git-clean: show items of del_list in columns

When there are lots of items to be cleaned, it is hard to see them all
in one screen. Show them in columns will solve this problem.

Signed-off-by: Jiang Xin <worldhello.net@gmail.com>
Comments-by: Matthieu Moy <Matthieu.Moy@imag.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/config.txt

@@ -955,6 +955,10 @@ column.branch::
 	Specify whether to output branch listing in `git branch` in columns.
 	See `column.ui` for details.
 
+column.clean::
+	Specify the layout when list items in `git clean -i`, which always
+	shows files and directories in columns. See `column.ui` for details.
+
 column.status::
 	Specify whether to output untracked files in `git status` in columns.
 	See `column.ui` for details.

builtin/clean.c

@@ -13,10 +13,12 @@
 #include "refs.h"
 #include "string-list.h"
 #include "quote.h"
+#include "column.h"
 
 static int force = -1; /* unset */
 static int interactive;
 static struct string_list del_list = STRING_LIST_INIT_DUP;
+static unsigned int colopts;
 
 static const char *const builtin_clean_usage[] = {
 	N_("git clean [-d] [-f] [-i] [-n] [-q] [-e <pattern>] [-x | -X] [--] <paths>..."),
@@ -31,8 +33,13 @@ static const char *msg_warn_remove_failed = N_("failed to remove %s");
 
 static int git_clean_config(const char *var, const char *value, void *cb)
 {
-	if (!strcmp(var, "clean.requireforce"))
+	if (!prefixcmp(var, "column."))
+		return git_column_config(var, value, "clean", &colopts);
+
+	if (!strcmp(var, "clean.requireforce")) {
 		force = !git_config_bool(var, value);
+		return 0;
+	}
 	return git_default_config(var, value, cb);
 }
 
@@ -144,21 +151,46 @@ static int remove_dirs(struct strbuf *path, const char *prefix, int force_flag,
 	return ret;
 }
 
-static void interactive_main_loop(void)
+static void pretty_print_dels(void)
 {
-	struct strbuf confirm = STRBUF_INIT;
-	struct strbuf buf = STRBUF_INIT;
+	struct string_list list = STRING_LIST_INIT_DUP;
 	struct string_list_item *item;
+	struct strbuf buf = STRBUF_INIT;
 	const char *qname;
+	struct column_options copts;
+
+	for_each_string_list_item(item, &del_list) {
+		qname = quote_path_relative(item->string, NULL, &buf);
+		string_list_append(&list, qname);
+	}
+
+	/*
+	 * always enable column display, we only consult column.*
+	 * about layout strategy and stuff
+	 */
+	colopts = (colopts & ~COL_ENABLE_MASK) | COL_ENABLED;
+	memset(&copts, 0, sizeof(copts));
+	copts.indent = "  ";
+	copts.padding = 2;
+	print_columns(&list, colopts, &copts);
+	putchar('\n');
+	strbuf_release(&buf);
+	string_list_clear(&list, 0);
+}
+
+static void interactive_main_loop(void)
+{
+	struct strbuf confirm = STRBUF_INIT;
 
 	while (del_list.nr) {
 		putchar('\n');
-		for_each_string_list_item(item, &del_list) {
-			qname = quote_path_relative(item->string, NULL, &buf);
-			printf(_(msg_would_remove), qname);
-		}
+		printf_ln(Q_("Would remove the following item:",
+			     "Would remove the following items:",
+			     del_list.nr));
 		putchar('\n');
 
+		pretty_print_dels();
+
 		printf(_("Remove [y/n]? "));
 		if (strbuf_getline(&confirm, stdin, '\n') != EOF) {
 			strbuf_trim(&confirm);
@@ -184,7 +216,6 @@ static void interactive_main_loop(void)
 		}
 	}
 
-	strbuf_release(&buf);
 	strbuf_release(&confirm);
 }