[PATCH v2] commit.c: Replace starts_with() with skip_prefix()

[Karthik Nayak <karthik.188@gmail.com>]

Replaces all instances of starts_with() by skip_prefix(),
which can not only be used to check presence of a prefix,
but also used further on as it returns the string after the prefix,
if the prefix is present.

Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
---

Hey Eric,
Here are the changes i have made in this Patch v2:
1. Edited the variables names to fit their usage
2. set my emacs to indent 8 tabs, so proper indentation
3. fixed my error where i increased the value by 1 in parse_signed_commit().
Thanks again for your patience.

---
 commit.c | 23 ++++++++++++-----------
 1 file changed, 12 insertions(+), 11 deletions(-)

diff --git a/commit.c b/commit.c
index 6bf4fe0..f006490 100644
--- a/commit.c
+++ b/commit.c
@@ -553,6 +553,7 @@ static void record_author_date(struct author_date_slab *author_date,
 	struct ident_split ident;
 	char *date_end;
 	unsigned long date;
+	const char *buf_split;
 
 	if (!commit->buffer) {
 		unsigned long size;
@@ -562,18 +563,19 @@ static void record_author_date(struct author_date_slab *author_date,
 			return;
 	}
 
+	buf_split = skip_prefix(buf, "author ");
+
 	for (buf = commit->buffer ? commit->buffer : buffer;
 	     buf;
 	     buf = line_end + 1) {
 		line_end = strchrnul(buf, '\n');
-		if (!starts_with(buf, "author ")) {
+		if (!buf_split) {
 			if (!line_end[0] || line_end[1] == '\n')
 				return; /* end of header */
 			continue;
 		}
-		if (split_ident_line(&ident,
-				     buf + strlen("author "),
-				     line_end - (buf + strlen("author "))) ||
+		if (split_ident_line(&ident, buf_split,
+				     line_end - buf_split) ||
 		    !ident.date_begin || !ident.date_end)
 			goto fail_exit; /* malformed "author" line */
 		break;
@@ -1098,6 +1100,7 @@ int parse_signed_commit(const unsigned char *sha1,
 	char *buffer = read_sha1_file(sha1, &type, &size);
 	int in_signature, saw_signature = -1;
 	char *line, *tail;
+	const char *line_split;
 
 	if (!buffer || type != OBJ_COMMIT)
 		goto cleanup;
@@ -1111,11 +1114,11 @@ int parse_signed_commit(const unsigned char *sha1,
 		char *next = memchr(line, '\n', tail - line);
 
 		next = next ? next + 1 : tail;
+		line_split = skip_prefix(line, gpg_sig_header);
 		if (in_signature && line[0] == ' ')
 			sig = line + 1;
-		else if (starts_with(line, gpg_sig_header) &&
-			 line[gpg_sig_header_len] == ' ')
-			sig = line + gpg_sig_header_len + 1;
+		else if (line_split && line_split[0] == ' ')
+			sig = line_split + 1;
 		if (sig) {
 			strbuf_add(signature, sig, next - sig);
 			saw_signature = 1;
@@ -1193,10 +1196,8 @@ static void parse_gpg_output(struct signature_check *sigc)
 	for (i = 0; i < ARRAY_SIZE(sigcheck_gpg_status); i++) {
 		const char *found, *next;
 
-		if (starts_with(buf, sigcheck_gpg_status[i].check + 1)) {
-			/* At the very beginning of the buffer */
-			found = buf + strlen(sigcheck_gpg_status[i].check + 1);
-		} else {
+		found = skip_prefix(buf, sigcheck_gpg_status[i].check + 1);
+		if(!found) {
 			found = strstr(buf, sigcheck_gpg_status[i].check);
 			if (!found)
 				continue;
-- 
1.9.0.138.g2de3478