drop_privileges_or_die(): Check return value of setuid().
[paraslash.git] / mood.c
1 /*
2 * Copyright (C) 2007-2009 Andre Noll <maan@systemlinux.org>
3 *
4 * Licensed under the GPL v2. For licencing details see COPYING.
5 */
6
7 /** \file mood.c Paraslash's mood handling functions. */
8
9 #include <fnmatch.h>
10 #include "para.h"
11 #include "error.h"
12 #include "string.h"
13 #include "afh.h"
14 #include "afs.h"
15 #include "list.h"
16 #include "ipc.h"
17
18 /**
19 * Contains statistical data of the currently admissible audio files.
20 *
21 * It is used to assign normalized score values to each admissible audio file.
22 */
23 struct afs_statistics {
24 /** Sum of num played over all admissible files. */
25 int64_t num_played_sum;
26 /** Sum of last played times over all admissible files. */
27 int64_t last_played_sum;
28 /** Quadratic deviation of num played time. */
29 int64_t num_played_qd;
30 /** Quadratic deviation of last played time. */
31 int64_t last_played_qd;
32 /** Number of admissible files */
33 unsigned num;
34 };
35 struct afs_statistics statistics;
36
37 /**
38 * Assign scores according to a mood_method.
39 *
40 * Each mood_method has its own mood_score_function. The first three parameters
41 * passed to that function are informations about the audio file whose score is
42 * to be computed. The data argument depends on the mood method this function
43 * is used for. It usually is the argument given at the end of a mood line.
44 *
45 * Mood score functions must return values between -100 and +100 inclusively.
46 * Boolean score functions should always return either -100 or +100.
47 *
48 * \sa struct mood_method, mood_parser.
49 */
50 typedef int mood_score_function(const char *path, const struct afs_info *afsi,
51 const struct afh_info *afhi, const void *data);
52
53 /**
54 * Pre-process a mood line.
55 *
56 * The mood_parser of a mood_method is called once at mood open time for each
57 * line of the current mood definition that contains the mood_method's name as
58 * a keyword. The line is passed to the mood_parser as the first argument. The
59 * mood_parser must determine whether the line is syntactically correct and
60 * return a positive value if so and a negative value otherwise.
61 *
62 * Some mood parsers pre-process the data given in the mood line to compute a
63 * structure which depends of the particular mood_method and which is used
64 * later in the mood_score_function of the mood_method. The mood_parser may
65 * store a pointer to its structure via the second argument.
66 *
67 * \sa mood_open(), mood_cleanup_function, mood_score_function.
68 */
69 typedef int mood_parser(const char *, void **);
70
71 /**
72 * Deallocate resources which were allocated by the mood_parser.
73 *
74 * This optional function of a mood_method is used to free any resources
75 * allocated in mood_open() by the mood_parser. The argument passed is a
76 * pointer to the mood_method specific data structure that was returned by the
77 * mood_parser.
78 *
79 * \sa mood_parser.
80 */
81 typedef void mood_cleanup_function(void *);
82
83 /**
84 * Used for scoring and to determine whether a file is admissible.
85 */
86 struct mood_method {
87 /** The name of the method. */
88 const char *name;
89 /** Pointer to the mood parser. */
90 mood_parser *parser;
91 /** Pointer to the score function */
92 mood_score_function *score_function;
93 /** Optional cleanup function. */
94 mood_cleanup_function *cleanup;
95 };
96
97 /**
98 * Each line of the current mood corresponds to a mood_item.
99 */
100 struct mood_item {
101 /** The method this line is referring to. */
102 const struct mood_method *method;
103 /** The data structure computed by the mood parser. */
104 void *parser_data;
105 /** The given score value, or zero if none was given. */
106 int32_t score_arg;
107 /** Non-zero if random scoring was requested. */
108 int random_score;
109 /** Whether the "not" keyword was given in the mood line. */
110 int logical_not;
111 /** The position in the list of items. */
112 struct list_head mood_item_node;
113 };
114
115 /**
116 * Created from the mood definition by mood_open().
117 *
118 * When a mood is opened, each line of its definition is investigated, and a
119 * corresponding mood item is produced. Each mood line starts with \p accept,
120 * \p deny, or \p score which determines the type of the mood line. For each
121 * such type a linked list is maintained whose entries are the mood items.
122 *
123 * \sa mood_item, mood_open().
124 */
125 struct mood {
126 /** The name of this mood. */
127 char *name;
128 /** The list of mood items of type \p accept. */
129 struct list_head accept_list;
130 /** The list of mood items of type \p deny. */
131 struct list_head deny_list;
132 /** The list of mood items of type \p score. */
133 struct list_head score_list;
134 };
135
136 static struct mood *current_mood;
137
138 /**
139 * Rough approximation to sqrt.
140 *
141 * \param x Integer of which to calculate the sqrt.
142 *
143 * \return An integer res with res * res <= x.
144 */
145 static uint64_t int_sqrt(uint64_t x)
146 {
147 uint64_t op, res, one = 1;
148 op = x;
149 res = 0;
150
151 one = one << 62;
152 while (one > op)
153 one >>= 2;
154
155 while (one != 0) {
156 if (op >= res + one) {
157 op = op - (res + one);
158 res = res + 2 * one;
159 }
160 res /= 2;
161 one /= 4;
162 }
163 // PARA_NOTICE_LOG("sqrt(%llu) = %llu\n", x, res);
164 return res;
165 }
166
167 static int mm_no_attributes_set_parser(const char *arg, __a_unused void **ignored)
168 {
169 if (arg && *arg)
170 PARA_WARNING_LOG("ignored junk at eol: %s\n", arg);
171 return 1;
172 }
173
174 static int mm_no_attributes_set_score_function(__a_unused const char *path,
175 const struct afs_info *afsi,
176 __a_unused const struct afh_info *afhi,
177 __a_unused const void *data)
178 {
179 if (!afsi->attributes)
180 return 100;
181 return -100;
182 }
183
184 static int mm_played_rarely_score_function(__a_unused const char *path,
185 const struct afs_info *afsi,
186 __a_unused const struct afh_info *afhi,
187 __a_unused const void *data)
188 {
189 unsigned num;
190 int ret = get_num_admissible_files(&num);
191
192 if (ret < 0)
193 return 0;
194 if (statistics.num_played_sum - num * afsi->num_played
195 > int_sqrt(statistics.num_played_qd * num))
196 return 100;
197 return -100;
198 }
199
200 static int mm_played_rarely_parser(const char *arg, __a_unused void **ignored)
201 {
202 if (arg && *arg)
203 PARA_WARNING_LOG("ignored junk at eol: %s\n", arg);
204 return 1;
205 }
206
207 static int mm_path_matches_score_function(const char *path,
208 __a_unused const struct afs_info *afsi,
209 __a_unused const struct afh_info *afhi,
210 const void *data)
211 {
212 if (fnmatch(data, path, 0))
213 return -100;
214 return 100;
215 }
216
217 static int mm_path_matches_parser(const char *arg, void **data)
218 {
219 *data = para_strdup(arg);
220 return 1;
221 }
222
223 static void mm_path_matches_cleanup(void *data)
224 {
225 free(data);
226 }
227
228 static int mm_is_set_parser(const char *arg, void **bitnum)
229 {
230 unsigned char *c = para_malloc(1);
231 int ret = get_attribute_bitnum_by_name(arg, c);
232
233 if (ret >= 0)
234 *bitnum = c;
235 else
236 free(c);
237 return ret;
238 }
239
240 static int mm_is_set_score_function(__a_unused const char *path,
241 __a_unused const struct afs_info *afsi,
242 __a_unused const struct afh_info *afhi,
243 const void *data)
244 {
245 const unsigned char *bn = data;
246 if (afsi->attributes & (1ULL << *bn))
247 return 100;
248 return -100;
249 }
250
251 /* returns 1 if row matches score item, 0 if not, negative on errors */
252 static int get_item_score(const struct osl_row *row, struct mood_item *item,
253 long *score, long *score_arg_sum)
254 {
255 struct afs_info afsi;
256 struct afh_info afhi;
257 char *path;
258 int ret, match = 1;
259
260 *score_arg_sum += item->random_score? 100 : PARA_ABS(item->score_arg);
261 ret = 100;
262 if (item->method) {
263 ret = get_afsi_of_row(row, &afsi);
264 if (ret< 0)
265 return ret;
266 ret = get_afhi_of_row(row, &afhi);
267 if (ret< 0)
268 return ret;
269 free(afhi.info_string); /* don't need the tag info */
270 ret = get_audio_file_path_of_row(row, &path);
271 if (ret< 0)
272 return ret;
273 ret = item->method->score_function(path, &afsi, &afhi,
274 item->parser_data);
275 if ((ret < 0 && !item->logical_not) || (ret >= 0 && item->logical_not))
276 match = 0; /* no match */
277 }
278 if (item->random_score)
279 *score = PARA_ABS(ret) * para_random(100);
280 else
281 *score = PARA_ABS(ret) * item->score_arg;
282 return match;
283 }
284
285 /* returns 1 if row admissible, 0 if not, negative on errors */
286 static int compute_mood_score(const struct osl_row *aft_row, struct mood *m,
287 long *result)
288 {
289 struct mood_item *item;
290 int ret, match = 0;
291 long score_arg_sum = 0, score = 0, item_score;
292
293 if (!m)
294 return -E_NO_MOOD;
295 /* reject audio file if it matches any entry in the deny list */
296 list_for_each_entry(item, &m->deny_list, mood_item_node) {
297 ret = get_item_score(aft_row, item, &item_score,
298 &score_arg_sum);
299 if (ret < 0)
300 return ret;
301 if (ret > 0) /* not admissible */
302 return 0;
303 score += item_score;
304 }
305 list_for_each_entry(item, &m->accept_list, mood_item_node) {
306 ret = get_item_score(aft_row, item, &item_score,
307 &score_arg_sum);
308 if (ret < 0)
309 return ret;
310 if (ret == 0)
311 continue;
312 match = 1;
313 score += item_score;
314 }
315 /* reject if there is no matching entry in the accept list */
316 if (!match && !list_empty(&m->accept_list))
317 return 0;
318 list_for_each_entry(item, &m->score_list, mood_item_node) {
319 ret = get_item_score(aft_row, item, &item_score,
320 &score_arg_sum);
321 if (ret < 0)
322 return ret;
323 score += item_score;
324 }
325 if (score_arg_sum)
326 score /= score_arg_sum;
327 *result = score;
328 return 1;
329 }
330
331 #define DEFINE_MOOD_METHOD(_name) \
332 .parser = mm_ ## _name ## _parser, \
333 .score_function = mm_ ## _name ## _score_function, \
334 .name = #_name
335
336 #define DEFINE_MOOD_METHOD_WITH_CLEANUP(_name) \
337 DEFINE_MOOD_METHOD(_name), \
338 .cleanup = mm_ ## _name ## _cleanup
339
340 static const struct mood_method mood_methods[] = {
341 {DEFINE_MOOD_METHOD(no_attributes_set)},
342 {DEFINE_MOOD_METHOD(played_rarely)},
343 {DEFINE_MOOD_METHOD(is_set)},
344 {DEFINE_MOOD_METHOD_WITH_CLEANUP(path_matches)},
345 {.parser = NULL}
346 };
347
348 static void cleanup_list_entry(struct mood_item *item)
349 {
350 if (item->method && item->method->cleanup)
351 item->method->cleanup(item->parser_data);
352 else
353 free(item->parser_data);
354 list_del(&item->mood_item_node);
355 free(item);
356 }
357
358 static void destroy_mood(struct mood *m)
359 {
360 struct mood_item *tmp, *item;
361
362 if (!m)
363 return;
364 list_for_each_entry_safe(item, tmp, &m->accept_list, mood_item_node)
365 cleanup_list_entry(item);
366 list_for_each_entry_safe(item, tmp, &m->deny_list, mood_item_node)
367 cleanup_list_entry(item);
368 list_for_each_entry_safe(item, tmp, &m->score_list, mood_item_node)
369 cleanup_list_entry(item);
370 free(m->name);
371 free(m);
372 }
373
374 static struct mood *alloc_new_mood(const char *name)
375 {
376 struct mood *m = para_calloc(sizeof(struct mood));
377 m->name = para_strdup(name);
378 INIT_LIST_HEAD(&m->accept_list);
379 INIT_LIST_HEAD(&m->deny_list);
380 INIT_LIST_HEAD(&m->score_list);
381 return m;
382 }
383
384 /** The different types of a mood line. */
385 enum mood_line_type {
386 /** Invalid. */
387 ML_INVALID,
388 /** Accept line. */
389 ML_ACCEPT,
390 /** Deny line. */
391 ML_DENY,
392 /** Score line. */
393 ML_SCORE
394 };
395
396 /** Data passed to the parser of a mood line. */
397 struct mood_line_parser_data {
398 /** The mood this mood line belongs to. */
399 struct mood *m;
400 /** The line number in the mood definition. */
401 unsigned line_num;
402 };
403
404 /*
405 * <accept [with score <score>] | deny [with score <score>] | score <score>>
406 * [if] [not] <mood_method> [options]
407 * <score> is either an integer or "random" which assigns a random score to
408 * all matching files
409 */
410
411 static int parse_mood_line(char *mood_line, void *data)
412 {
413 struct mood_line_parser_data *mlpd = data;
414 char **argv;
415 char *delim = " \t";
416 unsigned num_words;
417 char **w;
418 int i, ret;
419 enum mood_line_type mlt = ML_INVALID;
420 struct mood_item *mi = NULL;
421 char *buf = para_strdup(mood_line);
422
423 mlpd->line_num++;
424 num_words = split_args(buf, &argv, delim);
425 ret = 1;
426 if (!num_words) /* empty line */
427 goto out;
428 w = argv;
429 if (**w == '#') /* comment */
430 goto out;
431 if (!strcmp(*w, "accept"))
432 mlt = ML_ACCEPT;
433 else if (!strcmp(*w, "deny"))
434 mlt = ML_DENY;
435 else if (!strcmp(*w, "score"))
436 mlt = ML_SCORE;
437 ret = -E_MOOD_SYNTAX;
438 if (mlt == ML_INVALID)
439 goto out;
440 mi = para_calloc(sizeof(struct mood_item));
441 if (mlt != ML_SCORE) {
442 ret = -E_MOOD_SYNTAX;
443 w++;
444 if (!*w)
445 goto out;
446 if (strcmp(*w, "with"))
447 goto check_for_if;
448 w++;
449 if (!*w)
450 goto out;
451 if (strcmp(*w, "score"))
452 goto out;
453 }
454 if (mlt == ML_SCORE || !strcmp(*w, "score")) {
455 ret = -E_MOOD_SYNTAX;
456 w++;
457 if (!*w)
458 goto out;
459 if (strcmp(*w, "random")) {
460 mi->random_score = 0;
461 ret = para_atoi32(*w, &mi->score_arg);
462 if (ret < 0)
463 goto out;
464 } else {
465 mi->random_score = 1;
466 if (!*(w + 1))
467 goto success; /* the line "score random" is valid */
468 }
469 } else
470 mi->score_arg = 0;
471 ret = -E_MOOD_SYNTAX;
472 w++;
473 if (!*w)
474 goto out;
475 check_for_if:
476 if (!strcmp(*w, "if")) {
477 ret = -E_MOOD_SYNTAX;
478 w++;
479 if (!*w)
480 goto out;
481 }
482 if (!strcmp(*w, "not")) {
483 ret = -E_MOOD_SYNTAX;
484 w++;
485 if (!*w)
486 goto out;
487 mi->logical_not = 1;
488 } else
489 mi->logical_not = 0;
490 for (i = 0; mood_methods[i].parser; i++) {
491 if (strcmp(*w, mood_methods[i].name))
492 continue;
493 break;
494 }
495 ret = -E_MOOD_SYNTAX;
496 if (!mood_methods[i].parser)
497 goto out;
498 w++;
499 ret = mood_methods[i].parser(*w, &mi->parser_data);
500 if (ret < 0)
501 goto out;
502 mi->method = &mood_methods[i];
503 success:
504 if (mlpd->m) {
505 if (mlt == ML_ACCEPT)
506 para_list_add(&mi->mood_item_node, &mlpd->m->accept_list);
507 else if (mlt == ML_DENY)
508 para_list_add(&mi->mood_item_node, &mlpd->m->deny_list);
509 else
510 para_list_add(&mi->mood_item_node, &mlpd->m->score_list);
511 }
512 PARA_DEBUG_LOG("%s entry added, method: %p\n", mlt == ML_ACCEPT? "accept" :
513 (mlt == ML_DENY? "deny" : "score"), mi->method);
514 ret = 1;
515 out:
516 free(argv);
517 free(buf);
518 if (ret >= 0)
519 return ret;
520 if (mi) {
521 free(mi->parser_data);
522 free(mi);
523 }
524 return ret;
525 }
526
527 static int load_mood(const struct osl_row *mood_row, struct mood **m)
528 {
529 char *mood_name;
530 struct osl_object mood_def;
531 struct mood_line_parser_data mlpd = {.line_num = 0};
532 int ret = mood_get_name_and_def_by_row(mood_row, &mood_name, &mood_def);
533
534 if (ret < 0)
535 return ret;
536 if (!*mood_name)
537 return -E_DUMMY_ROW;
538 mlpd.m = alloc_new_mood(mood_name);
539 ret = for_each_line_ro(mood_def.data, mood_def.size,
540 parse_mood_line, &mlpd);
541 osl_close_disk_object(&mood_def);
542 if (ret < 0) {
543 PARA_ERROR_LOG("unable to load mood %s: %s\n", mlpd.m->name,
544 para_strerror(-ret));
545 destroy_mood(mlpd.m);
546 return ret;
547 }
548 *m = mlpd.m;
549 return 1;
550 }
551
552 static int check_mood(struct osl_row *mood_row, void *data)
553 {
554 struct para_buffer *pb = data;
555 char *mood_name;
556 struct osl_object mood_def;
557 struct mood_line_parser_data mlpd = {.line_num = 0};
558
559 int ret = mood_get_name_and_def_by_row(mood_row, &mood_name, &mood_def);
560
561 if (ret < 0) {
562 para_printf(pb, "failed to get mood definition: %s\n",
563 para_strerror(-ret));
564 return ret;
565 }
566 if (!*mood_name) /* ignore dummy row */
567 goto out;
568 ret = para_printf(pb, "checking mood %s...\n", mood_name);
569 if (ret < 0)
570 goto out;
571 ret = for_each_line_ro(mood_def.data, mood_def.size,
572 parse_mood_line, &mlpd);
573 if (ret < 0)
574 para_printf(pb, "%s line %u: %s\n", mood_name, mlpd.line_num,
575 para_strerror(-ret));
576 out:
577 osl_close_disk_object(&mood_def);
578 return ret;
579 }
580
581 /**
582 * Check all moods for syntax errors.
583 *
584 * \param fd The afs socket.
585 * \param query Unused.
586 */
587 void mood_check_callback(int fd, __a_unused const struct osl_object *query)
588 {
589 struct para_buffer pb = {
590 .max_size = SHMMAX,
591 .private_data = &fd,
592 .max_size_handler = pass_buffer_as_shm
593 };
594
595 int ret = para_printf(&pb, "checking moods...\n");
596 if (ret < 0)
597 return;
598 osl_rbtree_loop(moods_table, BLOBCOL_ID, &pb,
599 check_mood);
600 if (pb.offset)
601 pass_buffer_as_shm(pb.buf, pb.offset, &fd);
602 free(pb.buf);
603 }
604
605 #if 0
606 static unsigned int_log2(uint64_t x)
607 {
608 unsigned res = 0;
609
610 while (x) {
611 x /= 2;
612 res++;
613 }
614 return res;
615 }
616 #endif
617
618 static int64_t normalized_value(int64_t x, int64_t n, int64_t sum, int64_t qd)
619 {
620 if (!n || !qd)
621 return 0;
622 return 100 * (n * x - sum) / (int64_t)int_sqrt(n * qd);
623 }
624
625 static long compute_num_played_score(struct afs_info *afsi)
626 {
627 return -normalized_value(afsi->num_played, statistics.num,
628 statistics.num_played_sum, statistics.num_played_qd);
629 }
630
631 static long compute_last_played_score(struct afs_info *afsi)
632 {
633 return -normalized_value(afsi->last_played, statistics.num,
634 statistics.last_played_sum, statistics.last_played_qd);
635 }
636
637 static long compute_dynamic_score(const struct osl_row *aft_row)
638 {
639 struct afs_info afsi;
640 int64_t score, nscore = 0, lscore = 0;
641 int ret;
642
643 ret = get_afsi_of_row(aft_row, &afsi);
644 if (ret < 0)
645 return -100;
646 nscore = compute_num_played_score(&afsi);
647 lscore = compute_last_played_score(&afsi);
648 score = nscore + lscore;
649 return score;
650 }
651
652 static int add_afs_statistics(const struct osl_row *row)
653 {
654 uint64_t n, x, s;
655 struct afs_info afsi;
656 int ret;
657
658 ret = get_afsi_of_row(row, &afsi);
659 if (ret < 0)
660 return ret;
661 n = statistics.num;
662 x = afsi.last_played;
663 s = statistics.last_played_sum;
664 if (n > 0)
665 statistics.last_played_qd += (x - s / n) * (x - s / n) * n / (n + 1);
666 statistics.last_played_sum += x;
667
668 x = afsi.num_played;
669 s = statistics.num_played_sum;
670 if (n > 0)
671 statistics.num_played_qd += (x - s / n) * (x - s / n) * n / (n + 1);
672 statistics.num_played_sum += x;
673 statistics.num++;
674 return 1;
675 }
676
677 static int del_afs_statistics(const struct osl_row *row)
678 {
679 uint64_t n, s, q, a, new_s;
680 struct afs_info afsi;
681 int ret;
682 ret = get_afsi_of_row(row, &afsi);
683 if (ret < 0)
684 return ret;
685 n = statistics.num;
686 assert(n);
687 if (n == 1) {
688 memset(&statistics, 0, sizeof(statistics));
689 return 1;
690 }
691
692 s = statistics.last_played_sum;
693 q = statistics.last_played_qd;
694 a = afsi.last_played;
695 new_s = s - a;
696 statistics.last_played_sum = new_s;
697 statistics.last_played_qd = q + s * s / n - a * a
698 - new_s * new_s / (n - 1);
699
700 s = statistics.num_played_sum;
701 q = statistics.num_played_qd;
702 a = afsi.num_played;
703 new_s = s - a;
704 statistics.num_played_sum = new_s;
705 statistics.num_played_qd = q + s * s / n - a * a
706 - new_s * new_s / (n - 1);
707
708 statistics.num--;
709 return 1;
710 }
711
712 /**
713 * Structure used during mood_open().
714 *
715 * At mood open time, we look at each file in the audio file table in order to
716 * determine whether it is admissible. If a file happens to be admissible, its
717 * mood score is computed by calling each relevant mood_score_function. Next,
718 * we update the afs_statistics and add a struct admissible_file_info to a
719 * temporary array.
720 *
721 * If all files have been processed that way, the final score of each
722 * admissible file is computed by adding the dynamic score (which depends on
723 * the afs_statistics) to the mood score. Finally, all audio files in the
724 * array are added to the score table and the admissible array is freed.
725 *
726 * \sa mood_method, admissible_array.
727 */
728 struct admissible_file_info
729 {
730 /** The admissible audio file. */
731 struct osl_row *aft_row;
732 /** Its score. */
733 long score;
734 };
735
736 /** The temporary array of admissible files. */
737 struct admissible_array {
738 /** Files are admissible wrt. this mood. */
739 struct mood *m;
740 /** The size of the array */
741 unsigned size;
742 /** Pointer to the array of admissible files. */
743 struct admissible_file_info *array;
744 };
745
746 /**
747 * Add an entry to the array of admissible files.
748 *
749 * \param aft_row The audio file to be added.
750 * \param private_data Pointer to a struct admissible_file_info.
751 *
752 * \return 1 if row admissible, 0 if not, negative on errors.
753 */
754 static int add_if_admissible(struct osl_row *aft_row, void *data)
755 {
756 struct admissible_array *aa = data;
757 int ret;
758 long score = 0;
759
760 ret = compute_mood_score(aft_row, aa->m, &score);
761 if (ret <= 0)
762 return ret;
763 if (statistics.num >= aa->size) {
764 aa->size *= 2;
765 aa->size += 100;
766 aa->array = para_realloc(aa->array,
767 aa->size * sizeof(struct admissible_file_info));
768 }
769 aa->array[statistics.num].aft_row = aft_row;
770 aa->array[statistics.num].score = score;
771 ret = add_afs_statistics(aft_row);
772 if (ret < 0)
773 return ret;
774 return 1;
775 }
776
777 /**
778 * Compute the new quadratic deviation in case one element changes.
779 *
780 * \param n Number of elements.
781 * \param old_qd The quadratic deviation before the change.
782 * \param old_val The value that was replaced.
783 * \param new_val The replacement value.
784 * \param old_sum The sum of all elements before the update.
785 *
786 * \return The new quadratic deviation resulting from replacing old_val
787 * by new_val.
788 *
789 * Given n real numbers a_1, ..., a_n, their sum S = a_1 + ... + a_n,
790 * their quadratic deviation
791 *
792 * q = (a_1 - S/n)^2 + ... + (a_n - S/n)^2,
793 *
794 * and a real number b, the quadratic deviation q' of a_1,...a_{n-1}, b (ie.
795 * the last number a_n was replaced by b) may be computed in O(1) time in terms
796 * of n, q, a_n, b, and S as
797 *
798 * q' = q + d * s - (2 * S + d) * d / n,
799 *
800 * where d = b - a_n, and s = b + a_n.
801 *
802 * Example: n = 3, a_1 = 3, a_2 = 5, a_3 = 7, b = 10. Then S = 15, q = 8, d = 3,
803 * s = 17, so
804 *
805 * q + d * s - (2 * S + d) * d / n = 8 + 51 - 33 = 26,
806 *
807 * which equals q' = (3 - 6)^2 + (5 - 6)^2 + (10 - 6)^2.
808 *
809 */
810 _static_inline_ int64_t update_quadratic_deviation(int64_t n, int64_t old_qd,
811 int64_t old_val, int64_t new_val, int64_t old_sum)
812 {
813 int64_t delta = new_val - old_val;
814 int64_t sigma = new_val + old_val;
815 return old_qd + delta * sigma - (2 * old_sum + delta) * delta / n;
816 }
817
818 static int update_afs_statistics(struct afs_info *old_afsi, struct afs_info *new_afsi)
819 {
820 unsigned n;
821 int ret = get_num_admissible_files(&n);
822
823 if (ret < 0)
824 return ret;
825 assert(n);
826
827 statistics.last_played_qd = update_quadratic_deviation(n,
828 statistics.last_played_qd, old_afsi->last_played,
829 new_afsi->last_played, statistics.last_played_sum);
830 statistics.last_played_sum += new_afsi->last_played - old_afsi->last_played;
831
832 statistics.num_played_qd = update_quadratic_deviation(n,
833 statistics.num_played_qd, old_afsi->num_played,
834 new_afsi->num_played, statistics.num_played_sum);
835 statistics.num_played_sum += new_afsi->num_played - old_afsi->num_played;
836 return 1;
837 }
838
839 static int add_to_score_table(const struct osl_row *aft_row, long mood_score)
840 {
841 long score = (compute_dynamic_score(aft_row) + mood_score) / 3;
842 return score_add(aft_row, score);
843 }
844
845 static int delete_from_statistics_and_score_table(const struct osl_row *aft_row)
846 {
847 int ret = del_afs_statistics(aft_row);
848 if (ret < 0)
849 return ret;
850 return score_delete(aft_row);
851 }
852
853 /**
854 * Delete one entry from the statistics and from the score table.
855 *
856 * \param aft_row The audio file which is no longer admissible.
857 *
858 * \return Positive on success, negative on errors.
859 *
860 * \sa score_delete().
861 */
862 static int mood_delete_audio_file(const struct osl_row *aft_row)
863 {
864 int ret;
865
866 ret = row_belongs_to_score_table(aft_row, NULL);
867 if (ret < 0)
868 return ret;
869 if (!ret) /* not admissible, nothing to do */
870 return 1;
871 return delete_from_statistics_and_score_table(aft_row);
872 }
873
874 /**
875 * Compute the new score of an audio file wrt. the current mood.
876 *
877 * \param aft_row Determines the audio file.
878 * \param old_afsi The audio file selector info before updating.
879 *
880 * The \a old_afsi argument may be \p NULL which indicates that no changes to
881 * the audio file info were made.
882 *
883 * \return Positive on success, negative on errors.
884 */
885 static int mood_update_audio_file(const struct osl_row *aft_row,
886 struct afs_info *old_afsi)
887 {
888 long score, percent;
889 int ret, is_admissible, was_admissible = 0;
890 struct afs_info afsi;
891 unsigned rank;
892
893 if (!current_mood)
894 return 1; /* nothing to do */
895 ret = row_belongs_to_score_table(aft_row, &rank);
896 if (ret < 0)
897 return ret;
898 was_admissible = ret;
899 ret = compute_mood_score(aft_row, current_mood, &score);
900 if (ret < 0)
901 return ret;
902 is_admissible = (ret > 0);
903 if (!was_admissible && !is_admissible)
904 return 1;
905 if (was_admissible && !is_admissible)
906 return delete_from_statistics_and_score_table(aft_row);
907 if (!was_admissible && is_admissible) {
908 ret = add_afs_statistics(aft_row);
909 if (ret < 0)
910 return ret;
911 return add_to_score_table(aft_row, score);
912 }
913 /* update score */
914 ret = get_afsi_of_row(aft_row, &afsi);
915 if (ret < 0)
916 return ret;
917 if (old_afsi) {
918 ret = update_afs_statistics(old_afsi, &afsi);
919 if (ret < 0)
920 return ret;
921 }
922 score += compute_num_played_score(&afsi);
923 score += compute_last_played_score(&afsi);
924 score /= 3;
925 PARA_DEBUG_LOG("score: %li\n", score);
926 percent = (score + 100) / 3;
927 if (percent > 100)
928 percent = 100;
929 else if (percent < 0)
930 percent = 0;
931 PARA_DEBUG_LOG("moving from rank %u to %lu%%\n", rank, percent);
932 return score_update(aft_row, percent);
933 }
934
935 static void log_statistics(void)
936 {
937 unsigned n = statistics.num;
938
939 if (!n) {
940 PARA_NOTICE_LOG("no admissible files\n");
941 return;
942 }
943 PARA_INFO_LOG("last_played mean: %lli, last_played sigma: %llu\n",
944 (long long int)(statistics.last_played_sum / n),
945 (long long unsigned)int_sqrt(statistics.last_played_qd / n));
946 PARA_INFO_LOG("num_played mean: %lli, num_played sigma: %llu\n",
947 (long long int)statistics.num_played_sum / n,
948 (long long unsigned)int_sqrt(statistics.num_played_qd / n));
949 }
950
951 /**
952 * Close the current mood.
953 *
954 * Free all resources of the current mood which were allocated during
955 * mood_open().
956 */
957 void close_current_mood(void)
958 {
959 destroy_mood(current_mood);
960 current_mood = NULL;
961 memset(&statistics, 0, sizeof(statistics));
962 }
963
964
965 /**
966 * Change the current mood.
967 *
968 * \param mood_name The name of the mood to open.
969 *
970 * If \a mood_name is \a NULL, load the dummy mood that accepts every audio file
971 * and uses a scoring method based only on the \a last_played information.
972 *
973 * If there is already an open mood, it will be closed first.
974 *
975 * \return Positive on success, negative on errors. Loading the dummy mood
976 * always succeeds.
977 *
978 * \sa struct admissible_file_info, struct admissible_array, struct
979 * afs_info::last_played, mood_close().
980 */
981 int change_current_mood(char *mood_name)
982 {
983 int i, ret;
984 struct admissible_array aa = {
985 .size = 0,
986 .array = NULL
987 };
988
989 if (mood_name) {
990 struct mood *m;
991 struct osl_row *row;
992 struct osl_object obj = {
993 .data = mood_name,
994 .size = strlen(mood_name) + 1
995 };
996 ret = osl_get_row(moods_table, BLOBCOL_NAME, &obj, &row);
997 if (ret < 0) {
998 PARA_NOTICE_LOG("no such mood: %s\n", mood_name);
999 return ret;
1000 }
1001 ret = load_mood(row, &m);
1002 if (ret < 0)
1003 return ret;
1004 close_current_mood();
1005 current_mood = m;
1006 } else {
1007 close_current_mood();
1008 current_mood = alloc_new_mood("dummy");
1009 }
1010 aa.m = current_mood;
1011 PARA_NOTICE_LOG("computing statistics of admissible files\n");
1012 ret = audio_file_loop(&aa, add_if_admissible);
1013 if (ret < 0)
1014 return ret;
1015 log_statistics();
1016 PARA_INFO_LOG("%d admissible files \n", statistics.num);
1017 for (i = 0; i < statistics.num; i++) {
1018 struct admissible_file_info *a = aa.array + i;
1019 ret = add_to_score_table(a->aft_row, a->score);
1020 if (ret < 0)
1021 goto out;
1022 }
1023 PARA_NOTICE_LOG("loaded mood %s\n", current_mood->name);
1024 ret = statistics.num;
1025 out:
1026 free(aa.array);
1027 return ret;
1028 }
1029 /**
1030 * Close and re-open the current mood.
1031 *
1032 * This function is used if changes to the audio file table or the
1033 * attribute table were made that render the current list of admissible
1034 * files useless. For example, if an attribute is removed from the
1035 * attribute table, this function is called.
1036 *
1037 * \return Positive on success, negative on errors. If no mood is currently
1038 * open, the function returns success.
1039 *
1040 * \sa mood_open(), mood_close().
1041 */
1042 int reload_current_mood(void)
1043 {
1044 int ret;
1045 char *mood_name = NULL;
1046
1047 if (!current_mood)
1048 return 1;
1049 PARA_NOTICE_LOG("reloading %s\n", current_mood->name?
1050 current_mood->name : "(dummy)");
1051 if (current_mood->name)
1052 mood_name = para_strdup(current_mood->name);
1053 close_current_mood();
1054 ret = change_current_mood(mood_name);
1055 free(mood_name);
1056 return ret;
1057 }
1058
1059 int moods_event_handler(enum afs_events event, __a_unused struct para_buffer *pb,
1060 void *data)
1061 {
1062 if (!current_mood)
1063 return 0;
1064 switch (event) {
1065 /*
1066 * The three blob events might change the set of admissible files,
1067 * so we must reload the score list.
1068 */
1069 case BLOB_RENAME:
1070 case BLOB_REMOVE:
1071 case BLOB_ADD:
1072 if (data == moods_table || data == playlists_table)
1073 return 1; /* no reload necessary for these */
1074 return reload_current_mood();
1075 /* these also require reload of the score table */
1076 case ATTRIBUTE_ADD:
1077 case ATTRIBUTE_REMOVE:
1078 case ATTRIBUTE_RENAME:
1079 return reload_current_mood();
1080 /* changes to the aft only require to re-examine the audio file */
1081 case AFSI_CHANGE: {
1082 struct afsi_change_event_data *aced = data;
1083 return mood_update_audio_file(aced->aft_row, aced->old_afsi);
1084 }
1085 case AFHI_CHANGE:
1086 case AUDIO_FILE_RENAME:
1087 case AUDIO_FILE_ADD:
1088 return mood_update_audio_file(data, NULL);
1089 case AUDIO_FILE_REMOVE:
1090 return mood_delete_audio_file(data);
1091 default:
1092 return 1;
1093 }
1094 }
1095