date.con commit Merge branch 'jh/trace2-pretty-output' (93fc876)
   1/*
   2 * GIT - The information manager from hell
   3 *
   4 * Copyright (C) Linus Torvalds, 2005
   5 */
   6
   7#include "cache.h"
   8
   9/*
  10 * This is like mktime, but without normalization of tm_wday and tm_yday.
  11 */
  12static time_t tm_to_time_t(const struct tm *tm)
  13{
  14        static const int mdays[] = {
  15            0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334
  16        };
  17        int year = tm->tm_year - 70;
  18        int month = tm->tm_mon;
  19        int day = tm->tm_mday;
  20
  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        if (tm->tm_hour < 0 || tm->tm_min < 0 || tm->tm_sec < 0)
  28                return -1;
  29        return (year * 365 + (year + 1) / 4 + mdays[month] + day) * 24*60*60UL +
  30                tm->tm_hour * 60*60 + tm->tm_min * 60 + tm->tm_sec;
  31}
  32
  33static const char *month_names[] = {
  34        "January", "February", "March", "April", "May", "June",
  35        "July", "August", "September", "October", "November", "December"
  36};
  37
  38static const char *weekday_names[] = {
  39        "Sundays", "Mondays", "Tuesdays", "Wednesdays", "Thursdays", "Fridays", "Saturdays"
  40};
  41
  42static time_t gm_time_t(timestamp_t time, int tz)
  43{
  44        int minutes;
  45
  46        minutes = tz < 0 ? -tz : tz;
  47        minutes = (minutes / 100)*60 + (minutes % 100);
  48        minutes = tz < 0 ? -minutes : minutes;
  49
  50        if (minutes > 0) {
  51                if (unsigned_add_overflows(time, minutes * 60))
  52                        die("Timestamp+tz too large: %"PRItime" +%04d",
  53                            time, tz);
  54        } else if (time < -minutes * 60)
  55                die("Timestamp before Unix epoch: %"PRItime" %04d", time, tz);
  56        time += minutes * 60;
  57        if (date_overflows(time))
  58                die("Timestamp too large for this system: %"PRItime, time);
  59        return (time_t)time;
  60}
  61
  62/*
  63 * The "tz" thing is passed in as this strange "decimal parse of tz"
  64 * thing, which means that tz -0100 is passed in as the integer -100,
  65 * even though it means "sixty minutes off"
  66 */
  67static struct tm *time_to_tm(timestamp_t time, int tz)
  68{
  69        time_t t = gm_time_t(time, tz);
  70        return gmtime(&t);
  71}
  72
  73static struct tm *time_to_tm_local(timestamp_t time)
  74{
  75        time_t t = time;
  76        return localtime(&t);
  77}
  78
  79/*
  80 * Fill in the localtime 'struct tm' for the supplied time,
  81 * and return the local tz.
  82 */
  83static int local_time_tzoffset(time_t t, struct tm *tm)
  84{
  85        time_t t_local;
  86        int offset, eastwest;
  87
  88        localtime_r(&t, tm);
  89        t_local = tm_to_time_t(tm);
  90        if (t_local == -1)
  91                return 0; /* error; just use +0000 */
  92        if (t_local < t) {
  93                eastwest = -1;
  94                offset = t - t_local;
  95        } else {
  96                eastwest = 1;
  97                offset = t_local - t;
  98        }
  99        offset /= 60; /* in minutes */
 100        offset = (offset % 60) + ((offset / 60) * 100);
 101        return offset * eastwest;
 102}
 103
 104/*
 105 * What value of "tz" was in effect back then at "time" in the
 106 * local timezone?
 107 */
 108static int local_tzoffset(timestamp_t time)
 109{
 110        struct tm tm;
 111
 112        if (date_overflows(time))
 113                die("Timestamp too large for this system: %"PRItime, time);
 114
 115        return local_time_tzoffset((time_t)time, &tm);
 116}
 117
 118static void get_time(struct timeval *now)
 119{
 120        const char *x;
 121
 122        x = getenv("GIT_TEST_DATE_NOW");
 123        if (x) {
 124                now->tv_sec = atoi(x);
 125                now->tv_usec = 0;
 126        }
 127        else
 128                gettimeofday(now, NULL);
 129}
 130
 131void show_date_relative(timestamp_t time,
 132                        const struct timeval *now,
 133                        struct strbuf *timebuf)
 134{
 135        timestamp_t diff;
 136        if (now->tv_sec < time) {
 137                strbuf_addstr(timebuf, _("in the future"));
 138                return;
 139        }
 140        diff = now->tv_sec - time;
 141        if (diff < 90) {
 142                strbuf_addf(timebuf,
 143                         Q_("%"PRItime" second ago", "%"PRItime" seconds ago", diff), diff);
 144                return;
 145        }
 146        /* Turn it into minutes */
 147        diff = (diff + 30) / 60;
 148        if (diff < 90) {
 149                strbuf_addf(timebuf,
 150                         Q_("%"PRItime" minute ago", "%"PRItime" minutes ago", diff), diff);
 151                return;
 152        }
 153        /* Turn it into hours */
 154        diff = (diff + 30) / 60;
 155        if (diff < 36) {
 156                strbuf_addf(timebuf,
 157                         Q_("%"PRItime" hour ago", "%"PRItime" hours ago", diff), diff);
 158                return;
 159        }
 160        /* We deal with number of days from here on */
 161        diff = (diff + 12) / 24;
 162        if (diff < 14) {
 163                strbuf_addf(timebuf,
 164                         Q_("%"PRItime" day ago", "%"PRItime" days ago", diff), diff);
 165                return;
 166        }
 167        /* Say weeks for the past 10 weeks or so */
 168        if (diff < 70) {
 169                strbuf_addf(timebuf,
 170                         Q_("%"PRItime" week ago", "%"PRItime" weeks ago", (diff + 3) / 7),
 171                         (diff + 3) / 7);
 172                return;
 173        }
 174        /* Say months for the past 12 months or so */
 175        if (diff < 365) {
 176                strbuf_addf(timebuf,
 177                         Q_("%"PRItime" month ago", "%"PRItime" months ago", (diff + 15) / 30),
 178                         (diff + 15) / 30);
 179                return;
 180        }
 181        /* Give years and months for 5 years or so */
 182        if (diff < 1825) {
 183                timestamp_t totalmonths = (diff * 12 * 2 + 365) / (365 * 2);
 184                timestamp_t years = totalmonths / 12;
 185                timestamp_t months = totalmonths % 12;
 186                if (months) {
 187                        struct strbuf sb = STRBUF_INIT;
 188                        strbuf_addf(&sb, Q_("%"PRItime" year", "%"PRItime" years", years), years);
 189                        strbuf_addf(timebuf,
 190                                 /* TRANSLATORS: "%s" is "<n> years" */
 191                                 Q_("%s, %"PRItime" month ago", "%s, %"PRItime" months ago", months),
 192                                 sb.buf, months);
 193                        strbuf_release(&sb);
 194                } else
 195                        strbuf_addf(timebuf,
 196                                 Q_("%"PRItime" year ago", "%"PRItime" years ago", years), years);
 197                return;
 198        }
 199        /* Otherwise, just years. Centuries is probably overkill. */
 200        strbuf_addf(timebuf,
 201                 Q_("%"PRItime" year ago", "%"PRItime" years ago", (diff + 183) / 365),
 202                 (diff + 183) / 365);
 203}
 204
 205struct date_mode *date_mode_from_type(enum date_mode_type type)
 206{
 207        static struct date_mode mode;
 208        if (type == DATE_STRFTIME)
 209                BUG("cannot create anonymous strftime date_mode struct");
 210        mode.type = type;
 211        mode.local = 0;
 212        return &mode;
 213}
 214
 215static void show_date_normal(struct strbuf *buf, timestamp_t time, struct tm *tm, int tz, struct tm *human_tm, int human_tz, int local)
 216{
 217        struct {
 218                unsigned int    year:1,
 219                                date:1,
 220                                wday:1,
 221                                time:1,
 222                                seconds:1,
 223                                tz:1;
 224        } hide = { 0 };
 225
 226        hide.tz = local || tz == human_tz;
 227        hide.year = tm->tm_year == human_tm->tm_year;
 228        if (hide.year) {
 229                if (tm->tm_mon == human_tm->tm_mon) {
 230                        if (tm->tm_mday > human_tm->tm_mday) {
 231                                /* Future date: think timezones */
 232                        } else if (tm->tm_mday == human_tm->tm_mday) {
 233                                hide.date = hide.wday = 1;
 234                        } else if (tm->tm_mday + 5 > human_tm->tm_mday) {
 235                                /* Leave just weekday if it was a few days ago */
 236                                hide.date = 1;
 237                        }
 238                }
 239        }
 240
 241        /* Show "today" times as just relative times */
 242        if (hide.wday) {
 243                struct timeval now;
 244                get_time(&now);
 245                show_date_relative(time, &now, buf);
 246                return;
 247        }
 248
 249        /*
 250         * Always hide seconds for human-readable.
 251         * Hide timezone if showing date.
 252         * Hide weekday and time if showing year.
 253         *
 254         * The logic here is two-fold:
 255         *  (a) only show details when recent enough to matter
 256         *  (b) keep the maximum length "similar", and in check
 257         */
 258        if (human_tm->tm_year) {
 259                hide.seconds = 1;
 260                hide.tz |= !hide.date;
 261                hide.wday = hide.time = !hide.year;
 262        }
 263
 264        if (!hide.wday)
 265                strbuf_addf(buf, "%.3s ", weekday_names[tm->tm_wday]);
 266        if (!hide.date)
 267                strbuf_addf(buf, "%.3s %d ", month_names[tm->tm_mon], tm->tm_mday);
 268
 269        /* Do we want AM/PM depending on locale? */
 270        if (!hide.time) {
 271                strbuf_addf(buf, "%02d:%02d", tm->tm_hour, tm->tm_min);
 272                if (!hide.seconds)
 273                        strbuf_addf(buf, ":%02d", tm->tm_sec);
 274        } else
 275                strbuf_rtrim(buf);
 276
 277        if (!hide.year)
 278                strbuf_addf(buf, " %d", tm->tm_year + 1900);
 279
 280        if (!hide.tz)
 281                strbuf_addf(buf, " %+05d", tz);
 282}
 283
 284const char *show_date(timestamp_t time, int tz, const struct date_mode *mode)
 285{
 286        struct tm *tm;
 287        struct tm human_tm = { 0 };
 288        int human_tz = -1;
 289        static struct strbuf timebuf = STRBUF_INIT;
 290
 291        if (mode->type == DATE_UNIX) {
 292                strbuf_reset(&timebuf);
 293                strbuf_addf(&timebuf, "%"PRItime, time);
 294                return timebuf.buf;
 295        }
 296
 297        if (mode->type == DATE_HUMAN) {
 298                struct timeval now;
 299
 300                get_time(&now);
 301
 302                /* Fill in the data for "current time" in human_tz and human_tm */
 303                human_tz = local_time_tzoffset(now.tv_sec, &human_tm);
 304        }
 305
 306        if (mode->local)
 307                tz = local_tzoffset(time);
 308
 309        if (mode->type == DATE_RAW) {
 310                strbuf_reset(&timebuf);
 311                strbuf_addf(&timebuf, "%"PRItime" %+05d", time, tz);
 312                return timebuf.buf;
 313        }
 314
 315        if (mode->type == DATE_RELATIVE) {
 316                struct timeval now;
 317
 318                strbuf_reset(&timebuf);
 319                get_time(&now);
 320                show_date_relative(time, &now, &timebuf);
 321                return timebuf.buf;
 322        }
 323
 324        if (mode->local)
 325                tm = time_to_tm_local(time);
 326        else
 327                tm = time_to_tm(time, tz);
 328        if (!tm) {
 329                tm = time_to_tm(0, 0);
 330                tz = 0;
 331        }
 332
 333        strbuf_reset(&timebuf);
 334        if (mode->type == DATE_SHORT)
 335                strbuf_addf(&timebuf, "%04d-%02d-%02d", tm->tm_year + 1900,
 336                                tm->tm_mon + 1, tm->tm_mday);
 337        else if (mode->type == DATE_ISO8601)
 338                strbuf_addf(&timebuf, "%04d-%02d-%02d %02d:%02d:%02d %+05d",
 339                                tm->tm_year + 1900,
 340                                tm->tm_mon + 1,
 341                                tm->tm_mday,
 342                                tm->tm_hour, tm->tm_min, tm->tm_sec,
 343                                tz);
 344        else if (mode->type == DATE_ISO8601_STRICT) {
 345                char sign = (tz >= 0) ? '+' : '-';
 346                tz = abs(tz);
 347                strbuf_addf(&timebuf, "%04d-%02d-%02dT%02d:%02d:%02d%c%02d:%02d",
 348                                tm->tm_year + 1900,
 349                                tm->tm_mon + 1,
 350                                tm->tm_mday,
 351                                tm->tm_hour, tm->tm_min, tm->tm_sec,
 352                                sign, tz / 100, tz % 100);
 353        } else if (mode->type == DATE_RFC2822)
 354                strbuf_addf(&timebuf, "%.3s, %d %.3s %d %02d:%02d:%02d %+05d",
 355                        weekday_names[tm->tm_wday], tm->tm_mday,
 356                        month_names[tm->tm_mon], tm->tm_year + 1900,
 357                        tm->tm_hour, tm->tm_min, tm->tm_sec, tz);
 358        else if (mode->type == DATE_STRFTIME)
 359                strbuf_addftime(&timebuf, mode->strftime_fmt, tm, tz,
 360                                !mode->local);
 361        else
 362                show_date_normal(&timebuf, time, tm, tz, &human_tm, human_tz, mode->local);
 363        return timebuf.buf;
 364}
 365
 366/*
 367 * Check these. And note how it doesn't do the summer-time conversion.
 368 *
 369 * In my world, it's always summer, and things are probably a bit off
 370 * in other ways too.
 371 */
 372static const struct {
 373        const char *name;
 374        int offset;
 375        int dst;
 376} timezone_names[] = {
 377        { "IDLW", -12, 0, },    /* International Date Line West */
 378        { "NT",   -11, 0, },    /* Nome */
 379        { "CAT",  -10, 0, },    /* Central Alaska */
 380        { "HST",  -10, 0, },    /* Hawaii Standard */
 381        { "HDT",  -10, 1, },    /* Hawaii Daylight */
 382        { "YST",   -9, 0, },    /* Yukon Standard */
 383        { "YDT",   -9, 1, },    /* Yukon Daylight */
 384        { "PST",   -8, 0, },    /* Pacific Standard */
 385        { "PDT",   -8, 1, },    /* Pacific Daylight */
 386        { "MST",   -7, 0, },    /* Mountain Standard */
 387        { "MDT",   -7, 1, },    /* Mountain Daylight */
 388        { "CST",   -6, 0, },    /* Central Standard */
 389        { "CDT",   -6, 1, },    /* Central Daylight */
 390        { "EST",   -5, 0, },    /* Eastern Standard */
 391        { "EDT",   -5, 1, },    /* Eastern Daylight */
 392        { "AST",   -3, 0, },    /* Atlantic Standard */
 393        { "ADT",   -3, 1, },    /* Atlantic Daylight */
 394        { "WAT",   -1, 0, },    /* West Africa */
 395
 396        { "GMT",    0, 0, },    /* Greenwich Mean */
 397        { "UTC",    0, 0, },    /* Universal (Coordinated) */
 398        { "Z",      0, 0, },    /* Zulu, alias for UTC */
 399
 400        { "WET",    0, 0, },    /* Western European */
 401        { "BST",    0, 1, },    /* British Summer */
 402        { "CET",   +1, 0, },    /* Central European */
 403        { "MET",   +1, 0, },    /* Middle European */
 404        { "MEWT",  +1, 0, },    /* Middle European Winter */
 405        { "MEST",  +1, 1, },    /* Middle European Summer */
 406        { "CEST",  +1, 1, },    /* Central European Summer */
 407        { "MESZ",  +1, 1, },    /* Middle European Summer */
 408        { "FWT",   +1, 0, },    /* French Winter */
 409        { "FST",   +1, 1, },    /* French Summer */
 410        { "EET",   +2, 0, },    /* Eastern Europe, USSR Zone 1 */
 411        { "EEST",  +2, 1, },    /* Eastern European Daylight */
 412        { "WAST",  +7, 0, },    /* West Australian Standard */
 413        { "WADT",  +7, 1, },    /* West Australian Daylight */
 414        { "CCT",   +8, 0, },    /* China Coast, USSR Zone 7 */
 415        { "JST",   +9, 0, },    /* Japan Standard, USSR Zone 8 */
 416        { "EAST", +10, 0, },    /* Eastern Australian Standard */
 417        { "EADT", +10, 1, },    /* Eastern Australian Daylight */
 418        { "GST",  +10, 0, },    /* Guam Standard, USSR Zone 9 */
 419        { "NZT",  +12, 0, },    /* New Zealand */
 420        { "NZST", +12, 0, },    /* New Zealand Standard */
 421        { "NZDT", +12, 1, },    /* New Zealand Daylight */
 422        { "IDLE", +12, 0, },    /* International Date Line East */
 423};
 424
 425static int match_string(const char *date, const char *str)
 426{
 427        int i = 0;
 428
 429        for (i = 0; *date; date++, str++, i++) {
 430                if (*date == *str)
 431                        continue;
 432                if (toupper(*date) == toupper(*str))
 433                        continue;
 434                if (!isalnum(*date))
 435                        break;
 436                return 0;
 437        }
 438        return i;
 439}
 440
 441static int skip_alpha(const char *date)
 442{
 443        int i = 0;
 444        do {
 445                i++;
 446        } while (isalpha(date[i]));
 447        return i;
 448}
 449
 450/*
 451* Parse month, weekday, or timezone name
 452*/
 453static int match_alpha(const char *date, struct tm *tm, int *offset)
 454{
 455        int i;
 456
 457        for (i = 0; i < 12; i++) {
 458                int match = match_string(date, month_names[i]);
 459                if (match >= 3) {
 460                        tm->tm_mon = i;
 461                        return match;
 462                }
 463        }
 464
 465        for (i = 0; i < 7; i++) {
 466                int match = match_string(date, weekday_names[i]);
 467                if (match >= 3) {
 468                        tm->tm_wday = i;
 469                        return match;
 470                }
 471        }
 472
 473        for (i = 0; i < ARRAY_SIZE(timezone_names); i++) {
 474                int match = match_string(date, timezone_names[i].name);
 475                if (match >= 3 || match == strlen(timezone_names[i].name)) {
 476                        int off = timezone_names[i].offset;
 477
 478                        /* This is bogus, but we like summer */
 479                        off += timezone_names[i].dst;
 480
 481                        /* Only use the tz name offset if we don't have anything better */
 482                        if (*offset == -1)
 483                                *offset = 60*off;
 484
 485                        return match;
 486                }
 487        }
 488
 489        if (match_string(date, "PM") == 2) {
 490                tm->tm_hour = (tm->tm_hour % 12) + 12;
 491                return 2;
 492        }
 493
 494        if (match_string(date, "AM") == 2) {
 495                tm->tm_hour = (tm->tm_hour % 12) + 0;
 496                return 2;
 497        }
 498
 499        /* BAD CRAP */
 500        return skip_alpha(date);
 501}
 502
 503static int is_date(int year, int month, int day, struct tm *now_tm, time_t now, struct tm *tm)
 504{
 505        if (month > 0 && month < 13 && day > 0 && day < 32) {
 506                struct tm check = *tm;
 507                struct tm *r = (now_tm ? &check : tm);
 508                time_t specified;
 509
 510                r->tm_mon = month - 1;
 511                r->tm_mday = day;
 512                if (year == -1) {
 513                        if (!now_tm)
 514                                return 1;
 515                        r->tm_year = now_tm->tm_year;
 516                }
 517                else if (year >= 1970 && year < 2100)
 518                        r->tm_year = year - 1900;
 519                else if (year > 70 && year < 100)
 520                        r->tm_year = year;
 521                else if (year < 38)
 522                        r->tm_year = year + 100;
 523                else
 524                        return 0;
 525                if (!now_tm)
 526                        return 1;
 527
 528                specified = tm_to_time_t(r);
 529
 530                /* Be it commit time or author time, it does not make
 531                 * sense to specify timestamp way into the future.  Make
 532                 * sure it is not later than ten days from now...
 533                 */
 534                if ((specified != -1) && (now + 10*24*3600 < specified))
 535                        return 0;
 536                tm->tm_mon = r->tm_mon;
 537                tm->tm_mday = r->tm_mday;
 538                if (year != -1)
 539                        tm->tm_year = r->tm_year;
 540                return 1;
 541        }
 542        return 0;
 543}
 544
 545static int match_multi_number(timestamp_t num, char c, const char *date,
 546                              char *end, struct tm *tm, time_t now)
 547{
 548        struct tm now_tm;
 549        struct tm *refuse_future;
 550        long num2, num3;
 551
 552        num2 = strtol(end+1, &end, 10);
 553        num3 = -1;
 554        if (*end == c && isdigit(end[1]))
 555                num3 = strtol(end+1, &end, 10);
 556
 557        /* Time? Date? */
 558        switch (c) {
 559        case ':':
 560                if (num3 < 0)
 561                        num3 = 0;
 562                if (num < 25 && num2 >= 0 && num2 < 60 && num3 >= 0 && num3 <= 60) {
 563                        tm->tm_hour = num;
 564                        tm->tm_min = num2;
 565                        tm->tm_sec = num3;
 566                        break;
 567                }
 568                return 0;
 569
 570        case '-':
 571        case '/':
 572        case '.':
 573                if (!now)
 574                        now = time(NULL);
 575                refuse_future = NULL;
 576                if (gmtime_r(&now, &now_tm))
 577                        refuse_future = &now_tm;
 578
 579                if (num > 70) {
 580                        /* yyyy-mm-dd? */
 581                        if (is_date(num, num2, num3, NULL, now, tm))
 582                                break;
 583                        /* yyyy-dd-mm? */
 584                        if (is_date(num, num3, num2, NULL, now, tm))
 585                                break;
 586                }
 587                /* Our eastern European friends say dd.mm.yy[yy]
 588                 * is the norm there, so giving precedence to
 589                 * mm/dd/yy[yy] form only when separator is not '.'
 590                 */
 591                if (c != '.' &&
 592                    is_date(num3, num, num2, refuse_future, now, tm))
 593                        break;
 594                /* European dd.mm.yy[yy] or funny US dd/mm/yy[yy] */
 595                if (is_date(num3, num2, num, refuse_future, now, tm))
 596                        break;
 597                /* Funny European mm.dd.yy */
 598                if (c == '.' &&
 599                    is_date(num3, num, num2, refuse_future, now, tm))
 600                        break;
 601                return 0;
 602        }
 603        return end - date;
 604}
 605
 606/*
 607 * Have we filled in any part of the time/date yet?
 608 * We just do a binary 'and' to see if the sign bit
 609 * is set in all the values.
 610 */
 611static inline int nodate(struct tm *tm)
 612{
 613        return (tm->tm_year &
 614                tm->tm_mon &
 615                tm->tm_mday &
 616                tm->tm_hour &
 617                tm->tm_min &
 618                tm->tm_sec) < 0;
 619}
 620
 621/*
 622 * We've seen a digit. Time? Year? Date?
 623 */
 624static int match_digit(const char *date, struct tm *tm, int *offset, int *tm_gmt)
 625{
 626        int n;
 627        char *end;
 628        timestamp_t num;
 629
 630        num = parse_timestamp(date, &end, 10);
 631
 632        /*
 633         * Seconds since 1970? We trigger on that for any numbers with
 634         * more than 8 digits. This is because we don't want to rule out
 635         * numbers like 20070606 as a YYYYMMDD date.
 636         */
 637        if (num >= 100000000 && nodate(tm)) {
 638                time_t time = num;
 639                if (gmtime_r(&time, tm)) {
 640                        *tm_gmt = 1;
 641                        return end - date;
 642                }
 643        }
 644
 645        /*
 646         * Check for special formats: num[-.:/]num[same]num
 647         */
 648        switch (*end) {
 649        case ':':
 650        case '.':
 651        case '/':
 652        case '-':
 653                if (isdigit(end[1])) {
 654                        int match = match_multi_number(num, *end, date, end, tm, 0);
 655                        if (match)
 656                                return match;
 657                }
 658        }
 659
 660        /*
 661         * None of the special formats? Try to guess what
 662         * the number meant. We use the number of digits
 663         * to make a more educated guess..
 664         */
 665        n = 0;
 666        do {
 667                n++;
 668        } while (isdigit(date[n]));
 669
 670        /* Four-digit year or a timezone? */
 671        if (n == 4) {
 672                if (num <= 1400 && *offset == -1) {
 673                        unsigned int minutes = num % 100;
 674                        unsigned int hours = num / 100;
 675                        *offset = hours*60 + minutes;
 676                } else if (num > 1900 && num < 2100)
 677                        tm->tm_year = num - 1900;
 678                return n;
 679        }
 680
 681        /*
 682         * Ignore lots of numerals. We took care of 4-digit years above.
 683         * Days or months must be one or two digits.
 684         */
 685        if (n > 2)
 686                return n;
 687
 688        /*
 689         * NOTE! We will give precedence to day-of-month over month or
 690         * year numbers in the 1-12 range. So 05 is always "mday 5",
 691         * unless we already have a mday..
 692         *
 693         * IOW, 01 Apr 05 parses as "April 1st, 2005".
 694         */
 695        if (num > 0 && num < 32 && tm->tm_mday < 0) {
 696                tm->tm_mday = num;
 697                return n;
 698        }
 699
 700        /* Two-digit year? */
 701        if (n == 2 && tm->tm_year < 0) {
 702                if (num < 10 && tm->tm_mday >= 0) {
 703                        tm->tm_year = num + 100;
 704                        return n;
 705                }
 706                if (num >= 70) {
 707                        tm->tm_year = num;
 708                        return n;
 709                }
 710        }
 711
 712        if (num > 0 && num < 13 && tm->tm_mon < 0)
 713                tm->tm_mon = num-1;
 714
 715        return n;
 716}
 717
 718static int match_tz(const char *date, int *offp)
 719{
 720        char *end;
 721        int hour = strtoul(date + 1, &end, 10);
 722        int n = end - (date + 1);
 723        int min = 0;
 724
 725        if (n == 4) {
 726                /* hhmm */
 727                min = hour % 100;
 728                hour = hour / 100;
 729        } else if (n != 2) {
 730                min = 99; /* random crap */
 731        } else if (*end == ':') {
 732                /* hh:mm? */
 733                min = strtoul(end + 1, &end, 10);
 734                if (end - (date + 1) != 5)
 735                        min = 99; /* random crap */
 736        } /* otherwise we parsed "hh" */
 737
 738        /*
 739         * Don't accept any random crap. Even though some places have
 740         * offset larger than 12 hours (e.g. Pacific/Kiritimati is at
 741         * UTC+14), there is something wrong if hour part is much
 742         * larger than that. We might also want to check that the
 743         * minutes are divisible by 15 or something too. (Offset of
 744         * Kathmandu, Nepal is UTC+5:45)
 745         */
 746        if (min < 60 && hour < 24) {
 747                int offset = hour * 60 + min;
 748                if (*date == '-')
 749                        offset = -offset;
 750                *offp = offset;
 751        }
 752        return end - date;
 753}
 754
 755static void date_string(timestamp_t date, int offset, struct strbuf *buf)
 756{
 757        int sign = '+';
 758
 759        if (offset < 0) {
 760                offset = -offset;
 761                sign = '-';
 762        }
 763        strbuf_addf(buf, "%"PRItime" %c%02d%02d", date, sign, offset / 60, offset % 60);
 764}
 765
 766/*
 767 * Parse a string like "0 +0000" as ancient timestamp near epoch, but
 768 * only when it appears not as part of any other string.
 769 */
 770static int match_object_header_date(const char *date, timestamp_t *timestamp, int *offset)
 771{
 772        char *end;
 773        timestamp_t stamp;
 774        int ofs;
 775
 776        if (*date < '0' || '9' < *date)
 777                return -1;
 778        stamp = parse_timestamp(date, &end, 10);
 779        if (*end != ' ' || stamp == TIME_MAX || (end[1] != '+' && end[1] != '-'))
 780                return -1;
 781        date = end + 2;
 782        ofs = strtol(date, &end, 10);
 783        if ((*end != '\0' && (*end != '\n')) || end != date + 4)
 784                return -1;
 785        ofs = (ofs / 100) * 60 + (ofs % 100);
 786        if (date[-1] == '-')
 787                ofs = -ofs;
 788        *timestamp = stamp;
 789        *offset = ofs;
 790        return 0;
 791}
 792
 793/* Gr. strptime is crap for this; it doesn't have a way to require RFC2822
 794   (i.e. English) day/month names, and it doesn't work correctly with %z. */
 795int parse_date_basic(const char *date, timestamp_t *timestamp, int *offset)
 796{
 797        struct tm tm;
 798        int tm_gmt;
 799        timestamp_t dummy_timestamp;
 800        int dummy_offset;
 801
 802        if (!timestamp)
 803                timestamp = &dummy_timestamp;
 804        if (!offset)
 805                offset = &dummy_offset;
 806
 807        memset(&tm, 0, sizeof(tm));
 808        tm.tm_year = -1;
 809        tm.tm_mon = -1;
 810        tm.tm_mday = -1;
 811        tm.tm_isdst = -1;
 812        tm.tm_hour = -1;
 813        tm.tm_min = -1;
 814        tm.tm_sec = -1;
 815        *offset = -1;
 816        tm_gmt = 0;
 817
 818        if (*date == '@' &&
 819            !match_object_header_date(date + 1, timestamp, offset))
 820                return 0; /* success */
 821        for (;;) {
 822                int match = 0;
 823                unsigned char c = *date;
 824
 825                /* Stop at end of string or newline */
 826                if (!c || c == '\n')
 827                        break;
 828
 829                if (isalpha(c))
 830                        match = match_alpha(date, &tm, offset);
 831                else if (isdigit(c))
 832                        match = match_digit(date, &tm, offset, &tm_gmt);
 833                else if ((c == '-' || c == '+') && isdigit(date[1]))
 834                        match = match_tz(date, offset);
 835
 836                if (!match) {
 837                        /* BAD CRAP */
 838                        match = 1;
 839                }
 840
 841                date += match;
 842        }
 843
 844        /* do not use mktime(), which uses local timezone, here */
 845        *timestamp = tm_to_time_t(&tm);
 846        if (*timestamp == -1)
 847                return -1;
 848
 849        if (*offset == -1) {
 850                time_t temp_time;
 851
 852                /* gmtime_r() in match_digit() may have clobbered it */
 853                tm.tm_isdst = -1;
 854                temp_time = mktime(&tm);
 855                if ((time_t)*timestamp > temp_time) {
 856                        *offset = ((time_t)*timestamp - temp_time) / 60;
 857                } else {
 858                        *offset = -(int)((temp_time - (time_t)*timestamp) / 60);
 859                }
 860        }
 861
 862        if (!tm_gmt)
 863                *timestamp -= *offset * 60;
 864        return 0; /* success */
 865}
 866
 867int parse_expiry_date(const char *date, timestamp_t *timestamp)
 868{
 869        int errors = 0;
 870
 871        if (!strcmp(date, "never") || !strcmp(date, "false"))
 872                *timestamp = 0;
 873        else if (!strcmp(date, "all") || !strcmp(date, "now"))
 874                /*
 875                 * We take over "now" here, which usually translates
 876                 * to the current timestamp.  This is because the user
 877                 * really means to expire everything she has done in
 878                 * the past, and by definition reflogs are the record
 879                 * of the past, and there is nothing from the future
 880                 * to be kept.
 881                 */
 882                *timestamp = TIME_MAX;
 883        else
 884                *timestamp = approxidate_careful(date, &errors);
 885
 886        return errors;
 887}
 888
 889int parse_date(const char *date, struct strbuf *result)
 890{
 891        timestamp_t timestamp;
 892        int offset;
 893        if (parse_date_basic(date, &timestamp, &offset))
 894                return -1;
 895        date_string(timestamp, offset, result);
 896        return 0;
 897}
 898
 899static enum date_mode_type parse_date_type(const char *format, const char **end)
 900{
 901        if (skip_prefix(format, "relative", end))
 902                return DATE_RELATIVE;
 903        if (skip_prefix(format, "iso8601-strict", end) ||
 904            skip_prefix(format, "iso-strict", end))
 905                return DATE_ISO8601_STRICT;
 906        if (skip_prefix(format, "iso8601", end) ||
 907            skip_prefix(format, "iso", end))
 908                return DATE_ISO8601;
 909        if (skip_prefix(format, "rfc2822", end) ||
 910            skip_prefix(format, "rfc", end))
 911                return DATE_RFC2822;
 912        if (skip_prefix(format, "short", end))
 913                return DATE_SHORT;
 914        if (skip_prefix(format, "default", end))
 915                return DATE_NORMAL;
 916        if (skip_prefix(format, "human", end))
 917                return DATE_HUMAN;
 918        if (skip_prefix(format, "raw", end))
 919                return DATE_RAW;
 920        if (skip_prefix(format, "unix", end))
 921                return DATE_UNIX;
 922        if (skip_prefix(format, "format", end))
 923                return DATE_STRFTIME;
 924        /*
 925         * Please update $__git_log_date_formats in
 926         * git-completion.bash when you add new formats.
 927         */
 928
 929        die("unknown date format %s", format);
 930}
 931
 932void parse_date_format(const char *format, struct date_mode *mode)
 933{
 934        const char *p;
 935
 936        /* "auto:foo" is "if tty/pager, then foo, otherwise normal" */
 937        if (skip_prefix(format, "auto:", &p)) {
 938                if (isatty(1) || pager_in_use())
 939                        format = p;
 940                else
 941                        format = "default";
 942        }
 943
 944        /* historical alias */
 945        if (!strcmp(format, "local"))
 946                format = "default-local";
 947
 948        mode->type = parse_date_type(format, &p);
 949        mode->local = 0;
 950
 951        if (skip_prefix(p, "-local", &p))
 952                mode->local = 1;
 953
 954        if (mode->type == DATE_STRFTIME) {
 955                if (!skip_prefix(p, ":", &p))
 956                        die("date format missing colon separator: %s", format);
 957                mode->strftime_fmt = xstrdup(p);
 958        } else if (*p)
 959                die("unknown date format %s", format);
 960}
 961
 962void datestamp(struct strbuf *out)
 963{
 964        time_t now;
 965        int offset;
 966
 967        time(&now);
 968
 969        offset = tm_to_time_t(localtime(&now)) - now;
 970        offset /= 60;
 971
 972        date_string(now, offset, out);
 973}
 974
 975/*
 976 * Relative time update (eg "2 days ago").  If we haven't set the time
 977 * yet, we need to set it from current time.
 978 */
 979static time_t update_tm(struct tm *tm, struct tm *now, time_t sec)
 980{
 981        time_t n;
 982
 983        if (tm->tm_mday < 0)
 984                tm->tm_mday = now->tm_mday;
 985        if (tm->tm_mon < 0)
 986                tm->tm_mon = now->tm_mon;
 987        if (tm->tm_year < 0) {
 988                tm->tm_year = now->tm_year;
 989                if (tm->tm_mon > now->tm_mon)
 990                        tm->tm_year--;
 991        }
 992
 993        n = mktime(tm) - sec;
 994        localtime_r(&n, tm);
 995        return n;
 996}
 997
 998/*
 999 * Do we have a pending number at the end, or when
1000 * we see a new one? Let's assume it's a month day,
1001 * as in "Dec 6, 1992"
1002 */
1003static void pending_number(struct tm *tm, int *num)
1004{
1005        int number = *num;
1006
1007        if (number) {
1008                *num = 0;
1009                if (tm->tm_mday < 0 && number < 32)
1010                        tm->tm_mday = number;
1011                else if (tm->tm_mon < 0 && number < 13)
1012                        tm->tm_mon = number-1;
1013                else if (tm->tm_year < 0) {
1014                        if (number > 1969 && number < 2100)
1015                                tm->tm_year = number - 1900;
1016                        else if (number > 69 && number < 100)
1017                                tm->tm_year = number;
1018                        else if (number < 38)
1019                                tm->tm_year = 100 + number;
1020                        /* We screw up for number = 00 ? */
1021                }
1022        }
1023}
1024
1025static void date_now(struct tm *tm, struct tm *now, int *num)
1026{
1027        *num = 0;
1028        update_tm(tm, now, 0);
1029}
1030
1031static void date_yesterday(struct tm *tm, struct tm *now, int *num)
1032{
1033        *num = 0;
1034        update_tm(tm, now, 24*60*60);
1035}
1036
1037static void date_time(struct tm *tm, struct tm *now, int hour)
1038{
1039        if (tm->tm_hour < hour)
1040                update_tm(tm, now, 24*60*60);
1041        tm->tm_hour = hour;
1042        tm->tm_min = 0;
1043        tm->tm_sec = 0;
1044}
1045
1046static void date_midnight(struct tm *tm, struct tm *now, int *num)
1047{
1048        pending_number(tm, num);
1049        date_time(tm, now, 0);
1050}
1051
1052static void date_noon(struct tm *tm, struct tm *now, int *num)
1053{
1054        pending_number(tm, num);
1055        date_time(tm, now, 12);
1056}
1057
1058static void date_tea(struct tm *tm, struct tm *now, int *num)
1059{
1060        pending_number(tm, num);
1061        date_time(tm, now, 17);
1062}
1063
1064static void date_pm(struct tm *tm, struct tm *now, int *num)
1065{
1066        int hour, n = *num;
1067        *num = 0;
1068
1069        hour = tm->tm_hour;
1070        if (n) {
1071                hour = n;
1072                tm->tm_min = 0;
1073                tm->tm_sec = 0;
1074        }
1075        tm->tm_hour = (hour % 12) + 12;
1076}
1077
1078static void date_am(struct tm *tm, struct tm *now, int *num)
1079{
1080        int hour, n = *num;
1081        *num = 0;
1082
1083        hour = tm->tm_hour;
1084        if (n) {
1085                hour = n;
1086                tm->tm_min = 0;
1087                tm->tm_sec = 0;
1088        }
1089        tm->tm_hour = (hour % 12);
1090}
1091
1092static void date_never(struct tm *tm, struct tm *now, int *num)
1093{
1094        time_t n = 0;
1095        localtime_r(&n, tm);
1096        *num = 0;
1097}
1098
1099static const struct special {
1100        const char *name;
1101        void (*fn)(struct tm *, struct tm *, int *);
1102} special[] = {
1103        { "yesterday", date_yesterday },
1104        { "noon", date_noon },
1105        { "midnight", date_midnight },
1106        { "tea", date_tea },
1107        { "PM", date_pm },
1108        { "AM", date_am },
1109        { "never", date_never },
1110        { "now", date_now },
1111        { NULL }
1112};
1113
1114static const char *number_name[] = {
1115        "zero", "one", "two", "three", "four",
1116        "five", "six", "seven", "eight", "nine", "ten",
1117};
1118
1119static const struct typelen {
1120        const char *type;
1121        int length;
1122} typelen[] = {
1123        { "seconds", 1 },
1124        { "minutes", 60 },
1125        { "hours", 60*60 },
1126        { "days", 24*60*60 },
1127        { "weeks", 7*24*60*60 },
1128        { NULL }
1129};
1130
1131static const char *approxidate_alpha(const char *date, struct tm *tm, struct tm *now, int *num, int *touched)
1132{
1133        const struct typelen *tl;
1134        const struct special *s;
1135        const char *end = date;
1136        int i;
1137
1138        while (isalpha(*++end))
1139                ;
1140
1141        for (i = 0; i < 12; i++) {
1142                int match = match_string(date, month_names[i]);
1143                if (match >= 3) {
1144                        tm->tm_mon = i;
1145                        *touched = 1;
1146                        return end;
1147                }
1148        }
1149
1150        for (s = special; s->name; s++) {
1151                int len = strlen(s->name);
1152                if (match_string(date, s->name) == len) {
1153                        s->fn(tm, now, num);
1154                        *touched = 1;
1155                        return end;
1156                }
1157        }
1158
1159        if (!*num) {
1160                for (i = 1; i < 11; i++) {
1161                        int len = strlen(number_name[i]);
1162                        if (match_string(date, number_name[i]) == len) {
1163                                *num = i;
1164                                *touched = 1;
1165                                return end;
1166                        }
1167                }
1168                if (match_string(date, "last") == 4) {
1169                        *num = 1;
1170                        *touched = 1;
1171                }
1172                return end;
1173        }
1174
1175        tl = typelen;
1176        while (tl->type) {
1177                int len = strlen(tl->type);
1178                if (match_string(date, tl->type) >= len-1) {
1179                        update_tm(tm, now, tl->length * *num);
1180                        *num = 0;
1181                        *touched = 1;
1182                        return end;
1183                }
1184                tl++;
1185        }
1186
1187        for (i = 0; i < 7; i++) {
1188                int match = match_string(date, weekday_names[i]);
1189                if (match >= 3) {
1190                        int diff, n = *num -1;
1191                        *num = 0;
1192
1193                        diff = tm->tm_wday - i;
1194                        if (diff <= 0)
1195                                n++;
1196                        diff += 7*n;
1197
1198                        update_tm(tm, now, diff * 24 * 60 * 60);
1199                        *touched = 1;
1200                        return end;
1201                }
1202        }
1203
1204        if (match_string(date, "months") >= 5) {
1205                int n;
1206                update_tm(tm, now, 0); /* fill in date fields if needed */
1207                n = tm->tm_mon - *num;
1208                *num = 0;
1209                while (n < 0) {
1210                        n += 12;
1211                        tm->tm_year--;
1212                }
1213                tm->tm_mon = n;
1214                *touched = 1;
1215                return end;
1216        }
1217
1218        if (match_string(date, "years") >= 4) {
1219                update_tm(tm, now, 0); /* fill in date fields if needed */
1220                tm->tm_year -= *num;
1221                *num = 0;
1222                *touched = 1;
1223                return end;
1224        }
1225
1226        return end;
1227}
1228
1229static const char *approxidate_digit(const char *date, struct tm *tm, int *num,
1230                                     time_t now)
1231{
1232        char *end;
1233        timestamp_t number = parse_timestamp(date, &end, 10);
1234
1235        switch (*end) {
1236        case ':':
1237        case '.':
1238        case '/':
1239        case '-':
1240                if (isdigit(end[1])) {
1241                        int match = match_multi_number(number, *end, date, end,
1242                                                       tm, now);
1243                        if (match)
1244                                return date + match;
1245                }
1246        }
1247
1248        /* Accept zero-padding only for small numbers ("Dec 02", never "Dec 0002") */
1249        if (date[0] != '0' || end - date <= 2)
1250                *num = number;
1251        return end;
1252}
1253
1254static timestamp_t approxidate_str(const char *date,
1255                                   const struct timeval *tv,
1256                                   int *error_ret)
1257{
1258        int number = 0;
1259        int touched = 0;
1260        struct tm tm, now;
1261        time_t time_sec;
1262
1263        time_sec = tv->tv_sec;
1264        localtime_r(&time_sec, &tm);
1265        now = tm;
1266
1267        tm.tm_year = -1;
1268        tm.tm_mon = -1;
1269        tm.tm_mday = -1;
1270
1271        for (;;) {
1272                unsigned char c = *date;
1273                if (!c)
1274                        break;
1275                date++;
1276                if (isdigit(c)) {
1277                        pending_number(&tm, &number);
1278                        date = approxidate_digit(date-1, &tm, &number, time_sec);
1279                        touched = 1;
1280                        continue;
1281                }
1282                if (isalpha(c))
1283                        date = approxidate_alpha(date-1, &tm, &now, &number, &touched);
1284        }
1285        pending_number(&tm, &number);
1286        if (!touched)
1287                *error_ret = 1;
1288        return (timestamp_t)update_tm(&tm, &now, 0);
1289}
1290
1291timestamp_t approxidate_relative(const char *date, const struct timeval *tv)
1292{
1293        timestamp_t timestamp;
1294        int offset;
1295        int errors = 0;
1296
1297        if (!parse_date_basic(date, &timestamp, &offset))
1298                return timestamp;
1299        return approxidate_str(date, tv, &errors);
1300}
1301
1302timestamp_t approxidate_careful(const char *date, int *error_ret)
1303{
1304        struct timeval tv;
1305        timestamp_t timestamp;
1306        int offset;
1307        int dummy = 0;
1308        if (!error_ret)
1309                error_ret = &dummy;
1310
1311        if (!parse_date_basic(date, &timestamp, &offset)) {
1312                *error_ret = 0;
1313                return timestamp;
1314        }
1315
1316        get_time(&tv);
1317        return approxidate_str(date, &tv, error_ret);
1318}
1319
1320int date_overflows(timestamp_t t)
1321{
1322        time_t sys;
1323
1324        /* If we overflowed our timestamp data type, that's bad... */
1325        if ((uintmax_t)t >= TIME_MAX)
1326                return 1;
1327
1328        /*
1329         * ...but we also are going to feed the result to system
1330         * functions that expect time_t, which is often "signed long".
1331         * Make sure that we fit into time_t, as well.
1332         */
1333        sys = t;
1334        return t != sys || (t < 1) != (sys < 1);
1335}