replace strbuf_expand() with strbuf_expand_step()

Avoid the overhead of passing context to a callback function of
strbuf_expand() by using strbuf_expand_step() in a loop instead.  It
requires explicit handling of %% and unrecognized placeholders, but is
simpler, more direct and avoids void pointers.

Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 43 insertions, 29 deletions

diff --git a/pretty.c b/pretty.c
index d2df561..cffbf32 100644
--- a/pretty.c
+++ b/pretty.c
@@ -1254,9 +1254,19 @@ static struct strbuf *expand_separator(struct strbuf *sb,
 				       const char *argval, size_t arglen)
 {
 	char *fmt = xstrndup(argval, arglen);
+	const char *format = fmt;
 
 	strbuf_reset(sb);
-	strbuf_expand(sb, fmt, strbuf_expand_literal_cb, NULL);
+	while (strbuf_expand_step(sb, &format)) {
+		size_t len;
+
+		if (skip_prefix(format, "%", &format))
+			strbuf_addch(sb, '%');
+		else if ((len = strbuf_expand_literal_cb(sb, format, NULL)))
+			format += len;
+		else
+			strbuf_addch(sb, '%');
+	}
 	free(fmt);
 	return sb;
 }
@@ -1803,7 +1813,7 @@ static size_t format_and_pad_commit(struct strbuf *sb, /* in UTF-8 */
 
 static size_t format_commit_item(struct strbuf *sb, /* in UTF-8 */
 				 const char *placeholder,
-				 void *context)
+				 struct format_commit_context *context)
 {
 	size_t consumed, orig_len;
 	enum {
@@ -1842,7 +1852,7 @@ static size_t format_commit_item(struct strbuf *sb, /* in UTF-8 */
 	}
 
 	orig_len = sb->len;
-	if (((struct format_commit_context *)context)->flush_type != no_flush)
+	if ((context)->flush_type != no_flush)
 		consumed = format_and_pad_commit(sb, placeholder, context);
 	else
 		consumed = format_commit_one(sb, placeholder, context);
@@ -1861,30 +1871,6 @@ static size_t format_commit_item(struct strbuf *sb, /* in UTF-8 */
 	return consumed + 1;
 }
 
-static size_t userformat_want_item(struct strbuf *sb UNUSED,
-				   const char *placeholder,
-				   void *context)
-{
-	struct userformat_want *w = context;
-
-	if (*placeholder == '+' || *placeholder == '-' || *placeholder == ' ')
-		placeholder++;
-
-	switch (*placeholder) {
-	case 'N':
-		w->notes = 1;
-		break;
-	case 'S':
-		w->source = 1;
-		break;
-	case 'd':
-	case 'D':
-		w->decorate = 1;
-		break;
-	}
-	return 0;
-}
-
 void userformat_find_requirements(const char *fmt, struct userformat_want *w)
 {
 	struct strbuf dummy = STRBUF_INIT;
@@ -1894,7 +1880,26 @@ void userformat_find_requirements(const char *fmt, struct userformat_want *w)
 			return;
 		fmt = user_format;
 	}
-	strbuf_expand(&dummy, fmt, userformat_want_item, w);
+	while (strbuf_expand_step(&dummy, &fmt)) {
+		if (skip_prefix(fmt, "%", &fmt))
+			continue;
+
+		if (*fmt == '+' || *fmt == '-' || *fmt == ' ')
+			fmt++;
+
+		switch (*fmt) {
+		case 'N':
+			w->notes = 1;
+			break;
+		case 'S':
+			w->source = 1;
+			break;
+		case 'd':
+		case 'D':
+			w->decorate = 1;
+			break;
+		}
+	}
 	strbuf_release(&dummy);
 }
 
@@ -1912,7 +1917,16 @@ void repo_format_commit_message(struct repository *r,
 	const char *output_enc = pretty_ctx->output_encoding;
 	const char *utf8 = "UTF-8";
 
-	strbuf_expand(sb, format, format_commit_item, &context);
+	while (strbuf_expand_step(sb, &format)) {
+		size_t len;
+
+		if (skip_prefix(format, "%", &format))
+			strbuf_addch(sb, '%');
+		else if ((len = format_commit_item(sb, format, &context)))
+			format += len;
+		else
+			strbuf_addch(sb, '%');
+	}
 	rewrap_message_tail(sb, &context, 0, 0, 0);
 
 	/*