diff.c: emit_diff_symbol learns DIFF_SYMBOL_HEADER

The header is constructed lazily including line breaks, so just emit
the raw string as is.

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: stefanbeller

diff.c

@@ -561,6 +561,7 @@ static void emit_line(struct diff_options *o, const char *set, const char *reset
 }
 
 enum diff_symbol {
+	DIFF_SYMBOL_HEADER,
 	DIFF_SYMBOL_FILEPAIR_PLUS,
 	DIFF_SYMBOL_FILEPAIR_MINUS,
 	DIFF_SYMBOL_WORDS_PORCELAIN,
@@ -689,6 +690,9 @@ static void emit_diff_symbol(struct diff_options *o, enum diff_symbol s,
 			line, reset,
 			strchr(line, ' ') ? "\t" : "");
 		break;
+	case DIFF_SYMBOL_HEADER:
+		fprintf(o->file, "%s", line);
+		break;
 	default:
 		die("BUG: unknown diff symbol");
 	}
@@ -1385,7 +1389,8 @@ static void fn_out_consume(void *priv, char *line, unsigned long len)
 	o->found_changes = 1;
 
 	if (ecbdata->header) {
-		fprintf(o->file, "%s", ecbdata->header->buf);
+		emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
+				 ecbdata->header->buf, ecbdata->header->len, 0);
 		strbuf_reset(ecbdata->header);
 		ecbdata->header = NULL;
 	}
@@ -2519,7 +2524,8 @@ static void builtin_diff(const char *name_a,
 		if (complete_rewrite &&
 		    (textconv_one || !diff_filespec_is_binary(one)) &&
 		    (textconv_two || !diff_filespec_is_binary(two))) {
-			fprintf(o->file, "%s", header.buf);
+			emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
+					 header.buf, header.len, 0);
 			strbuf_reset(&header);
 			emit_rewrite_diff(name_a, name_b, one, two,
 						textconv_one, textconv_two, o);
@@ -2529,7 +2535,8 @@ static void builtin_diff(const char *name_a,
 	}
 
 	if (o->irreversible_delete && lbl[1][0] == '/') {
-		fprintf(o->file, "%s", header.buf);
+		emit_diff_symbol(o, DIFF_SYMBOL_HEADER, header.buf,
+				 header.len, 0);
 		strbuf_reset(&header);
 		goto free_ab_and_return;
 	} else if (!DIFF_OPT_TST(o, TEXT) &&
@@ -2540,10 +2547,13 @@ static void builtin_diff(const char *name_a,
 		    !DIFF_OPT_TST(o, BINARY)) {
 			if (!oidcmp(&one->oid, &two->oid)) {
 				if (must_show_header)
-					fprintf(o->file, "%s", header.buf);
+					emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
+							 header.buf, header.len,
+							 0);
 				goto free_ab_and_return;
 			}
-			fprintf(o->file, "%s", header.buf);
+			emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
+					 header.buf, header.len, 0);
 			fprintf(o->file, "%sBinary files %s and %s differ\n",
 				line_prefix, lbl[0], lbl[1]);
 			goto free_ab_and_return;
@@ -2554,10 +2564,11 @@ static void builtin_diff(const char *name_a,
 		if (mf1.size == mf2.size &&
 		    !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
 			if (must_show_header)
-				fprintf(o->file, "%s", header.buf);
+				emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
+						 header.buf, header.len, 0);
 			goto free_ab_and_return;
 		}
-		fprintf(o->file, "%s", header.buf);
+		emit_diff_symbol(o, DIFF_SYMBOL_HEADER, header.buf, header.len, 0);
 		strbuf_reset(&header);
 		if (DIFF_OPT_TST(o, BINARY))
 			emit_binary_diff(o->file, &mf1, &mf2, line_prefix);
@@ -2575,7 +2586,8 @@ static void builtin_diff(const char *name_a,
 		const struct userdiff_funcname *pe;
 
 		if (must_show_header) {
-			fprintf(o->file, "%s", header.buf);
+			emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
+					 header.buf, header.len, 0);
 			strbuf_reset(&header);
 		}