chiark / gitweb /
disorder-choose rejects tracks in queue/recent list
[disorder] / server / choose.c
CommitLineData
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1/*
2 * This file is part of DisOrder
3 * Copyright (C) 2008 Richard Kettlewell
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
18 * USA
19 */
20/** @file choose.c
21 * @brief Random track chooser
22 *
23 * Picks a track at random and writes it to standard output. If for
24 * any reason no track can be picked - even a trivial reason like a
25 * deadlock - it just exits and expects the server to try again.
26 */
27
28#include <config.h>
29#include "types.h"
30
31#include <getopt.h>
32#include <stdio.h>
33#include <stdlib.h>
34#include <db.h>
35#include <locale.h>
36#include <errno.h>
37#include <sys/types.h>
38#include <unistd.h>
39#include <pcre.h>
40#include <string.h>
41#include <fcntl.h>
42#include <syslog.h>
91c9324a 43#include <time.h>
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44
45#include "configuration.h"
46#include "log.h"
47#include "defs.h"
48#include "mem.h"
49#include "kvp.h"
50#include "syscalls.h"
51#include "printf.h"
52#include "trackdb.h"
53#include "trackdb-int.h"
54#include "version.h"
91c9324a 55#include "trackname.h"
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56#include "queue.h"
57#include "server-queue.h"
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58
59static DB_TXN *global_tid;
60
61static const struct option options[] = {
62 { "help", no_argument, 0, 'h' },
63 { "version", no_argument, 0, 'V' },
64 { "config", required_argument, 0, 'c' },
65 { "debug", no_argument, 0, 'd' },
66 { "no-debug", no_argument, 0, 'D' },
67 { "syslog", no_argument, 0, 's' },
68 { "no-syslog", no_argument, 0, 'S' },
69 { 0, 0, 0, 0 }
70};
71
72/* display usage message and terminate */
73static void help(void) {
74 xprintf("Usage:\n"
75 " disorder-choose [OPTIONS]\n"
76 "Options:\n"
77 " --help, -h Display usage message\n"
78 " --version, -V Display version number\n"
79 " --config PATH, -c PATH Set configuration file\n"
80 " --debug, -d Turn on debugging\n"
81 " --[no-]syslog Enable/disable logging to syslog\n"
82 "\n"
83 "Track choose for DisOrder. Not intended to be run\n"
84 "directly.\n");
85 xfclose(stdout);
86 exit(0);
87}
88
89/** @brief Weighted track record */
90struct weighted_track {
91 /** @brief Next track in the list */
92 struct weighted_track *next;
93 /** @brief Track name */
94 const char *track;
95 /** @brief Weight for this track (always positive) */
96 unsigned long weight;
97};
98
99/** @brief List of tracks with nonzero weight */
100static struct weighted_track *tracks;
101
102/** @brief Sum of all weights */
103static unsigned long long total_weight;
104
105/** @brief Count of tracks */
106static long ntracks;
107
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108static char **required_tags;
109static char **prohibited_tags;
110
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111static int queue_contains(const struct queue_entry *head,
112 const char *track) {
113 const struct queue_entry *q;
114
115 for(q = head->next; q != head; q = q->next)
116 if(!strcmp(q->track, track))
117 return 1;
118 return 0;
119}
120
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121/** @brief Compute the weight of a track
122 * @param track Track name (UTF-8)
123 * @param data Track data
124 * @param prefs Track preferences
125 * @return Track weight (non-negative)
126 *
127 * Tracks to be excluded entirely are given a weight of 0.
128 */
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129static unsigned long compute_weight(const char *track,
130 struct kvp *data,
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131 struct kvp *prefs) {
132 const char *s;
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133 char **track_tags;
134 time_t last, now;
135
136 /* Reject tracks not in any collection (race between edit config and
137 * rescan) */
138 if(!find_track_root(track)) {
139 info("found track not in any collection: %s", track);
140 return 0;
141 }
bea6f6d5 142
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143 /* Reject aliases to avoid giving aliased tracks extra weight */
144 if(kvp_get(data, "_alias_for"))
145 return 0;
146
147 /* Reject tracks with random play disabled */
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148 if((s = kvp_get(prefs, "pick_at_random"))
149 && !strcmp(s, "0"))
150 return 0;
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151
152 /* Reject tracks played within the last 8 hours */
153 if((s = kvp_get(prefs, "played_time"))) {
154 last = atoll(s);
155 now = time(0);
156 if(now < last + 8 * 3600) /* TODO configurable */
157 return 0;
158 }
159
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160 /* Reject tracks currently in the queue or in the recent list */
161 if(queue_contains(&qhead, track)
162 || queue_contains(&phead, track))
163 return 0;
164
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165 /* We'll need tags for a number of things */
166 track_tags = parsetags(kvp_get(prefs, "tags"));
167
168 /* Reject tracks with prohibited tags */
169 if(prohibited_tags && tag_intersection(track_tags, prohibited_tags))
170 return 0;
171
172 /* Reject tracks that lack required tags */
173 if(*required_tags && !tag_intersection(track_tags, required_tags))
174 return 0;
175
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176 return 90000;
177}
178
179/** @brief Called for each track */
180static int collect_tracks_callback(const char *track,
181 struct kvp *data,
182 struct kvp *prefs,
183 void attribute((unused)) *u,
184 DB_TXN attribute((unused)) *tid) {
185 const unsigned long weight = compute_weight(track, data, prefs);
186
187 if(weight) {
188 struct weighted_track *const t = xmalloc(sizeof *t);
189
190 t->next = tracks;
191 t->track = track;
192 t->weight = weight;
193 tracks = t;
194 total_weight += weight;
195 ++ntracks;
196 }
197 return 0;
198}
199
200/** @brief Pick a random integer uniformly from [0, limit) */
201static unsigned long long pick_weight(unsigned long long limit) {
202 unsigned long long n;
203 static int fd = -1;
204 int r;
205
206 if(fd < 0) {
207 if((fd = open("/dev/urandom", O_RDONLY)) < 0)
208 fatal(errno, "opening /dev/urandom");
209 }
210 if((r = read(fd, &n, sizeof n)) < 0)
211 fatal(errno, "reading /dev/urandom");
212 if((size_t)r < sizeof n)
213 fatal(0, "short read from /dev/urandom");
214 return n % limit;
215}
216
217/** @brief Pick a track at random and write it to stdout */
218static void pick_track(void) {
219 long long w;
220 struct weighted_track *t;
221
222 w = pick_weight(total_weight);
223 t = tracks;
224 while(t && w >= t->weight) {
225 w -= t->weight;
226 t = t->next;
227 }
228 if(!t)
229 fatal(0, "ran out of tracks but %lld weighting left", w);
230 xprintf("%s", t->track);
231}
232
233int main(int argc, char **argv) {
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234 int n, logsyslog = !isatty(2), err;
235 const char *tags;
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236
237 set_progname(argv);
238 mem_init();
239 if(!setlocale(LC_CTYPE, "")) fatal(errno, "error calling setlocale");
240 while((n = getopt_long(argc, argv, "hVc:dDSs", options, 0)) >= 0) {
241 switch(n) {
242 case 'h': help();
243 case 'V': version("disorder-choose");
244 case 'c': configfile = optarg; break;
245 case 'd': debugging = 1; break;
246 case 'D': debugging = 0; break;
247 case 'S': logsyslog = 0; break;
248 case 's': logsyslog = 1; break;
249 default: fatal(0, "invalid option");
250 }
251 }
252 if(logsyslog) {
253 openlog(progname, LOG_PID, LOG_DAEMON);
254 log_default = &log_syslog;
255 }
256 if(config_read(0)) fatal(0, "cannot read configuration");
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257 /* Find out current queue/recent list */
258 queue_read();
259 recent_read();
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260 /* Generate the candidate track list */
261 trackdb_init(TRACKDB_NO_RECOVER);
262 trackdb_open(TRACKDB_NO_UPGRADE|TRACKDB_READ_ONLY);
263 global_tid = trackdb_begin_transaction();
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264 if((err = trackdb_get_global_tid("required-tags", global_tid, &tags)))
265 fatal(0, "error getting required-tags: %s", db_strerror(err));
266 required_tags = parsetags(tags);
267 if((err = trackdb_get_global_tid("prohibited-tags", global_tid, &tags)))
268 fatal(0, "error getting prohibited-tags: %s", db_strerror(err));
269 prohibited_tags = parsetags(tags);
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270 if(trackdb_scan(0, collect_tracks_callback, 0, global_tid))
271 exit(1);
272 trackdb_commit_transaction(global_tid);
273 trackdb_close();
274 trackdb_deinit();
275 //info("ntracks=%ld total_weight=%lld", ntracks, total_weight);
276 if(!total_weight)
277 fatal(0, "no tracks match random choice criteria");
278 /* Pick a track */
279 pick_track();
280 xfclose(stdout);
281 return 0;
282}
283
284/*
285Local Variables:
286c-basic-offset:2
287comment-column:40
288fill-column:79
289indent-tabs-mode:nil
290End:
291*/