revert: refactor code to find commit subject in find_commit_subject()

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/builtin/revert.c b/builtin/revert.c
index c170715..d477944 100644
--- a/builtin/revert.c
+++ b/builtin/revert.c
@@ -98,7 +98,7 @@
 static int get_message(const char *raw_message, struct commit_message *out)
 {
 	const char *encoding;
-	const char *p, *abbrev, *eol;
+	const char *p, *abbrev;
 	char *q;
 	int abbrev_len, oneline_len;
 
@@ -121,17 +121,7 @@
 	abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
 	abbrev_len = strlen(abbrev);
 
-	/* Find beginning and end of commit subject. */
-	p = out->message;
-	while (*p && (*p != '\n' || p[1] != '\n'))
-		p++;
-	if (*p) {
-		p += 2;
-		for (eol = p; *eol && *eol != '\n'; eol++)
-			; /* do nothing */
-	} else
-		eol = p;
-	oneline_len = eol - p;
+	oneline_len = find_commit_subject(out->message, &p);
 
 	out->parent_label = xmalloc(strlen("parent of ") + abbrev_len +
 			      strlen("... ") + oneline_len + 1);
diff --git a/commit.c b/commit.c
index 731191e..fa1a5ba 100644
--- a/commit.c
+++ b/commit.c
@@ -315,6 +315,25 @@
 	return ret;
 }
 
+int find_commit_subject(const char *commit_buffer, const char **subject)
+{
+	const char *eol;
+	const char *p = commit_buffer;
+
+	while (*p && (*p != '\n' || p[1] != '\n'))
+		p++;
+	if (*p) {
+		p += 2;
+		for (eol = p; *eol && *eol != '\n'; eol++)
+			; /* do nothing */
+	} else
+		eol = p;
+
+	*subject = p;
+
+	return eol - p;
+}
+
 struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
 {
 	struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
diff --git a/commit.h b/commit.h
index 26ec8c0..236cf13 100644
--- a/commit.h
+++ b/commit.h
@@ -40,6 +40,9 @@
 
 int parse_commit(struct commit *item);
 
+/* Find beginning and length of commit subject. */
+int find_commit_subject(const char *commit_buffer, const char **subject);
+
 struct commit_list * commit_list_insert(struct commit *item, struct commit_list **list_p);
 unsigned commit_list_count(const struct commit_list *l);
 struct commit_list * insert_by_date(struct commit *item, struct commit_list **list);