git-clean: add filter by pattern interactive action

Add a new action for interactive git-clean: filter by pattern. When the
user chooses this action, user can input space-separated patterns (the
same syntax as gitignore), and each clean candidate that matches with
one of the patterns will be excluded from cleaning. When the user feels
it's OK, presses ENTER and backs to the confirmation dialog.

Signed-off-by: Jiang Xin <worldhello.net@gmail.com>
Suggested-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/clean.c

@@ -614,6 +614,72 @@ static int clean_cmd(void)
 	return MENU_RETURN_NO_LOOP;
 }
 
+static int filter_by_patterns_cmd(void)
+{
+	struct dir_struct dir;
+	struct strbuf confirm = STRBUF_INIT;
+	struct strbuf **ignore_list;
+	struct string_list_item *item;
+	struct exclude_list *el;
+	int changed = -1, i;
+
+	for (;;) {
+		if (!del_list.nr)
+			break;
+
+		if (changed)
+			pretty_print_dels();
+
+		clean_print_color(CLEAN_COLOR_PROMPT);
+		printf(_("Input ignore patterns>> "));
+		clean_print_color(CLEAN_COLOR_RESET);
+		if (strbuf_getline(&confirm, stdin, '\n') != EOF)
+			strbuf_trim(&confirm);
+		else
+			putchar('\n');
+
+		/* quit filter_by_pattern mode if press ENTER or Ctrl-D */
+		if (!confirm.len)
+			break;
+
+		memset(&dir, 0, sizeof(dir));
+		el = add_exclude_list(&dir, EXC_CMDL, "manual exclude");
+		ignore_list = strbuf_split_max(&confirm, ' ', 0);
+
+		for (i = 0; ignore_list[i]; i++) {
+			strbuf_trim(ignore_list[i]);
+			if (!ignore_list[i]->len)
+				continue;
+
+			add_exclude(ignore_list[i]->buf, "", 0, el, -(i+1));
+		}
+
+		changed = 0;
+		for_each_string_list_item(item, &del_list) {
+			int dtype = DT_UNKNOWN;
+
+			if (is_excluded(&dir, item->string, &dtype)) {
+				*item->string = '\0';
+				changed++;
+			}
+		}
+
+		if (changed) {
+			string_list_remove_empty_items(&del_list, 0);
+		} else {
+			clean_print_color(CLEAN_COLOR_ERROR);
+			printf_ln(_("WARNING: Cannot find items matched by: %s"), confirm.buf);
+			clean_print_color(CLEAN_COLOR_RESET);
+		}
+
+		strbuf_list_free(ignore_list);
+		clear_directory(&dir);
+	}
+
+	strbuf_release(&confirm);
+	return 0;
+}
+
 static int quit_cmd(void)
 {
 	string_list_clear(&del_list, 0);
@@ -626,6 +692,7 @@ static int help_cmd(void)
 	clean_print_color(CLEAN_COLOR_HELP);
 	printf_ln(_(
 		    "clean               - start cleaning\n"
+		    "filter by pattern   - exclude items from deletion\n"
 		    "quit                - stop cleaning\n"
 		    "help                - this screen\n"
 		    "?                   - help for prompt selection"
@@ -641,6 +708,7 @@ static void interactive_main_loop(void)
 		struct menu_stuff menu_stuff;
 		struct menu_item menus[] = {
 			{'c', "clean",			0, clean_cmd},
+			{'f', "filter by pattern",	0, filter_by_patterns_cmd},
 			{'q', "quit",			0, quit_cmd},
 			{'h', "help",			0, help_cmd},
 		};