[PATCH 07/10] diff.c: convert fn_out_consume to use emit_line_*

[Stefan Beller <stefanbeller@gmail.com>]

From: Stefan Beller <sbeller@google.com>

In the coming patches we want to eliminate writes that do not go
though emit_line_* as we later want to hook into the emit_line_*
functions to add a buffered output. To make the conversion easy,
add a function that takes a format string.

Signed-off-by: Stefan Beller <stefanbeller@gmail.com>
---
 diff.c | 24 +++++++++++++++++++-----
 1 file changed, 19 insertions(+), 5 deletions(-)

diff --git a/diff.c b/diff.c
index 2aefd0f..7dcef73 100644
--- a/diff.c
+++ b/diff.c
@@ -493,6 +493,19 @@ static void emit_line(struct diff_options *o, const char *set, const char *reset
 	emit_line_0(o, set, reset, line[0], line+1, len-1);
 }
 
+static void emit_line_fmt(struct diff_options *o,
+			  const char *set, const char *reset,
+			  const char *fmt, ...)
+{
+	struct strbuf sb = STRBUF_INIT;
+	va_list ap;
+	va_start(ap, fmt);
+	strbuf_vaddf(&sb, fmt, ap);
+	va_end(ap);
+
+	emit_line(o, set, reset, sb.buf, sb.len);
+}
+
 static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
 {
 	if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
@@ -1217,7 +1230,6 @@ static void fn_out_consume(void *priv, char *line, unsigned long len)
 	const char *context = diff_get_color(ecbdata->color_diff, DIFF_CONTEXT);
 	const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
 	struct diff_options *o = ecbdata->opt;
-	const char *line_prefix = diff_line_prefix(o);
 
 	o->found_changes = 1;
 
@@ -1233,10 +1245,12 @@ static void fn_out_consume(void *priv, char *line, unsigned long len)
 		name_a_tab = strchr(ecbdata->label_path[0], ' ') ? "\t" : "";
 		name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
 
-		fprintf(o->file, "%s%s--- %s%s%s\n",
-			line_prefix, meta, ecbdata->label_path[0], reset, name_a_tab);
-		fprintf(o->file, "%s%s+++ %s%s%s\n",
-			line_prefix, meta, ecbdata->label_path[1], reset, name_b_tab);
+		emit_line_fmt(o, meta, reset, "--- %s%s\n",
+			      ecbdata->label_path[0], name_a_tab);
+
+		emit_line_fmt(o, meta, reset, "+++ %s%s\n",
+			      ecbdata->label_path[1], name_b_tab);
+
 		ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
 	}
 
-- 
2.7.4