#!/bin/rc

rfork e

if(! ~ $#* 1){
	echo 'usage: patch/apply patch-name' >[1=2]
	exit usage
}

if(! test -d /n/sources/patch){
	rfork n
	9fs sources
}

if(! test -d /n/sources/patch/$1){
	echo 'no such patch' /n/sources/patch/$1 >[1=2]
	exit nopatch
}

cd /n/sources/patch/$1 || exit nopatch
if(! patch/okay .){
	echo 'bad patch: '$status >[1=2]
	exit badpatch
}

if(! echo >.tmp || ! rm .tmp){
	echo no write permission >[1=2]
	exit 'no write permission'
}

echo -n merge... >[1=2]
fn xxx {
	if(! test -f $1)
		cp $2 $2.new
	if not
		ape/diff3 -m $1 $2.orig $2 >$2.new
	if(grep -s '^<<<<' $2.new){
		echo conflicts merging $1';' see $d/$2.new >[1=2]
		
		touch failed
	}
}
rm -f failed
cat files | sed 's/^/xxx /' | rc
if(test -f failed){
	echo exiting without changes >[1=2]
	exit failed
}

echo -n backup... >[1=2]
fn xxx {
	# echo cp $1 $2.backup
	cp $1 $2.backup
}
cat files | sed 's/^/xxx /' |rc

echo -n copy... >[1=2]
fn xxx {
	# echo cp $2.new $1
	cp $2.new $1 || touch failed
}
cat files | sed 's/^/xxx /' | rc

fn xxx {
	# echo cp $2.backup $1
	cp $2.backup $1
}

if(test -f failed){
	echo copying failed, restoring backups >[1=2]
	cat files | sed 's/^/xxx /' | rc
	exit failed
}

echo >[1=2]

echo to update sources: >[1=2]
cat files | awk '{print "	update " $1 }' >[1=2]