.h"
- #include "lib/container/smartlist.h"
- #include "lib/dispatch/dispatch.h"
- #include "lib/dispatch/dispatch_naming.h"
- #include "lib/evloop/compat_libevent.h"
- #include "lib/pubsub/pubsub.h"
- #include "lib/pubsub/pubsub_build.h"
- /**
- * Dispatcher to use for delivering messages.
- **/
- static dispatch_t *the_dispatcher = NULL;
- static pubsub_items_t *the_pubsub_items = NULL;
- /**
- * A list of mainloop_event_t, indexed by channel ID, to flush the messages
- * on a channel.
- **/
- static smartlist_t *alert_events = NULL;
- /**
- * Mainloop event callback: flush all the messages in a channel.
- *
- * The channel is encoded as a pointer, and passed via arg.
- **/
- static void
- flush_channel_event(mainloop_event_t *ev, void *arg)
- {
- (void)ev;
- if (!the_dispatcher)
- return;
- channel_id_t chan = (channel_id_t)(uintptr_t)(arg);
- dispatch_flush(the_dispatcher, chan, INT_MAX);
- }
- /**
- * Construct our global pubsub object from <b>builder</b>. Return 0 on
- * success, -1 on failure. */
- int
- tor_mainloop_connect_pubsub(struct pubsub_builder_t *builder)
- {
- int rv = -1;
- tor_mainloop_disconnect_pubsub();
- the_dispatcher = pubsub_builder_finalize(builder, &the_pubsub_items);
- if (! the_dispatcher)
- goto err;
- rv = 0;
- goto done;
- err:
- tor_mainloop_disconnect_pubsub();
- done:
- return rv;
- }
- /**
- * Install libevent events for all of the pubsub channels.
- *
- * Invoke this after tor_mainloop_connect_pubsub, and after libevent has been
- * initialized.
- */
- void
- tor_mainloop_connect_pubsub_events(void)
- {
- tor_assert(the_dispatcher);
- tor_assert(! alert_events);
- const size_t num_channels = get_num_channel_ids();
- alert_events = smartlist_new();
- for (size_t i = 0; i < num_channels; ++i) {
- smartlist_add(alert_events,
- mainloop_event_postloop_new(flush_channel_event,
- (void*)(uintptr_t)(i)));
- }
- }
- /**
- * Dispatch alertfn callback: do nothing. Implements DELIV_NEVER.
- **/
- static void
- alertfn_never(dispatch_t *d, channel_id_t chan, void *arg)
- {
- (void)d;
- (void)chan;
- (void)arg;
- }
- /**
- * Dispatch alertfn callback: activate a mainloop event. Implements
- * DELIV_PROMPT.
- **/
- static void
- alertfn_prompt(dispatch_t *d, channel_id_t chan, void *arg)
- {
- (void)d;
- (void)chan;
- mainloop_event_t *event = arg;
- mainloop_event_activate(event);
- }
- /**
- * Dispatch alertfn callback: flush all messages right now. Implements
- * DELIV_IMMEDIATE.
- **/
- static void
- alertfn_immediate(dispatch_t *d, channel_id_t chan, void *arg)
- {
- (void) arg;
- dispatch_flush(d, chan, INT_MAX);
- }
- /**
- * Set the strategy to be used for delivering messages on the named channel.
- *
- * This function needs to be called once globally for each channel, to
- * set up how messages are delivered.
- **/
- int
- tor_mainloop_set_delivery_strategy(const char *msg_channel_name,
- deliv_strategy_t strategy)
- {
- channel_id_t chan = get_channel_id(msg_channel_name);
- if (BUG(chan == ERROR_ID) ||
- BUG(chan >= smartlist_len(alert_events)))
- return -1;
- switch (strategy) {
- case DELIV_NEVER:
- dispatch_set_alert_fn(the_dispatcher, chan, alertfn_never, NULL);
- break;
- case DELIV_PROMPT:
- dispatch_set_alert_fn(the_dispatcher, chan, alertfn_prompt,
- smartlist_get(alert_events, chan));
- break;
- case DELIV_IMMEDIATE:
- dispatch_set_alert_fn(the_dispatcher, chan, alertfn_immediate, NULL);
- break;
- }
- return 0;
- }
- /**
- * Remove all pubsub dispatchers and events from the mainloop.
- **/
- void
- tor_mainloop_disconnect_pubsub(void)
- {
- if (the_pubsub_items) {
- pubsub_items_clear_bindings(the_pubsub_items);
- pubsub_items_free(the_pubsub_items);
- }
- if (alert_events) {
- SMARTLIST_FOREACH(alert_events, mainloop_event_t *, ev,
- mainloop_event_free(ev));
- smartlist_free(alert_events);
- }
- dispatch_free(the_dispatcher);
- }
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