Rework pretty_print_commit to use strbufs instead of custom buffers.

  Also remove the "len" parameter, as:
  (1) it was used as a max boundary, and every caller used ~0u
  (2) we check for final NUL no matter what, so it doesn't help for speed.

  As a result most of the pp_* function takes 3 arguments less, and we need
a lot less local variables, this makes the code way more readable, and
easier to extend if needed.

  This patch also fixes some spacing and cosmetic issues.

  This patch also fixes (as a side effect) a memory leak intoruced in
builtin-archive.c at commit df4a394f (fmt was xmalloc'ed and not free'd)

Signed-off-by: Pierre Habouzit <madcoder@debian.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 16 insertions, 23 deletions

diff --git a/builtin-archive.c b/builtin-archive.c
index a90c65ce54..b50d5ad196 100644
--- a/builtin-archive.c
+++ b/builtin-archive.c
@@ -84,14 +84,16 @@ static int run_remote_archiver(const char *remote, int argc,
 static void *format_subst(const struct commit *commit, const char *format,
                           unsigned long *sizep)
 {
-	unsigned long len = *sizep, result_len = 0;
+	unsigned long len = *sizep;
 	const char *a = format;
-	char *result = NULL;
+	struct strbuf result;
+	struct strbuf fmt;
+
+	strbuf_init(&result, 0);
+	strbuf_init(&fmt, 0);
 
 	for (;;) {
 		const char *b, *c;
-		char *fmt, *formatted = NULL;
-		unsigned long a_len, fmt_len, formatted_len, allocated = 0;
 
 		b = memmem(a, len, "$Format:", 8);
 		if (!b || a + len < b + 9)
@@ -100,32 +102,23 @@ static void *format_subst(const struct commit *commit, const char *format,
 		if (!c)
 			break;
 
-		a_len = b - a;
-		fmt_len = c - b - 8;
-		fmt = xmalloc(fmt_len + 1);
-		memcpy(fmt, b + 8, fmt_len);
-		fmt[fmt_len] = '\0';
-
-		formatted_len = format_commit_message(commit, fmt, &formatted,
-		                                      &allocated);
-		free(fmt);
-		result = xrealloc(result, result_len + a_len + formatted_len);
-		memcpy(result + result_len, a, a_len);
-		memcpy(result + result_len + a_len, formatted, formatted_len);
-		result_len += a_len + formatted_len;
+		strbuf_reset(&fmt);
+		strbuf_add(&fmt, b + 8, c - b - 8);
+
+		strbuf_add(&result, a, b - a);
+		format_commit_message(commit, fmt.buf, &result);
 		len -= c + 1 - a;
 		a = c + 1;
 	}
 
-	if (result && len) {
-		result = xrealloc(result, result_len + len);
-		memcpy(result + result_len, a, len);
-		result_len += len;
+	if (result.len && len) {
+		strbuf_add(&result, a, len);
 	}
 
-	*sizep = result_len;
+	*sizep = result.len;
 
-	return result;
+	strbuf_release(&fmt);
+	return strbuf_detach(&result);
 }
 
 static void *convert_to_archive(const char *path,