#!/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 ''