/* trackdb_rescan ************************************************************/
+/** @brief Node in the list of rescan-complete callbacks */
+struct rescanned_node {
+ struct rescanned_node *next;
+ void (*rescanned)(void *ru);
+ void *ru;
+};
+
+/** @brief List of rescan-complete callbacks */
+static struct rescanned_node *rescanned_list;
+
+/** @brief Add a rescan completion callback */
+void trackdb_add_rescanned(void (*rescanned)(void *ru),
+ void *ru) {
+ if(rescanned) {
+ struct rescanned_node *n = xmalloc(sizeof *n);
+ n->next = rescanned_list;
+ n->rescanned = rescanned;
+ n->ru = ru;
+ rescanned_list = n;
+ }
+}
+
/* called when the rescanner terminates */
static int reap_rescan(ev_source attribute((unused)) *ev,
pid_t pid,
/* Our cache of file lookups is out of date now */
cache_clean(&cache_files_type);
eventlog("rescanned", (char *)0);
+ /* Call rescanned callbacks */
+ while(rescanned_list) {
+ void (*rescanned)(void *u) = rescanned_list->rescanned;
+ void *ru = rescanned_list->ru;
+
+ rescanned_list = rescanned_list->next;
+ rescanned(ru);
+ }
return 0;
}
/** @brief Initiate a rescan
* @param ev Event loop or 0 to block
* @param recheck 1 to recheck lengths, 0 to suppress check
+ * @param rescanned Called on completion (if not NULL)
+ * @param u Passed to @p rescanned
*/
-void trackdb_rescan(ev_source *ev, int recheck) {
+void trackdb_rescan(ev_source *ev, int recheck,
+ void (*rescanned)(void *ru),
+ void *ru) {
int w;
if(rescan_pid != -1) {
+ trackdb_add_rescanned(rescanned, ru);
error(0, "rescan already underway");
return;
}
rescan_pid = subprogram(ev, -1, RESCAN,
recheck ? "--check" : "--no-check",
(char *)0);
+ trackdb_add_rescanned(rescanned, ru);
if(ev) {
ev_child(ev, rescan_pid, 0, reap_rescan, 0);
D(("started rescanner"));
return 1;
}
+/** @brief Return true if a rescan is underway */
+int trackdb_rescan_underway(void) {
+ return rescan_pid != -1;
+}
+
/* global prefs **************************************************************/
void trackdb_set_global(const char *name,
rights_type rights;
/** @brief Next connection */
struct conn *next;
+ /** @brief True if pending rescan had 'wait' set */
+ int rescan_wait;
};
/** @brief Linked list of connections */
return 1; /* completed */
}
+static void finished_rescan(void *ru) {
+ struct conn *const c = ru;
+
+ sink_writes(ev_writer_sink(c->w), "250 rescan completed\n");
+ /* Turn this connection back on */
+ ev_reader_enable(c->r);
+}
+
+static void start_fresh_rescan(void *ru) {
+ struct conn *const c = ru;
+
+ if(trackdb_rescan_underway()) {
+ /* Some other waiter beat us to it. However in this case we're happy to
+ * piggyback; the requirement is that a new rescan be started, not that it
+ * was _our_ rescan. */
+ if(c->rescan_wait) {
+ /* We block until the rescan completes */
+ trackdb_add_rescanned(finished_rescan, c);
+ } else {
+ /* We report that the new rescan has started */
+ sink_writes(ev_writer_sink(c->w), "250 rescan initiated\n");
+ /* Turn this connection back on */
+ ev_reader_enable(c->r);
+ }
+ } else {
+ /* We are the first connection to get a callback so we must start a
+ * rescan. */
+ if(c->rescan_wait) {
+ /* We want to block until the new rescan completes */
+ trackdb_rescan(c->ev, 1/*check*/, finished_rescan, c);
+ } else {
+ /* We can report back immediately */
+ trackdb_rescan(c->ev, 1/*check*/, 0, 0);
+ sink_writes(ev_writer_sink(c->w), "250 rescan initiated\n");
+ /* Turn this connection back on */
+ ev_reader_enable(c->r);
+ }
+ }
+}
+
static int c_rescan(struct conn *c,
- char attribute((unused)) **vec,
- int attribute((unused)) nvec) {
- info("S%x rescan by %s", c->tag, c->who);
- trackdb_rescan(c->ev, 1/*check*/);
- sink_writes(ev_writer_sink(c->w), "250 initiated rescan\n");
- return 1; /* completed */
+ char **vec,
+ int nvec) {
+ int wait = 0, fresh = 0, n;
+
+ /* Parse flags */
+ for(n = 0; n < nvec; ++n) {
+ if(!strcmp(vec[n], "wait"))
+ wait = 1; /* wait for rescan to complete */
+#if 0
+ /* Currently disabled because untested (and hard to test). */
+ else if(!strcmp(vec[n], "fresh"))
+ fresh = 1; /* don't piggyback underway rescan */
+#endif
+ else {
+ sink_writes(ev_writer_sink(c->w), "550 unknown flag\n");
+ return 1; /* completed */
+ }
+ }
+ /* Report what was requested */
+ info("S%x rescan by %s (%s %s)", c->tag, c->who,
+ wait ? "wait" : "",
+ fresh ? "fresh" : "");
+ if(trackdb_rescan_underway()) {
+ if(fresh) {
+ /* We want a fresh rescan but there is already one underway. Arrange a
+ * callback when it completes and then set off a new one. */
+ c->rescan_wait = wait;
+ trackdb_add_rescanned(start_fresh_rescan, c);
+ if(wait)
+ return 0;
+ else {
+ sink_writes(ev_writer_sink(c->w), "250 rescan queued\n");
+ return 1;
+ }
+ } else {
+ /* There's a rescan underway, and it's acceptable to piggyback on it */
+ if(wait) {
+ /* We want to block until completion. */
+ trackdb_add_rescanned(finished_rescan, c);
+ return 0;
+ } else {
+ /* We don't want to block. So we just report that things are in
+ * hand. */
+ sink_writes(ev_writer_sink(c->w), "250 rescan already underway\n");
+ return 1;
+ }
+ }
+ } else {
+ /* No rescan is underway. fresh is therefore irrelevant. */
+ if(wait) {
+ /* We want to block until completion */
+ trackdb_rescan(c->ev, 1/*check*/, finished_rescan, c);
+ return 0;
+ } else {
+ /* We don't want to block. */
+ trackdb_rescan(c->ev, 1/*check*/, 0, 0);
+ sink_writes(ev_writer_sink(c->w), "250 rescan initiated\n");
+ return 1; /* completed */
+ }
+ }
}
static int c_version(struct conn *c,
{ "register", 3, 3, c_register, RIGHT_REGISTER|RIGHT__LOCAL },
{ "reminder", 1, 1, c_reminder, RIGHT__LOCAL },
{ "remove", 1, 1, c_remove, RIGHT_REMOVE__MASK },
- { "rescan", 0, 0, c_rescan, RIGHT_RESCAN },
+ { "rescan", 0, INT_MAX, c_rescan, RIGHT_RESCAN },
{ "resolve", 1, 1, c_resolve, RIGHT_READ },
{ "resume", 0, 0, c_resume, RIGHT_PAUSE },
{ "revoke", 0, 0, c_revoke, RIGHT_READ },
~mdw / disorder / commitdiff