+/** @brief Retrieve the most recently added tracks
+ * @param ntracksp Where to put count, or 0
+ * @param maxtracks Maximum number of tracks to retrieve
+ * @return null-terminated array of track names
+ *
+ * The most recently added track is first in the array.
+ */
+char **trackdb_new(int *ntracksp,
+ int maxtracks) {
+ DB_TXN *tid;
+ char **tracks;
+
+ for(;;) {
+ tid = trackdb_begin_transaction();
+ tracks = trackdb_new_tid(ntracksp, maxtracks, tid);
+ if(tracks)
+ break;
+ trackdb_abort_transaction(tid);
+ }
+ trackdb_commit_transaction(tid);
+ return tracks;
+}
+
+/** @brief Retrieve the most recently added tracks
+ * @param ntracksp Where to put count, or 0
+ * @param maxtracks Maximum number of tracks to retrieve, or 0 for all
+ * @param tid Transaction ID
+ * @return null-terminated array of track names, or NULL on deadlock
+ *
+ * The most recently added track is first in the array.
+ */
+static char **trackdb_new_tid(int *ntracksp,
+ int maxtracks,
+ DB_TXN *tid) {
+ DBC *c;
+ DBT k, d;
+ int err = 0;
+ struct vector tracks[1];
+
+ vector_init(tracks);
+ c = trackdb_opencursor(trackdb_noticeddb, tid);
+ while((maxtracks <= 0 || tracks->nvec < maxtracks)
+ && !(err = c->c_get(c, prepare_data(&k), prepare_data(&d), DB_PREV)))
+ vector_append(tracks, xstrndup(d.data, d.size));
+ switch(err) {
+ case 0: /* hit maxtracks */
+ case DB_NOTFOUND: /* ran out of tracks */
+ break;
+ case DB_LOCK_DEADLOCK:
+ trackdb_closecursor(c);
+ return 0;
+ default:
+ fatal(0, "error reading noticed.db: %s", db_strerror(err));
+ }
+ if((err = trackdb_closecursor(c)))
+ return 0; /* deadlock */
+ vector_terminate(tracks);
+ if(ntracksp)
+ *ntracksp = tracks->nvec;
+ return tracks->vec;
+}
+
+/** @brief Expire noticed.db
+ * @param earliest Earliest timestamp to keep
+ */
+void trackdb_expire_noticed(time_t earliest) {
+ DB_TXN *tid;
+
+ for(;;) {
+ tid = trackdb_begin_transaction();
+ if(!trackdb_expire_noticed_tid(earliest, tid))
+ break;
+ trackdb_abort_transaction(tid);
+ }
+ trackdb_commit_transaction(tid);
+}
+
+/** @brief Expire noticed.db
+ * @param earliest Earliest timestamp to keep
+ * @param tid Transaction ID
+ * @return 0 or DB_LOCK_DEADLOCK
+ */
+static int trackdb_expire_noticed_tid(time_t earliest, DB_TXN *tid) {
+ DBC *c;
+ DBT k, d;
+ int err = 0, ret;
+ time_t when;
+ uint32_t *kk;
+ int count = 0;
+
+ c = trackdb_opencursor(trackdb_noticeddb, tid);
+ while(!(err = c->c_get(c, prepare_data(&k), prepare_data(&d), DB_NEXT))) {
+ kk = k.data;
+ when = (time_t)(((uint64_t)ntohl(kk[0]) << 32) + ntohl(kk[1]));
+ if(when >= earliest)
+ break;
+ if((err = c->c_del(c, 0))) {
+ if(err != DB_LOCK_DEADLOCK)
+ fatal(0, "error deleting expired noticed.db entry: %s",
+ db_strerror(err));
+ break;
+ }
+ ++count;
+ }
+ if(err == DB_NOTFOUND)
+ err = 0;
+ if(err && err != DB_LOCK_DEADLOCK)
+ fatal(0, "error expiring noticed.db: %s", db_strerror(err));
+ ret = err;
+ if((err = trackdb_closecursor(c))) {
+ if(err != DB_LOCK_DEADLOCK)
+ fatal(0, "error closing cursor: %s", db_strerror(err));
+ ret = err;
+ }
+ if(!ret && count)
+ info("expired %d tracks from noticed.db", count);
+ return ret;
+}
+