Our approxidate cannot handle simple times like "5 PM yesterday", and to
fix that, we will need to add some logic for number handling.  This just
splits that out into a function of its own (the same way the _real_ date
parsing works).
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

I noticed that I was looking at the kernel gitweb output at some point
rather than just do "git log", simply because I liked seeing the
simplified date-format, ie the "5 days ago" rather than a full date.

This adds infrastructure to do that for "git log" too. It does NOT add the
actual flag to enable it, though, so right now this patch is a no-op, but
it should now be easy to add a command line flag (and possibly a config
file option) to just turn on the "relative" date format.

The exact cut-off points when it switches from days to weeks etc are
totally arbitrary, but are picked somewhat to avoid the "1 weeks ago"
thing (by making it show "10 days ago" rather than "1 week", or "70
minutes ago" rather than "1 hour ago").

[jc: with minor fix and tweak around "month" and "week" area.]
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

date.c::approxidate_alpha() counts the number of alphabets
while moving the pointer but does not use the count.
Signed-off-by: NPierre Habouzit <madcoder@debian.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

When match_digit() guesses a four-digit string to tell if it is
a year or a timezone, it did not consider that some real-world
places have UTC offsets equal to +1400.

   $ date; TZ=UTC0 date; TZ=Pacific/Kiritimati date
   Wed Jun  7 23:25:42 PDT 2006
   Thu Jun  8 06:25:42 UTC 2006
   Thu Jun  8 20:25:42 LINT 2006
Signed-off-by: NPaul Eggert <eggert@CS.UCLA.EDU>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Still Work-in-progress git fmt-patch (should it be known as
format-patch-ng?) is matched with the fix made by Huw Davies
in 262a6ef7 commit to use
RFC2822 date format.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This does three things, only applies to cases where the user
manually tries to override the author/commit time by environment
variables, with non-ISO, non-2822 format date-string:

 - Refuses to use the interpretation to put the date in the
   future; recent kernel history has a commit made with
   10/03/2006 which is recorded as October 3rd.

 - Adds '.' as the possible year-month-date separator.  We
   learned from our European friends on the #git channel that
   dd.mm.yyyy is the norm there.

 - When the separator is '.', we prefer dd.mm.yyyy over
   mm.dd.yyyy; otherwise mm/dd/yy[yy] takes precedence over
   dd/mm/yy[yy].
Signed-off-by: NJunio C Hamano <junkio@cox.net>

The comment associated with the date parsing code for three
numbers separated with slashes or dashes implied we wanted to
interpret using this order:

	yyyy-mm-dd
	yyyy-dd-mm
	mm-dd-yy
	dd-mm-yy

However, the actual code had the last two wrong, and making it
prefer dd-mm-yy format over mm-dd-yy.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Signed-off-by: NJunio C Hamano <junkio@cox.net>

Stupid me.

If approxidate ends up with a month that is ahead of the current month, it
decrements the year to last year.

Which is correct, and means that "last december" does the right thing.

HOWEVER. It should only do so if the year is the same as the current year.

Without this fix, "5 days ago" ends up being in 2004, because it first
decrements five days, getting us to December 2005 (correct), but then it
also ends up decrementing the year once more to turn that December into
"last year" (incorrect, since it already _was_ last year).

Duh. Pass me a donut.
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Signed-off-by: NJunio C Hamano <junkio@cox.net>

On Fri, 18 Nov 2005, David Roundy wrote:
>
> Don't forget "high noon"!  (and perhaps "tea time"?)  :)

Done.

    [torvalds@g5 git]$ ./test-date "now" "midnight" "high noon" "tea-time"
    now -> bad -> Wed Dec 31 16:00:00 1969
    now -> Fri Nov 18 08:50:54 2005

    midnight -> bad -> Wed Dec 31 16:00:00 1969
    midnight -> Fri Nov 18 00:00:00 2005

    high noon -> bad -> Wed Dec 31 16:00:00 1969
    high noon -> Thu Nov 17 12:00:00 2005

    tea-time -> bad -> Wed Dec 31 16:00:00 1969
    tea-time -> Thu Nov 17 17:00:00 2005

Thanks for pointing out tea-time.

This is also written to easily extended to allow people to add their own
important dates like Christmas and their own birthdays.
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This allows people to use syntax like "last thursday" for the approxidate.

(Or, indeed, more complex "three thursdays ago", but I suspect that would
be pretty unusual).

NOTE! The parsing is strictly sequential, so if you do

	"one day before last thursday"

it will _not_ do what you think it does. It will take the current time,
subtract one day, and then go back to the thursday before that. So to get
what you want, you'd have to write it the other way around:

	"last thursday and one day before"

which is insane (it's usually the same as "last wednesday" _except_ if
today is Thursday, in which case "last wednesday" is yesterday, and "last
thursday and one day before" is eight days ago).

Similarly,

	"last thursday one month ago"

will first go back to last thursday, and then go back one month from
there, not the other way around.

I doubt anybody would ever use insane dates like that, but I thought I'd
point out that the approxidate parsing is not exactly "standard English".

Side note 2: if you want to avoid spaces (because of quoting issues), you
can use any non-alphanumberic character instead. So

	git log --since=2.days.ago

works without any quotes.
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Ok. This is the insane patch to do this.

It really isn't very careful, and the reason I call it "approxidate()"
will become obvious when you look at the code. It is very liberal in what
it accepts, to the point where sometimes the results may not make a whole
lot of sense.

It accepts "last week" as a date string, by virtue of "last" parsing as
the number 1, and it totally ignoring superfluous fluff like "ago", so
"last week" ends up being exactly the same thing as "1 week ago". Fine so
far.

It has strange side effects: "last december" will actually parse as "Dec
1", which actually _does_ turn out right, because it will then notice that
it's not December yet, so it will decide that you must be talking about a
date last year. So it actually gets it right, but it's kind of for the
"wrong" reasons.

It also accepts the numbers 1..10 in string format ("one" .. "ten"), so
you can do "ten weeks ago" or "ten hours ago" and it will do the right
thing.

But it will do some really strange thigns too: the string "this will last
forever", will not recognize anyting but "last", which is recognized as
"1", which since it doesn't understand anything else it will think is the
day of the month. So if you do

	gitk --since="this will last forever"

the date will actually parse as the first day of the current month.

And it will parse the string "now" as "now", but only because it doesn't
understand it at all, and it makes everything relative to "now".

Similarly, it doesn't actually parse the "ago" or "from now", so "2 weeks
ago" is exactly the same as "2 weeks from now". It's the current date
minus 14 days.

But hey, it's probably better (and certainly faster) than depending on GNU
date. So now you can portably do things like

	gitk --since="two weeks and three days ago"
	git log --since="July 5"
	git-whatchanged --since="10 hours ago"
	git log --since="last october"

and it will actually do exactly what you thought it would do (I think). It
will count 17 days backwards, and it will do so even if you don't have GNU
date installed.

(I don't do "last monday" or similar yet, but I can extend it to that too
if people want).

It was kind of fun trying to write code that uses such totally relaxed
"understanding" of dates yet tries to get it right for the trivial cases.
The result should be mixed with a few strange preprocessor tricks, and be
submitted for the IOCCC ;)

Feel free to try it out, and see how many strange dates it gets right. Or
wrong.

And if you find some interesting (and valid - not "interesting" as in
"strange", but "interesting" as in "I'd be interested in actually doing
this) thing it gets wrong - usually by not understanding it and silently
just doing some strange things - please holler.

Now, as usual this certainly hasn't been getting a lot of testing. But my
code always works, no?

		Linus
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Do our own ctype.h, just to get the sane semantics: we want
locale-independence, _and_ we want the right signed behaviour. Plus we
only use a very small subset of ctype.h anyway (isspace, isalpha,
isdigit and isalnum).
Signed-off-by: NJunio C Hamano <junkio@cox.net>

We generate the ASCII representation of our internal date representation
("seconds since 1970, UTC + timezone information") in two different
places.

One of them uses the stupid and obvious way to make sure that it gets the
sexagecimal representation right for negative timezones even if they might
not be exact hours, and the other one depends on the modulus operator
always matching the sign of argument.

Hey, the clever one works. And C90 even specifies that behaviour. But I
had to think about it for a while when I was re-visiting this area, and
even if I didn't have to, it's kind of strange to have two different ways
to print out the same data format.

So use a common helper for this. And select the stupid and straighforward
way.
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Right now we don't return any error value at all from parse_date(), and if
we can't parse it, we just silently leave the result buffer unchanged.

That's fine for the current user, which will always default to the current
date, but it's a crappy interface, and we might well be better off with an
error message rather than just the default date.

So let's change the thing to return a negative value if an error occurs,
and the length of the result otherwise (snprintf behaviour: if the buffer
is too small, it returns how big it _would_ have been).

[ I started looking at this in case we could support date-based revision
  names. Looks ugly. Would have to parse relative dates.. ]
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This is part of breaking up the tag ID patch by Eric Biederman.

Usually all of the match_xxx routines in date.c fill tm
structure assuming that the parsed string talks about local
time, and parse_date routine compensates for it by adjusting the
value with tz offset parsed out separately.  However, this logic
does not work well when we feed GIT raw commit timestamp to it,
because what match_digits gets is already in GMT.

A good testcase is:

    $ make test-date
    $ ./test-date 'Fri Jun 24 16:55:27 2005 -0700' '1119657327 -0700'

These two timestamps represent the same time, but the second one
without the fix this commit introduces gives you 7 hours off.
Signed-off-by: NJunio C Hamano <junkio@cox.net>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Add <limits.h> to the include files handled by "cache.h", and remove
extraneous #include directives from various .c files. The rule is that
"cache.h" gets all the basic stuff, so that we'll have as few system
dependencies as possible.

Fix various things that sparse complains about:
 - use NULL instead of 0
 - make sure we declare everything properly, or mark it static
 - use proper function declarations ("fn(void)" instead of "fn()")

Sparse is always right.

Signed-off-by: NNicolas Pitre <nico@cam.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Kind of like ctime(), but not as broken.

And be a bitmore careful about matching: if we don't recognize a word
or a number, we skip the whole thing, rather than trying the next character
in that word/number.

Finally: since ctime() adds the final '\n', don't add another one in test-date.

(and some added checks for truly non-sensical stuff)

We'd get the sign wrong for the minutes part of a negative offset.

Also, add EEST (hey, it's Finland).

This still doesn't actually really _use_ it properly, nor make any
distinction between different DST rules, but at least we could (if
we wanted to) fake it a bit better.

Right now the code actually still says "it's always summer". I'm
from Finland, I don't like winter.

We looked at the year one character too early, and we
didn't accept a two-character year date after 2000.

This date parser turns line-noise into a date. Cool.

...since everything out there is either strange (libc mktime has issues
with timezones) or introduces unnecessary dependencies for people (libcurl).

This goes back to the old date parsing, but moves it out into a file of
its own, and does the "struct tm" to "seconds since epoch" handling by
hand. 

I grepped through the tz-database and it seems there's one "country"
left that has non-60-minute DST: Lord Howe Island.  All others dropped
that before 1970.