osc: kitty notifications: implement focus|report

This patch adds support for window focusing, and sending events back
to the client application when a notification is closed.

* Refactor notification related configuration options:
    - add desktop-notifications sub-section
    - deprecate 'notify' in favor of 'desktop-notifications.command'
    - deprecate 'notify-focus-inhibit' in favor of
      'desktop-notifications.inhibit-when-focused'
* Refactor: rename 'struct kitty_notification' to 'struct
  notification'
* Pass a 'struct notification' to notify_notify(), instead of many
  arguments.
* notify_notify() now registers a reaper callback. When the notifier
  process has terminated, the notification is considered closed, and we
  either try to focus (activate) the window, or send an event to the
  client application, depending on the notification setting.
* For the window activation, we need an XDG activation token. For now,
  assume *everything* written on stdout is part of the token.
* Refactor: remove much of the warnings from OSC-99; we don't
  typically log anything when an OSC/CSI has invalid values.
* Add icon support to OSC-99. This isn't part of the upstream
  spec. Foot's implementation:
    - uses the 'I' parameter
    - the value is expected to be a symbolic icon name
    - a quick check for absolute paths is done, and such icon requests
      are ignored.
* Added ${icon} to the 'desktop-notifications.command' template. Uses
  the icon specified in the notification, or ${app-id} if not set.

config.c

@@ -1024,11 +1024,29 @@ parse_section_main(struct context *ctx)
     else if (streq(key, "word-delimiters"))
         return value_to_wchars(ctx, &conf->word_delimiters);
 
-    else if (streq(key, "notify"))
-        return value_to_spawn_template(ctx, &conf->notify);
+    else if (streq(key, "notify")) {
+        user_notification_add(
+            &conf->notifications, USER_NOTIFICATION_DEPRECATED,
+            xstrdup("notify: use desktop-notifications.command instead"));
+        log_msg(
+            LOG_CLASS_WARNING, LOG_MODULE, __FILE__, __LINE__,
+            "deprecated: notify: use desktop-notifications.command instead");
+        return value_to_spawn_template(
+            ctx, &conf->desktop_notifications.command);
+    }
 
-    else if (streq(key, "notify-focus-inhibit"))
-        return value_to_bool(ctx, &conf->notify_focus_inhibit);
+    else if (streq(key, "notify-focus-inhibit")) {
+        user_notification_add(
+            &conf->notifications, USER_NOTIFICATION_DEPRECATED,
+            xstrdup("notify-focus-inhibit: "
+                    "use desktop-notifications.inhibit-when-focused instead"));
+        log_msg(
+            LOG_CLASS_WARNING, LOG_MODULE, __FILE__, __LINE__,
+            "deprecrated: notify-focus-inhibit: "
+            "use desktop-notifications.inhibit-when-focused instead");
+        return value_to_bool(
+            ctx, &conf->desktop_notifications.inhibit_when_focused);
+    }
 
     else if (streq(key, "selection-target")) {
         _Static_assert(sizeof(conf->selection_target) == sizeof(int),
@@ -1083,6 +1101,24 @@ parse_section_bell(struct context *ctx)
     }
 }
 
+static bool
+parse_section_desktop_notifications(struct context *ctx)
+{
+    struct config *conf = ctx->conf;
+    const char *key = ctx->key;
+
+    if (streq(key, "command"))
+        return value_to_spawn_template(
+            ctx, &conf->desktop_notifications.command);
+    else if (streq(key, "inhibit-when-focused"))
+        return value_to_bool(
+            ctx, &conf->desktop_notifications.inhibit_when_focused);
+    else {
+        LOG_CONTEXTUAL_ERR("not a valid option: %s", key);
+        return false;
+    }
+}
+
 static bool
 parse_section_scrollback(struct context *ctx)
 {
@@ -2662,6 +2698,7 @@ parse_key_value(char *kv, const char **section, const char **key, const char **v
 enum section {
     SECTION_MAIN,
     SECTION_BELL,
+    SECTION_DESKTOP_NOTIFICATIONS,
     SECTION_SCROLLBACK,
     SECTION_URL,
     SECTION_COLORS,
@@ -2688,6 +2725,7 @@ static const struct {
 } section_info[] = {
     [SECTION_MAIN] =            {&parse_section_main, "main"},
     [SECTION_BELL] =            {&parse_section_bell, "bell"},
+    [SECTION_DESKTOP_NOTIFICATIONS] = {&parse_section_desktop_notifications, "desktop-notifications"},
     [SECTION_SCROLLBACK] =      {&parse_section_scrollback, "scrollback"},
     [SECTION_URL] =             {&parse_section_url, "url"},
     [SECTION_COLORS] =          {&parse_section_colors, "colors"},
@@ -3144,10 +3182,12 @@ config_load(struct config *conf, const char *conf_path,
         .presentation_timings = false,
         .selection_target = SELECTION_TARGET_PRIMARY,
         .hold_at_exit = false,
-        .notify = {
-            .argv = {.args = NULL},
+        .desktop_notifications = {
+            .command = {
+                .argv = {.args = NULL},
+            },
+            .inhibit_when_focused = true,
         },
-        .notify_focus_inhibit = true,
 
         .tweak = {
             .fcft_filter = FCFT_SCALING_FILTER_LANCZOS3,
@@ -3185,8 +3225,8 @@ config_load(struct config *conf, const char *conf_path,
     parse_modifiers(XKB_MOD_NAME_SHIFT, 5, &conf->mouse.selection_override_modifiers);
 
     tokenize_cmdline(
-        "notify-send -a ${app-id} -i ${app-id} -u ${urgency} ${title} ${body}",
-        &conf->notify.argv.args);
+        "notify-send --wait --app-name ${app-id} --icon ${icon} --urgency ${urgency} -- ${title} ${body}",
+        &conf->desktop_notifications.command.argv.args);
     tokenize_cmdline("xdg-open ${url}", &conf->url.launch.argv.args);
 
     static const char32_t *url_protocols[] = {
@@ -3439,7 +3479,8 @@ config_clone(const struct config *old)
     conf->scrollback.indicator.text = xc32dup(old->scrollback.indicator.text);
     conf->server_socket_path = xstrdup(old->server_socket_path);
     spawn_template_clone(&conf->bell.command, &old->bell.command);
-    spawn_template_clone(&conf->notify, &old->notify);
+    spawn_template_clone(&conf->desktop_notifications.command,
+                         &old->desktop_notifications.command);
 
     for (size_t i = 0; i < ALEN(conf->fonts); i++)
         config_font_list_clone(&conf->fonts[i], &old->fonts[i]);
@@ -3521,7 +3562,7 @@ config_free(struct config *conf)
     free(conf->word_delimiters);
     spawn_template_free(&conf->bell.command);
     free(conf->scrollback.indicator.text);
-    spawn_template_free(&conf->notify);
+    spawn_template_free(&conf->desktop_notifications.command);
     for (size_t i = 0; i < ALEN(conf->fonts); i++)
         config_font_list_destroy(&conf->fonts[i]);
     free(conf->server_socket_path);