1 files changed, 43 insertions, 10 deletions

diff --git a/builtin-diff-files.c b/builtin-diff-files.c
index 6ba5077a2..5b64011de 100644
--- a/builtin-diff-files.c
+++ b/builtin-diff-files.c
@@ -10,26 +10,59 @@
 #include "builtin.h"
 
 static const char diff_files_usage[] =
-"git-diff-files [-q] [-0/-1/2/3 |-c|--cc|-n|--no-index] [<common diff options>] [<path>...]"
+"git diff-files [-q] [-0/-1/2/3 |-c|--cc] [<common diff options>] [<path>...]"
 COMMON_DIFF_OPTIONS_HELP;
 
 int cmd_diff_files(int argc, const char **argv, const char *prefix)
 {
 	struct rev_info rev;
-	int nongit = 0;
 	int result;
+	unsigned options = 0;
 
-	prefix = setup_git_directory_gently(&nongit);
 	init_revisions(&rev, prefix);
-	git_config(git_default_config); /* no "diff" UI options */
+	git_config(git_diff_basic_config, NULL); /* no "diff" UI options */
 	rev.abbrev = 0;
 
-	if (!setup_diff_no_index(&rev, argc, argv, nongit, prefix))
-		argc = 0;
-	else
-		argc = setup_revisions(argc, argv, &rev, NULL);
+	argc = setup_revisions(argc, argv, &rev, NULL);
+	while (1 < argc && argv[1][0] == '-') {
+		if (!strcmp(argv[1], "--base"))
+			rev.max_count = 1;
+		else if (!strcmp(argv[1], "--ours"))
+			rev.max_count = 2;
+		else if (!strcmp(argv[1], "--theirs"))
+			rev.max_count = 3;
+		else if (!strcmp(argv[1], "-q"))
+			options |= DIFF_SILENT_ON_REMOVED;
+		else
+			usage(diff_files_usage);
+		argv++; argc--;
+	}
 	if (!rev.diffopt.output_format)
 		rev.diffopt.output_format = DIFF_FORMAT_RAW;
-	result = run_diff_files_cmd(&rev, argc, argv);
-	return rev.diffopt.exit_with_status ? rev.diffopt.has_changes: result;
+
+	/*
+	 * Make sure there are NO revision (i.e. pending object) parameter,
+	 * rev.max_count is reasonable (0 <= n <= 3), and
+	 * there is no other revision filtering parameters.
+	 */
+	if (rev.pending.nr ||
+	    rev.min_age != -1 || rev.max_age != -1 ||
+	    3 < rev.max_count)
+		usage(diff_files_usage);
+
+	/*
+	 * "diff-files --base -p" should not combine merges because it
+	 * was not asked to.  "diff-files -c -p" should not densify
+	 * (the user should ask with "diff-files --cc" explicitly).
+	 */
+	if (rev.max_count == -1 && !rev.combine_merges &&
+	    (rev.diffopt.output_format & DIFF_FORMAT_PATCH))
+		rev.combine_merges = rev.dense_combined_merges = 1;
+
+	if (read_cache_preload(rev.diffopt.paths) < 0) {
+		perror("read_cache_preload");
+		return -1;
+	}
+	result = run_diff_files(&rev, options);
+	return diff_result_code(&rev.diffopt, result);
 }