osc: kitty notifications: implement the 'close' request

Add a new config option, desktop-notifications.close, defining what to
execute to close a notification. It has a single template parameter,
${id}, that is expanded to the external notification ID foot may have
picked up from the notification helper.

notify-send does not support closing notifications, and it appears
impossible to pass an *unsigned* integer as argument to gdbus. Hence
no default value for the new 'close' option.

Example:

    printf '\e]99;i=123;this is a notification\e\\'
    printf '\e]99;i=123:p=close;\e\\'

CHANGELOG.md

@@ -77,6 +77,9 @@
   `notify-focus-inhibit`.
 * `${icon}`, `${urgency}`,`${action-name}` and `${action-label}` added
   to the `desktop-notifications.command` template.
+* `desktop-notifications.close` option, defining what to execute when
+  an application wants to close an existing notification (via an
+  OSC-99 escape sequence).
 
 [1707]: https://codeberg.org/dnkl/foot/issues/1707
 [1738]: https://codeberg.org/dnkl/foot/issues/1738

config.c

@@ -1110,6 +1110,9 @@ parse_section_desktop_notifications(struct context *ctx)
     if (streq(key, "command"))
         return value_to_spawn_template(
             ctx, &conf->desktop_notifications.command);
+    else if (streq(key, "close"))
+        return value_to_spawn_template(
+            ctx, &conf->desktop_notifications.close);
     else if (streq(key, "inhibit-when-focused"))
         return value_to_bool(
             ctx, &conf->desktop_notifications.inhibit_when_focused);
@@ -3186,6 +3189,9 @@ config_load(struct config *conf, const char *conf_path,
             .command = {
                 .argv = {.args = NULL},
             },
+            .close = {
+                .argv = {.args = NULL},
+            },
             .inhibit_when_focused = true,
         },
 
@@ -3481,6 +3487,8 @@ config_clone(const struct config *old)
     spawn_template_clone(&conf->bell.command, &old->bell.command);
     spawn_template_clone(&conf->desktop_notifications.command,
                          &old->desktop_notifications.command);
+    spawn_template_clone(&conf->desktop_notifications.close,
+                         &old->desktop_notifications.close);
 
     for (size_t i = 0; i < ALEN(conf->fonts); i++)
         config_font_list_clone(&conf->fonts[i], &old->fonts[i]);
@@ -3563,6 +3571,7 @@ config_free(struct config *conf)
     spawn_template_free(&conf->bell.command);
     free(conf->scrollback.indicator.text);
     spawn_template_free(&conf->desktop_notifications.command);
+    spawn_template_free(&conf->desktop_notifications.close);
     for (size_t i = 0; i < ALEN(conf->fonts); i++)
         config_font_list_destroy(&conf->fonts[i]);
     free(conf->server_socket_path);

config.h

@@ -340,6 +340,7 @@ struct config {
 
     struct {
         struct config_spawn_template command;
+        struct config_spawn_template close;
         bool inhibit_when_focused;
     } desktop_notifications;
 

doc/foot.ini.5.scd

@@ -513,6 +513,18 @@ xdgtoken=95ebdfe56e4f47ddb5bba9d7dc3a2c35
 
 	Default: _notify-send --wait --app-name ${app-id} --icon ${icon} --urgency ${urgency} --action ${action-name}=${action-label} --print-id -- ${title} ${body}_.
 
+*close*
+	Command to execute to close an existing notification.
+	
+	_${id}_ is expanded to the ID of the notification that should be
+	closed. For example:
+	
+		fyi --close ${id}
+	
+	Closing a notification is only supported by the Kitty Desktop
+	Notification protocol, OSC-99.
+	
+	Default: _not set_
 
 *inhibit-when-focused*
 	Boolean. If enabled, foot will not display notifications if the

foot.ini

@@ -48,6 +48,7 @@
 
 [desktop-notifications]
 # command=notify-send --wait --app-name ${app-id} --icon ${icon} --urgency ${urgency} --action ${action-name}=${action-label} --print-id -- ${title} ${body}
+# close=""
 # inhibit-when-focused=yes
 
 

notify.c

@@ -339,6 +339,51 @@ notify_notify(struct terminal *term, struct notification *notif)
     return true;
 }
 
+void
+notify_close(struct terminal *term, const char *id)
+{
+    LOG_DBG("close notification %s", id);
+
+    if (term->conf->desktop_notifications.close.argv.args == NULL)
+        return;
+
+    tll_foreach(term->active_notifications, it) {
+        const struct notification *notif = &it->item;
+        if (notif->id == 0 || !streq(notif->id, id))
+            continue;
+
+        if (notif->external_id == 0)
+            return;
+
+        char **argv = NULL;
+        size_t argc = 0;
+
+        char external_id[16];
+        xsnprintf(external_id, sizeof(external_id), "%u", notif->external_id);
+
+        if (!spawn_expand_template(
+            &term->conf->desktop_notifications.close, 1,
+            (const char *[]){"id"},
+            (const char *[]){external_id},
+            &argc, &argv))
+        {
+            return;
+        }
+
+        int devnull = open("/dev/null", O_RDONLY);
+        spawn(
+            term->reaper, NULL, argv, devnull, -1, -1,
+            NULL, (void *)term, NULL);
+
+        if (devnull >= 0)
+            close(devnull);
+
+        for (size_t i = 0; i < argc; i++)
+            free(argv[i]);
+        free(argv);
+    }
+}
+
 static void
 add_icon(struct notification_icon *icon, const char *id, const char *symbolic_name,
          const uint8_t *data, size_t data_sz)

notify.h

@@ -65,6 +65,7 @@ struct notification_icon {
 };
 
 bool notify_notify(struct terminal *term, struct notification *notif);
+void notify_close(struct terminal *term, const char *id);
 void notify_free(struct terminal *term, struct notification *notif);
 
 void notify_icon_add(struct terminal *term, const char *id,

osc.c

@@ -590,6 +590,7 @@ kitty_notification(struct terminal *term, char *string)
     enum {
         PAYLOAD_TITLE,
         PAYLOAD_BODY,
+        PAYLOAD_CLOSE,
         PAYLOAD_ICON,
     } payload_type = PAYLOAD_TITLE; /* The 'p' parameter */
 
@@ -672,6 +673,8 @@ kitty_notification(struct terminal *term, char *string)
                 payload_type = PAYLOAD_TITLE;
             else if (streq(value, "body"))
                 payload_type = PAYLOAD_BODY;
+            else if (streq(value, "close"))
+                payload_type = PAYLOAD_CLOSE;
             else if (streq(value, "icon"))
                 payload_type = PAYLOAD_ICON;
             else if (streq(value, "?")) {
@@ -687,7 +690,7 @@ kitty_notification(struct terminal *term, char *string)
                 char reply[128];
                 int n = xsnprintf(
                     reply, sizeof(reply),
-                    "\033]99;i=%s:p=?;p=title,body,icon:a=focus,report:o=%s:u=0,1,2:c=1%s",
+                    "\033]99;i=%s:p=?;p=title,body,close,icon:a=focus,report:o=%s:u=0,1,2:c=1%s",
                     id, when_str, terminator);
 
                 term_to_slave(term, reply, n);
@@ -815,6 +818,10 @@ kitty_notification(struct terminal *term, char *string)
         break;
     }
 
+    case PAYLOAD_CLOSE:
+        /* Ignore payload */
+        break;
+
     case PAYLOAD_ICON:
         if (notif->icon_data == NULL) {
             notif->icon_data = (uint8_t *)payload;
@@ -847,14 +854,18 @@ kitty_notification(struct terminal *term, char *string)
             notif->icon_data_sz = 0;
         }
 
-        /*
-         * Show notification.
-         *
-         * The checks for title|body is to handle notifications that
-         * only load icon data into the icon cache
-         */
-        if (notif->title != NULL || notif->body != NULL) {
-            notify_notify(term, notif);
+        if (payload_type == PAYLOAD_CLOSE) {
+            notify_close(term, notif->id);
+        } else {
+            /*
+             * Show notification.
+             *
+             * The checks for title|body is to handle notifications that
+             * only load icon data into the icon cache
+             */
+            if (notif->title != NULL || notif->body != NULL) {
+                notify_notify(term, notif);
+            }
         }
 
         tll_foreach(term->kitty_notifications, it) {