Add undopatch script

3 files changed, 38 insertions, 6 deletions

diff --git a/Makefile b/Makefile
index d514a8c..949d8e2 100644
--- a/Makefile
+++ b/Makefile
@@ -1,2 +1,2 @@
 install:
-	install conv /usr/local/bin
+	install conv undopatch /usr/local/bin
diff --git a/README b/README
index ca429cb..13f65cb 100644
--- a/README
+++ b/README
@@ -30,15 +30,21 @@ they are formatted correctly and placed in the correct directory.
 
 = Undoing patches =
 
-I haven't tried it yet, but the following command should work:
+In order to undo all patches, you need to extract the original
+files from the downloaded archive.
 
-	cd /usr/pkgsrc/path-to/package/work/
+	cd /usr/pkgsrc/path-to/package
+	w=/usr/pkgsrc/distfiles/$(sed -n '/.*(\(.*\)).*/{s//\1/;p;q}' distinfo)
+	cd $(dirname $w)
+	tar xf $w
+	cd -
 	find . -name '*.orig' | while read f; do
-		mv "$f" "${f%.orig}"
+		f=${f%.orig}
+		cp $w/${f#work/} $f
 	done
 
-It probably won't work if you've tried to apply patches twice, as
-each do-patch theoretically presumably creates new .orig files.
+It is not reliable to restore the original files using the .orig
+files, as multiple patches may have been applied to the same file.
 
 = Rebuilding with new patch =
 
diff --git a/undopatch b/undopatch
new file mode 100755
index 0000000..0112101
--- /dev/null
+++ b/undopatch
@@ -0,0 +1,26 @@
+#!/bin/sh
+
+case "$PWD" in
+/usr/pkgsrc/*/*) ;;
+*) echo not in package directory 1>&2; exit 1 ;;
+esac
+
+w=/usr/pkgsrc/distfiles/$(sed -n '/.*(\(.*\)).*/{s//\1/;p;q}' distinfo)
+
+done=$(dirname $w)/.$(basename $w).done
+
+if [ ! -e "$done" ]; then
+	echo extracting archive... 1>&2
+	cd $(dirname $w)
+	tar xf $w
+	touch $done
+	cd -
+fi
+
+echo undoing patches... 1>&2
+cmd=echo\ cp
+[ x"$1" = x"-x" ] && cmd=cp || echo '(preview, no -x)' 1>&2
+find . -name '*.orig' | while read f; do
+	f=${f%.orig}
+	$cmd $w/${f#work/} $f
+done