Re: git and time

From: Junio C Hamano <junkio@cox.net>
Date: Sep 28, 2006, 16:05 UTC
Message-ID: <7vodt0vux0.fsf@assigned-by-dhcp.cox.net>
In-Reply-To: <Pine.LNX.4.64.0609281029300.9349@xanadu.home>

Nicolas Pitre <nico@cam.org> writes:

Show 22 quoted lines

>> Nicolas Pitre <nico@cam.org> writes:
>> 
>> > SYNOPSIS
>> >
>> > 	git-local-arrival <committish>
>> >
>> > DESCRIPTION
>> >
>> > 	The command displays the time when given commit appeared in the 
>> > 	local repository.
>> 
>> This should be certainly doable, but local-arrival may not be
>> interesting if the repository has more than one branches.  Maybe
>> 
>> 	git-local-arrival <committish> [<branch>]
>> 
>> which defaults to the current branch?
>
> Indeed.  I didn't mention it initially because it is really easy to do 
> once you have it working for the current branch.  The technical 
> challenge is about making it efficient to find out which reflog entry 
> with a path to given commit is the oldest.

Perhaps bisect it like this. This assumes you never rewind the branch in question and the tip already contains the commit in question.

-- >8 --

#!/bin/sh

. git-sh-setup commit=`git rev-parse "$1"` && branch="${2-`git symbolic-ref HEAD`} || exit

contains () {
	contains=`git merge-base --all $1 $commit`
	case "$LF$contains$LF" in
	*"$LF$contains$LF"*)
		: ;;
	*)
		false ;;
	esac
}

LF='
'
script='{
	s/	.*//
	p
}' ;# strip things after TAB if a TAB exists
reflog="$GIT_DIR/logs/refs/heads/$branch";
lo=1;
hi=`wc -l <$reflog`
ld=$hi
while expr "$lo" \< "$hi" >/dev/null
do
	mi=`expr \( $hi \+ $lo \) / 2`
	line=`sed -ne "$mi$script" "$reflog"`
	to=`expr "$line" : '[^ ]* \([^ ]*\) '`
	if contains $to
	then
		ld=$hi
		hi=$mi
	else
		lo=`expr "$mi" + 1`
	fi
done

case "$ld" in	
'')
	echo >&2 Oops
	exit 1;;
?*)	
	line=`sed -ne "$ld$script" "$reflog"`
	time=`expr "$line" : '.*> \([0-9]*\) '`
	zone=`expr "$line" : '.*> [0-9]* \(.[0-9][0-9][0-9][0-9]\)$'`
	echo "$time $zone"
esac