[PATCH v2 16/22] ui-snapshot: use a struct strbuf instead of fixed-size buffers

[John Keeping]

Signed-off-by: John Keeping <john at keeping.me.uk>
---
Changes since v1:
- Fix completely bogus reset-then-use code.

 ui-snapshot.c | 37 ++++++++++++++++++++++---------------
 1 file changed, 22 insertions(+), 15 deletions(-)

diff --git a/ui-snapshot.c b/ui-snapshot.c
index 1b361c1..8e76977 100644
--- a/ui-snapshot.c
+++ b/ui-snapshot.c
@@ -148,29 +148,36 @@ static const char *get_ref_from_filename(const char *url, const char *filename,
 {
 	const char *reponame;
 	unsigned char sha1[20];
-	char *snapshot;
+	struct strbuf snapshot = STRBUF_INIT;
+	int result = 1;
 
-	snapshot = xstrdup(filename);
-	snapshot[strlen(snapshot) - strlen(format->suffix)] = '\0';
+	strbuf_addstr(&snapshot, filename);
+	strbuf_setlen(&snapshot, snapshot.len - strlen(format->suffix));
 
-	if (get_sha1(snapshot, sha1) == 0)
-		return snapshot;
+	if (get_sha1(snapshot.buf, sha1) == 0)
+		goto out;
 
 	reponame = cgit_repobasename(url);
-	if (prefixcmp(snapshot, reponame) == 0) {
-		snapshot += strlen(reponame);
-		while (snapshot && (*snapshot == '-' || *snapshot == '_'))
-			snapshot++;
+	if (prefixcmp(snapshot.buf, reponame) == 0) {
+		const char *new_start = snapshot.buf;
+		new_start += strlen(reponame);
+		while (new_start && (*new_start == '-' || *new_start == '_'))
+			new_start++;
+		strbuf_splice(&snapshot, 0, new_start - snapshot.buf, "", 0);
 	}
 
-	if (get_sha1(snapshot, sha1) == 0)
-		return snapshot;
+	if (get_sha1(snapshot.buf, sha1) == 0)
+		goto out;
 
-	snapshot = fmt("v%s", snapshot);
-	if (get_sha1(snapshot, sha1) == 0)
-		return snapshot;
+	strbuf_insert(&snapshot, 0, "v", 1);
+	if (get_sha1(snapshot.buf, sha1) == 0)
+		goto out;
 
-	return NULL;
+	result = 0;
+	strbuf_release(&snapshot);
+
+out:
+	return result ? strbuf_detach(&snapshot, NULL) : NULL;
 }
 
 __attribute__((format (printf, 1, 2)))
-- 
1.8.2.692.g17a9715