contrib/plan9/9diff
author Jordi Gutiérrez Hermoso <jordigh@octave.org>
Mon, 18 Feb 2019 23:43:40 -0500
changeset 41728 36b62a522814
parent 16556 f9262456fb01
permissions -rwxr-xr-x
templatekw: make negrev return empty for wdir() and nullrev I considered just returning the same output that {rev} returns here, but {rev} also returns essentially gibberish: either an INT_MAX-kind of variable for wdir() or -1 for null. Since these are numbers that are intended to be used for calculations, and since the numbers for wdir() and -1 are not really very helpful for calculation (and worse, when used as a revision number -1 is equal to unhidden tip), I figured the most reasonable thing to do here is to just return nothing for negrev. This could potentially break scripts that are expecting to parse a nonempty integer out of a {negrev}, but that seems like a very remote concern at this juncture.

#!/bin/rc
# 9diff - Mercurial extdiff wrapper for diff(1)

rfork e

fn getfiles {
	cd $1 &&
	for(f in `{du -as | awk '{print $2}'})
		test -f $f && echo `{cleanname $f}
}

fn usage {
	echo >[1=2] usage: 9diff [diff options] parent child root
	exit usage
}

opts=()
while(~ $1 -*){
	opts=($opts $1)
	shift
}
if(! ~ $#* 3)
	usage

# extdiff will set the parent and child to a single file if there is
# only one change. If there are multiple changes, directories will be
# set. diff(1) does not cope particularly with directories; instead we
# do the recursion ourselves and diff each file individually.
if(test -f $1)
	diff $opts $1 $2
if not{
	# extdiff will create a snapshot of the working copy to prevent
	# conflicts during the diff. We circumvent this behavior by
	# diffing against the repository root to produce plumbable
	# output. This is antisocial.
	for(f in `{sort -u <{getfiles $1} <{getfiles $2}}){
		file1=$1/$f; test -f $file1 || file1=/dev/null
		file2=$3/$f; test -f $file2 || file2=/dev/null
		diff $opts $file1 $file2
	}
}
exit ''