action: add support for <prompt> in 'If' actions

...and allow If Action without activator view.

For example:

    <action name="If">
      <prompt message="Toggle maximize?"/>
      <then>
        <action name="ToggleMaximize" />
      </then>
    </action>

Also revert the change in b9c84f9 that <else> branch is always taken when
no window is focused.

Co-Authored-by: johanmalm
Co-Authored-by: tokyo4j

include/action.h

@@ -3,6 +3,7 @@
 #define LABWC_ACTION_H
 
 #include <stdbool.h>
+#include <sys/types.h>
 #include <wayland-util.h>
 
 struct view;
@@ -47,6 +48,8 @@ bool actions_contain_toggle_keybinds(struct wl_list *action_list);
 void actions_run(struct view *activator, struct server *server,
 	struct wl_list *actions, struct cursor_context *ctx);
 
+bool action_check_prompt_result(pid_t pid, int exit_code);
+
 void action_free(struct action *action);
 void action_list_free(struct wl_list *action_list);
 

src/action.c

@@ -493,6 +493,11 @@ action_arg_from_xml_node(struct action *action, const char *nodename, const char
 			goto cleanup;
 		}
 		break;
+	case ACTION_TYPE_IF:
+		if (!strcmp(argument, "message.prompt")) {
+			action_arg_add_str(action, "message.prompt", content);
+		}
+		goto cleanup;
 	}
 
 	wlr_log(WLR_ERROR, "Invalid argument for action %s: '%s'",
@@ -775,16 +780,115 @@ view_for_action(struct view *activator, struct server *server,
 	}
 }
 
+struct action_prompt {
+	/* Set when created */
+	struct server *server;
+	struct action *action;
+	struct view *view;
+
+	/* Set when executed */
+	pid_t pid;
+
+	struct {
+		struct wl_listener destroy;
+	} on_view;
+	struct wl_list link;
+};
+
+static struct wl_list prompts = WL_LIST_INIT(&prompts);
+
+static void
+action_prompt_destroy(struct action_prompt *prompt)
+{
+	wl_list_remove(&prompt->on_view.destroy.link);
+	wl_list_remove(&prompt->link);
+	free(prompt);
+}
+
+static void
+handle_view_destroy(struct wl_listener *listener, void *data)
+{
+	struct action_prompt *prompt = wl_container_of(listener, prompt, on_view.destroy);
+	wl_list_remove(&prompt->on_view.destroy.link);
+	wl_list_init(&prompt->on_view.destroy.link);
+	prompt->view = NULL;
+}
+
+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"),
+		_("Yes"), _("No"));
+
+	int pipe_fd;
+	pid_t prompt_pid = spawn_piped(command, &pipe_fd);
+	if (prompt_pid < 0) {
+		wlr_log(WLR_ERROR, "Failed to create action prompt");
+		goto cleanup;
+	}
+	/* FIXME: closing stdout might confuse clients */
+	close(pipe_fd);
+
+	struct action_prompt *prompt = znew(*prompt);
+	prompt->server = server;
+	prompt->action = action;
+	prompt->view = view;
+	prompt->pid = prompt_pid;
+	if (view) {
+		prompt->on_view.destroy.notify = handle_view_destroy;
+		wl_signal_add(&view->events.destroy, &prompt->on_view.destroy);
+	} else {
+		/* Allows removing during destroy */
+		wl_list_init(&prompt->on_view.destroy.link);
+	}
+
+	wl_list_insert(&prompts, &prompt->link);
+
+cleanup:
+	free(command);
+}
+
+bool
+action_check_prompt_result(pid_t pid, int exit_code)
+{
+	struct action_prompt *prompt, *tmp;
+	wl_list_for_each_safe(prompt, tmp, &prompts, link) {
+		if (prompt->pid != pid) {
+			continue;
+		}
+
+		wlr_log(WLR_INFO, "Found pending prompt for exit code %d", exit_code);
+		struct wl_list *actions = NULL;
+		if (exit_code == 0) {
+			wlr_log(WLR_INFO, "Selected the 'then' branch");
+			actions = action_get_actionlist(prompt->action, "then");
+		} else {
+			wlr_log(WLR_INFO, "Selected the 'else' branch");
+			actions = action_get_actionlist(prompt->action, "else");
+		}
+		if (actions) {
+			wlr_log(WLR_INFO, "Running actions");
+			actions_run(prompt->view, prompt->server,
+				actions, /*cursor_ctx*/ NULL);
+		} else {
+			wlr_log(WLR_INFO, "No actions for selected branch");
+		}
+		action_prompt_destroy(prompt);
+		return true;
+	}
+	return false;
+}
+
 static bool
 match_queries(struct view *view, struct action *action)
 {
+	assert(view);
+
 	struct wl_list *queries = action_get_querylist(action, "query");
 	if (!queries) {
 		return true;
 	}
-	if (!view) {
-		return false;
-	}
 
 	/* All queries are OR'ed */
 	struct view_query *query;
@@ -1205,14 +1309,23 @@ run_action(struct view *view, struct server *server, struct action *action,
 		break;
 	}
 	case ACTION_TYPE_IF: {
-		struct wl_list *actions;
+		/* At least one of the queries was matched or there was no query */
-		if (match_queries(view, action)) {
+		if (action_get_str(action, "message.prompt", NULL)) {
-			actions = action_get_actionlist(action, "then");
+			/*
-		} else {
+			 * We delay the selection and execution of the
-			actions = action_get_actionlist(action, "else");
+			 * branch until we get a response from the user.
-		}
+			 */
-		if (actions) {
+			action_prompt_create(view, server, action);
-			actions_run(view, server, actions, ctx);
+		} else if (view) {
+			struct wl_list *actions;
+			if (match_queries(view, action)) {
+				actions = action_get_actionlist(action, "then");
+			} else {
+				actions = action_get_actionlist(action, "else");
+			}
+			if (actions) {
+				actions_run(view, server, actions, ctx);
+			}
 		}
 		break;
 	}

src/server.c

@@ -46,6 +46,7 @@
 #endif
 
 #include "drm-lease-v1-protocol.h"
+#include "action.h"
 #include "common/macros.h"
 #include "common/scaled-scene-buffer.h"
 #include "config/rcxml.h"
@@ -160,9 +161,11 @@ handle_sigchld(int signal, void *data)
 	const char *signame;
 	switch (info.si_code) {
 	case CLD_EXITED:
-		wlr_log(info.si_status == 0 ? WLR_DEBUG : WLR_ERROR,
+		if (!action_check_prompt_result(info.si_pid, info.si_status)) {
-			"spawned child %ld exited with %d",
+			wlr_log(info.si_status == 0 ? WLR_DEBUG : WLR_ERROR,
-			(long)info.si_pid, info.si_status);
+				"spawned child %ld exited with %d",
+				(long)info.si_pid, info.si_status);
+		}
 		break;
 	case CLD_KILLED:
 	case CLD_DUMPED:
@@ -171,6 +174,8 @@ handle_sigchld(int signal, void *data)
 			"spawned child %ld terminated with signal %d (%s)",
 				(long)info.si_pid, info.si_status,
 				signame ? signame : "unknown");
+		/* Allow cleanup of killed prompt */
+		action_check_prompt_result(info.si_pid, -info.si_status);
 		break;
 	default:
 		wlr_log(WLR_ERROR,