git-clean: add colors to interactive git-clean

Show header, help, error messages, and prompt in colors for interactive
git-clean. Re-use config variables, such as "color.interactive" and
"color.interactive.<slot>" for command `git-add--interactive`.

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

@@ -876,16 +876,17 @@ The values of these variables may be specified as in color.branch.<slot>.
 
 color.interactive::
 	When set to `always`, always use colors for interactive prompts
-	and displays (such as those used by "git-add --interactive").
-	When false (or `never`), never.  When set to `true` or `auto`, use
-	colors only when the output is to the terminal. Defaults to false.
+	and displays (such as those used by "git-add --interactive" and
+	"git-clean --interactive"). When false (or `never`), never.
+	When set to `true` or `auto`, use colors only when the output is
+	to the terminal. Defaults to false.
 
 color.interactive.<slot>::
-	Use customized color for 'git add --interactive'
-	output. `<slot>` may be `prompt`, `header`, `help` or `error`, for
-	four distinct types of normal output from interactive
-	commands.  The values of these variables may be specified as
-	in color.branch.<slot>.
+	Use customized color for 'git add --interactive' and 'git clean
+	--interactive' output. `<slot>` may be `prompt`, `header`, `help`
+	or `error`, for four distinct types of normal output from
+	interactive commands.  The values of these variables may be
+	specified as in color.branch.<slot>.
 
 color.pager::
 	A boolean to enable/disable colored output when the pager is in

builtin/clean.c

@@ -14,6 +14,7 @@
 #include "string-list.h"
 #include "quote.h"
 #include "column.h"
+#include "color.h"
 
 static int force = -1; /* unset */
 static int interactive;
@@ -31,16 +32,82 @@ static const char *msg_skip_git_dir = N_("Skipping repository %s\n");
 static const char *msg_would_skip_git_dir = N_("Would skip repository %s\n");
 static const char *msg_warn_remove_failed = N_("failed to remove %s");
 
+static int clean_use_color = -1;
+static char clean_colors[][COLOR_MAXLEN] = {
+	GIT_COLOR_RESET,
+	GIT_COLOR_NORMAL,	/* PLAIN */
+	GIT_COLOR_BOLD_BLUE,	/* PROMPT */
+	GIT_COLOR_BOLD,		/* HEADER */
+	GIT_COLOR_BOLD_RED,	/* HELP */
+	GIT_COLOR_BOLD_RED,	/* ERROR */
+};
+enum color_clean {
+	CLEAN_COLOR_RESET = 0,
+	CLEAN_COLOR_PLAIN = 1,
+	CLEAN_COLOR_PROMPT = 2,
+	CLEAN_COLOR_HEADER = 3,
+	CLEAN_COLOR_HELP = 4,
+	CLEAN_COLOR_ERROR = 5,
+};
+
+static int parse_clean_color_slot(const char *var)
+{
+	if (!strcasecmp(var, "reset"))
+		return CLEAN_COLOR_RESET;
+	if (!strcasecmp(var, "plain"))
+		return CLEAN_COLOR_PLAIN;
+	if (!strcasecmp(var, "prompt"))
+		return CLEAN_COLOR_PROMPT;
+	if (!strcasecmp(var, "header"))
+		return CLEAN_COLOR_HEADER;
+	if (!strcasecmp(var, "help"))
+		return CLEAN_COLOR_HELP;
+	if (!strcasecmp(var, "error"))
+		return CLEAN_COLOR_ERROR;
+	return -1;
+}
+
 static int git_clean_config(const char *var, const char *value, void *cb)
 {
 	if (!prefixcmp(var, "column."))
 		return git_column_config(var, value, "clean", &colopts);
 
+	/* honors the color.interactive* config variables which also
+	   applied in git-add--interactive and git-stash */
+	if (!strcmp(var, "color.interactive")) {
+		clean_use_color = git_config_colorbool(var, value);
+		return 0;
+	}
+	if (!prefixcmp(var, "color.interactive.")) {
+		int slot = parse_clean_color_slot(var +
+						  strlen("color.interactive."));
+		if (slot < 0)
+			return 0;
+		if (!value)
+			return config_error_nonbool(var);
+		color_parse(value, var, clean_colors[slot]);
+		return 0;
+	}
+
 	if (!strcmp(var, "clean.requireforce")) {
 		force = !git_config_bool(var, value);
 		return 0;
 	}
-	return git_default_config(var, value, cb);
+
+	/* inspect the color.ui config variable and others */
+	return git_color_default_config(var, value, cb);
+}
+
+static const char *clean_get_color(enum color_clean ix)
+{
+	if (want_color(clean_use_color))
+		return clean_colors[ix];
+	return "";
+}
+
+static void clean_print_color(enum color_clean ix)
+{
+	printf("%s", clean_get_color(ix));
 }
 
 static int exclude_cb(const struct option *opt, const char *arg, int unset)
@@ -184,14 +251,18 @@ static void interactive_main_loop(void)
 
 	while (del_list.nr) {
 		putchar('\n');
+		clean_print_color(CLEAN_COLOR_HEADER);
 		printf_ln(Q_("Would remove the following item:",
 			     "Would remove the following items:",
 			     del_list.nr));
+		clean_print_color(CLEAN_COLOR_RESET);
 		putchar('\n');
 
 		pretty_print_dels();
 
+		clean_print_color(CLEAN_COLOR_PROMPT);
 		printf(_("Remove [y/n]? "));
+		clean_print_color(CLEAN_COLOR_RESET);
 		if (strbuf_getline(&confirm, stdin, '\n') != EOF) {
 			strbuf_trim(&confirm);
 		} else {