gitweb: use new Git::Repo API, and add optional caching
[git/gitweb-caching.git] / date.c
blob35a52576c53e5e1406d40ed4402b8834a29b9f0e
1 /*
2 * GIT - The information manager from hell
4 * Copyright (C) Linus Torvalds, 2005
5 */
7 #include "cache.h"
9 /*
10 * This is like mktime, but without normalization of tm_wday and tm_yday.
12 time_t tm_to_time_t(const struct tm *tm)
14 static const int mdays[] = {
15 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334
17 int year = tm->tm_year - 70;
18 int month = tm->tm_mon;
19 int day = tm->tm_mday;
21 if (year < 0 || year > 129) /* algo only works for 1970-2099 */
22 return -1;
23 if (month < 0 || month > 11) /* array bounds */
24 return -1;
25 if (month < 2 || (year + 2) % 4)
26 day--;
27 return (year * 365 + (year + 1) / 4 + mdays[month] + day) * 24*60*60UL +
28 tm->tm_hour * 60*60 + tm->tm_min * 60 + tm->tm_sec;
31 static const char *month_names[] = {
32 "January", "February", "March", "April", "May", "June",
33 "July", "August", "September", "October", "November", "December"
36 static const char *weekday_names[] = {
37 "Sundays", "Mondays", "Tuesdays", "Wednesdays", "Thursdays", "Fridays", "Saturdays"
40 static time_t gm_time_t(unsigned long time, int tz)
42 int minutes;
44 minutes = tz < 0 ? -tz : tz;
45 minutes = (minutes / 100)*60 + (minutes % 100);
46 minutes = tz < 0 ? -minutes : minutes;
47 return time + minutes * 60;
51 * The "tz" thing is passed in as this strange "decimal parse of tz"
52 * thing, which means that tz -0100 is passed in as the integer -100,
53 * even though it means "sixty minutes off"
55 static struct tm *time_to_tm(unsigned long time, int tz)
57 time_t t = gm_time_t(time, tz);
58 return gmtime(&t);
62 * What value of "tz" was in effect back then at "time" in the
63 * local timezone?
65 static int local_tzoffset(unsigned long time)
67 time_t t, t_local;
68 struct tm tm;
69 int offset, eastwest;
71 t = time;
72 localtime_r(&t, &tm);
73 t_local = tm_to_time_t(&tm);
75 if (t_local < t) {
76 eastwest = -1;
77 offset = t - t_local;
78 } else {
79 eastwest = 1;
80 offset = t_local - t;
82 offset /= 60; /* in minutes */
83 offset = (offset % 60) + ((offset / 60) * 100);
84 return offset * eastwest;
87 const char *show_date(unsigned long time, int tz, enum date_mode mode)
89 struct tm *tm;
90 static char timebuf[200];
92 if (mode == DATE_RELATIVE) {
93 unsigned long diff;
94 struct timeval now;
95 gettimeofday(&now, NULL);
96 if (now.tv_sec < time)
97 return "in the future";
98 diff = now.tv_sec - time;
99 if (diff < 90) {
100 snprintf(timebuf, sizeof(timebuf), "%lu seconds ago", diff);
101 return timebuf;
103 /* Turn it into minutes */
104 diff = (diff + 30) / 60;
105 if (diff < 90) {
106 snprintf(timebuf, sizeof(timebuf), "%lu minutes ago", diff);
107 return timebuf;
109 /* Turn it into hours */
110 diff = (diff + 30) / 60;
111 if (diff < 36) {
112 snprintf(timebuf, sizeof(timebuf), "%lu hours ago", diff);
113 return timebuf;
115 /* We deal with number of days from here on */
116 diff = (diff + 12) / 24;
117 if (diff < 14) {
118 snprintf(timebuf, sizeof(timebuf), "%lu days ago", diff);
119 return timebuf;
121 /* Say weeks for the past 10 weeks or so */
122 if (diff < 70) {
123 snprintf(timebuf, sizeof(timebuf), "%lu weeks ago", (diff + 3) / 7);
124 return timebuf;
126 /* Say months for the past 12 months or so */
127 if (diff < 360) {
128 snprintf(timebuf, sizeof(timebuf), "%lu months ago", (diff + 15) / 30);
129 return timebuf;
131 /* Else fall back on absolute format.. */
134 if (mode == DATE_LOCAL)
135 tz = local_tzoffset(time);
137 tm = time_to_tm(time, tz);
138 if (!tm)
139 return NULL;
140 if (mode == DATE_SHORT)
141 sprintf(timebuf, "%04d-%02d-%02d", tm->tm_year + 1900,
142 tm->tm_mon + 1, tm->tm_mday);
143 else if (mode == DATE_ISO8601)
144 sprintf(timebuf, "%04d-%02d-%02d %02d:%02d:%02d %+05d",
145 tm->tm_year + 1900,
146 tm->tm_mon + 1,
147 tm->tm_mday,
148 tm->tm_hour, tm->tm_min, tm->tm_sec,
149 tz);
150 else if (mode == DATE_RFC2822)
151 sprintf(timebuf, "%.3s, %d %.3s %d %02d:%02d:%02d %+05d",
152 weekday_names[tm->tm_wday], tm->tm_mday,
153 month_names[tm->tm_mon], tm->tm_year + 1900,
154 tm->tm_hour, tm->tm_min, tm->tm_sec, tz);
155 else
156 sprintf(timebuf, "%.3s %.3s %d %02d:%02d:%02d %d%c%+05d",
157 weekday_names[tm->tm_wday],
158 month_names[tm->tm_mon],
159 tm->tm_mday,
160 tm->tm_hour, tm->tm_min, tm->tm_sec,
161 tm->tm_year + 1900,
162 (mode == DATE_LOCAL) ? 0 : ' ',
163 tz);
164 return timebuf;
168 * Check these. And note how it doesn't do the summer-time conversion.
170 * In my world, it's always summer, and things are probably a bit off
171 * in other ways too.
173 static const struct {
174 const char *name;
175 int offset;
176 int dst;
177 } timezone_names[] = {
178 { "IDLW", -12, 0, }, /* International Date Line West */
179 { "NT", -11, 0, }, /* Nome */
180 { "CAT", -10, 0, }, /* Central Alaska */
181 { "HST", -10, 0, }, /* Hawaii Standard */
182 { "HDT", -10, 1, }, /* Hawaii Daylight */
183 { "YST", -9, 0, }, /* Yukon Standard */
184 { "YDT", -9, 1, }, /* Yukon Daylight */
185 { "PST", -8, 0, }, /* Pacific Standard */
186 { "PDT", -8, 1, }, /* Pacific Daylight */
187 { "MST", -7, 0, }, /* Mountain Standard */
188 { "MDT", -7, 1, }, /* Mountain Daylight */
189 { "CST", -6, 0, }, /* Central Standard */
190 { "CDT", -6, 1, }, /* Central Daylight */
191 { "EST", -5, 0, }, /* Eastern Standard */
192 { "EDT", -5, 1, }, /* Eastern Daylight */
193 { "AST", -3, 0, }, /* Atlantic Standard */
194 { "ADT", -3, 1, }, /* Atlantic Daylight */
195 { "WAT", -1, 0, }, /* West Africa */
197 { "GMT", 0, 0, }, /* Greenwich Mean */
198 { "UTC", 0, 0, }, /* Universal (Coordinated) */
200 { "WET", 0, 0, }, /* Western European */
201 { "BST", 0, 1, }, /* British Summer */
202 { "CET", +1, 0, }, /* Central European */
203 { "MET", +1, 0, }, /* Middle European */
204 { "MEWT", +1, 0, }, /* Middle European Winter */
205 { "MEST", +1, 1, }, /* Middle European Summer */
206 { "CEST", +1, 1, }, /* Central European Summer */
207 { "MESZ", +1, 1, }, /* Middle European Summer */
208 { "FWT", +1, 0, }, /* French Winter */
209 { "FST", +1, 1, }, /* French Summer */
210 { "EET", +2, 0, }, /* Eastern Europe, USSR Zone 1 */
211 { "EEST", +2, 1, }, /* Eastern European Daylight */
212 { "WAST", +7, 0, }, /* West Australian Standard */
213 { "WADT", +7, 1, }, /* West Australian Daylight */
214 { "CCT", +8, 0, }, /* China Coast, USSR Zone 7 */
215 { "JST", +9, 0, }, /* Japan Standard, USSR Zone 8 */
216 { "EAST", +10, 0, }, /* Eastern Australian Standard */
217 { "EADT", +10, 1, }, /* Eastern Australian Daylight */
218 { "GST", +10, 0, }, /* Guam Standard, USSR Zone 9 */
219 { "NZT", +12, 0, }, /* New Zealand */
220 { "NZST", +12, 0, }, /* New Zealand Standard */
221 { "NZDT", +12, 1, }, /* New Zealand Daylight */
222 { "IDLE", +12, 0, }, /* International Date Line East */
225 static int match_string(const char *date, const char *str)
227 int i = 0;
229 for (i = 0; *date; date++, str++, i++) {
230 if (*date == *str)
231 continue;
232 if (toupper(*date) == toupper(*str))
233 continue;
234 if (!isalnum(*date))
235 break;
236 return 0;
238 return i;
241 static int skip_alpha(const char *date)
243 int i = 0;
244 do {
245 i++;
246 } while (isalpha(date[i]));
247 return i;
251 * Parse month, weekday, or timezone name
253 static int match_alpha(const char *date, struct tm *tm, int *offset)
255 int i;
257 for (i = 0; i < 12; i++) {
258 int match = match_string(date, month_names[i]);
259 if (match >= 3) {
260 tm->tm_mon = i;
261 return match;
265 for (i = 0; i < 7; i++) {
266 int match = match_string(date, weekday_names[i]);
267 if (match >= 3) {
268 tm->tm_wday = i;
269 return match;
273 for (i = 0; i < ARRAY_SIZE(timezone_names); i++) {
274 int match = match_string(date, timezone_names[i].name);
275 if (match >= 3) {
276 int off = timezone_names[i].offset;
278 /* This is bogus, but we like summer */
279 off += timezone_names[i].dst;
281 /* Only use the tz name offset if we don't have anything better */
282 if (*offset == -1)
283 *offset = 60*off;
285 return match;
289 if (match_string(date, "PM") == 2) {
290 tm->tm_hour = (tm->tm_hour % 12) + 12;
291 return 2;
294 if (match_string(date, "AM") == 2) {
295 tm->tm_hour = (tm->tm_hour % 12) + 0;
296 return 2;
299 /* BAD CRAP */
300 return skip_alpha(date);
303 static int is_date(int year, int month, int day, struct tm *now_tm, time_t now, struct tm *tm)
305 if (month > 0 && month < 13 && day > 0 && day < 32) {
306 struct tm check = *tm;
307 struct tm *r = (now_tm ? &check : tm);
308 time_t specified;
310 r->tm_mon = month - 1;
311 r->tm_mday = day;
312 if (year == -1) {
313 if (!now_tm)
314 return 1;
315 r->tm_year = now_tm->tm_year;
317 else if (year >= 1970 && year < 2100)
318 r->tm_year = year - 1900;
319 else if (year > 70 && year < 100)
320 r->tm_year = year;
321 else if (year < 38)
322 r->tm_year = year + 100;
323 else
324 return 0;
325 if (!now_tm)
326 return 1;
328 specified = tm_to_time_t(r);
330 /* Be it commit time or author time, it does not make
331 * sense to specify timestamp way into the future. Make
332 * sure it is not later than ten days from now...
334 if (now + 10*24*3600 < specified)
335 return 0;
336 tm->tm_mon = r->tm_mon;
337 tm->tm_mday = r->tm_mday;
338 if (year != -1)
339 tm->tm_year = r->tm_year;
340 return 1;
342 return 0;
345 static int match_multi_number(unsigned long num, char c, const char *date, char *end, struct tm *tm)
347 time_t now;
348 struct tm now_tm;
349 struct tm *refuse_future;
350 long num2, num3;
352 num2 = strtol(end+1, &end, 10);
353 num3 = -1;
354 if (*end == c && isdigit(end[1]))
355 num3 = strtol(end+1, &end, 10);
357 /* Time? Date? */
358 switch (c) {
359 case ':':
360 if (num3 < 0)
361 num3 = 0;
362 if (num < 25 && num2 >= 0 && num2 < 60 && num3 >= 0 && num3 <= 60) {
363 tm->tm_hour = num;
364 tm->tm_min = num2;
365 tm->tm_sec = num3;
366 break;
368 return 0;
370 case '-':
371 case '/':
372 case '.':
373 now = time(NULL);
374 refuse_future = NULL;
375 if (gmtime_r(&now, &now_tm))
376 refuse_future = &now_tm;
378 if (num > 70) {
379 /* yyyy-mm-dd? */
380 if (is_date(num, num2, num3, refuse_future, now, tm))
381 break;
382 /* yyyy-dd-mm? */
383 if (is_date(num, num3, num2, refuse_future, now, tm))
384 break;
386 /* Our eastern European friends say dd.mm.yy[yy]
387 * is the norm there, so giving precedence to
388 * mm/dd/yy[yy] form only when separator is not '.'
390 if (c != '.' &&
391 is_date(num3, num, num2, refuse_future, now, tm))
392 break;
393 /* European dd.mm.yy[yy] or funny US dd/mm/yy[yy] */
394 if (is_date(num3, num2, num, refuse_future, now, tm))
395 break;
396 /* Funny European mm.dd.yy */
397 if (c == '.' &&
398 is_date(num3, num, num2, refuse_future, now, tm))
399 break;
400 return 0;
402 return end - date;
406 * We've seen a digit. Time? Year? Date?
408 static int match_digit(const char *date, struct tm *tm, int *offset, int *tm_gmt)
410 int n;
411 char *end;
412 unsigned long num;
414 num = strtoul(date, &end, 10);
417 * Seconds since 1970? We trigger on that for any numbers with
418 * more than 8 digits. This is because we don't want to rule out
419 * numbers like 20070606 as a YYYYMMDD date.
421 if (num >= 100000000) {
422 time_t time = num;
423 if (gmtime_r(&time, tm)) {
424 *tm_gmt = 1;
425 return end - date;
430 * Check for special formats: num[-.:/]num[same]num
432 switch (*end) {
433 case ':':
434 case '.':
435 case '/':
436 case '-':
437 if (isdigit(end[1])) {
438 int match = match_multi_number(num, *end, date, end, tm);
439 if (match)
440 return match;
445 * None of the special formats? Try to guess what
446 * the number meant. We use the number of digits
447 * to make a more educated guess..
449 n = 0;
450 do {
451 n++;
452 } while (isdigit(date[n]));
454 /* Four-digit year or a timezone? */
455 if (n == 4) {
456 if (num <= 1400 && *offset == -1) {
457 unsigned int minutes = num % 100;
458 unsigned int hours = num / 100;
459 *offset = hours*60 + minutes;
460 } else if (num > 1900 && num < 2100)
461 tm->tm_year = num - 1900;
462 return n;
466 * NOTE! We will give precedence to day-of-month over month or
467 * year numbers in the 1-12 range. So 05 is always "mday 5",
468 * unless we already have a mday..
470 * IOW, 01 Apr 05 parses as "April 1st, 2005".
472 if (num > 0 && num < 32 && tm->tm_mday < 0) {
473 tm->tm_mday = num;
474 return n;
477 /* Two-digit year? */
478 if (n == 2 && tm->tm_year < 0) {
479 if (num < 10 && tm->tm_mday >= 0) {
480 tm->tm_year = num + 100;
481 return n;
483 if (num >= 70) {
484 tm->tm_year = num;
485 return n;
489 if (num > 0 && num < 32) {
490 tm->tm_mday = num;
491 } else if (num > 1900) {
492 tm->tm_year = num - 1900;
493 } else if (num > 70) {
494 tm->tm_year = num;
495 } else if (num > 0 && num < 13) {
496 tm->tm_mon = num-1;
499 return n;
502 static int match_tz(const char *date, int *offp)
504 char *end;
505 int offset = strtoul(date+1, &end, 10);
506 int min, hour;
507 int n = end - date - 1;
509 min = offset % 100;
510 hour = offset / 100;
513 * Don't accept any random crap.. At least 3 digits, and
514 * a valid minute. We might want to check that the minutes
515 * are divisible by 30 or something too.
517 if (min < 60 && n > 2) {
518 offset = hour*60+min;
519 if (*date == '-')
520 offset = -offset;
522 *offp = offset;
524 return end - date;
527 static int date_string(unsigned long date, int offset, char *buf, int len)
529 int sign = '+';
531 if (offset < 0) {
532 offset = -offset;
533 sign = '-';
535 return snprintf(buf, len, "%lu %c%02d%02d", date, sign, offset / 60, offset % 60);
538 /* Gr. strptime is crap for this; it doesn't have a way to require RFC2822
539 (i.e. English) day/month names, and it doesn't work correctly with %z. */
540 int parse_date(const char *date, char *result, int maxlen)
542 struct tm tm;
543 int offset, tm_gmt;
544 time_t then;
546 memset(&tm, 0, sizeof(tm));
547 tm.tm_year = -1;
548 tm.tm_mon = -1;
549 tm.tm_mday = -1;
550 tm.tm_isdst = -1;
551 offset = -1;
552 tm_gmt = 0;
554 for (;;) {
555 int match = 0;
556 unsigned char c = *date;
558 /* Stop at end of string or newline */
559 if (!c || c == '\n')
560 break;
562 if (isalpha(c))
563 match = match_alpha(date, &tm, &offset);
564 else if (isdigit(c))
565 match = match_digit(date, &tm, &offset, &tm_gmt);
566 else if ((c == '-' || c == '+') && isdigit(date[1]))
567 match = match_tz(date, &offset);
569 if (!match) {
570 /* BAD CRAP */
571 match = 1;
574 date += match;
577 /* mktime uses local timezone */
578 then = tm_to_time_t(&tm);
579 if (offset == -1)
580 offset = (then - mktime(&tm)) / 60;
582 if (then == -1)
583 return -1;
585 if (!tm_gmt)
586 then -= offset * 60;
587 return date_string(then, offset, result, maxlen);
590 enum date_mode parse_date_format(const char *format)
592 if (!strcmp(format, "relative"))
593 return DATE_RELATIVE;
594 else if (!strcmp(format, "iso8601") ||
595 !strcmp(format, "iso"))
596 return DATE_ISO8601;
597 else if (!strcmp(format, "rfc2822") ||
598 !strcmp(format, "rfc"))
599 return DATE_RFC2822;
600 else if (!strcmp(format, "short"))
601 return DATE_SHORT;
602 else if (!strcmp(format, "local"))
603 return DATE_LOCAL;
604 else if (!strcmp(format, "default"))
605 return DATE_NORMAL;
606 else
607 die("unknown date format %s", format);
610 void datestamp(char *buf, int bufsize)
612 time_t now;
613 int offset;
615 time(&now);
617 offset = tm_to_time_t(localtime(&now)) - now;
618 offset /= 60;
620 date_string(now, offset, buf, bufsize);
623 static void update_tm(struct tm *tm, unsigned long sec)
625 time_t n = mktime(tm) - sec;
626 localtime_r(&n, tm);
629 static void date_yesterday(struct tm *tm, int *num)
631 update_tm(tm, 24*60*60);
634 static void date_time(struct tm *tm, int hour)
636 if (tm->tm_hour < hour)
637 date_yesterday(tm, NULL);
638 tm->tm_hour = hour;
639 tm->tm_min = 0;
640 tm->tm_sec = 0;
643 static void date_midnight(struct tm *tm, int *num)
645 date_time(tm, 0);
648 static void date_noon(struct tm *tm, int *num)
650 date_time(tm, 12);
653 static void date_tea(struct tm *tm, int *num)
655 date_time(tm, 17);
658 static void date_pm(struct tm *tm, int *num)
660 int hour, n = *num;
661 *num = 0;
663 hour = tm->tm_hour;
664 if (n) {
665 hour = n;
666 tm->tm_min = 0;
667 tm->tm_sec = 0;
669 tm->tm_hour = (hour % 12) + 12;
672 static void date_am(struct tm *tm, int *num)
674 int hour, n = *num;
675 *num = 0;
677 hour = tm->tm_hour;
678 if (n) {
679 hour = n;
680 tm->tm_min = 0;
681 tm->tm_sec = 0;
683 tm->tm_hour = (hour % 12);
686 static void date_never(struct tm *tm, int *num)
688 time_t n = 0;
689 localtime_r(&n, tm);
692 static const struct special {
693 const char *name;
694 void (*fn)(struct tm *, int *);
695 } special[] = {
696 { "yesterday", date_yesterday },
697 { "noon", date_noon },
698 { "midnight", date_midnight },
699 { "tea", date_tea },
700 { "PM", date_pm },
701 { "AM", date_am },
702 { "never", date_never },
703 { NULL }
706 static const char *number_name[] = {
707 "zero", "one", "two", "three", "four",
708 "five", "six", "seven", "eight", "nine", "ten",
711 static const struct typelen {
712 const char *type;
713 int length;
714 } typelen[] = {
715 { "seconds", 1 },
716 { "minutes", 60 },
717 { "hours", 60*60 },
718 { "days", 24*60*60 },
719 { "weeks", 7*24*60*60 },
720 { NULL }
723 static const char *approxidate_alpha(const char *date, struct tm *tm, int *num)
725 const struct typelen *tl;
726 const struct special *s;
727 const char *end = date;
728 int i;
730 while (isalpha(*++end));
733 for (i = 0; i < 12; i++) {
734 int match = match_string(date, month_names[i]);
735 if (match >= 3) {
736 tm->tm_mon = i;
737 return end;
741 for (s = special; s->name; s++) {
742 int len = strlen(s->name);
743 if (match_string(date, s->name) == len) {
744 s->fn(tm, num);
745 return end;
749 if (!*num) {
750 for (i = 1; i < 11; i++) {
751 int len = strlen(number_name[i]);
752 if (match_string(date, number_name[i]) == len) {
753 *num = i;
754 return end;
757 if (match_string(date, "last") == 4)
758 *num = 1;
759 return end;
762 tl = typelen;
763 while (tl->type) {
764 int len = strlen(tl->type);
765 if (match_string(date, tl->type) >= len-1) {
766 update_tm(tm, tl->length * *num);
767 *num = 0;
768 return end;
770 tl++;
773 for (i = 0; i < 7; i++) {
774 int match = match_string(date, weekday_names[i]);
775 if (match >= 3) {
776 int diff, n = *num -1;
777 *num = 0;
779 diff = tm->tm_wday - i;
780 if (diff <= 0)
781 n++;
782 diff += 7*n;
784 update_tm(tm, diff * 24 * 60 * 60);
785 return end;
789 if (match_string(date, "months") >= 5) {
790 int n = tm->tm_mon - *num;
791 *num = 0;
792 while (n < 0) {
793 n += 12;
794 tm->tm_year--;
796 tm->tm_mon = n;
797 return end;
800 if (match_string(date, "years") >= 4) {
801 tm->tm_year -= *num;
802 *num = 0;
803 return end;
806 return end;
809 static const char *approxidate_digit(const char *date, struct tm *tm, int *num)
811 char *end;
812 unsigned long number = strtoul(date, &end, 10);
814 switch (*end) {
815 case ':':
816 case '.':
817 case '/':
818 case '-':
819 if (isdigit(end[1])) {
820 int match = match_multi_number(number, *end, date, end, tm);
821 if (match)
822 return date + match;
826 *num = number;
827 return end;
830 unsigned long approxidate(const char *date)
832 int number = 0;
833 struct tm tm, now;
834 struct timeval tv;
835 char buffer[50];
837 if (parse_date(date, buffer, sizeof(buffer)) > 0)
838 return strtoul(buffer, NULL, 10);
840 gettimeofday(&tv, NULL);
841 localtime_r(&tv.tv_sec, &tm);
842 now = tm;
843 for (;;) {
844 unsigned char c = *date;
845 if (!c)
846 break;
847 date++;
848 if (isdigit(c)) {
849 date = approxidate_digit(date-1, &tm, &number);
850 continue;
852 if (isalpha(c))
853 date = approxidate_alpha(date-1, &tm, &number);
855 if (number > 0 && number < 32)
856 tm.tm_mday = number;
857 if (tm.tm_mon > now.tm_mon && tm.tm_year == now.tm_year)
858 tm.tm_year--;
859 return mktime(&tm);