ls-files: learn a debugging dump format

Teach git-ls-files a new option --debug that just tacks all available
data from the cache onto each file's line.
Signed-off-by: NThomas Rast <trast@student.ethz.ch>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Documentation/git-ls-files.txt

@@ -140,6 +140,12 @@ a space) at the start of each line:
 	lines, show only a partial prefix.
 	Non default number of digits can be specified with --abbrev=<n>.
 
+--debug::
+	After each line that describes a file, add more data about its
+	cache entry.  This is intended to show as much information as
+	possible for manual inspection; the exact format may change at
+	any time.
+
 \--::
 	Do not interpret any more arguments as options.
 

builtin/ls-files.c

@@ -25,6 +25,7 @@ static int show_modified;
 static int show_killed;
 static int show_valid_bit;
 static int line_terminator = '\n';
+static int debug_mode;
 
 static const char *prefix;
 static int max_prefix_len;
@@ -162,6 +163,13 @@ static void show_ce_entry(const char *tag, struct cache_entry *ce)
 		       ce_stage(ce));
 	}
 	write_name(ce->name, ce_namelen(ce));
+	if (debug_mode) {
+		printf("  ctime: %d:%d\n", ce->ce_ctime.sec, ce->ce_ctime.nsec);
+		printf("  mtime: %d:%d\n", ce->ce_mtime.sec, ce->ce_mtime.nsec);
+		printf("  dev: %d\tino: %d\n", ce->ce_dev, ce->ce_ino);
+		printf("  uid: %d\tgid: %d\n", ce->ce_uid, ce->ce_gid);
+		printf("  size: %d\tflags: %x\n", ce->ce_size, ce->ce_flags);
+	}
 }
 
 static int show_one_ru(struct string_list_item *item, void *cbdata)
@@ -519,6 +527,7 @@ int cmd_ls_files(int argc, const char **argv, const char *cmd_prefix)
 		OPT_STRING(0, "with-tree", &with_tree, "tree-ish",
 			"pretend that paths removed since <tree-ish> are still present"),
 		OPT__ABBREV(&abbrev),
+		OPT_BOOLEAN(0, "debug", &debug_mode, "show debugging data"),
 		OPT_END()
 	};