Rev-parse: @{time} syntax.

Ported date.c (for approxidate_careful) from git.git
revision aa39b85. Trimmed out the parts we're not
using.

include/git2.h

@@ -25,6 +25,7 @@
 #include "git2/merge.h"
 #include "git2/refs.h"
 #include "git2/reflog.h"
+#include "git2/revparse.h"
 
 #include "git2/object.h"
 #include "git2/blob.h"

src/date.c

+/*
+ * GIT - The information manager from hell
+ *
+ * Copyright (C) Linus Torvalds, 2005
+ */
+
+#include "date.h"
+#include "cache.h"
+
+#include <ctype.h>
+#include <sys/time.h>
+
+typedef enum {
+	DATE_NORMAL = 0,
+	DATE_RELATIVE,
+	DATE_SHORT,
+	DATE_LOCAL,
+	DATE_ISO8601,
+	DATE_RFC2822,
+	DATE_RAW
+} date_mode;
+
+/*
+ * This is like mktime, but without normalization of tm_wday and tm_yday.
+ */
+static 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--;
+	if (tm->tm_hour < 0 || tm->tm_min < 0 || tm->tm_sec < 0)
+		return -1;
+	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"
+};
+
+
+
+/*
+ * 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) */
+	{ "Z",      0, 0, },    /* Zulu, alias for UTC */
+
+	{ "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)
+{
+	unsigned 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 || match == (int)strlen(timezone_names[i].name)) {
+			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?
+ * We just do a binary 'and' to see if the sign bit
+ * is set in all the values.
+ */
+static inline int nodate(struct tm *tm)
+{
+	return (tm->tm_year &
+		tm->tm_mon &
+		tm->tm_mday &
+		tm->tm_hour &
+		tm->tm_min &
+		tm->tm_sec) < 0;
+}
+
+/*
+ * 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 < 13 && tm->tm_mon < 0)
+		tm->tm_mon = num-1;
+
+	return n;
+}
+
+static int match_tz(const char *date, int *offp)
+{
+	char *end;
+	int hour = strtoul(date + 1, &end, 10);
+	int n = end - (date + 1);
+	int min = 0;
+
+	if (n == 4) {
+		/* hhmm */
+		min = hour % 100;
+		hour = hour / 100;
+	} else if (n != 2) {
+		min = 99; /* random crap */
+	} else if (*end == ':') {
+		/* hh:mm? */
+		min = strtoul(end + 1, &end, 10);
+		if (end - (date + 1) != 5)
+			min = 99; /* random crap */
+	} /* otherwise we parsed "hh" */
+
+	/*
+	 * Don't accept any random crap. Even though some places have
+	 * offset larger than 12 hours (e.g. Pacific/Kiritimati is at
+	 * UTC+14), there is something wrong if hour part is much
+	 * larger than that. We might also want to check that the
+	 * minutes are divisible by 15 or something too. (Offset of
+	 * Kathmandu, Nepal is UTC+5:45)
+	 */
+	if (min < 60 && hour < 24) {
+		int offset = hour * 60 + min;
+		if (*date == '-')
+			offset = -offset;
+		*offp = offset;
+	}
+	return end - date;
+}
+
+/*
+ * Parse a string like "0 +0000" as ancient timestamp near epoch, but
+ * only when it appears not as part of any other string.
+ */
+static int match_object_header_date(const char *date, unsigned long *timestamp, int *offset)
+{
+	char *end;
+	unsigned long stamp;
+	int ofs;
+
+	if (*date < '0' || '9' <= *date)
+		return -1;
+	stamp = strtoul(date, &end, 10);
+	if (*end != ' ' || stamp == ULONG_MAX || (end[1] != '+' && end[1] != '-'))
+		return -1;
+	date = end + 2;
+	ofs = strtol(date, &end, 10);
+	if ((*end != '\0' && (*end != '\n')) || end != date + 4)
+		return -1;
+	ofs = (ofs / 100) * 60 + (ofs % 100);
+	if (date[-1] == '-')
+		ofs = -ofs;
+	*timestamp = stamp;
+	*offset = ofs;
+	return 0;
+}
+
+/* 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. */
+static int parse_date_basic(const char *date, unsigned long *timestamp, int *offset)
+{
+	struct tm tm;
+	int tm_gmt;
+	unsigned long dummy_timestamp;
+	int dummy_offset;
+
+	if (!timestamp)
+		timestamp = &dummy_timestamp;
+	if (!offset)
+		offset = &dummy_offset;
+
+	memset(&tm, 0, sizeof(tm));
+	tm.tm_year = -1;
+	tm.tm_mon = -1;
+	tm.tm_mday = -1;
+	tm.tm_isdst = -1;
+	tm.tm_hour = -1;
+	tm.tm_min = -1;
+	tm.tm_sec = -1;
+	*offset = -1;
+	tm_gmt = 0;
+
+	if (*date == '@' &&
+	    !match_object_header_date(date + 1, timestamp, offset))
+		return 0; /* success */
+	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 */
+	*timestamp = tm_to_time_t(&tm);
+	if (*offset == -1)
+		*offset = ((time_t)*timestamp - mktime(&tm)) / 60;
+
+	if (*timestamp == (unsigned long)-1)
+		return -1;
+
+	if (!tm_gmt)
+		*timestamp -= *offset * 60;
+	return 0; /* success */
+}
+
+
+/*
+ * Relative time update (eg "2 days ago").  If we haven't set the time
+ * yet, we need to set it from current time.
+ */
+static unsigned long update_tm(struct tm *tm, struct tm *now, unsigned long sec)
+{
+	time_t n;
+
+	if (tm->tm_mday < 0)
+		tm->tm_mday = now->tm_mday;
+	if (tm->tm_mon < 0)
+		tm->tm_mon = now->tm_mon;
+	if (tm->tm_year < 0) {
+		tm->tm_year = now->tm_year;
+		if (tm->tm_mon > now->tm_mon)
+			tm->tm_year--;
+	}
+
+	n = mktime(tm) - sec;
+	localtime_r(&n, tm);
+	return n;
+}
+
+static void date_now(struct tm *tm, struct tm *now, int *num)
+{
+   GIT_UNUSED(num);
+	update_tm(tm, now, 0);
+}
+
+static void date_yesterday(struct tm *tm, struct tm *now, int *num)
+{
+   GIT_UNUSED(num);
+	update_tm(tm, now, 24*60*60);
+}
+
+static void date_time(struct tm *tm, struct tm *now, int hour)
+{
+	if (tm->tm_hour < hour)
+		date_yesterday(tm, now, NULL);
+	tm->tm_hour = hour;
+	tm->tm_min = 0;
+	tm->tm_sec = 0;
+}
+
+static void date_midnight(struct tm *tm, struct tm *now, int *num)
+{
+   GIT_UNUSED(num);
+	date_time(tm, now, 0);
+}
+
+static void date_noon(struct tm *tm, struct tm *now, int *num)
+{
+   GIT_UNUSED(num);
+	date_time(tm, now, 12);
+}
+
+static void date_tea(struct tm *tm, struct tm *now, int *num)
+{
+   GIT_UNUSED(num);
+	date_time(tm, now, 17);
+}
+
+static void date_pm(struct tm *tm, struct tm *now, int *num)
+{
+   GIT_UNUSED(now);
+	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, struct tm *now, int *num)
+{
+   GIT_UNUSED(now);
+	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, struct tm *now, int *num)
+{
+   GIT_UNUSED(now);
+   GIT_UNUSED(num);
+	time_t n = 0;
+	localtime_r(&n, tm);
+}
+
+static const struct special {
+	const char *name;
+	void (*fn)(struct tm *, 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 },
+	{ "now", date_now },
+	{ 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, struct tm *now, int *num, int *touched)
+{
+	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;
+			*touched = 1;
+			return end;
+		}
+	}
+
+	for (s = special; s->name; s++) {
+		int len = strlen(s->name);
+		if (match_string(date, s->name) == len) {
+			s->fn(tm, now, num);
+			*touched = 1;
+			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;
+				*touched = 1;
+				return end;
+			}
+		}
+		if (match_string(date, "last") == 4) {
+			*num = 1;
+			*touched = 1;
+		}
+		return end;
+	}
+
+	tl = typelen;
+	while (tl->type) {
+		int len = strlen(tl->type);
+		if (match_string(date, tl->type) >= len-1) {
+			update_tm(tm, now, tl->length * *num);
+			*num = 0;
+			*touched = 1;
+			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, now, diff * 24 * 60 * 60);
+			*touched = 1;
+			return end;
+		}
+	}
+
+	if (match_string(date, "months") >= 5) {
+		int n;
+		update_tm(tm, now, 0); /* fill in date fields if needed */
+		n = tm->tm_mon - *num;
+		*num = 0;
+		while (n < 0) {
+			n += 12;
+			tm->tm_year--;
+		}
+		tm->tm_mon = n;
+		*touched = 1;
+		return end;
+	}
+
+	if (match_string(date, "years") >= 4) {
+		update_tm(tm, now, 0); /* fill in date fields if needed */
+		tm->tm_year -= *num;
+		*num = 0;
+		*touched = 1;
+		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;
+}
+
+/*
+ * Do we have a pending number at the end, or when
+ * we see a new one? Let's assume it's a month day,
+ * as in "Dec 6, 1992"
+ */
+static void pending_number(struct tm *tm, int *num)
+{
+	int number = *num;
+
+	if (number) {
+		*num = 0;
+		if (tm->tm_mday < 0 && number < 32)
+			tm->tm_mday = number;
+		else if (tm->tm_mon < 0 && number < 13)
+			tm->tm_mon = number-1;
+		else if (tm->tm_year < 0) {
+			if (number > 1969 && number < 2100)
+				tm->tm_year = number - 1900;
+			else if (number > 69 && number < 100)
+				tm->tm_year = number;
+			else if (number < 38)
+				tm->tm_year = 100 + number;
+			/* We screw up for number = 00 ? */
+		}
+	}
+}
+
+static unsigned long approxidate_str(const char *date,
+				     const struct timeval *tv,
+				     int *error_ret)
+{
+	int number = 0;
+	int touched = 0;
+	struct tm tm, now;
+	time_t time_sec;
+
+	time_sec = tv->tv_sec;
+	localtime_r(&time_sec, &tm);
+	now = tm;
+
+	tm.tm_year = -1;
+	tm.tm_mon = -1;
+	tm.tm_mday = -1;
+
+	for (;;) {
+		unsigned char c = *date;
+		if (!c)
+			break;
+		date++;
+		if (isdigit(c)) {
+			pending_number(&tm, &number);
+			date = approxidate_digit(date-1, &tm, &number);
+			touched = 1;
+			continue;
+		}
+		if (isalpha(c))
+			date = approxidate_alpha(date-1, &tm, &now, &number, &touched);
+	}
+	pending_number(&tm, &number);
+	if (!touched)
+		*error_ret = 1;
+	return update_tm(&tm, &now, 0);
+}
+
+unsigned long approxidate_careful(const char *date, int *error_ret)
+{
+	struct timeval tv;
+	unsigned long timestamp;
+	int offset;
+	int dummy = 0;
+	if (!error_ret)
+		error_ret = &dummy;
+
+	if (!parse_date_basic(date, &timestamp, &offset)) {
+		*error_ret = 0;
+		return timestamp;
+	}
+
+	gettimeofday(&tv, NULL);
+	return approxidate_str(date, &tv, error_ret);
+}

src/date.h

+/*
+ * Copyright (C) 2009-2012 the libgit2 contributors
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+#ifndef INCLUDE_date_h__
+#define INCLUDE_date_h__
+
+unsigned long approxidate_careful(const char *date, int *error_ret);
+
+#endif

src/revparse.c

@@ -9,18 +9,9 @@
 
 #include "common.h"
 #include "buffer.h"
+#include "date.h"
 
-#include "git2/revparse.h"
-#include "git2/object.h"
-#include "git2/oid.h"
-#include "git2/refs.h"
-#include "git2/tag.h"
-#include "git2/commit.h"
-#include "git2/reflog.h"
-#include "git2/refs.h"
-#include "git2/repository.h"
-#include "git2/config.h"
-#include "git2/revwalk.h"
+#include "git2.h"
 
 GIT_BEGIN_DECL
 
@@ -116,6 +107,36 @@ static int revparse_lookup_object(git_object **out, git_repository *repo, const
 }
 
 
+static int all_chars_are_digits(const char *str, size_t len)
+{
+   size_t i=0;
+   for (i=0; i<len; i++) {
+      if (str[i] < '0' || str[i] > '9') return 0;
+   }
+   return 1;
+}
+
+static void normalize_maybe_empty_refname(git_buf *buf, git_repository *repo, const char *refspec, size_t refspeclen)
+{
+   git_reference *ref;
+
+   if (!refspeclen) {
+      /* Empty refspec means current branch (target of HEAD) */
+      git_reference_lookup(&ref, repo, "HEAD");
+      git_buf_puts(buf, git_reference_target(ref));
+      git_reference_free(ref);
+   } else if (strstr(refspec, "HEAD")) {
+      /* Explicit head */
+      git_buf_puts(buf, refspec);
+   }else {
+      if (git__prefixcmp(refspec, "refs/heads/") != 0) {
+         git_buf_printf(buf, "refs/heads/%s", refspec);
+      } else {
+         git_buf_puts(buf, refspec);
+      }
+   }
+}
+
 static int walk_ref_history(git_object **out, git_repository *repo, const char *refspec, const char *reflogspec)
 {
    git_reference *ref;
@@ -125,6 +146,7 @@ static int walk_ref_history(git_object **out, git_repository *repo, const char *
    const git_reflog_entry *entry;
    git_buf buf = GIT_BUF_INIT;
    size_t refspeclen = strlen(refspec);
+   size_t reflogspeclen = strlen(reflogspec);
 
    if (git__prefixcmp(reflogspec, "@{") != 0 ||
        git__suffixcmp(reflogspec, "}") != 0) {
@@ -153,26 +175,16 @@ static int walk_ref_history(git_object **out, git_repository *repo, const char *
             n--;
             if (!n) {
                char *branchname = strrchr(msg, ' ') + 1;
-               git_buf_printf(&buf, "refs/heads/%s", branchname);
-               retcode = revparse_lookup_fully_qualifed_ref(out, repo, git_buf_cstr(&buf));
+               retcode = revparse_lookup_object(out, repo, branchname);
                break;
             }
          }
       }
    } else {
-      if (!refspeclen) {
-         /* Empty refspec means current branch */
-         /* Get the target of HEAD */
-         git_reference_lookup(&ref, repo, "HEAD");
-         git_buf_puts(&buf, git_reference_target(ref));
-         git_reference_free(ref);
-      } else {
-         if (git__prefixcmp(refspec, "refs/heads/") != 0) {
-            git_buf_printf(&buf, "refs/heads/%s", refspec);
-         } else {
-            git_buf_puts(&buf, refspec);
-         }
-      }
+      git_buf datebuf = GIT_BUF_INIT;
+      git_buf_put(&datebuf, reflogspec+2, reflogspeclen-3);
+      int date_error = 0;
+      time_t timestamp = approxidate_careful(git_buf_cstr(&datebuf), &date_error);
 
       /* @{u} or @{upstream} -> upstream branch, for a tracking branch. This is stored in the config. */
       if (!strcmp(reflogspec, "@{u}") || !strcmp(reflogspec, "@{upstream}")) {
@@ -200,24 +212,72 @@ static int walk_ref_history(git_object **out, git_repository *repo, const char *
       }
 
       /* @{N} -> Nth prior value for the ref (from reflog) */
-      else if (!git__strtol32(&n, reflogspec+2, NULL, 0)) {
+      else if (all_chars_are_digits(reflogspec+2, reflogspeclen-3) &&
+               !git__strtol32(&n, reflogspec+2, NULL, 0) &&
+               n <= 100000000) { /* Allow integer time */
+         normalize_maybe_empty_refname(&buf, repo, refspec, refspeclen);
+
          if (n == 0) {
             retcode = revparse_lookup_fully_qualifed_ref(out, repo, git_buf_cstr(&buf));
          } else if (!git_reference_lookup(&ref, repo, git_buf_cstr(&buf))) {
             if (!git_reflog_read(&reflog, ref)) {
-               const git_reflog_entry *entry = git_reflog_entry_byindex(reflog, n);
-               const git_oid *oid = git_reflog_entry_oidold(entry);
-               retcode = git_object_lookup(out, repo, oid, GIT_OBJ_ANY);
+               int numentries = git_reflog_entrycount(reflog);
+               if (numentries < n) {
+                  giterr_set(GITERR_REFERENCE, "Reflog for '%s' has only %d entries, asked for %d",
+                             git_buf_cstr(&buf), numentries, n);
+                  retcode = GIT_ERROR;
+               } else {
+                  const git_reflog_entry *entry = git_reflog_entry_byindex(reflog, n);
+                  const git_oid *oid = git_reflog_entry_oidold(entry);
+                  retcode = git_object_lookup(out, repo, oid, GIT_OBJ_ANY);
+               }
             }
             git_reference_free(ref);
          }
       }
 
-      /* @{Anything else} -> try to parse the expression into a date, and get the value of the ref as it
-         was then. */
-      else {
-         /* TODO */
+      else if (!date_error) {
+         /* Ref as it was on a certain date */
+         normalize_maybe_empty_refname(&buf, repo, refspec, refspeclen);
+
+         if (!git_reference_lookup(&ref, repo, git_buf_cstr(&buf))) {
+            git_reflog *reflog;
+            if (!git_reflog_read(&reflog, ref)) {
+               /* Keep walking until we find an entry older than the given date */
+               int numentries = git_reflog_entrycount(reflog);
+               int i;
+
+               /* TODO: clunky. Factor "now" into a utility */
+               git_signature *sig;
+               git_signature_now(&sig, "blah", "blah");
+               git_time as_of = sig->when;
+               git_signature_free(sig);
+
+               as_of.time = (timestamp > 0)
+                  ? timestamp
+                  : sig->when.time + timestamp;
+
+               for (i=numentries-1; i>0; i--) {
+                  const git_reflog_entry *entry = git_reflog_entry_byindex(reflog, i);
+                  git_time commit_time = git_reflog_entry_committer(entry)->when;
+                  if (git__time_cmp(&commit_time, &as_of) <= 0 ) {
+                     retcode = git_object_lookup(out, repo, git_reflog_entry_oidnew(entry), GIT_OBJ_ANY);
+                     break;
+                  }
+               }
+
+               if (!i) {
+                  /* Didn't find a match. Use the oldest revision in the reflog. */
+                  const git_reflog_entry *entry = git_reflog_entry_byindex(reflog, 0);
+                  retcode = git_object_lookup(out, repo, git_reflog_entry_oidnew(entry), GIT_OBJ_ANY);
+               }
+            }
+
+            git_reference_free(ref);
+         }
       }
+
+      git_buf_free(&datebuf);
    }
 
    if (reflog) git_reflog_free(reflog);
@@ -367,6 +427,9 @@ static int handle_caret_syntax(git_object **out, git_repository *repo, git_objec
             git_buf_free(&buf);
             git_revwalk_free(walk);
          }
+         if (retcode < 0) {
+            giterr_set(GITERR_REFERENCE, "Couldn't find a match for %s", movement);
+         }
          return retcode;
       }
 

src/util.h

@@ -209,4 +209,11 @@ GIT_INLINE(bool) git__isspace(int c)
     return (c == ' ' || c == '\t' || c == '\n' || c == '\f' || c == '\r' || c == '\v');
 }
 
+GIT_INLINE(int) git__time_cmp(const git_time *a, const git_time *b)
+{
+   /* Adjust for time zones. Times are in seconds, offsets are in minutes. */
+   git_time_t adjusted_a = a->time + ((b->offset - a->offset) * 60);
+   return adjusted_a - b->time;
+}
+
 #endif /* INCLUDE_util_h__ */

tests-clar/refs/revparse.c

@@ -113,6 +113,7 @@ void test_refs_revparse__reflog(void)
 {
    cl_git_fail(git_revparse_single(&g_obj, g_repo, "@{-xyz}"));
    cl_git_fail(git_revparse_single(&g_obj, g_repo, "@{-0}"));
+   cl_git_fail(git_revparse_single(&g_obj, g_repo, "@{1000}"));
 
    test_object("@{-2}", "a65fedf39aefe402d3bb6e24df4d4f5fe4547750");
    test_object("@{-1}", "a4a7dce85cf63874e984719f4fdd239f5145052f");
@@ -137,8 +138,14 @@ void test_refs_revparse__revwalk(void)
 
 void test_refs_revparse__date(void)
 {
-   /* Not ready yet
-   test_object("HEAD@{100 years ago}", "a65fedf39aefe402d3bb6e24df4d4f5fe4547750");
-   test_object("master@{2012-4-30 10:23:20}", "be3563ae3f795b2b4353bcce3a527ad0a4f7f644");
-   */
+   test_object("HEAD@{10 years ago}", "be3563ae3f795b2b4353bcce3a527ad0a4f7f644");
+   test_object("HEAD@{1 second}", "a65fedf39aefe402d3bb6e24df4d4f5fe4547750");
+   test_object("master@{2012-4-30 10:23:20 -0800}", "be3563ae3f795b2b4353bcce3a527ad0a4f7f644");
+   test_object("master@{2012-4-30 10:24 -0800}", "a65fedf39aefe402d3bb6e24df4d4f5fe4547750");
+   test_object("master@{2012-4-30 16:24 -0200}", "a65fedf39aefe402d3bb6e24df4d4f5fe4547750");
+   test_object("master@{1335806600}", "be3563ae3f795b2b4353bcce3a527ad0a4f7f644");
+   test_object("master@{1335816640}", "a65fedf39aefe402d3bb6e24df4d4f5fe4547750");
+
+   /* Core git gives a65fedf, because they don't take time zones into account. */
+   test_object("master@{1335806640}", "be3563ae3f795b2b4353bcce3a527ad0a4f7f644");
 }

tests/resources/testrepo.git/logs/HEAD

 0000000000000000000000000000000000000000 be3563ae3f795b2b4353bcce3a527ad0a4f7f644 Ben Straub <bstraub@github.com> 1335806563 -0700	clone: from /Users/ben/src/libgit2/tests/resources/testrepo.git
-be3563ae3f795b2b4353bcce3a527ad0a4f7f644 a65fedf39aefe402d3bb6e24df4d4f5fe4547750 Ben Straub <bstraub@github.com> 1335806603 -0700	commit: 
-a65fedf39aefe402d3bb6e24df4d4f5fe4547750 c47800c7266a2be04c571c04d5a6614691ea99bd Ben Straub <bstraub@github.com> 1335806608 -0700	checkout: moving from master to br2
-c47800c7266a2be04c571c04d5a6614691ea99bd a4a7dce85cf63874e984719f4fdd239f5145052f Ben Straub <bstraub@github.com> 1335806617 -0700	commit: checking in
-a4a7dce85cf63874e984719f4fdd239f5145052f a65fedf39aefe402d3bb6e24df4d4f5fe4547750 Ben Straub <bstraub@github.com> 1335806621 -0700	checkout: moving from br2 to master
+be3563ae3f795b2b4353bcce3a527ad0a4f7f644 a65fedf39aefe402d3bb6e24df4d4f5fe4547750 Ben Straub <bstraub@github.com> 1335806603 -0900	commit: 
+a65fedf39aefe402d3bb6e24df4d4f5fe4547750 c47800c7266a2be04c571c04d5a6614691ea99bd Ben Straub <bstraub@github.com> 1335806608 -0900	checkout: moving from master to br2
+c47800c7266a2be04c571c04d5a6614691ea99bd a4a7dce85cf63874e984719f4fdd239f5145052f Ben Straub <bstraub@github.com> 1335806617 -0900	commit: checking in
+a4a7dce85cf63874e984719f4fdd239f5145052f a65fedf39aefe402d3bb6e24df4d4f5fe4547750 Ben Straub <bstraub@github.com> 1335806621 -0900	checkout: moving from br2 to master

tests/resources/testrepo.git/logs/refs/heads/master

-0000000000000000000000000000000000000000 be3563ae3f795b2b4353bcce3a527ad0a4f7f644 Ben Straub <bstraub@github.com> 1335806563 -0700	clone: from /Users/ben/src/libgit2/tests/resources/testrepo.git
-be3563ae3f795b2b4353bcce3a527ad0a4f7f644 a65fedf39aefe402d3bb6e24df4d4f5fe4547750 Ben Straub <bstraub@github.com> 1335806603 -0700	commit: checking in
+0000000000000000000000000000000000000000 be3563ae3f795b2b4353bcce3a527ad0a4f7f644 Ben Straub <bstraub@github.com> 1335806563 -0800	clone: from /Users/ben/src/libgit2/tests/resources/testrepo.git
+be3563ae3f795b2b4353bcce3a527ad0a4f7f644 a65fedf39aefe402d3bb6e24df4d4f5fe4547750 Ben Straub <bstraub@github.com> 1335806603 -0800	commit: checking in