date.con commit Merge branch 'jc/merge' (bcd1ecd)
   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(unsigned long 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        return time + minutes * 60;
  50}
  51
  52/*
  53 * The "tz" thing is passed in as this strange "decimal parse of tz"
  54 * thing, which means that tz -0100 is passed in as the integer -100,
  55 * even though it means "sixty minutes off"
  56 */
  57static struct tm *time_to_tm(unsigned long time, int tz)
  58{
  59        time_t t = gm_time_t(time, tz);
  60        return gmtime(&t);
  61}
  62
  63/*
  64 * What value of "tz" was in effect back then at "time" in the
  65 * local timezone?
  66 */
  67static int local_tzoffset(unsigned long time)
  68{
  69        time_t t, t_local;
  70        struct tm tm;
  71        int offset, eastwest;
  72
  73        t = time;
  74        localtime_r(&t, &tm);
  75        t_local = tm_to_time_t(&tm);
  76
  77        if (t_local < t) {
  78                eastwest = -1;
  79                offset = t - t_local;
  80        } else {
  81                eastwest = 1;
  82                offset = t_local - t;
  83        }
  84        offset /= 60; /* in minutes */
  85        offset = (offset % 60) + ((offset / 60) * 100);
  86        return offset * eastwest;
  87}
  88
  89void show_date_relative(unsigned long time, int tz,
  90                               const struct timeval *now,
  91                               struct strbuf *timebuf)
  92{
  93        unsigned long diff;
  94        if (now->tv_sec < time) {
  95                strbuf_addstr(timebuf, _("in the future"));
  96                return;
  97        }
  98        diff = now->tv_sec - time;
  99        if (diff < 90) {
 100                strbuf_addf(timebuf,
 101                         Q_("%lu second ago", "%lu seconds ago", diff), diff);
 102                return;
 103        }
 104        /* Turn it into minutes */
 105        diff = (diff + 30) / 60;
 106        if (diff < 90) {
 107                strbuf_addf(timebuf,
 108                         Q_("%lu minute ago", "%lu minutes ago", diff), diff);
 109                return;
 110        }
 111        /* Turn it into hours */
 112        diff = (diff + 30) / 60;
 113        if (diff < 36) {
 114                strbuf_addf(timebuf,
 115                         Q_("%lu hour ago", "%lu hours ago", diff), diff);
 116                return;
 117        }
 118        /* We deal with number of days from here on */
 119        diff = (diff + 12) / 24;
 120        if (diff < 14) {
 121                strbuf_addf(timebuf,
 122                         Q_("%lu day ago", "%lu days ago", diff), diff);
 123                return;
 124        }
 125        /* Say weeks for the past 10 weeks or so */
 126        if (diff < 70) {
 127                strbuf_addf(timebuf,
 128                         Q_("%lu week ago", "%lu weeks ago", (diff + 3) / 7),
 129                         (diff + 3) / 7);
 130                return;
 131        }
 132        /* Say months for the past 12 months or so */
 133        if (diff < 365) {
 134                strbuf_addf(timebuf,
 135                         Q_("%lu month ago", "%lu months ago", (diff + 15) / 30),
 136                         (diff + 15) / 30);
 137                return;
 138        }
 139        /* Give years and months for 5 years or so */
 140        if (diff < 1825) {
 141                unsigned long totalmonths = (diff * 12 * 2 + 365) / (365 * 2);
 142                unsigned long years = totalmonths / 12;
 143                unsigned long months = totalmonths % 12;
 144                if (months) {
 145                        struct strbuf sb = STRBUF_INIT;
 146                        strbuf_addf(&sb, Q_("%lu year", "%lu years", years), years);
 147                        strbuf_addf(timebuf,
 148                                 /* TRANSLATORS: "%s" is "<n> years" */
 149                                 Q_("%s, %lu month ago", "%s, %lu months ago", months),
 150                                 sb.buf, months);
 151                        strbuf_release(&sb);
 152                } else
 153                        strbuf_addf(timebuf,
 154                                 Q_("%lu year ago", "%lu years ago", years), years);
 155                return;
 156        }
 157        /* Otherwise, just years. Centuries is probably overkill. */
 158        strbuf_addf(timebuf,
 159                 Q_("%lu year ago", "%lu years ago", (diff + 183) / 365),
 160                 (diff + 183) / 365);
 161}
 162
 163const char *show_date(unsigned long time, int tz, enum date_mode mode)
 164{
 165        struct tm *tm;
 166        static struct strbuf timebuf = STRBUF_INIT;
 167
 168        if (mode == DATE_RAW) {
 169                strbuf_reset(&timebuf);
 170                strbuf_addf(&timebuf, "%lu %+05d", time, tz);
 171                return timebuf.buf;
 172        }
 173
 174        if (mode == DATE_RELATIVE) {
 175                struct timeval now;
 176
 177                strbuf_reset(&timebuf);
 178                gettimeofday(&now, NULL);
 179                show_date_relative(time, tz, &now, &timebuf);
 180                return timebuf.buf;
 181        }
 182
 183        if (mode == DATE_LOCAL)
 184                tz = local_tzoffset(time);
 185
 186        tm = time_to_tm(time, tz);
 187        if (!tm) {
 188                tm = time_to_tm(0, 0);
 189                tz = 0;
 190        }
 191
 192        strbuf_reset(&timebuf);
 193        if (mode == DATE_SHORT)
 194                strbuf_addf(&timebuf, "%04d-%02d-%02d", tm->tm_year + 1900,
 195                                tm->tm_mon + 1, tm->tm_mday);
 196        else if (mode == DATE_ISO8601)
 197                strbuf_addf(&timebuf, "%04d-%02d-%02d %02d:%02d:%02d %+05d",
 198                                tm->tm_year + 1900,
 199                                tm->tm_mon + 1,
 200                                tm->tm_mday,
 201                                tm->tm_hour, tm->tm_min, tm->tm_sec,
 202                                tz);
 203        else if (mode == DATE_ISO8601_STRICT) {
 204                char sign = (tz >= 0) ? '+' : '-';
 205                tz = abs(tz);
 206                strbuf_addf(&timebuf, "%04d-%02d-%02dT%02d:%02d:%02d%c%02d:%02d",
 207                                tm->tm_year + 1900,
 208                                tm->tm_mon + 1,
 209                                tm->tm_mday,
 210                                tm->tm_hour, tm->tm_min, tm->tm_sec,
 211                                sign, tz / 100, tz % 100);
 212        } else if (mode == DATE_RFC2822)
 213                strbuf_addf(&timebuf, "%.3s, %d %.3s %d %02d:%02d:%02d %+05d",
 214                        weekday_names[tm->tm_wday], tm->tm_mday,
 215                        month_names[tm->tm_mon], tm->tm_year + 1900,
 216                        tm->tm_hour, tm->tm_min, tm->tm_sec, tz);
 217        else
 218                strbuf_addf(&timebuf, "%.3s %.3s %d %02d:%02d:%02d %d%c%+05d",
 219                                weekday_names[tm->tm_wday],
 220                                month_names[tm->tm_mon],
 221                                tm->tm_mday,
 222                                tm->tm_hour, tm->tm_min, tm->tm_sec,
 223                                tm->tm_year + 1900,
 224                                (mode == DATE_LOCAL) ? 0 : ' ',
 225                                tz);
 226        return timebuf.buf;
 227}
 228
 229/*
 230 * Check these. And note how it doesn't do the summer-time conversion.
 231 *
 232 * In my world, it's always summer, and things are probably a bit off
 233 * in other ways too.
 234 */
 235static const struct {
 236        const char *name;
 237        int offset;
 238        int dst;
 239} timezone_names[] = {
 240        { "IDLW", -12, 0, },    /* International Date Line West */
 241        { "NT",   -11, 0, },    /* Nome */
 242        { "CAT",  -10, 0, },    /* Central Alaska */
 243        { "HST",  -10, 0, },    /* Hawaii Standard */
 244        { "HDT",  -10, 1, },    /* Hawaii Daylight */
 245        { "YST",   -9, 0, },    /* Yukon Standard */
 246        { "YDT",   -9, 1, },    /* Yukon Daylight */
 247        { "PST",   -8, 0, },    /* Pacific Standard */
 248        { "PDT",   -8, 1, },    /* Pacific Daylight */
 249        { "MST",   -7, 0, },    /* Mountain Standard */
 250        { "MDT",   -7, 1, },    /* Mountain Daylight */
 251        { "CST",   -6, 0, },    /* Central Standard */
 252        { "CDT",   -6, 1, },    /* Central Daylight */
 253        { "EST",   -5, 0, },    /* Eastern Standard */
 254        { "EDT",   -5, 1, },    /* Eastern Daylight */
 255        { "AST",   -3, 0, },    /* Atlantic Standard */
 256        { "ADT",   -3, 1, },    /* Atlantic Daylight */
 257        { "WAT",   -1, 0, },    /* West Africa */
 258
 259        { "GMT",    0, 0, },    /* Greenwich Mean */
 260        { "UTC",    0, 0, },    /* Universal (Coordinated) */
 261        { "Z",      0, 0, },    /* Zulu, alias for UTC */
 262
 263        { "WET",    0, 0, },    /* Western European */
 264        { "BST",    0, 1, },    /* British Summer */
 265        { "CET",   +1, 0, },    /* Central European */
 266        { "MET",   +1, 0, },    /* Middle European */
 267        { "MEWT",  +1, 0, },    /* Middle European Winter */
 268        { "MEST",  +1, 1, },    /* Middle European Summer */
 269        { "CEST",  +1, 1, },    /* Central European Summer */
 270        { "MESZ",  +1, 1, },    /* Middle European Summer */
 271        { "FWT",   +1, 0, },    /* French Winter */
 272        { "FST",   +1, 1, },    /* French Summer */
 273        { "EET",   +2, 0, },    /* Eastern Europe, USSR Zone 1 */
 274        { "EEST",  +2, 1, },    /* Eastern European Daylight */
 275        { "WAST",  +7, 0, },    /* West Australian Standard */
 276        { "WADT",  +7, 1, },    /* West Australian Daylight */
 277        { "CCT",   +8, 0, },    /* China Coast, USSR Zone 7 */
 278        { "JST",   +9, 0, },    /* Japan Standard, USSR Zone 8 */
 279        { "EAST", +10, 0, },    /* Eastern Australian Standard */
 280        { "EADT", +10, 1, },    /* Eastern Australian Daylight */
 281        { "GST",  +10, 0, },    /* Guam Standard, USSR Zone 9 */
 282        { "NZT",  +12, 0, },    /* New Zealand */
 283        { "NZST", +12, 0, },    /* New Zealand Standard */
 284        { "NZDT", +12, 1, },    /* New Zealand Daylight */
 285        { "IDLE", +12, 0, },    /* International Date Line East */
 286};
 287
 288static int match_string(const char *date, const char *str)
 289{
 290        int i = 0;
 291
 292        for (i = 0; *date; date++, str++, i++) {
 293                if (*date == *str)
 294                        continue;
 295                if (toupper(*date) == toupper(*str))
 296                        continue;
 297                if (!isalnum(*date))
 298                        break;
 299                return 0;
 300        }
 301        return i;
 302}
 303
 304static int skip_alpha(const char *date)
 305{
 306        int i = 0;
 307        do {
 308                i++;
 309        } while (isalpha(date[i]));
 310        return i;
 311}
 312
 313/*
 314* Parse month, weekday, or timezone name
 315*/
 316static int match_alpha(const char *date, struct tm *tm, int *offset)
 317{
 318        int i;
 319
 320        for (i = 0; i < 12; i++) {
 321                int match = match_string(date, month_names[i]);
 322                if (match >= 3) {
 323                        tm->tm_mon = i;
 324                        return match;
 325                }
 326        }
 327
 328        for (i = 0; i < 7; i++) {
 329                int match = match_string(date, weekday_names[i]);
 330                if (match >= 3) {
 331                        tm->tm_wday = i;
 332                        return match;
 333                }
 334        }
 335
 336        for (i = 0; i < ARRAY_SIZE(timezone_names); i++) {
 337                int match = match_string(date, timezone_names[i].name);
 338                if (match >= 3 || match == strlen(timezone_names[i].name)) {
 339                        int off = timezone_names[i].offset;
 340
 341                        /* This is bogus, but we like summer */
 342                        off += timezone_names[i].dst;
 343
 344                        /* Only use the tz name offset if we don't have anything better */
 345                        if (*offset == -1)
 346                                *offset = 60*off;
 347
 348                        return match;
 349                }
 350        }
 351
 352        if (match_string(date, "PM") == 2) {
 353                tm->tm_hour = (tm->tm_hour % 12) + 12;
 354                return 2;
 355        }
 356
 357        if (match_string(date, "AM") == 2) {
 358                tm->tm_hour = (tm->tm_hour % 12) + 0;
 359                return 2;
 360        }
 361
 362        /* BAD CRAP */
 363        return skip_alpha(date);
 364}
 365
 366static int is_date(int year, int month, int day, struct tm *now_tm, time_t now, struct tm *tm)
 367{
 368        if (month > 0 && month < 13 && day > 0 && day < 32) {
 369                struct tm check = *tm;
 370                struct tm *r = (now_tm ? &check : tm);
 371                time_t specified;
 372
 373                r->tm_mon = month - 1;
 374                r->tm_mday = day;
 375                if (year == -1) {
 376                        if (!now_tm)
 377                                return 1;
 378                        r->tm_year = now_tm->tm_year;
 379                }
 380                else if (year >= 1970 && year < 2100)
 381                        r->tm_year = year - 1900;
 382                else if (year > 70 && year < 100)
 383                        r->tm_year = year;
 384                else if (year < 38)
 385                        r->tm_year = year + 100;
 386                else
 387                        return 0;
 388                if (!now_tm)
 389                        return 1;
 390
 391                specified = tm_to_time_t(r);
 392
 393                /* Be it commit time or author time, it does not make
 394                 * sense to specify timestamp way into the future.  Make
 395                 * sure it is not later than ten days from now...
 396                 */
 397                if ((specified != -1) && (now + 10*24*3600 < specified))
 398                        return 0;
 399                tm->tm_mon = r->tm_mon;
 400                tm->tm_mday = r->tm_mday;
 401                if (year != -1)
 402                        tm->tm_year = r->tm_year;
 403                return 1;
 404        }
 405        return 0;
 406}
 407
 408static int match_multi_number(unsigned long num, char c, const char *date,
 409                              char *end, struct tm *tm, time_t now)
 410{
 411        struct tm now_tm;
 412        struct tm *refuse_future;
 413        long num2, num3;
 414
 415        num2 = strtol(end+1, &end, 10);
 416        num3 = -1;
 417        if (*end == c && isdigit(end[1]))
 418                num3 = strtol(end+1, &end, 10);
 419
 420        /* Time? Date? */
 421        switch (c) {
 422        case ':':
 423                if (num3 < 0)
 424                        num3 = 0;
 425                if (num < 25 && num2 >= 0 && num2 < 60 && num3 >= 0 && num3 <= 60) {
 426                        tm->tm_hour = num;
 427                        tm->tm_min = num2;
 428                        tm->tm_sec = num3;
 429                        break;
 430                }
 431                return 0;
 432
 433        case '-':
 434        case '/':
 435        case '.':
 436                if (!now)
 437                        now = time(NULL);
 438                refuse_future = NULL;
 439                if (gmtime_r(&now, &now_tm))
 440                        refuse_future = &now_tm;
 441
 442                if (num > 70) {
 443                        /* yyyy-mm-dd? */
 444                        if (is_date(num, num2, num3, NULL, now, tm))
 445                                break;
 446                        /* yyyy-dd-mm? */
 447                        if (is_date(num, num3, num2, NULL, now, tm))
 448                                break;
 449                }
 450                /* Our eastern European friends say dd.mm.yy[yy]
 451                 * is the norm there, so giving precedence to
 452                 * mm/dd/yy[yy] form only when separator is not '.'
 453                 */
 454                if (c != '.' &&
 455                    is_date(num3, num, num2, refuse_future, now, tm))
 456                        break;
 457                /* European dd.mm.yy[yy] or funny US dd/mm/yy[yy] */
 458                if (is_date(num3, num2, num, refuse_future, now, tm))
 459                        break;
 460                /* Funny European mm.dd.yy */
 461                if (c == '.' &&
 462                    is_date(num3, num, num2, refuse_future, now, tm))
 463                        break;
 464                return 0;
 465        }
 466        return end - date;
 467}
 468
 469/*
 470 * Have we filled in any part of the time/date yet?
 471 * We just do a binary 'and' to see if the sign bit
 472 * is set in all the values.
 473 */
 474static inline int nodate(struct tm *tm)
 475{
 476        return (tm->tm_year &
 477                tm->tm_mon &
 478                tm->tm_mday &
 479                tm->tm_hour &
 480                tm->tm_min &
 481                tm->tm_sec) < 0;
 482}
 483
 484/*
 485 * We've seen a digit. Time? Year? Date?
 486 */
 487static int match_digit(const char *date, struct tm *tm, int *offset, int *tm_gmt)
 488{
 489        int n;
 490        char *end;
 491        unsigned long num;
 492
 493        num = strtoul(date, &end, 10);
 494
 495        /*
 496         * Seconds since 1970? We trigger on that for any numbers with
 497         * more than 8 digits. This is because we don't want to rule out
 498         * numbers like 20070606 as a YYYYMMDD date.
 499         */
 500        if (num >= 100000000 && nodate(tm)) {
 501                time_t time = num;
 502                if (gmtime_r(&time, tm)) {
 503                        *tm_gmt = 1;
 504                        return end - date;
 505                }
 506        }
 507
 508        /*
 509         * Check for special formats: num[-.:/]num[same]num
 510         */
 511        switch (*end) {
 512        case ':':
 513        case '.':
 514        case '/':
 515        case '-':
 516                if (isdigit(end[1])) {
 517                        int match = match_multi_number(num, *end, date, end, tm, 0);
 518                        if (match)
 519                                return match;
 520                }
 521        }
 522
 523        /*
 524         * None of the special formats? Try to guess what
 525         * the number meant. We use the number of digits
 526         * to make a more educated guess..
 527         */
 528        n = 0;
 529        do {
 530                n++;
 531        } while (isdigit(date[n]));
 532
 533        /* Four-digit year or a timezone? */
 534        if (n == 4) {
 535                if (num <= 1400 && *offset == -1) {
 536                        unsigned int minutes = num % 100;
 537                        unsigned int hours = num / 100;
 538                        *offset = hours*60 + minutes;
 539                } else if (num > 1900 && num < 2100)
 540                        tm->tm_year = num - 1900;
 541                return n;
 542        }
 543
 544        /*
 545         * Ignore lots of numerals. We took care of 4-digit years above.
 546         * Days or months must be one or two digits.
 547         */
 548        if (n > 2)
 549                return n;
 550
 551        /*
 552         * NOTE! We will give precedence to day-of-month over month or
 553         * year numbers in the 1-12 range. So 05 is always "mday 5",
 554         * unless we already have a mday..
 555         *
 556         * IOW, 01 Apr 05 parses as "April 1st, 2005".
 557         */
 558        if (num > 0 && num < 32 && tm->tm_mday < 0) {
 559                tm->tm_mday = num;
 560                return n;
 561        }
 562
 563        /* Two-digit year? */
 564        if (n == 2 && tm->tm_year < 0) {
 565                if (num < 10 && tm->tm_mday >= 0) {
 566                        tm->tm_year = num + 100;
 567                        return n;
 568                }
 569                if (num >= 70) {
 570                        tm->tm_year = num;
 571                        return n;
 572                }
 573        }
 574
 575        if (num > 0 && num < 13 && tm->tm_mon < 0)
 576                tm->tm_mon = num-1;
 577
 578        return n;
 579}
 580
 581static int match_tz(const char *date, int *offp)
 582{
 583        char *end;
 584        int hour = strtoul(date + 1, &end, 10);
 585        int n = end - (date + 1);
 586        int min = 0;
 587
 588        if (n == 4) {
 589                /* hhmm */
 590                min = hour % 100;
 591                hour = hour / 100;
 592        } else if (n != 2) {
 593                min = 99; /* random crap */
 594        } else if (*end == ':') {
 595                /* hh:mm? */
 596                min = strtoul(end + 1, &end, 10);
 597                if (end - (date + 1) != 5)
 598                        min = 99; /* random crap */
 599        } /* otherwise we parsed "hh" */
 600
 601        /*
 602         * Don't accept any random crap. Even though some places have
 603         * offset larger than 12 hours (e.g. Pacific/Kiritimati is at
 604         * UTC+14), there is something wrong if hour part is much
 605         * larger than that. We might also want to check that the
 606         * minutes are divisible by 15 or something too. (Offset of
 607         * Kathmandu, Nepal is UTC+5:45)
 608         */
 609        if (min < 60 && hour < 24) {
 610                int offset = hour * 60 + min;
 611                if (*date == '-')
 612                        offset = -offset;
 613                *offp = offset;
 614        }
 615        return end - date;
 616}
 617
 618static void date_string(unsigned long date, int offset, struct strbuf *buf)
 619{
 620        int sign = '+';
 621
 622        if (offset < 0) {
 623                offset = -offset;
 624                sign = '-';
 625        }
 626        strbuf_addf(buf, "%lu %c%02d%02d", date, sign, offset / 60, offset % 60);
 627}
 628
 629/*
 630 * Parse a string like "0 +0000" as ancient timestamp near epoch, but
 631 * only when it appears not as part of any other string.
 632 */
 633static int match_object_header_date(const char *date, unsigned long *timestamp, int *offset)
 634{
 635        char *end;
 636        unsigned long stamp;
 637        int ofs;
 638
 639        if (*date < '0' || '9' < *date)
 640                return -1;
 641        stamp = strtoul(date, &end, 10);
 642        if (*end != ' ' || stamp == ULONG_MAX || (end[1] != '+' && end[1] != '-'))
 643                return -1;
 644        date = end + 2;
 645        ofs = strtol(date, &end, 10);
 646        if ((*end != '\0' && (*end != '\n')) || end != date + 4)
 647                return -1;
 648        ofs = (ofs / 100) * 60 + (ofs % 100);
 649        if (date[-1] == '-')
 650                ofs = -ofs;
 651        *timestamp = stamp;
 652        *offset = ofs;
 653        return 0;
 654}
 655
 656/* Gr. strptime is crap for this; it doesn't have a way to require RFC2822
 657   (i.e. English) day/month names, and it doesn't work correctly with %z. */
 658int parse_date_basic(const char *date, unsigned long *timestamp, int *offset)
 659{
 660        struct tm tm;
 661        int tm_gmt;
 662        unsigned long dummy_timestamp;
 663        int dummy_offset;
 664
 665        if (!timestamp)
 666                timestamp = &dummy_timestamp;
 667        if (!offset)
 668                offset = &dummy_offset;
 669
 670        memset(&tm, 0, sizeof(tm));
 671        tm.tm_year = -1;
 672        tm.tm_mon = -1;
 673        tm.tm_mday = -1;
 674        tm.tm_isdst = -1;
 675        tm.tm_hour = -1;
 676        tm.tm_min = -1;
 677        tm.tm_sec = -1;
 678        *offset = -1;
 679        tm_gmt = 0;
 680
 681        if (*date == '@' &&
 682            !match_object_header_date(date + 1, timestamp, offset))
 683                return 0; /* success */
 684        for (;;) {
 685                int match = 0;
 686                unsigned char c = *date;
 687
 688                /* Stop at end of string or newline */
 689                if (!c || c == '\n')
 690                        break;
 691
 692                if (isalpha(c))
 693                        match = match_alpha(date, &tm, offset);
 694                else if (isdigit(c))
 695                        match = match_digit(date, &tm, offset, &tm_gmt);
 696                else if ((c == '-' || c == '+') && isdigit(date[1]))
 697                        match = match_tz(date, offset);
 698
 699                if (!match) {
 700                        /* BAD CRAP */
 701                        match = 1;
 702                }
 703
 704                date += match;
 705        }
 706
 707        /* do not use mktime(), which uses local timezone, here */
 708        *timestamp = tm_to_time_t(&tm);
 709        if (*timestamp == -1)
 710                return -1;
 711
 712        if (*offset == -1) {
 713                time_t temp_time;
 714
 715                /* gmtime_r() in match_digit() may have clobbered it */
 716                tm.tm_isdst = -1;
 717                temp_time = mktime(&tm);
 718                if ((time_t)*timestamp > temp_time) {
 719                        *offset = ((time_t)*timestamp - temp_time) / 60;
 720                } else {
 721                        *offset = -(int)((temp_time - (time_t)*timestamp) / 60);
 722                }
 723        }
 724
 725        if (!tm_gmt)
 726                *timestamp -= *offset * 60;
 727        return 0; /* success */
 728}
 729
 730int parse_expiry_date(const char *date, unsigned long *timestamp)
 731{
 732        int errors = 0;
 733
 734        if (!strcmp(date, "never") || !strcmp(date, "false"))
 735                *timestamp = 0;
 736        else if (!strcmp(date, "all") || !strcmp(date, "now"))
 737                /*
 738                 * We take over "now" here, which usually translates
 739                 * to the current timestamp.  This is because the user
 740                 * really means to expire everything she has done in
 741                 * the past, and by definition reflogs are the record
 742                 * of the past, and there is nothing from the future
 743                 * to be kept.
 744                 */
 745                *timestamp = ULONG_MAX;
 746        else
 747                *timestamp = approxidate_careful(date, &errors);
 748
 749        return errors;
 750}
 751
 752int parse_date(const char *date, struct strbuf *result)
 753{
 754        unsigned long timestamp;
 755        int offset;
 756        if (parse_date_basic(date, &timestamp, &offset))
 757                return -1;
 758        date_string(timestamp, offset, result);
 759        return 0;
 760}
 761
 762enum date_mode parse_date_format(const char *format)
 763{
 764        if (!strcmp(format, "relative"))
 765                return DATE_RELATIVE;
 766        else if (!strcmp(format, "iso8601") ||
 767                 !strcmp(format, "iso"))
 768                return DATE_ISO8601;
 769        else if (!strcmp(format, "iso8601-strict") ||
 770                 !strcmp(format, "iso-strict"))
 771                return DATE_ISO8601_STRICT;
 772        else if (!strcmp(format, "rfc2822") ||
 773                 !strcmp(format, "rfc"))
 774                return DATE_RFC2822;
 775        else if (!strcmp(format, "short"))
 776                return DATE_SHORT;
 777        else if (!strcmp(format, "local"))
 778                return DATE_LOCAL;
 779        else if (!strcmp(format, "default"))
 780                return DATE_NORMAL;
 781        else if (!strcmp(format, "raw"))
 782                return DATE_RAW;
 783        else
 784                die("unknown date format %s", format);
 785}
 786
 787void datestamp(struct strbuf *out)
 788{
 789        time_t now;
 790        int offset;
 791
 792        time(&now);
 793
 794        offset = tm_to_time_t(localtime(&now)) - now;
 795        offset /= 60;
 796
 797        date_string(now, offset, out);
 798}
 799
 800/*
 801 * Relative time update (eg "2 days ago").  If we haven't set the time
 802 * yet, we need to set it from current time.
 803 */
 804static unsigned long update_tm(struct tm *tm, struct tm *now, unsigned long sec)
 805{
 806        time_t n;
 807
 808        if (tm->tm_mday < 0)
 809                tm->tm_mday = now->tm_mday;
 810        if (tm->tm_mon < 0)
 811                tm->tm_mon = now->tm_mon;
 812        if (tm->tm_year < 0) {
 813                tm->tm_year = now->tm_year;
 814                if (tm->tm_mon > now->tm_mon)
 815                        tm->tm_year--;
 816        }
 817
 818        n = mktime(tm) - sec;
 819        localtime_r(&n, tm);
 820        return n;
 821}
 822
 823static void date_now(struct tm *tm, struct tm *now, int *num)
 824{
 825        update_tm(tm, now, 0);
 826}
 827
 828static void date_yesterday(struct tm *tm, struct tm *now, int *num)
 829{
 830        update_tm(tm, now, 24*60*60);
 831}
 832
 833static void date_time(struct tm *tm, struct tm *now, int hour)
 834{
 835        if (tm->tm_hour < hour)
 836                date_yesterday(tm, now, NULL);
 837        tm->tm_hour = hour;
 838        tm->tm_min = 0;
 839        tm->tm_sec = 0;
 840}
 841
 842static void date_midnight(struct tm *tm, struct tm *now, int *num)
 843{
 844        date_time(tm, now, 0);
 845}
 846
 847static void date_noon(struct tm *tm, struct tm *now, int *num)
 848{
 849        date_time(tm, now, 12);
 850}
 851
 852static void date_tea(struct tm *tm, struct tm *now, int *num)
 853{
 854        date_time(tm, now, 17);
 855}
 856
 857static void date_pm(struct tm *tm, struct tm *now, int *num)
 858{
 859        int hour, n = *num;
 860        *num = 0;
 861
 862        hour = tm->tm_hour;
 863        if (n) {
 864                hour = n;
 865                tm->tm_min = 0;
 866                tm->tm_sec = 0;
 867        }
 868        tm->tm_hour = (hour % 12) + 12;
 869}
 870
 871static void date_am(struct tm *tm, struct tm *now, int *num)
 872{
 873        int hour, n = *num;
 874        *num = 0;
 875
 876        hour = tm->tm_hour;
 877        if (n) {
 878                hour = n;
 879                tm->tm_min = 0;
 880                tm->tm_sec = 0;
 881        }
 882        tm->tm_hour = (hour % 12);
 883}
 884
 885static void date_never(struct tm *tm, struct tm *now, int *num)
 886{
 887        time_t n = 0;
 888        localtime_r(&n, tm);
 889}
 890
 891static const struct special {
 892        const char *name;
 893        void (*fn)(struct tm *, struct tm *, int *);
 894} special[] = {
 895        { "yesterday", date_yesterday },
 896        { "noon", date_noon },
 897        { "midnight", date_midnight },
 898        { "tea", date_tea },
 899        { "PM", date_pm },
 900        { "AM", date_am },
 901        { "never", date_never },
 902        { "now", date_now },
 903        { NULL }
 904};
 905
 906static const char *number_name[] = {
 907        "zero", "one", "two", "three", "four",
 908        "five", "six", "seven", "eight", "nine", "ten",
 909};
 910
 911static const struct typelen {
 912        const char *type;
 913        int length;
 914} typelen[] = {
 915        { "seconds", 1 },
 916        { "minutes", 60 },
 917        { "hours", 60*60 },
 918        { "days", 24*60*60 },
 919        { "weeks", 7*24*60*60 },
 920        { NULL }
 921};
 922
 923static const char *approxidate_alpha(const char *date, struct tm *tm, struct tm *now, int *num, int *touched)
 924{
 925        const struct typelen *tl;
 926        const struct special *s;
 927        const char *end = date;
 928        int i;
 929
 930        while (isalpha(*++end))
 931                ;
 932
 933        for (i = 0; i < 12; i++) {
 934                int match = match_string(date, month_names[i]);
 935                if (match >= 3) {
 936                        tm->tm_mon = i;
 937                        *touched = 1;
 938                        return end;
 939                }
 940        }
 941
 942        for (s = special; s->name; s++) {
 943                int len = strlen(s->name);
 944                if (match_string(date, s->name) == len) {
 945                        s->fn(tm, now, num);
 946                        *touched = 1;
 947                        return end;
 948                }
 949        }
 950
 951        if (!*num) {
 952                for (i = 1; i < 11; i++) {
 953                        int len = strlen(number_name[i]);
 954                        if (match_string(date, number_name[i]) == len) {
 955                                *num = i;
 956                                *touched = 1;
 957                                return end;
 958                        }
 959                }
 960                if (match_string(date, "last") == 4) {
 961                        *num = 1;
 962                        *touched = 1;
 963                }
 964                return end;
 965        }
 966
 967        tl = typelen;
 968        while (tl->type) {
 969                int len = strlen(tl->type);
 970                if (match_string(date, tl->type) >= len-1) {
 971                        update_tm(tm, now, tl->length * *num);
 972                        *num = 0;
 973                        *touched = 1;
 974                        return end;
 975                }
 976                tl++;
 977        }
 978
 979        for (i = 0; i < 7; i++) {
 980                int match = match_string(date, weekday_names[i]);
 981                if (match >= 3) {
 982                        int diff, n = *num -1;
 983                        *num = 0;
 984
 985                        diff = tm->tm_wday - i;
 986                        if (diff <= 0)
 987                                n++;
 988                        diff += 7*n;
 989
 990                        update_tm(tm, now, diff * 24 * 60 * 60);
 991                        *touched = 1;
 992                        return end;
 993                }
 994        }
 995
 996        if (match_string(date, "months") >= 5) {
 997                int n;
 998                update_tm(tm, now, 0); /* fill in date fields if needed */
 999                n = tm->tm_mon - *num;
1000                *num = 0;
1001                while (n < 0) {
1002                        n += 12;
1003                        tm->tm_year--;
1004                }
1005                tm->tm_mon = n;
1006                *touched = 1;
1007                return end;
1008        }
1009
1010        if (match_string(date, "years") >= 4) {
1011                update_tm(tm, now, 0); /* fill in date fields if needed */
1012                tm->tm_year -= *num;
1013                *num = 0;
1014                *touched = 1;
1015                return end;
1016        }
1017
1018        return end;
1019}
1020
1021static const char *approxidate_digit(const char *date, struct tm *tm, int *num,
1022                                     time_t now)
1023{
1024        char *end;
1025        unsigned long number = strtoul(date, &end, 10);
1026
1027        switch (*end) {
1028        case ':':
1029        case '.':
1030        case '/':
1031        case '-':
1032                if (isdigit(end[1])) {
1033                        int match = match_multi_number(number, *end, date, end,
1034                                                       tm, now);
1035                        if (match)
1036                                return date + match;
1037                }
1038        }
1039
1040        /* Accept zero-padding only for small numbers ("Dec 02", never "Dec 0002") */
1041        if (date[0] != '0' || end - date <= 2)
1042                *num = number;
1043        return end;
1044}
1045
1046/*
1047 * Do we have a pending number at the end, or when
1048 * we see a new one? Let's assume it's a month day,
1049 * as in "Dec 6, 1992"
1050 */
1051static void pending_number(struct tm *tm, int *num)
1052{
1053        int number = *num;
1054
1055        if (number) {
1056                *num = 0;
1057                if (tm->tm_mday < 0 && number < 32)
1058                        tm->tm_mday = number;
1059                else if (tm->tm_mon < 0 && number < 13)
1060                        tm->tm_mon = number-1;
1061                else if (tm->tm_year < 0) {
1062                        if (number > 1969 && number < 2100)
1063                                tm->tm_year = number - 1900;
1064                        else if (number > 69 && number < 100)
1065                                tm->tm_year = number;
1066                        else if (number < 38)
1067                                tm->tm_year = 100 + number;
1068                        /* We screw up for number = 00 ? */
1069                }
1070        }
1071}
1072
1073static unsigned long approxidate_str(const char *date,
1074                                     const struct timeval *tv,
1075                                     int *error_ret)
1076{
1077        int number = 0;
1078        int touched = 0;
1079        struct tm tm, now;
1080        time_t time_sec;
1081
1082        time_sec = tv->tv_sec;
1083        localtime_r(&time_sec, &tm);
1084        now = tm;
1085
1086        tm.tm_year = -1;
1087        tm.tm_mon = -1;
1088        tm.tm_mday = -1;
1089
1090        for (;;) {
1091                unsigned char c = *date;
1092                if (!c)
1093                        break;
1094                date++;
1095                if (isdigit(c)) {
1096                        pending_number(&tm, &number);
1097                        date = approxidate_digit(date-1, &tm, &number, time_sec);
1098                        touched = 1;
1099                        continue;
1100                }
1101                if (isalpha(c))
1102                        date = approxidate_alpha(date-1, &tm, &now, &number, &touched);
1103        }
1104        pending_number(&tm, &number);
1105        if (!touched)
1106                *error_ret = 1;
1107        return update_tm(&tm, &now, 0);
1108}
1109
1110unsigned long approxidate_relative(const char *date, const struct timeval *tv)
1111{
1112        unsigned long timestamp;
1113        int offset;
1114        int errors = 0;
1115
1116        if (!parse_date_basic(date, &timestamp, &offset))
1117                return timestamp;
1118        return approxidate_str(date, tv, &errors);
1119}
1120
1121unsigned long approxidate_careful(const char *date, int *error_ret)
1122{
1123        struct timeval tv;
1124        unsigned long timestamp;
1125        int offset;
1126        int dummy = 0;
1127        if (!error_ret)
1128                error_ret = &dummy;
1129
1130        if (!parse_date_basic(date, &timestamp, &offset)) {
1131                *error_ret = 0;
1132                return timestamp;
1133        }
1134
1135        gettimeofday(&tv, NULL);
1136        return approxidate_str(date, &tv, error_ret);
1137}
1138
1139int date_overflows(unsigned long t)
1140{
1141        time_t sys;
1142
1143        /* If we overflowed our unsigned long, that's bad... */
1144        if (t == ULONG_MAX)
1145                return 1;
1146
1147        /*
1148         * ...but we also are going to feed the result to system
1149         * functions that expect time_t, which is often "signed long".
1150         * Make sure that we fit into time_t, as well.
1151         */
1152        sys = t;
1153        return t != sys || (t < 1) != (sys < 1);
1154}