git-am: refactor 'cleaning up and aborting'

Introduce a clean_abort function that echoes an optional error message
to standard error, removes the dotest directory and exits with status 1.

Use it when patch format detection or patch splitting fails early.

Signed-off-by: Giuseppe Bilotta <giuseppe.bilotta@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: Oblomov

git-am.sh

@@ -134,6 +134,12 @@ It does not apply to blobs recorded in its index."
     unset GITHEAD_$his_tree
 }
 
+clean_abort () {
+	test $# = 0 || echo >&2 "$@"
+	rm -fr "$dotest"
+	exit 1
+}
+
 patch_format=
 
 check_patch_format () {
@@ -180,22 +186,19 @@ check_patch_format () {
 			esac
 			;;
 		esac
-	} < "$1"
+	} < "$1" || clean_abort
 }
 
 split_patches () {
 	case "$patch_format" in
 	mbox)
-		git mailsplit -d"$prec" -o"$dotest" -b -- "$@" > "$dotest/last" ||  {
-			rm -fr "$dotest"
-			exit 1
-		}
+		git mailsplit -d"$prec" -o"$dotest" -b -- "$@" > "$dotest/last" ||
+		clean_abort
 		;;
 	stgit-series)
 		if test $# -ne 1
 		then
-			echo "Only one StGIT patch series can be applied at once"
-			exit 1
+			clean_abort "Only one StGIT patch series can be applied at once"
 		fi
 		series_dir=`dirname "$1"`
 		series_file="$1"
@@ -210,7 +213,7 @@ split_patches () {
 			shift
 			# remove the arg coming from the first-line comment
 			shift
-		} < "$series_file"
+		} < "$series_file" || clean_abort
 		# set the patch format appropriately
 		patch_format=stgit
 		# now handle the actual StGIT patches
@@ -239,18 +242,14 @@ split_patches () {
 					print "Subject: ", $_ ;
 					$subject = 1;
 				}
-			' < "$stgit" > "$dotest/$msgnum" || {
-				echo "Failed to import $patch_format patch $stgit"
-				exit 1
-			}
+			' < "$stgit" > "$dotest/$msgnum" || clean_abort
 		done
 		echo "$this" > "$dotest/last"
 		this=
 		msgnum=
 		;;
 	*)
-		echo "Patch format $patch_format is not supported."
-		exit 1
+		clean_abort "Patch format $patch_format is not supported."
 		;;
 	esac
 }