config: add <core><promptCommand>

...to enable configuration of the action prompt command.

Also set some better defaults for labnag.

The new default command is:

    labnag \
        --message '%m' \
        --button-dismiss '%n' \
        --button-dismiss '%y' \
        --background '%b' \
        --text '%t' \
        --border '%t' \
        --border-bottom '%t' \
        --button-background '%b' \
        --button-text '%t' \
        --border-bottom-size 1 \
        --button-border-size 3 \
        --timeout 0

...where the conversion specifiers are defined as follows:

    %m: the `<prompt>` message option
    %n: _("No")
    %y: _("Yes")
    %b: osd.bg.color
    %t: osd.label.text.color

This config options also enables the use of a different dialog client, for
example like this:

    <core>
      <promptCommand>zenity --question --text="%m"</promptCommand>
    </core>

src/action-prompt-command.c

@@ -0,0 +1,108 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#define _POSIX_C_SOURCE 200809L
+#include "action-prompt-command.h"
+#include <stdio.h>
+#include <wlr/util/log.h>
+#include "action.h"
+#include "common/buf.h"
+#include "labwc.h" /* for gettext */
+#include "theme.h"
+
+enum {
+	LAB_PROMPT_NONE = 0,
+	LAB_PROMPT_MESSAGE,
+	LAB_PROMPT_NO,
+	LAB_PROMPT_YES,
+	LAB_PROMPT_BG_COL,
+	LAB_PROMPT_TEXT_COL,
+
+	LAB_PROMPT_COUNT
+};
+
+typedef void field_conversion_type(struct buf *buf, struct action *action,
+		struct theme *theme);
+
+struct field_converter {
+	const char fmt_char;
+	field_conversion_type *fn;
+};
+
+/* %m */
+static void
+set_message(struct buf *buf, struct action *action, struct theme *theme)
+{
+	buf_add(buf, action_get_str(action, "message.prompt", "Choose wisely"));
+}
+
+/* %n */
+static void
+set_no(struct buf *buf, struct action *action, struct theme *theme)
+{
+	buf_add(buf, _("No"));
+}
+
+/* %y */
+static void
+set_yes(struct buf *buf, struct action *action, struct theme *theme)
+{
+	buf_add(buf, _("Yes"));
+}
+
+/* %b */
+static void
+set_bg_col(struct buf *buf, struct action *action, struct theme *theme)
+{
+	buf_add_hex_color(buf, theme->osd_bg_color);
+}
+
+/* %t */
+static void
+set_text_col(struct buf *buf, struct action *action, struct theme *theme)
+{
+	buf_add_hex_color(buf, theme->osd_label_text_color);
+}
+
+static const struct field_converter field_converter[LAB_PROMPT_COUNT] = {
+	[LAB_PROMPT_MESSAGE]           = { 'm', set_message },
+	[LAB_PROMPT_NO]                = { 'n', set_no },
+	[LAB_PROMPT_YES]               = { 'y', set_yes },
+	[LAB_PROMPT_BG_COL]            = { 'b', set_bg_col },
+	[LAB_PROMPT_TEXT_COL]          = { 't', set_text_col },
+};
+
+void
+action_prompt_command(struct buf *buf, const char *format,
+		struct action *action, struct theme *theme)
+{
+	if (!format) {
+		wlr_log(WLR_ERROR, "missing format");
+		return;
+	}
+
+	for (const char *p = format; *p; p++) {
+		/*
+		 * If we're not on a conversion specifier (like %m) then just
+		 * keep adding it to the buffer
+		 */
+		if (*p != '%') {
+			buf_add_char(buf, *p);
+			continue;
+		}
+
+		/* Process the %* conversion specifier */
+		++p;
+
+		bool found = false;
+		for (unsigned char i = 0; i < LAB_PROMPT_COUNT; i++) {
+			if (*p == field_converter[i].fmt_char) {
+				field_converter[i].fn(buf, action, theme);
+				found = true;
+				break;
+			}
+		}
+		if (!found) {
+			wlr_log(WLR_ERROR,
+				"invalid prompt command conversion specifier '%c'", *p);
+		}
+	}
+}

src/action.c

@@ -10,6 +10,7 @@
 #include <wlr/types/wlr_scene.h>
 #include <wlr/util/log.h>
 #include "action-prompt-codes.h"
+#include "action-prompt-command.h"
 #include "common/buf.h"
 #include "common/macros.h"
 #include "common/list.h"
@@ -281,7 +282,7 @@ action_get_arg(struct action *action, const char *key, enum action_arg_type type
 	return NULL;
 }
 
-static const char *
+const char *
 action_get_str(struct action *action, const char *key, const char *default_value)
 {
 	struct action_arg_str *arg = action_get_arg(action, key, LAB_ACTION_ARG_STR);
@@ -833,12 +834,13 @@ handle_view_destroy(struct wl_listener *listener, void *data)
 static void
 action_prompt_create(struct view *view, struct server *server, struct action *action)
 {
-	char *command = strdup_printf("labnag -m \"%s\" -Z \"%s\" -Z \"%s\"",
-		action_get_str(action, "message.prompt", "Choose wisely"),
-		_("No"), _("Yes"));
+	struct buf command = BUF_INIT;
+	action_prompt_command(&command, rc.prompt_command, action, rc.theme);
+
+	wlr_log(WLR_INFO, "prompt command: '%s'", command.data);
 
 	int pipe_fd;
-	pid_t prompt_pid = spawn_piped(command, &pipe_fd);
+	pid_t prompt_pid = spawn_piped(command.data, &pipe_fd);
 	if (prompt_pid < 0) {
 		wlr_log(WLR_ERROR, "Failed to create action prompt");
 		goto cleanup;
@@ -862,7 +864,7 @@ action_prompt_create(struct view *view, struct server *server, struct action *ac
 	wl_list_insert(&prompts, &prompt->link);
 
 cleanup:
-	free(command);
+	buf_reset(&command);
 }
 
 bool

src/common/buf.c

@@ -128,6 +128,30 @@ buf_add_fmt(struct buf *s, const char *fmt, ...)
 	s->data[s->len] = 0;
 }
 
+void
+buf_add_hex_color(struct buf *s, float color[4])
+{
+	/*
+	 * In theme.c parse_hexstr() colors are pre-multiplied (by alpha) as
+	 * expected by wlr_scene(). We therefore need to reverse that here.
+	 *
+	 * For details, see https://github.com/labwc/labwc/pull/1685
+	 */
+	float alpha = color[3];
+
+	/* Avoid division by zero */
+	if (alpha == 0.0f) {
+		buf_add(s, "#00000000");
+		return;
+	}
+
+	buf_add_fmt(s, "#%02x%02x%02x%02x",
+		(int)(color[0] / alpha * 255),
+		(int)(color[1] / alpha * 255),
+		(int)(color[2] / alpha * 255),
+		(int)(alpha * 255));
+}
+
 void
 buf_add(struct buf *s, const char *data)
 {

src/config/rcxml.c

@@ -1102,6 +1102,10 @@ entry(xmlNode *node, char *nodename, char *content)
 		set_bool(content, &rc.xwayland_persistence);
 	} else if (!strcasecmp(nodename, "primarySelection.core")) {
 		set_bool(content, &rc.primary_selection);
+
+	} else if (!strcasecmp(nodename, "promptCommand.core")) {
+		xstrdup_replace(rc.prompt_command, content);
+
 	} else if (!strcmp(nodename, "policy.placement")) {
 		enum lab_placement_policy policy = view_placement_parse(content);
 		if (policy != LAB_PLACE_INVALID) {
@@ -1624,6 +1628,22 @@ post_processing(void)
 		load_default_mouse_bindings();
 	}
 
+	if (!rc.prompt_command) {
+		rc.prompt_command =
+			xstrdup("labnag "
+				"--message '%m' "
+				"--button-dismiss '%n' "
+				"--button-dismiss '%y' "
+				"--background '%b' "
+				"--text '%t' "
+				"--border '%t' "
+				"--border-bottom '%t' "
+				"--button-background '%b' "
+				"--button-text '%t' "
+				"--border-bottom-size 1 "
+				"--button-border-size 3 "
+				"--timeout 0");
+	}
 	if (!rc.fallback_app_icon_name) {
 		rc.fallback_app_icon_name = xstrdup("labwc");
 	}
@@ -1886,6 +1906,7 @@ rcxml_finish(void)
 	zfree(rc.font_menuheader.name);
 	zfree(rc.font_menuitem.name);
 	zfree(rc.font_osd.name);
+	zfree(rc.prompt_command);
 	zfree(rc.theme_name);
 	zfree(rc.icon_theme_name);
 	zfree(rc.fallback_app_icon_name);

src/meson.build

@@ -1,5 +1,6 @@
 labwc_sources = files(
   'action.c',
+  'action-prompt-command.c',
   'buffer.c',
   'debug.c',
   'desktop.c',