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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> |
bea6f6d5 RK |
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" |
bea6f6d5 RK |
56 | |
57 | static DB_TXN *global_tid; | |
58 | ||
59 | static const struct option options[] = { | |
60 | { "help", no_argument, 0, 'h' }, | |
61 | { "version", no_argument, 0, 'V' }, | |
62 | { "config", required_argument, 0, 'c' }, | |
63 | { "debug", no_argument, 0, 'd' }, | |
64 | { "no-debug", no_argument, 0, 'D' }, | |
65 | { "syslog", no_argument, 0, 's' }, | |
66 | { "no-syslog", no_argument, 0, 'S' }, | |
67 | { 0, 0, 0, 0 } | |
68 | }; | |
69 | ||
70 | /* display usage message and terminate */ | |
71 | static void help(void) { | |
72 | xprintf("Usage:\n" | |
73 | " disorder-choose [OPTIONS]\n" | |
74 | "Options:\n" | |
75 | " --help, -h Display usage message\n" | |
76 | " --version, -V Display version number\n" | |
77 | " --config PATH, -c PATH Set configuration file\n" | |
78 | " --debug, -d Turn on debugging\n" | |
79 | " --[no-]syslog Enable/disable logging to syslog\n" | |
80 | "\n" | |
81 | "Track choose for DisOrder. Not intended to be run\n" | |
82 | "directly.\n"); | |
83 | xfclose(stdout); | |
84 | exit(0); | |
85 | } | |
86 | ||
87 | /** @brief Weighted track record */ | |
88 | struct weighted_track { | |
89 | /** @brief Next track in the list */ | |
90 | struct weighted_track *next; | |
91 | /** @brief Track name */ | |
92 | const char *track; | |
93 | /** @brief Weight for this track (always positive) */ | |
94 | unsigned long weight; | |
95 | }; | |
96 | ||
97 | /** @brief List of tracks with nonzero weight */ | |
98 | static struct weighted_track *tracks; | |
99 | ||
100 | /** @brief Sum of all weights */ | |
101 | static unsigned long long total_weight; | |
102 | ||
103 | /** @brief Count of tracks */ | |
104 | static long ntracks; | |
105 | ||
91c9324a RK |
106 | static char **required_tags; |
107 | static char **prohibited_tags; | |
108 | ||
bea6f6d5 RK |
109 | /** @brief Compute the weight of a track |
110 | * @param track Track name (UTF-8) | |
111 | * @param data Track data | |
112 | * @param prefs Track preferences | |
113 | * @return Track weight (non-negative) | |
114 | * | |
115 | * Tracks to be excluded entirely are given a weight of 0. | |
116 | */ | |
91c9324a RK |
117 | static unsigned long compute_weight(const char *track, |
118 | struct kvp *data, | |
bea6f6d5 RK |
119 | struct kvp *prefs) { |
120 | const char *s; | |
91c9324a RK |
121 | char **track_tags; |
122 | time_t last, now; | |
123 | ||
124 | /* Reject tracks not in any collection (race between edit config and | |
125 | * rescan) */ | |
126 | if(!find_track_root(track)) { | |
127 | info("found track not in any collection: %s", track); | |
128 | return 0; | |
129 | } | |
bea6f6d5 | 130 | |
91c9324a RK |
131 | /* Reject aliases to avoid giving aliased tracks extra weight */ |
132 | if(kvp_get(data, "_alias_for")) | |
133 | return 0; | |
134 | ||
135 | /* Reject tracks with random play disabled */ | |
bea6f6d5 RK |
136 | if((s = kvp_get(prefs, "pick_at_random")) |
137 | && !strcmp(s, "0")) | |
138 | return 0; | |
91c9324a RK |
139 | |
140 | /* Reject tracks played within the last 8 hours */ | |
141 | if((s = kvp_get(prefs, "played_time"))) { | |
142 | last = atoll(s); | |
143 | now = time(0); | |
144 | if(now < last + 8 * 3600) /* TODO configurable */ | |
145 | return 0; | |
146 | } | |
147 | ||
148 | /* We'll need tags for a number of things */ | |
149 | track_tags = parsetags(kvp_get(prefs, "tags")); | |
150 | ||
151 | /* Reject tracks with prohibited tags */ | |
152 | if(prohibited_tags && tag_intersection(track_tags, prohibited_tags)) | |
153 | return 0; | |
154 | ||
155 | /* Reject tracks that lack required tags */ | |
156 | if(*required_tags && !tag_intersection(track_tags, required_tags)) | |
157 | return 0; | |
158 | ||
bea6f6d5 RK |
159 | return 90000; |
160 | } | |
161 | ||
162 | /** @brief Called for each track */ | |
163 | static int collect_tracks_callback(const char *track, | |
164 | struct kvp *data, | |
165 | struct kvp *prefs, | |
166 | void attribute((unused)) *u, | |
167 | DB_TXN attribute((unused)) *tid) { | |
168 | const unsigned long weight = compute_weight(track, data, prefs); | |
169 | ||
170 | if(weight) { | |
171 | struct weighted_track *const t = xmalloc(sizeof *t); | |
172 | ||
173 | t->next = tracks; | |
174 | t->track = track; | |
175 | t->weight = weight; | |
176 | tracks = t; | |
177 | total_weight += weight; | |
178 | ++ntracks; | |
179 | } | |
180 | return 0; | |
181 | } | |
182 | ||
183 | /** @brief Pick a random integer uniformly from [0, limit) */ | |
184 | static unsigned long long pick_weight(unsigned long long limit) { | |
185 | unsigned long long n; | |
186 | static int fd = -1; | |
187 | int r; | |
188 | ||
189 | if(fd < 0) { | |
190 | if((fd = open("/dev/urandom", O_RDONLY)) < 0) | |
191 | fatal(errno, "opening /dev/urandom"); | |
192 | } | |
193 | if((r = read(fd, &n, sizeof n)) < 0) | |
194 | fatal(errno, "reading /dev/urandom"); | |
195 | if((size_t)r < sizeof n) | |
196 | fatal(0, "short read from /dev/urandom"); | |
197 | return n % limit; | |
198 | } | |
199 | ||
200 | /** @brief Pick a track at random and write it to stdout */ | |
201 | static void pick_track(void) { | |
202 | long long w; | |
203 | struct weighted_track *t; | |
204 | ||
205 | w = pick_weight(total_weight); | |
206 | t = tracks; | |
207 | while(t && w >= t->weight) { | |
208 | w -= t->weight; | |
209 | t = t->next; | |
210 | } | |
211 | if(!t) | |
212 | fatal(0, "ran out of tracks but %lld weighting left", w); | |
213 | xprintf("%s", t->track); | |
214 | } | |
215 | ||
216 | int main(int argc, char **argv) { | |
91c9324a RK |
217 | int n, logsyslog = !isatty(2), err; |
218 | const char *tags; | |
bea6f6d5 RK |
219 | |
220 | set_progname(argv); | |
221 | mem_init(); | |
222 | if(!setlocale(LC_CTYPE, "")) fatal(errno, "error calling setlocale"); | |
223 | while((n = getopt_long(argc, argv, "hVc:dDSs", options, 0)) >= 0) { | |
224 | switch(n) { | |
225 | case 'h': help(); | |
226 | case 'V': version("disorder-choose"); | |
227 | case 'c': configfile = optarg; break; | |
228 | case 'd': debugging = 1; break; | |
229 | case 'D': debugging = 0; break; | |
230 | case 'S': logsyslog = 0; break; | |
231 | case 's': logsyslog = 1; break; | |
232 | default: fatal(0, "invalid option"); | |
233 | } | |
234 | } | |
235 | if(logsyslog) { | |
236 | openlog(progname, LOG_PID, LOG_DAEMON); | |
237 | log_default = &log_syslog; | |
238 | } | |
239 | if(config_read(0)) fatal(0, "cannot read configuration"); | |
240 | /* Generate the candidate track list */ | |
241 | trackdb_init(TRACKDB_NO_RECOVER); | |
242 | trackdb_open(TRACKDB_NO_UPGRADE|TRACKDB_READ_ONLY); | |
243 | global_tid = trackdb_begin_transaction(); | |
91c9324a RK |
244 | if((err = trackdb_get_global_tid("required-tags", global_tid, &tags))) |
245 | fatal(0, "error getting required-tags: %s", db_strerror(err)); | |
246 | required_tags = parsetags(tags); | |
247 | if((err = trackdb_get_global_tid("prohibited-tags", global_tid, &tags))) | |
248 | fatal(0, "error getting prohibited-tags: %s", db_strerror(err)); | |
249 | prohibited_tags = parsetags(tags); | |
bea6f6d5 RK |
250 | if(trackdb_scan(0, collect_tracks_callback, 0, global_tid)) |
251 | exit(1); | |
252 | trackdb_commit_transaction(global_tid); | |
253 | trackdb_close(); | |
254 | trackdb_deinit(); | |
255 | //info("ntracks=%ld total_weight=%lld", ntracks, total_weight); | |
256 | if(!total_weight) | |
257 | fatal(0, "no tracks match random choice criteria"); | |
258 | /* Pick a track */ | |
259 | pick_track(); | |
260 | xfclose(stdout); | |
261 | return 0; | |
262 | } | |
263 | ||
264 | /* | |
265 | Local Variables: | |
266 | c-basic-offset:2 | |
267 | comment-column:40 | |
268 | fill-column:79 | |
269 | indent-tabs-mode:nil | |
270 | End: | |
271 | */ |