verify-tag: factor out signature detection

into tag.h/c for later reuse and modification.

Signed-off-by: Michael J Gruber <git@drmicha.warpmail.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/verify-tag.c

@@ -17,13 +17,11 @@ static const char * const verify_tag_usage[] = {
 		NULL
 };
 
-#define PGP_SIGNATURE "-----BEGIN PGP SIGNATURE-----"
-
 static int run_gpg_verify(const char *buf, unsigned long size, int verbose)
 {
 	struct child_process gpg;
 	const char *args_gpg[] = {"gpg", "--verify", "FILE", "-", NULL};
-	char path[PATH_MAX], *eol;
+	char path[PATH_MAX];
 	size_t len;
 	int fd, ret;
 
@@ -37,11 +35,7 @@ static int run_gpg_verify(const char *buf, unsigned long size, int verbose)
 	close(fd);
 
 	/* find the length without signature */
-	len = 0;
-	while (len < size && prefixcmp(buf + len, PGP_SIGNATURE)) {
-		eol = memchr(buf + len, '\n', size - len);
-		len += eol ? eol - (buf + len) + 1 : size - len;
-	}
+	len = parse_signature(buf, size);
 	if (verbose)
 		write_in_full(1, buf, len);
 

tag.c

@@ -4,6 +4,8 @@
 #include "tree.h"
 #include "blob.h"
 
+#define PGP_SIGNATURE "-----BEGIN PGP SIGNATURE-----"
+
 const char *tag_type = "tag";
 
 struct object *deref_tag(struct object *o, const char *warn, int warnlen)
@@ -133,3 +135,14 @@ int parse_tag(struct tag *item)
 	free(data);
 	return ret;
 }
+
+size_t parse_signature(const char *buf, unsigned long size)
+{
+	char *eol;
+	size_t len = 0;
+	while (len < size && prefixcmp(buf + len, PGP_SIGNATURE)) {
+		eol = memchr(buf + len, '\n', size - len);
+		len += eol ? eol - (buf + len) + 1 : size - len;
+	}
+	return len;
+}

tag.h

@@ -16,5 +16,6 @@ extern struct tag *lookup_tag(const unsigned char *sha1);
 extern int parse_tag_buffer(struct tag *item, void *data, unsigned long size);
 extern int parse_tag(struct tag *item);
 extern struct object *deref_tag(struct object *, const char *, int);
+extern size_t parse_signature(const char *buf, unsigned long size);
 
 #endif /* TAG_H */