Add filter and validation functions to pre-commit hook

githooks/pre-commit

@@ -1,5 +1,7 @@
 #!/bin/sh
 
+filter=$(git config hooks.filter)
+validation=$(git config hooks.validation)
 indentation=$(git config hooks.indentation)
 temp=$(mktemp -p /dev/shm -d -t git-hook.XXXX)
 export GIT_DIR=$(git rev-parse --show-toplevel)/.git
@@ -22,6 +24,18 @@ check() {
 git checkout-index --prefix="$temp/index/" --all
 
 cd $temp/index/
+
+if [ -n "$filter" ]; then
+	ln -s $GIT_DIR/ .git
+	$filter
+	git add --all
+	rm -rf .git
+fi
+
+if [ -n "$validation" ]; then
+	$validation || error=1
+fi
+
 case $indentation in
 	tab|tabs)
 		echo "Checking tab indentation"