line-log: respect diffopt's configured output file stream

The diff machinery can optionally output to a file stream other than
stdout, by overriding diffopt.file. In such a case, the rest of the
log tree machinery should also write to that stream.

Currently, there is no user of the line level log that wants to
redirect output to a file. Therefore, one might argue that it is
superfluous to support that now. However, it is better to be
consistent now, rather than to face hard-to-debug problems later.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: dscho

line-log.c

@@ -841,7 +841,7 @@ static char *get_nth_line(long line, unsigned long *ends, void *data)
 
 static void print_line(const char *prefix, char first,
 		       long line, unsigned long *ends, void *data,
-		       const char *color, const char *reset)
+		       const char *color, const char *reset, FILE *file)
 {
 	char *begin = get_nth_line(line, ends, data);
 	char *end = get_nth_line(line+1, ends, data);
@@ -852,14 +852,14 @@ static void print_line(const char *prefix, char first,
 		had_nl = 1;
 	}
 
-	fputs(prefix, stdout);
-	fputs(color, stdout);
-	putchar(first);
-	fwrite(begin, 1, end-begin, stdout);
-	fputs(reset, stdout);
-	putchar('\n');
+	fputs(prefix, file);
+	fputs(color, file);
+	putc(first, file);
+	fwrite(begin, 1, end-begin, file);
+	fputs(reset, file);
+	putc('\n', file);
 	if (!had_nl)
-		fputs("\\ No newline at end of file\n", stdout);
+		fputs("\\ No newline at end of file\n", file);
 }
 
 static char *output_prefix(struct diff_options *opt)
@@ -898,12 +898,12 @@ static void dump_diff_hacky_one(struct rev_info *rev, struct line_log_data *rang
 		fill_line_ends(pair->one, &p_lines, &p_ends);
 	fill_line_ends(pair->two, &t_lines, &t_ends);
 
-	printf("%s%sdiff --git a/%s b/%s%s\n", prefix, c_meta, pair->one->path, pair->two->path, c_reset);
-	printf("%s%s--- %s%s%s\n", prefix, c_meta,
+	fprintf(opt->file, "%s%sdiff --git a/%s b/%s%s\n", prefix, c_meta, pair->one->path, pair->two->path, c_reset);
+	fprintf(opt->file, "%s%s--- %s%s%s\n", prefix, c_meta,
 	       pair->one->sha1_valid ? "a/" : "",
 	       pair->one->sha1_valid ? pair->one->path : "/dev/null",
 	       c_reset);
-	printf("%s%s+++ b/%s%s\n", prefix, c_meta, pair->two->path, c_reset);
+	fprintf(opt->file, "%s%s+++ b/%s%s\n", prefix, c_meta, pair->two->path, c_reset);
 	for (i = 0; i < range->ranges.nr; i++) {
 		long p_start, p_end;
 		long t_start = range->ranges.ranges[i].start;
@@ -945,26 +945,26 @@ static void dump_diff_hacky_one(struct rev_info *rev, struct line_log_data *rang
 		}
 
 		/* Now output a diff hunk for this range */
-		printf("%s%s@@ -%ld,%ld +%ld,%ld @@%s\n",
+		fprintf(opt->file, "%s%s@@ -%ld,%ld +%ld,%ld @@%s\n",
 		       prefix, c_frag,
 		       p_start+1, p_end-p_start, t_start+1, t_end-t_start,
 		       c_reset);
 		while (j < diff->target.nr && diff->target.ranges[j].start < t_end) {
 			int k;
 			for (; t_cur < diff->target.ranges[j].start; t_cur++)
 				print_line(prefix, ' ', t_cur, t_ends, pair->two->data,
-					   c_context, c_reset);
+					   c_context, c_reset, opt->file);
 			for (k = diff->parent.ranges[j].start; k < diff->parent.ranges[j].end; k++)
 				print_line(prefix, '-', k, p_ends, pair->one->data,
-					   c_old, c_reset);
+					   c_old, c_reset, opt->file);
 			for (; t_cur < diff->target.ranges[j].end && t_cur < t_end; t_cur++)
 				print_line(prefix, '+', t_cur, t_ends, pair->two->data,
-					   c_new, c_reset);
+					   c_new, c_reset, opt->file);
 			j++;
 		}
 		for (; t_cur < t_end; t_cur++)
 			print_line(prefix, ' ', t_cur, t_ends, pair->two->data,
-				   c_context, c_reset);
+				   c_context, c_reset, opt->file);
 	}
 
 	free(p_ends);
@@ -977,7 +977,7 @@ static void dump_diff_hacky_one(struct rev_info *rev, struct line_log_data *rang
  */
 static void dump_diff_hacky(struct rev_info *rev, struct line_log_data *range)
 {
-	puts(output_prefix(&rev->diffopt));
+	fprintf(rev->diffopt.file, "%s\n", output_prefix(&rev->diffopt));
 	while (range) {
 		dump_diff_hacky_one(rev, range);
 		range = range->next;