Add append_layout for declarative layout restore

include/sway/commands.h

@@ -105,6 +105,7 @@ sway_cmd cmd_exec_validate;
 sway_cmd cmd_exec_process;
 
 sway_cmd cmd_allow_tearing;
+sway_cmd cmd_append_layout;
 sway_cmd cmd_assign;
 sway_cmd cmd_bar;
 sway_cmd cmd_bindcode;

include/sway/criteria.h

@@ -83,6 +83,18 @@ struct criteria *criteria_parse(char *raw, char **error);
  */
 list_t *criteria_for_view(struct sway_view *view, enum criteria_type types);
 
+/**
+ * Match a criteria against a view without requiring view->container to be
+ * set. Used by append_layout's swallow matching, which runs before a view
+ * is attached to a container in the tree. Only view-intrinsic fields are
+ * considered: title, shell, app_id, sandbox_*, tag, pid, and (when xwayland
+ * is enabled) class, instance, window_role, window_type, X11 id. Criteria
+ * fields that depend on container state (con_mark, con_id, floating, tiling,
+ * workspace, urgent) are ignored.
+ */
+bool criteria_matches_view_unmapped(struct criteria *criteria,
+		struct sway_view *view);
+
 /**
  * Compile a list of containers matching the given criteria.
  */

include/sway/tree/container.h

@@ -9,6 +9,7 @@
 
 struct sway_view;
 struct sway_seat;
+struct json_object;
 
 enum sway_container_layout {
 	L_NONE,
@@ -141,11 +142,20 @@ struct sway_container {
 
 	list_t *marks; // char *
 
+	// append_layout placeholder: view==NULL, swallows holds matchers for the
+	// view that should be installed here. swallows_json retains the original
+	// i3-shaped array so IPC can echo it verbatim for round-trip.
+	bool is_placeholder;
+	list_t *swallows; // struct criteria *
+	struct json_object *swallows_json;
+
 	struct {
 		struct wl_signal destroy;
 	} events;
 };
 
+void container_init_border_rects(struct sway_container *c, bool *failed);
+
 struct sway_container *container_create(struct sway_view *view);
 
 void container_destroy(struct sway_container *con);

include/sway/tree/load_layout.h

@@ -0,0 +1,34 @@
+#ifndef _SWAY_LOAD_LAYOUT_H
+#define _SWAY_LOAD_LAYOUT_H
+
+#include <stdbool.h>
+
+struct sway_workspace;
+struct sway_view;
+struct sway_container;
+
+/**
+ * Append the container tree described by the JSON file at `path` to the given
+ * workspace. The file may be either strict JSON (a single object or array) or
+ * the i3-save-tree concatenated-object form (}\n{ between siblings). On error
+ * leaves the workspace unmodified, returns false, and writes an allocated
+ * error string to *error_out. Caller frees the error string.
+ *
+ * Currently tiling-only. Top-level `floating_nodes` (and any nested
+ * floating_nodes) are skipped with a debug log.
+ */
+bool load_layout_from_file(struct sway_workspace *ws, const char *path,
+		char **error_out);
+
+/**
+ * Walk the tree looking for a placeholder container (is_placeholder == true)
+ * whose swallows list contains a criteria that matches the given view. Walks
+ * tiling lists only, depth-first, document order. Returns the first match, or
+ * NULL if none.
+ *
+ * Used by view_map to decide whether an incoming view should be installed
+ * into a pre-existing placeholder slot rather than a freshly created one.
+ */
+struct sway_container *find_swallow_match(struct sway_view *view);
+
+#endif

meson.build

@@ -127,6 +127,7 @@ if scdoc.found()
 		'sway/sway-output.5.scd',
 		'swaybar/swaybar-protocol.7.scd',
 		'swaymsg/swaymsg.1.scd',
+		'swaysavetree/sway-save-tree.1.scd',
 	]
 
 	if get_option('swaynag')
@@ -195,6 +196,7 @@ subdir('protocols')
 subdir('common')
 subdir('sway')
 subdir('swaymsg')
+subdir('swaysavetree')
 
 if get_option('swaybar') or get_option('swaynag')
 	subdir('client')

sway/commands.c

@@ -42,6 +42,7 @@ struct cmd_results *checkarg(int argc, const char *name, enum expected_args type
 
 /* Keep alphabetized */
 static const struct cmd_handler handlers[] = {
+	{ "append_layout", cmd_append_layout },
 	{ "assign", cmd_assign },
 	{ "bar", cmd_bar },
 	{ "bindcode", cmd_bindcode },

sway/commands/append_layout.c

@@ -0,0 +1,47 @@
+#include "log.h"
+#include "stringop.h"
+#include "sway/commands.h"
+#include "sway/config.h"
+#include "sway/input/input-manager.h"
+#include "sway/input/seat.h"
+#include "sway/tree/load_layout.h"
+#include "sway/tree/workspace.h"
+
+struct cmd_results *cmd_append_layout(int argc, char **argv) {
+	struct cmd_results *error = NULL;
+	if ((error = checkarg(argc, "append_layout", EXPECTED_AT_LEAST, 1))) {
+		return error;
+	}
+
+	if (config->reading || !config->active) {
+		return cmd_results_new(CMD_DEFER, NULL);
+	}
+
+	struct sway_seat *seat = input_manager_current_seat();
+	struct sway_workspace *ws = seat_get_focused_workspace(seat);
+	if (!ws) {
+		return cmd_results_new(CMD_FAILURE,
+				"append_layout: no focused workspace");
+	}
+
+	char *path = join_args(argv, argc);
+	if (!path) {
+		return cmd_results_new(CMD_FAILURE, "append_layout: out of memory");
+	}
+	if (!expand_path(&path)) {
+		free(path);
+		return cmd_results_new(CMD_FAILURE,
+				"append_layout: failed to expand path");
+	}
+
+	char *err = NULL;
+	bool ok = load_layout_from_file(ws, path, &err);
+	free(path);
+	if (!ok) {
+		struct cmd_results *res = cmd_results_new(CMD_FAILURE, "%s",
+				err ? err : "append_layout: unknown error");
+		free(err);
+		return res;
+	}
+	return cmd_results_new(CMD_SUCCESS, NULL);
+}

sway/criteria.c

@@ -190,16 +190,9 @@ static bool criteria_matches_container(struct criteria *criteria,
 	return true;
 }
 
-static bool criteria_matches_view(struct criteria *criteria,
-		struct sway_view *view) {
-	struct sway_seat *seat = input_manager_current_seat();
-	struct sway_container *focus = seat_get_focused_container(seat);
-	struct sway_view *focused = focus ? focus->view : NULL;
-
-	if (!view->container) {
-		return false;
-	}
-
+// View-intrinsic checks; does not require view->container.
+static bool match_view_intrinsic(struct criteria *criteria,
+		struct sway_view *view, struct sway_view *focused) {
 	if (criteria->title) {
 		const char *title = view_get_title(view);
 		if (!title) {
@@ -340,10 +333,6 @@ static bool criteria_matches_view(struct criteria *criteria,
 		}
 	}
 
-	if (!criteria_matches_container(criteria, view->container)) {
-		return false;
-	}
-
 #if WLR_HAS_XWAYLAND
 	if (criteria->id) { // X11 window ID
 		uint32_t x11_window_id = view_get_x11_window_id(view);
@@ -419,6 +408,42 @@ static bool criteria_matches_view(struct criteria *criteria,
 	}
 #endif
 
+	if (criteria->pid) {
+		if (criteria->pid != view->pid) {
+			return false;
+		}
+	}
+
+	return true;
+}
+
+bool criteria_matches_view_unmapped(struct criteria *criteria,
+		struct sway_view *view) {
+	struct sway_seat *seat = input_manager_current_seat();
+	struct sway_container *focus = seat_get_focused_container(seat);
+	struct sway_view *focused = focus ? focus->view : NULL;
+
+	return match_view_intrinsic(criteria, view, focused);
+}
+
+static bool criteria_matches_view(struct criteria *criteria,
+		struct sway_view *view) {
+	struct sway_seat *seat = input_manager_current_seat();
+	struct sway_container *focus = seat_get_focused_container(seat);
+	struct sway_view *focused = focus ? focus->view : NULL;
+
+	if (!view->container) {
+		return false;
+	}
+
+	if (!match_view_intrinsic(criteria, view, focused)) {
+		return false;
+	}
+
+	if (!criteria_matches_container(criteria, view->container)) {
+		return false;
+	}
+
 	if (criteria->floating) {
 		if (!container_is_floating(view->container)) {
 			return false;
@@ -471,12 +496,6 @@ static bool criteria_matches_view(struct criteria *criteria,
 		}
 	}
 
-	if (criteria->pid) {
-		if (criteria->pid != view->pid) {
-			return false;
-		}
-	}
-
 	return true;
 }
 

sway/ipc-json.c

@@ -776,6 +776,11 @@ static void ipc_json_describe_container(struct sway_container *c, json_object *o
 	if (c->view) {
 		ipc_json_describe_view(c, object);
 	}
+
+	if (c->is_placeholder && c->swallows_json) {
+		json_object_object_add(object, "swallows",
+				json_object_get(c->swallows_json));
+	}
 }
 
 struct focus_inactive_data {

sway/meson.build

@@ -43,6 +43,7 @@ sway_sources = files(
 	'config/input.c',
 
 	'commands/allow_tearing.c',
+	'commands/append_layout.c',
 	'commands/assign.c',
 	'commands/bar.c',
 	'commands/bind.c',
@@ -211,6 +212,7 @@ sway_sources = files(
 
 	'tree/arrange.c',
 	'tree/container.c',
+	'tree/load_layout.c',
 	'tree/node.c',
 	'tree/root.c',
 	'tree/view.c',

sway/sway.5.scd

@@ -414,6 +414,52 @@ set|plus|minus|toggle <amount>
 The following commands may be used either in the configuration file or at
 runtime.
 
+*append_layout* <path>
+	Appends the container tree described by the JSON file at _path_ to the
+	currently focused workspace. Useful for restoring a saved layout: each
+	leaf container in the JSON is a _placeholder_ with a *swallows* array of
+	matchers; when a window opens whose properties match an unmatched
+	placeholder, sway installs that window into the placeholder's slot
+	instead of the usual focus-based placement.
+
+	The format mirrors i3's, with one extension: in addition to i3's
+	*class*, *instance*, *title*, *window_role*, and *window_type* keys
+	(which target xwayland views), each *swallows* entry may include
+	*app_id* to match Wayland views. The *machine* key is logged and
+	ignored. *class*, *instance*, *title*, *window_role* and *app_id*
+	are PCRE2 regex strings. *window_type* must be a literal atom name
+	(*normal*, *dialog*, *utility*, *toolbar*, *splash*, *menu*,
+	*dropdown_menu*, *popup_menu*, *tooltip*, *notification*); the
+	i3-save-tree anchored form _^name$_ is accepted, but regex
+	alternation such as _^(normal|dialog)$_ is rejected, split such
+	patterns into multiple swallows entries (which match as OR).
+
+	A minimal example targeting one Wayland and one xwayland window in
+	a vertical split:
+
+```
+[
+	{
+		"layout": "splitv",
+		"nodes": [
+			{ "swallows": [{ "app_id": "^foot$" }] },
+			{ "swallows": [{ "class": "^Firefox$" }] }
+		]
+	}
+]
+```
+
+	The companion command-line tool *sway-save-tree*(1) generates such
+	files from a live workspace. The i3-save-tree(1) concatenated-object
+	output form is also accepted.
+
+	Floating placeholders (the *floating_nodes* JSON array) are not
+	supported in this release; entries are skipped with a debug-log entry.
+	Placeholder match runs before *assign* rules: an explicit slot wins
+	over workspace assignment. *for_window* rules still run on the
+	swallowed view after placement. If multiple placeholders match the
+	same incoming view, the depth-first, document-order first match wins.
+
 *assign* <criteria> [→] [workspace] [number] <workspace>
 	Assigns windows matching _criteria_ (see *CRITERIA* for details) to
 	_workspace_. The → (U+2192) is optional and cosmetic. This command is