contrib/plan9/9diff

convert: p4: ignore purged files with p4d 2012.2 and later

Perforce has the concept of "+Sn" files where only the last revisions of the
file is stored. In p4d 2012.1 old purged revisions were not included in the
"manifest". With 2012.2 they started being included and convert's getfile
failed to recognize the "purged" flag and saw it as an empty file. That made
test-convert-p4-filetypes.t fail.

There is no point in storing an empty file as placeholder for a purged file so
we restore the old behaviour by checking the flag and letting getfile consider
purged files deleted.

(It is questionable whether it makes sense to convert not-yet-purged +S files
to mercurial ... but that is another question.)

#!/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 ''