git/date.c
Jeff King 10edf37796 never fallback relative times to absolute
Previously, for dates older than 12 months we fell back to just giving the
absolute time.  This can be a bit jarring when reading a list of times.

Instead, let's switch to "Y years, M months" for five years, and then just
"Y years" after that.

No particular reason on the 5 year cutoff except that it seemed reasonable
to me.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-02-25 00:44:43 -08:00

900 lines
20 KiB
C

/*
* GIT - The information manager from hell
*
* Copyright (C) Linus Torvalds, 2005
*/
#include "cache.h"
/*
* This is like mktime, but without normalization of tm_wday and tm_yday.
*/
time_t tm_to_time_t(const struct tm *tm)
{
static const int mdays[] = {
0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334
};
int year = tm->tm_year - 70;
int month = tm->tm_mon;
int day = tm->tm_mday;
if (year < 0 || year > 129) /* algo only works for 1970-2099 */
return -1;
if (month < 0 || month > 11) /* array bounds */
return -1;
if (month < 2 || (year + 2) % 4)
day--;
return (year * 365 + (year + 1) / 4 + mdays[month] + day) * 24*60*60UL +
tm->tm_hour * 60*60 + tm->tm_min * 60 + tm->tm_sec;
}
static const char *month_names[] = {
"January", "February", "March", "April", "May", "June",
"July", "August", "September", "October", "November", "December"
};
static const char *weekday_names[] = {
"Sundays", "Mondays", "Tuesdays", "Wednesdays", "Thursdays", "Fridays", "Saturdays"
};
static time_t gm_time_t(unsigned long time, int tz)
{
int minutes;
minutes = tz < 0 ? -tz : tz;
minutes = (minutes / 100)*60 + (minutes % 100);
minutes = tz < 0 ? -minutes : minutes;
return time + minutes * 60;
}
/*
* The "tz" thing is passed in as this strange "decimal parse of tz"
* thing, which means that tz -0100 is passed in as the integer -100,
* even though it means "sixty minutes off"
*/
static struct tm *time_to_tm(unsigned long time, int tz)
{
time_t t = gm_time_t(time, tz);
return gmtime(&t);
}
/*
* What value of "tz" was in effect back then at "time" in the
* local timezone?
*/
static int local_tzoffset(unsigned long time)
{
time_t t, t_local;
struct tm tm;
int offset, eastwest;
t = time;
localtime_r(&t, &tm);
t_local = tm_to_time_t(&tm);
if (t_local < t) {
eastwest = -1;
offset = t - t_local;
} else {
eastwest = 1;
offset = t_local - t;
}
offset /= 60; /* in minutes */
offset = (offset % 60) + ((offset / 60) * 100);
return offset * eastwest;
}
const char *show_date(unsigned long time, int tz, enum date_mode mode)
{
struct tm *tm;
static char timebuf[200];
if (mode == DATE_RAW) {
snprintf(timebuf, sizeof(timebuf), "%lu %+05d", time, tz);
return timebuf;
}
if (mode == DATE_RELATIVE) {
unsigned long diff;
struct timeval now;
gettimeofday(&now, NULL);
if (now.tv_sec < time)
return "in the future";
diff = now.tv_sec - time;
if (diff < 90) {
snprintf(timebuf, sizeof(timebuf), "%lu seconds ago", diff);
return timebuf;
}
/* Turn it into minutes */
diff = (diff + 30) / 60;
if (diff < 90) {
snprintf(timebuf, sizeof(timebuf), "%lu minutes ago", diff);
return timebuf;
}
/* Turn it into hours */
diff = (diff + 30) / 60;
if (diff < 36) {
snprintf(timebuf, sizeof(timebuf), "%lu hours ago", diff);
return timebuf;
}
/* We deal with number of days from here on */
diff = (diff + 12) / 24;
if (diff < 14) {
snprintf(timebuf, sizeof(timebuf), "%lu days ago", diff);
return timebuf;
}
/* Say weeks for the past 10 weeks or so */
if (diff < 70) {
snprintf(timebuf, sizeof(timebuf), "%lu weeks ago", (diff + 3) / 7);
return timebuf;
}
/* Say months for the past 12 months or so */
if (diff < 360) {
snprintf(timebuf, sizeof(timebuf), "%lu months ago", (diff + 15) / 30);
return timebuf;
}
/* Give years and months for 5 years or so */
if (diff < 1825) {
unsigned long years = (diff + 183) / 365;
unsigned long months = (diff % 365 + 15) / 30;
int n;
n = snprintf(timebuf, sizeof(timebuf), "%lu year%s",
years, (years > 1 ? "s" : ""));
if (months)
snprintf(timebuf + n, sizeof(timebuf) - n,
", %lu month%s ago",
months, (months > 1 ? "s" : ""));
else
snprintf(timebuf + n, sizeof(timebuf) - n,
" ago");
return timebuf;
}
/* Otherwise, just years. Centuries is probably overkill. */
snprintf(timebuf, sizeof(timebuf), "%lu years ago", (diff + 183) / 365);
return timebuf;
}
if (mode == DATE_LOCAL)
tz = local_tzoffset(time);
tm = time_to_tm(time, tz);
if (!tm)
return NULL;
if (mode == DATE_SHORT)
sprintf(timebuf, "%04d-%02d-%02d", tm->tm_year + 1900,
tm->tm_mon + 1, tm->tm_mday);
else if (mode == DATE_ISO8601)
sprintf(timebuf, "%04d-%02d-%02d %02d:%02d:%02d %+05d",
tm->tm_year + 1900,
tm->tm_mon + 1,
tm->tm_mday,
tm->tm_hour, tm->tm_min, tm->tm_sec,
tz);
else if (mode == DATE_RFC2822)
sprintf(timebuf, "%.3s, %d %.3s %d %02d:%02d:%02d %+05d",
weekday_names[tm->tm_wday], tm->tm_mday,
month_names[tm->tm_mon], tm->tm_year + 1900,
tm->tm_hour, tm->tm_min, tm->tm_sec, tz);
else
sprintf(timebuf, "%.3s %.3s %d %02d:%02d:%02d %d%c%+05d",
weekday_names[tm->tm_wday],
month_names[tm->tm_mon],
tm->tm_mday,
tm->tm_hour, tm->tm_min, tm->tm_sec,
tm->tm_year + 1900,
(mode == DATE_LOCAL) ? 0 : ' ',
tz);
return timebuf;
}
/*
* Check these. And note how it doesn't do the summer-time conversion.
*
* In my world, it's always summer, and things are probably a bit off
* in other ways too.
*/
static const struct {
const char *name;
int offset;
int dst;
} timezone_names[] = {
{ "IDLW", -12, 0, }, /* International Date Line West */
{ "NT", -11, 0, }, /* Nome */
{ "CAT", -10, 0, }, /* Central Alaska */
{ "HST", -10, 0, }, /* Hawaii Standard */
{ "HDT", -10, 1, }, /* Hawaii Daylight */
{ "YST", -9, 0, }, /* Yukon Standard */
{ "YDT", -9, 1, }, /* Yukon Daylight */
{ "PST", -8, 0, }, /* Pacific Standard */
{ "PDT", -8, 1, }, /* Pacific Daylight */
{ "MST", -7, 0, }, /* Mountain Standard */
{ "MDT", -7, 1, }, /* Mountain Daylight */
{ "CST", -6, 0, }, /* Central Standard */
{ "CDT", -6, 1, }, /* Central Daylight */
{ "EST", -5, 0, }, /* Eastern Standard */
{ "EDT", -5, 1, }, /* Eastern Daylight */
{ "AST", -3, 0, }, /* Atlantic Standard */
{ "ADT", -3, 1, }, /* Atlantic Daylight */
{ "WAT", -1, 0, }, /* West Africa */
{ "GMT", 0, 0, }, /* Greenwich Mean */
{ "UTC", 0, 0, }, /* Universal (Coordinated) */
{ "WET", 0, 0, }, /* Western European */
{ "BST", 0, 1, }, /* British Summer */
{ "CET", +1, 0, }, /* Central European */
{ "MET", +1, 0, }, /* Middle European */
{ "MEWT", +1, 0, }, /* Middle European Winter */
{ "MEST", +1, 1, }, /* Middle European Summer */
{ "CEST", +1, 1, }, /* Central European Summer */
{ "MESZ", +1, 1, }, /* Middle European Summer */
{ "FWT", +1, 0, }, /* French Winter */
{ "FST", +1, 1, }, /* French Summer */
{ "EET", +2, 0, }, /* Eastern Europe, USSR Zone 1 */
{ "EEST", +2, 1, }, /* Eastern European Daylight */
{ "WAST", +7, 0, }, /* West Australian Standard */
{ "WADT", +7, 1, }, /* West Australian Daylight */
{ "CCT", +8, 0, }, /* China Coast, USSR Zone 7 */
{ "JST", +9, 0, }, /* Japan Standard, USSR Zone 8 */
{ "EAST", +10, 0, }, /* Eastern Australian Standard */
{ "EADT", +10, 1, }, /* Eastern Australian Daylight */
{ "GST", +10, 0, }, /* Guam Standard, USSR Zone 9 */
{ "NZT", +12, 0, }, /* New Zealand */
{ "NZST", +12, 0, }, /* New Zealand Standard */
{ "NZDT", +12, 1, }, /* New Zealand Daylight */
{ "IDLE", +12, 0, }, /* International Date Line East */
};
static int match_string(const char *date, const char *str)
{
int i = 0;
for (i = 0; *date; date++, str++, i++) {
if (*date == *str)
continue;
if (toupper(*date) == toupper(*str))
continue;
if (!isalnum(*date))
break;
return 0;
}
return i;
}
static int skip_alpha(const char *date)
{
int i = 0;
do {
i++;
} while (isalpha(date[i]));
return i;
}
/*
* Parse month, weekday, or timezone name
*/
static int match_alpha(const char *date, struct tm *tm, int *offset)
{
int i;
for (i = 0; i < 12; i++) {
int match = match_string(date, month_names[i]);
if (match >= 3) {
tm->tm_mon = i;
return match;
}
}
for (i = 0; i < 7; i++) {
int match = match_string(date, weekday_names[i]);
if (match >= 3) {
tm->tm_wday = i;
return match;
}
}
for (i = 0; i < ARRAY_SIZE(timezone_names); i++) {
int match = match_string(date, timezone_names[i].name);
if (match >= 3) {
int off = timezone_names[i].offset;
/* This is bogus, but we like summer */
off += timezone_names[i].dst;
/* Only use the tz name offset if we don't have anything better */
if (*offset == -1)
*offset = 60*off;
return match;
}
}
if (match_string(date, "PM") == 2) {
tm->tm_hour = (tm->tm_hour % 12) + 12;
return 2;
}
if (match_string(date, "AM") == 2) {
tm->tm_hour = (tm->tm_hour % 12) + 0;
return 2;
}
/* BAD CRAP */
return skip_alpha(date);
}
static int is_date(int year, int month, int day, struct tm *now_tm, time_t now, struct tm *tm)
{
if (month > 0 && month < 13 && day > 0 && day < 32) {
struct tm check = *tm;
struct tm *r = (now_tm ? &check : tm);
time_t specified;
r->tm_mon = month - 1;
r->tm_mday = day;
if (year == -1) {
if (!now_tm)
return 1;
r->tm_year = now_tm->tm_year;
}
else if (year >= 1970 && year < 2100)
r->tm_year = year - 1900;
else if (year > 70 && year < 100)
r->tm_year = year;
else if (year < 38)
r->tm_year = year + 100;
else
return 0;
if (!now_tm)
return 1;
specified = tm_to_time_t(r);
/* Be it commit time or author time, it does not make
* sense to specify timestamp way into the future. Make
* sure it is not later than ten days from now...
*/
if (now + 10*24*3600 < specified)
return 0;
tm->tm_mon = r->tm_mon;
tm->tm_mday = r->tm_mday;
if (year != -1)
tm->tm_year = r->tm_year;
return 1;
}
return 0;
}
static int match_multi_number(unsigned long num, char c, const char *date, char *end, struct tm *tm)
{
time_t now;
struct tm now_tm;
struct tm *refuse_future;
long num2, num3;
num2 = strtol(end+1, &end, 10);
num3 = -1;
if (*end == c && isdigit(end[1]))
num3 = strtol(end+1, &end, 10);
/* Time? Date? */
switch (c) {
case ':':
if (num3 < 0)
num3 = 0;
if (num < 25 && num2 >= 0 && num2 < 60 && num3 >= 0 && num3 <= 60) {
tm->tm_hour = num;
tm->tm_min = num2;
tm->tm_sec = num3;
break;
}
return 0;
case '-':
case '/':
case '.':
now = time(NULL);
refuse_future = NULL;
if (gmtime_r(&now, &now_tm))
refuse_future = &now_tm;
if (num > 70) {
/* yyyy-mm-dd? */
if (is_date(num, num2, num3, refuse_future, now, tm))
break;
/* yyyy-dd-mm? */
if (is_date(num, num3, num2, refuse_future, now, tm))
break;
}
/* Our eastern European friends say dd.mm.yy[yy]
* is the norm there, so giving precedence to
* mm/dd/yy[yy] form only when separator is not '.'
*/
if (c != '.' &&
is_date(num3, num, num2, refuse_future, now, tm))
break;
/* European dd.mm.yy[yy] or funny US dd/mm/yy[yy] */
if (is_date(num3, num2, num, refuse_future, now, tm))
break;
/* Funny European mm.dd.yy */
if (c == '.' &&
is_date(num3, num, num2, refuse_future, now, tm))
break;
return 0;
}
return end - date;
}
/* Have we filled in any part of the time/date yet? */
static inline int nodate(struct tm *tm)
{
return tm->tm_year < 0 &&
tm->tm_mon < 0 &&
tm->tm_mday < 0 &&
!(tm->tm_hour | tm->tm_min | tm->tm_sec);
}
/*
* We've seen a digit. Time? Year? Date?
*/
static int match_digit(const char *date, struct tm *tm, int *offset, int *tm_gmt)
{
int n;
char *end;
unsigned long num;
num = strtoul(date, &end, 10);
/*
* Seconds since 1970? We trigger on that for any numbers with
* more than 8 digits. This is because we don't want to rule out
* numbers like 20070606 as a YYYYMMDD date.
*/
if (num >= 100000000 && nodate(tm)) {
time_t time = num;
if (gmtime_r(&time, tm)) {
*tm_gmt = 1;
return end - date;
}
}
/*
* Check for special formats: num[-.:/]num[same]num
*/
switch (*end) {
case ':':
case '.':
case '/':
case '-':
if (isdigit(end[1])) {
int match = match_multi_number(num, *end, date, end, tm);
if (match)
return match;
}
}
/*
* None of the special formats? Try to guess what
* the number meant. We use the number of digits
* to make a more educated guess..
*/
n = 0;
do {
n++;
} while (isdigit(date[n]));
/* Four-digit year or a timezone? */
if (n == 4) {
if (num <= 1400 && *offset == -1) {
unsigned int minutes = num % 100;
unsigned int hours = num / 100;
*offset = hours*60 + minutes;
} else if (num > 1900 && num < 2100)
tm->tm_year = num - 1900;
return n;
}
/*
* Ignore lots of numerals. We took care of 4-digit years above.
* Days or months must be one or two digits.
*/
if (n > 2)
return n;
/*
* NOTE! We will give precedence to day-of-month over month or
* year numbers in the 1-12 range. So 05 is always "mday 5",
* unless we already have a mday..
*
* IOW, 01 Apr 05 parses as "April 1st, 2005".
*/
if (num > 0 && num < 32 && tm->tm_mday < 0) {
tm->tm_mday = num;
return n;
}
/* Two-digit year? */
if (n == 2 && tm->tm_year < 0) {
if (num < 10 && tm->tm_mday >= 0) {
tm->tm_year = num + 100;
return n;
}
if (num >= 70) {
tm->tm_year = num;
return n;
}
}
if (num > 0 && num < 32) {
tm->tm_mday = num;
} else if (num > 0 && num < 13) {
tm->tm_mon = num-1;
}
return n;
}
static int match_tz(const char *date, int *offp)
{
char *end;
int offset = strtoul(date+1, &end, 10);
int min, hour;
int n = end - date - 1;
min = offset % 100;
hour = offset / 100;
/*
* Don't accept any random crap.. At least 3 digits, and
* a valid minute. We might want to check that the minutes
* are divisible by 30 or something too.
*/
if (min < 60 && n > 2) {
offset = hour*60+min;
if (*date == '-')
offset = -offset;
*offp = offset;
}
return end - date;
}
static int date_string(unsigned long date, int offset, char *buf, int len)
{
int sign = '+';
if (offset < 0) {
offset = -offset;
sign = '-';
}
return snprintf(buf, len, "%lu %c%02d%02d", date, sign, offset / 60, offset % 60);
}
/* Gr. strptime is crap for this; it doesn't have a way to require RFC2822
(i.e. English) day/month names, and it doesn't work correctly with %z. */
int parse_date(const char *date, char *result, int maxlen)
{
struct tm tm;
int offset, tm_gmt;
time_t then;
memset(&tm, 0, sizeof(tm));
tm.tm_year = -1;
tm.tm_mon = -1;
tm.tm_mday = -1;
tm.tm_isdst = -1;
offset = -1;
tm_gmt = 0;
for (;;) {
int match = 0;
unsigned char c = *date;
/* Stop at end of string or newline */
if (!c || c == '\n')
break;
if (isalpha(c))
match = match_alpha(date, &tm, &offset);
else if (isdigit(c))
match = match_digit(date, &tm, &offset, &tm_gmt);
else if ((c == '-' || c == '+') && isdigit(date[1]))
match = match_tz(date, &offset);
if (!match) {
/* BAD CRAP */
match = 1;
}
date += match;
}
/* mktime uses local timezone */
then = tm_to_time_t(&tm);
if (offset == -1)
offset = (then - mktime(&tm)) / 60;
if (then == -1)
return -1;
if (!tm_gmt)
then -= offset * 60;
return date_string(then, offset, result, maxlen);
}
enum date_mode parse_date_format(const char *format)
{
if (!strcmp(format, "relative"))
return DATE_RELATIVE;
else if (!strcmp(format, "iso8601") ||
!strcmp(format, "iso"))
return DATE_ISO8601;
else if (!strcmp(format, "rfc2822") ||
!strcmp(format, "rfc"))
return DATE_RFC2822;
else if (!strcmp(format, "short"))
return DATE_SHORT;
else if (!strcmp(format, "local"))
return DATE_LOCAL;
else if (!strcmp(format, "default"))
return DATE_NORMAL;
else if (!strcmp(format, "raw"))
return DATE_RAW;
else
die("unknown date format %s", format);
}
void datestamp(char *buf, int bufsize)
{
time_t now;
int offset;
time(&now);
offset = tm_to_time_t(localtime(&now)) - now;
offset /= 60;
date_string(now, offset, buf, bufsize);
}
static void update_tm(struct tm *tm, unsigned long sec)
{
time_t n = mktime(tm) - sec;
localtime_r(&n, tm);
}
static void date_yesterday(struct tm *tm, int *num)
{
update_tm(tm, 24*60*60);
}
static void date_time(struct tm *tm, int hour)
{
if (tm->tm_hour < hour)
date_yesterday(tm, NULL);
tm->tm_hour = hour;
tm->tm_min = 0;
tm->tm_sec = 0;
}
static void date_midnight(struct tm *tm, int *num)
{
date_time(tm, 0);
}
static void date_noon(struct tm *tm, int *num)
{
date_time(tm, 12);
}
static void date_tea(struct tm *tm, int *num)
{
date_time(tm, 17);
}
static void date_pm(struct tm *tm, int *num)
{
int hour, n = *num;
*num = 0;
hour = tm->tm_hour;
if (n) {
hour = n;
tm->tm_min = 0;
tm->tm_sec = 0;
}
tm->tm_hour = (hour % 12) + 12;
}
static void date_am(struct tm *tm, int *num)
{
int hour, n = *num;
*num = 0;
hour = tm->tm_hour;
if (n) {
hour = n;
tm->tm_min = 0;
tm->tm_sec = 0;
}
tm->tm_hour = (hour % 12);
}
static void date_never(struct tm *tm, int *num)
{
time_t n = 0;
localtime_r(&n, tm);
}
static const struct special {
const char *name;
void (*fn)(struct tm *, int *);
} special[] = {
{ "yesterday", date_yesterday },
{ "noon", date_noon },
{ "midnight", date_midnight },
{ "tea", date_tea },
{ "PM", date_pm },
{ "AM", date_am },
{ "never", date_never },
{ NULL }
};
static const char *number_name[] = {
"zero", "one", "two", "three", "four",
"five", "six", "seven", "eight", "nine", "ten",
};
static const struct typelen {
const char *type;
int length;
} typelen[] = {
{ "seconds", 1 },
{ "minutes", 60 },
{ "hours", 60*60 },
{ "days", 24*60*60 },
{ "weeks", 7*24*60*60 },
{ NULL }
};
static const char *approxidate_alpha(const char *date, struct tm *tm, int *num)
{
const struct typelen *tl;
const struct special *s;
const char *end = date;
int i;
while (isalpha(*++end));
;
for (i = 0; i < 12; i++) {
int match = match_string(date, month_names[i]);
if (match >= 3) {
tm->tm_mon = i;
return end;
}
}
for (s = special; s->name; s++) {
int len = strlen(s->name);
if (match_string(date, s->name) == len) {
s->fn(tm, num);
return end;
}
}
if (!*num) {
for (i = 1; i < 11; i++) {
int len = strlen(number_name[i]);
if (match_string(date, number_name[i]) == len) {
*num = i;
return end;
}
}
if (match_string(date, "last") == 4)
*num = 1;
return end;
}
tl = typelen;
while (tl->type) {
int len = strlen(tl->type);
if (match_string(date, tl->type) >= len-1) {
update_tm(tm, tl->length * *num);
*num = 0;
return end;
}
tl++;
}
for (i = 0; i < 7; i++) {
int match = match_string(date, weekday_names[i]);
if (match >= 3) {
int diff, n = *num -1;
*num = 0;
diff = tm->tm_wday - i;
if (diff <= 0)
n++;
diff += 7*n;
update_tm(tm, diff * 24 * 60 * 60);
return end;
}
}
if (match_string(date, "months") >= 5) {
int n = tm->tm_mon - *num;
*num = 0;
while (n < 0) {
n += 12;
tm->tm_year--;
}
tm->tm_mon = n;
return end;
}
if (match_string(date, "years") >= 4) {
tm->tm_year -= *num;
*num = 0;
return end;
}
return end;
}
static const char *approxidate_digit(const char *date, struct tm *tm, int *num)
{
char *end;
unsigned long number = strtoul(date, &end, 10);
switch (*end) {
case ':':
case '.':
case '/':
case '-':
if (isdigit(end[1])) {
int match = match_multi_number(number, *end, date, end, tm);
if (match)
return date + match;
}
}
/* Accept zero-padding only for small numbers ("Dec 02", never "Dec 0002") */
if (date[0] != '0' || end - date <= 2)
*num = number;
return end;
}
unsigned long approxidate(const char *date)
{
int number = 0;
struct tm tm, now;
struct timeval tv;
char buffer[50];
if (parse_date(date, buffer, sizeof(buffer)) > 0)
return strtoul(buffer, NULL, 10);
gettimeofday(&tv, NULL);
localtime_r(&tv.tv_sec, &tm);
now = tm;
for (;;) {
unsigned char c = *date;
if (!c)
break;
date++;
if (isdigit(c)) {
date = approxidate_digit(date-1, &tm, &number);
continue;
}
if (isalpha(c))
date = approxidate_alpha(date-1, &tm, &number);
}
if (number > 0 && number < 32)
tm.tm_mday = number;
if (tm.tm_mon > now.tm_mon && tm.tm_year == now.tm_year)
tm.tm_year--;
return mktime(&tm);
}