[RFC/PATCH 11/17] diff.c: convert emit_binary_diff_body to use emit_line_*

[Stefan Beller <sbeller@google.com>]

In a later patch, I want to propose an option to detect&color
moved lines in a diff, which cannot be done in a one-pass over
the diff. Instead we need to go over the whole diff twice,
because we cannot detect the first line of the two corresponding
lines (+ and -) that got moved.

So to prepare the diff machinery for two pass algorithms
(i.e. buffer it all up and then operate on the result),
move all emissions to places, such that the only emitting
function is emit_line_0.

This covers emit_binary_diff_body.

Signed-off-by: Stefan Beller <sbeller@google.com>
---
 diff.c | 39 ++++++++++++++++++++++-----------------
 1 file changed, 22 insertions(+), 17 deletions(-)

diff --git a/diff.c b/diff.c
index 1892c2b..ff1e829 100644
--- a/diff.c
+++ b/diff.c
@@ -2169,8 +2169,8 @@ static unsigned char *deflate_it(char *data,
 	return deflated;
 }
 
-static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two,
-				  const char *prefix)
+static void emit_binary_diff_body(struct diff_options *o,
+				  mmfile_t *one, mmfile_t *two)
 {
 	void *cp;
 	void *delta;
@@ -2199,13 +2199,12 @@ static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two,
 	}
 
 	if (delta && delta_size < deflate_size) {
-		fprintf(file, "%sdelta %lu\n", prefix, orig_size);
+		emit_line_fmt(o, 0, 0, "delta %lu\n", orig_size);
 		free(deflated);
 		data = delta;
 		data_size = delta_size;
-	}
-	else {
-		fprintf(file, "%sliteral %lu\n", prefix, two->size);
+	} else {
+		emit_line_fmt(o, 0, 0, "literal %lu\n", two->size);
 		free(delta);
 		data = deflated;
 		data_size = deflate_size;
@@ -2214,8 +2213,9 @@ static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two,
 	/* emit data encoded in base85 */
 	cp = data;
 	while (data_size) {
+		int len;
 		int bytes = (52 < data_size) ? 52 : data_size;
-		char line[70];
+		char line[71];
 		data_size -= bytes;
 		if (bytes <= 26)
 			line[0] = bytes + 'A' - 1;
@@ -2223,20 +2223,25 @@ static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two,
 			line[0] = bytes - 26 + 'a' - 1;
 		encode_85(line + 1, cp, bytes);
 		cp = (char *) cp + bytes;
-		fprintf(file, "%s", prefix);
-		fputs(line, file);
-		fputc('\n', file);
+
+		len = strlen(line);
+		line[len++] = '\n';
+		line[len] = '\0';
+
+		emit_line(o, 0, 0, line, len);
 	}
-	fprintf(file, "%s\n", prefix);
+	emit_line(o, 0, 0, "\n", 1);
 	free(data);
 }
 
-static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two,
-			     const char *prefix)
+static void emit_binary_diff(struct diff_options *o,
+			     mmfile_t *one, mmfile_t *two)
 {
-	fprintf(file, "%sGIT binary patch\n", prefix);
-	emit_binary_diff_body(file, one, two, prefix);
-	emit_binary_diff_body(file, two, one, prefix);
+	const char *s = "GIT binary patch\n";
+	const int len = strlen(s);
+	emit_line(o, 0, 0, s, len);
+	emit_binary_diff_body(o, one, two);
+	emit_binary_diff_body(o, two, one);
 }
 
 int diff_filespec_is_binary(struct diff_filespec *one)
@@ -2411,7 +2416,7 @@ static void builtin_diff(const char *name_a,
 			emit_line(o, 0, 0, header.buf, header.len);
 		strbuf_reset(&header);
 		if (DIFF_OPT_TST(o, BINARY))
-			emit_binary_diff(o->file, &mf1, &mf2, line_prefix);
+			emit_binary_diff(o, &mf1, &mf2);
 		else
 			emit_line_fmt(o, 0, 0, "Binary files %s and %s differ\n",
 				      lbl[0], lbl[1]);
-- 
2.10.0.21.g1da280f.dirty