Merge pull request #1668 from acrisci/split-containers

Basic split containers

include/sway/input/seat.h

@@ -72,7 +72,7 @@ struct sway_container *seat_get_focus_inactive(struct sway_seat *seat,
 		struct sway_container *container);
 
 struct sway_container *seat_get_focus_by_type(struct sway_seat *seat,
-		enum sway_container_type type);
+		struct sway_container *container, enum sway_container_type type);
 
 void seat_apply_config(struct sway_seat *seat, struct seat_config *seat_config);
 

include/sway/tree/container.h

@@ -91,37 +91,61 @@ struct sway_container {
 	} events;
 };
 
+// TODO make private and use the container-specific create functions
+struct sway_container *container_create(enum sway_container_type type);
+
 const char *container_type_to_str(enum sway_container_type type);
 
 // TODO only one container create function and pass the type?
 struct sway_container *container_output_create(
 		struct sway_output *sway_output);
 
-struct sway_container *container_workspace_create(
+/**
-		struct sway_container *output, const char *name);
+ * Create a new container container. A container container can be a a child of
+ * a workspace container or another container container.
+ */
+struct sway_container *container_container_create();
 
-struct sway_container *container_view_create(
+/**
-		struct sway_container *sibling, struct sway_view *sway_view);
+ * Create a new output. Outputs are children of the root container and have no
+ * order in the tree structure.
+ */
+struct sway_container *container_output_create(struct sway_output *sway_output);
 
-struct sway_container *container_output_destroy(struct sway_container *output);
+/**
+ * Create a new workspace container. Workspaces are children of an output
+ * container and are ordered alphabetically by name.
+ */
+struct sway_container *container_workspace_create(struct sway_container *output, const char *name);
 
-struct sway_container *container_workspace_destroy(
+/*
-		struct sway_container *workspace);
+ * Create a new view container. A view can be a child of a workspace container
+ * or a container container and are rendered in the order and structure of
+ * how they are attached to the tree.
+ */
+// TODO view containers should be created in a detached state.
+struct sway_container *container_view_create(
+		struct sway_container *sibling, struct sway_view *sway_view);
 
-struct sway_container *container_view_destroy(struct sway_container *view);
+// TODO don't return the parent on destroy
+struct sway_container *container_destroy(struct sway_container *container);
 
-struct sway_container *container_destroy(struct sway_container *cont);
+struct sway_container *container_workspace_destroy(struct sway_container *container);
+struct sway_container *container_output_destroy(struct sway_container *container);
+struct sway_container *container_view_destroy(struct sway_container *container);
 
+// TODO move to layout.c
 struct sway_container *container_set_layout(struct sway_container *container,
 		enum sway_container_layout layout);
 
+// TODO rename to container_descendants_for_each()
 void container_descendants(struct sway_container *root,
 		enum sway_container_type type,
 		void (*func)(struct sway_container *item, void *data), void *data);
 
 /**
- * Finds a container based on test criteria. Returns the first container that
+ * Search a container's descendants a container based on test criteria. Returns
- * passes the test.
+ * the first container that passes the test.
  */
 struct sway_container *container_find(struct sway_container *container,
 		bool (*test)(struct sway_container *view, void *data), void *data);
@@ -129,18 +153,21 @@ struct sway_container *container_find(struct sway_container *container,
 /**
  * Finds a parent container with the given struct sway_containerype.
  */
+// TODO rename to container_parent_of_type()
 struct sway_container *container_parent(struct sway_container *container,
 		enum sway_container_type type);
 
 /**
- * Find a container at the given coordinates.
+ * Find a container at the given coordinates. Returns the the surface and
+ * surface-local coordinates of the given layout coordinates if the container
+ * is a view and the view contains a surface at those coordinates.
  */
-struct sway_container *container_at(struct sway_container *parent,
+struct sway_container *container_at(struct sway_container *container,
 		double lx, double ly, struct wlr_surface **surface,
 		double *sx, double *sy);
 
 /**
- * Apply the function for each child of the container breadth first.
+ * Apply the function for each descendant of the container breadth first.
  */
 void container_for_each_descendant_bfs(struct sway_container *container,
 		void (*f)(struct sway_container *container, void *data), void *data);
@@ -151,7 +178,16 @@ void container_for_each_descendant_bfs(struct sway_container *container,
 void container_for_each_descendant_dfs(struct sway_container *container,
 		void (*f)(struct sway_container *container, void *data), void *data);
 
-bool container_has_anscestor(struct sway_container *descendant,
+/**
+ * Returns true if the given container is an ancestor of this container.
+ */
+bool container_has_anscestor(struct sway_container *container,
 		struct sway_container *anscestor);
 
+/**
+ * Returns true if the given container is a child descendant of this container.
+ */
+bool container_has_child(struct sway_container *con,
+		struct sway_container *child);
+
 #endif

include/sway/tree/layout.h

@@ -29,31 +29,43 @@ struct sway_root {
 
 void layout_init(void);
 
+// TODO move to tree.h
 void container_add_child(struct sway_container *parent,
 		struct sway_container *child);
 
+// TODO move to tree.h
 struct sway_container *container_add_sibling(struct sway_container *parent,
 		struct sway_container *child);
 
+// TODO move to tree.h
 struct sway_container *container_remove_child(struct sway_container *child);
 
+// TODO PRIVATE in tree.h
 struct sway_container *container_reap_empty(struct sway_container *container);
 
+// TODO move to tree.h
 void container_move_to(struct sway_container* container,
 		struct sway_container* destination);
 
 void container_move(struct sway_container *container,
 		enum movement_direction dir, int move_amt);
 
+// TODO move to output.c
 enum sway_container_layout container_get_default_layout(
 		struct sway_container *output);
 
+// TODO move to output.c
 void container_sort_workspaces(struct sway_container *output);
 
 void arrange_windows(struct sway_container *container,
 		double width, double height);
 
+// TODO move to container.h
 struct sway_container *container_get_in_direction(struct sway_container
 		*container, struct sway_seat *seat, enum movement_direction dir);
 
+// TODO move to tree.h
+struct sway_container *container_split(struct sway_container *child,
+		enum sway_container_layout layout);
+
 #endif

sway/commands.c

@@ -164,6 +164,10 @@ static struct cmd_handler command_handlers[] = {
 	{ "layout", cmd_layout },
 	{ "move", cmd_move },
 	{ "reload", cmd_reload },
+	{ "split", cmd_split },
+	{ "splith", cmd_splith },
+	{ "splitt", cmd_splitt },
+	{ "splitv", cmd_splitv },
 };
 
 static int handler_compare(const void *_a, const void *_b) {

sway/commands/kill.c

@@ -3,21 +3,28 @@
 #include "sway/input/input-manager.h"
 #include "sway/input/seat.h"
 #include "sway/tree/view.h"
+#include "sway/tree/container.h"
 #include "sway/commands.h"
 
 struct cmd_results *cmd_kill(int argc, char **argv) {
-	enum sway_container_type type = config->handler_context.current_container->type;
+	struct sway_container *con =
-	if (type != C_VIEW && type != C_CONTAINER) {
+		config->handler_context.current_container;
+
+	switch (con->type) {
+	case C_ROOT:
+	case C_OUTPUT:
+	case C_WORKSPACE:
+	case C_TYPES:
 		return cmd_results_new(CMD_INVALID, NULL,
 				"Can only kill views and containers with this command");
-	}
+		break;
-
+	case C_CONTAINER:
-	// TODO close arbitrary containers without a view
+		con = container_destroy(con);
-	struct sway_view *view =
+		arrange_windows(con, -1, -1);
-		config->handler_context.current_container->sway_view;
+		break;
-
+	case C_VIEW:
-	if (view) {
+		view_close(con->sway_view);
-		view_close(view);
+		break;
 	}
 
 	return cmd_results_new(CMD_SUCCESS, NULL, NULL);

sway/commands/split.c

@@ -0,0 +1,76 @@
+#include <string.h>
+#include <strings.h>
+#include "sway/commands.h"
+#include "sway/tree/container.h"
+#include "sway/tree/layout.h"
+#include "sway/tree/view.h"
+#include "sway/input/input-manager.h"
+#include "sway/input/seat.h"
+#include "log.h"
+
+static struct cmd_results *do_split(int layout) {
+	struct sway_container *con = config->handler_context.current_container;
+	struct sway_container *parent = container_split(con, layout);
+	arrange_windows(parent, -1, -1);
+
+	return cmd_results_new(CMD_SUCCESS, NULL, NULL);
+}
+
+struct cmd_results *cmd_split(int argc, char **argv) {
+	struct cmd_results *error = NULL;
+	if ((error = checkarg(argc, "split", EXPECTED_EQUAL_TO, 1))) {
+		return error;
+	}
+	if (strcasecmp(argv[0], "v") == 0 || strcasecmp(argv[0], "vertical") == 0) {
+		do_split(L_VERT);
+	} else if (strcasecmp(argv[0], "h") == 0 ||
+			strcasecmp(argv[0], "horizontal") == 0) {
+		do_split(L_HORIZ);
+	} else if (strcasecmp(argv[0], "t") == 0 ||
+			strcasecmp(argv[0], "toggle") == 0) {
+		struct sway_container *focused =
+			config->handler_context.current_container;
+
+		if (focused->parent->layout == L_VERT) {
+			do_split(L_HORIZ);
+		} else {
+			do_split(L_VERT);
+		}
+	} else {
+		error = cmd_results_new(CMD_FAILURE, "split",
+			"Invalid split command (expected either horizontal or vertical).");
+		return error;
+	}
+	return cmd_results_new(CMD_SUCCESS, NULL, NULL);
+}
+
+struct cmd_results *cmd_splitv(int argc, char **argv) {
+	struct cmd_results *error = NULL;
+	if ((error = checkarg(argc, "splitv", EXPECTED_EQUAL_TO, 0))) {
+		return error;
+	}
+	return do_split(L_VERT);
+}
+
+struct cmd_results *cmd_splith(int argc, char **argv) {
+	struct cmd_results *error = NULL;
+	if ((error = checkarg(argc, "splitv", EXPECTED_EQUAL_TO, 0))) {
+		return error;
+	}
+	return do_split(L_HORIZ);
+}
+
+struct cmd_results *cmd_splitt(int argc, char **argv) {
+	struct cmd_results *error = NULL;
+	if ((error = checkarg(argc, "splitv", EXPECTED_EQUAL_TO, 0))) {
+		return error;
+	}
+
+	struct sway_container *con = config->handler_context.current_container;
+
+	if (con->parent->layout == L_VERT) {
+		return do_split(L_HORIZ);
+	} else {
+		return do_split(L_VERT);
+	}
+}

sway/input/seat.c

@@ -1,4 +1,5 @@
 #define _XOPEN_SOURCE 700
+#include <assert.h>
 #include <wlr/types/wlr_cursor.h>
 #include <wlr/types/wlr_output_layout.h>
 #include <wlr/types/wlr_xcursor_manager.h>
@@ -35,31 +36,89 @@ void seat_destroy(struct sway_seat *seat) {
 	wlr_seat_destroy(seat->wlr_seat);
 }
 
+static struct sway_seat_container *seat_container_from_container(
+		struct sway_seat *seat, struct sway_container *con);
+
+static void seat_container_destroy(struct sway_seat_container *seat_con) {
+	struct sway_container *con = seat_con->container;
+	struct sway_container *child = NULL;
+
+	if (con->children != NULL) {
+		for (int i = 0; i < con->children->length; ++i) {
+			child = con->children->items[i];
+			struct sway_seat_container *seat_child =
+				seat_container_from_container(seat_con->seat, child);
+			seat_container_destroy(seat_child);
+		}
+	}
+
+	wl_list_remove(&seat_con->destroy.link);
+	wl_list_remove(&seat_con->link);
+	free(seat_con);
+}
+
+static void seat_send_focus(struct sway_seat *seat,
+		struct sway_container *con) {
+	if (con->type != C_VIEW) {
+		return;
+	}
+	struct sway_view *view = con->sway_view;
+	if (view->type == SWAY_XWAYLAND_VIEW) {
+		struct wlr_xwayland *xwayland =
+			seat->input->server->xwayland;
+		wlr_xwayland_set_seat(xwayland, seat->wlr_seat);
+	}
+	view_set_activated(view, true);
+	struct wlr_keyboard *keyboard =
+		wlr_seat_get_keyboard(seat->wlr_seat);
+	if (keyboard) {
+		wlr_seat_keyboard_notify_enter(seat->wlr_seat,
+				view->surface, keyboard->keycodes,
+				keyboard->num_keycodes, &keyboard->modifiers);
+	} else {
+		wlr_seat_keyboard_notify_enter(
+				seat->wlr_seat, view->surface, NULL, 0, NULL);
+	}
+
+}
+
 static void handle_seat_container_destroy(struct wl_listener *listener,
 		void *data) {
 	struct sway_seat_container *seat_con =
 		wl_container_of(listener, seat_con, destroy);
 	struct sway_seat *seat = seat_con->seat;
 	struct sway_container *con = seat_con->container;
+	struct sway_container *parent = con->parent;
+	struct sway_container *focus = seat_get_focus(seat);
 
-	bool is_focus = (seat_get_focus(seat) == con);
+	bool set_focus =
+		focus != NULL &&
+		(focus == con || container_has_child(con, focus)) &&
+		con->type != C_WORKSPACE;
 
-	wl_list_remove(&seat_con->link);
+	seat_container_destroy(seat_con);
 
-	if  (is_focus) {
+	if (set_focus) {
-		// pick next focus
+		struct sway_container *next_focus = NULL;
-		seat_set_focus(seat, NULL);
+		while (next_focus == NULL) {
-		struct sway_container *next =
+			next_focus = seat_get_focus_by_type(seat, parent, C_VIEW);
-			seat_get_focus_inactive(seat, con->parent);
+
-		if (next == NULL) {
+			if (next_focus == NULL && parent->type == C_WORKSPACE) {
-			next = con->parent;
+				next_focus = parent;
-		}
+				break;
-		seat_set_focus(seat, next);
 			}
 
-	wl_list_remove(&seat_con->destroy.link);
+			parent = parent->parent;
+		}
 
-	free(seat_con);
+		// the structure change might have caused it to move up to the top of
+		// the focus stack without sending focus notifications to the view
+		if (seat_get_focus(seat) == next_focus) {
+			seat_send_focus(seat, next_focus);
+		} else {
+			seat_set_focus(seat, next_focus);
+		}
+	}
 }
 
 static struct sway_seat_container *seat_container_from_container(
@@ -310,23 +369,7 @@ void seat_set_focus_warp(struct sway_seat *seat,
 		wl_list_insert(&seat->focus_stack, &seat_con->link);
 
 		if (container->type == C_VIEW) {
-			struct sway_view *view = container->sway_view;
+			seat_send_focus(seat, container);
-			view_set_activated(view, true);
-			if (view->type == SWAY_XWAYLAND_VIEW) {
-				struct wlr_xwayland *xwayland =
-					seat->input->server->xwayland;
-				wlr_xwayland_set_seat(xwayland, seat->wlr_seat);
-			}
-			struct wlr_keyboard *keyboard =
-				wlr_seat_get_keyboard(seat->wlr_seat);
-			if (keyboard) {
-				wlr_seat_keyboard_notify_enter(seat->wlr_seat,
-						view->surface, keyboard->keycodes,
-						keyboard->num_keycodes, &keyboard->modifiers);
-			} else {
-				wlr_seat_keyboard_notify_enter(
-						seat->wlr_seat, view->surface, NULL, 0, NULL);
-			}
 		}
 	}
 
@@ -378,17 +421,31 @@ void seat_set_focus(struct sway_seat *seat,
 
 struct sway_container *seat_get_focus_inactive(struct sway_seat *seat,
 		struct sway_container *container) {
+	return seat_get_focus_by_type(seat, container, C_TYPES);
+}
+
+struct sway_container *sway_seat_get_focus(struct sway_seat *seat) {
+	if (!seat->has_focus) {
+		return NULL;
+	}
+	return seat_get_focus_inactive(seat, &root_container);
+}
+
+struct sway_container *seat_get_focus_by_type(struct sway_seat *seat,
+		struct sway_container *container, enum sway_container_type type) {
 	struct sway_seat_container *current = NULL;
 	struct sway_container *parent = NULL;
 	wl_list_for_each(current, &seat->focus_stack, link) {
 		parent = current->container->parent;
 
-		if (current->container == container) {
+		if (current->container == container &&
+				(type == C_TYPES || container->type == type)) {
 			return current->container;
 		}
 
 		while (parent) {
-			if (parent == container) {
+			if (parent == container && (type == C_TYPES ||
+						current->container->type == type)) {
 				return current->container;
 			}
 			parent = parent->parent;
@@ -405,17 +462,6 @@ struct sway_container *seat_get_focus(struct sway_seat *seat) {
 	return seat_get_focus_inactive(seat, &root_container);
 }
 
-struct sway_container *seat_get_focus_by_type(struct sway_seat *seat,
-		enum sway_container_type type) {
-	struct sway_container *focus =
-		seat_get_focus_inactive(seat, &root_container);
-	if (focus->type == type) {
-		return focus;
-	}
-
-	return container_parent(focus, type);
-}
-
 void seat_apply_config(struct sway_seat *seat,
 		struct seat_config *seat_config) {
 	struct sway_seat_device *seat_device = NULL;

sway/main.c

@@ -118,7 +118,7 @@ void run_as_ipc_client(char *command, char *socket_path) {
 static void log_env() {
 	const char *log_vars[] = {
 		"PATH",
-		"LD_LOAD_PATH",
+		"LD_LIBRARY_PATH",
 		"LD_PRELOAD_PATH",
 		"LD_LIBRARY_PATH",
 		"SWAY_CURSOR_THEME",

sway/meson.build

@@ -19,6 +19,7 @@ sway_sources = files(
 	'commands/input.c',
 	'commands/layout.c',
 	'commands/mode.c',
+	'commands/split.c',
 	'commands/move.c',
 	'commands/seat.c',
 	'commands/seat/attach.c',

sway/tree/container.c

@@ -55,7 +55,7 @@ static void notify_new_container(struct sway_container *container) {
 	ipc_event_window(container, "new");
 }
 
-static struct sway_container *container_create(enum sway_container_type type) {
+struct sway_container *container_create(enum sway_container_type type) {
 	// next id starts at 1 because 0 is assigned to root_container in layout.c
 	static size_t next_id = 1;
 	struct sway_container *c = calloc(1, sizeof(struct sway_container));
@@ -76,7 +76,7 @@ static struct sway_container *container_create(enum sway_container_type type) {
 	return c;
 }
 
-struct sway_container *container_destroy(struct sway_container *cont) {
+static struct sway_container *_container_destroy(struct sway_container *cont) {
 	if (cont == NULL) {
 		return NULL;
 	}
@@ -84,13 +84,14 @@ struct sway_container *container_destroy(struct sway_container *cont) {
 	wl_signal_emit(&cont->events.destroy, cont);
 
 	struct sway_container *parent = cont->parent;
-	if (cont->children) {
+	if (cont->children != NULL) {
 		// remove children until there are no more, container_destroy calls
 		// container_remove_child, which removes child from this container
-		while (cont->children->length) {
+		while (cont->children != NULL && cont->children->length != 0) {
-			container_destroy(cont->children->items[0]);
+			struct sway_container *child = cont->children->items[0];
+			container_remove_child(child);
+			container_destroy(child);
 		}
-		list_free(cont->children);
 	}
 	if (cont->marks) {
 		list_foreach(cont->marks, free);
@@ -102,10 +103,19 @@ struct sway_container *container_destroy(struct sway_container *cont) {
 	if (cont->name) {
 		free(cont->name);
 	}
+	list_free(cont->children);
+	cont->children = NULL;
 	free(cont);
 	return parent;
 }
 
+struct sway_container *container_destroy(struct sway_container *cont) {
+	struct sway_container *parent = _container_destroy(cont);
+	parent = container_reap_empty(parent);
+	arrange_windows(&root_container, -1, -1);
+	return parent;
+}
+
 struct sway_container *container_output_create(
 		struct sway_output *sway_output) {
 	struct wlr_box size;
@@ -413,3 +423,17 @@ bool container_has_anscestor(struct sway_container *descendant,
 	}
 	return false;
 }
+
+static bool find_child_func(struct sway_container *con, void *data) {
+	struct sway_container *child = data;
+	return con == child;
+}
+
+bool container_has_child(struct sway_container *con,
+		struct sway_container *child) {
+	if (child == NULL || child->type == C_VIEW ||
+			child->children->length == 0) {
+		return false;
+	}
+	return container_find(con, find_child_func, child);
+}

sway/tree/layout.c

@@ -1,4 +1,5 @@
 #define _POSIX_C_SOURCE 200809L
+#include <assert.h>
 #include <ctype.h>
 #include <math.h>
 #include <stdbool.h>
@@ -103,7 +104,7 @@ void container_add_child(struct sway_container *parent,
 }
 
 struct sway_container *container_reap_empty(struct sway_container *container) {
-	if (!sway_assert(container, "reaping null container")) {
+	if (container == NULL) {
 		return NULL;
 	}
 	wlr_log(L_DEBUG, "Reaping %p %s '%s'", container,
@@ -137,7 +138,7 @@ struct sway_container *container_remove_child(struct sway_container *child) {
 		}
 	}
 	child->parent = NULL;
-	return container_reap_empty(parent);
+	return parent;
 }
 
 void container_move_to(struct sway_container *container,
@@ -348,8 +349,14 @@ static void apply_horiz_layout(struct sway_container *container,
 			wlr_log(L_DEBUG,
 				"Calculating arrangement for %p:%d (will scale %f by %f)",
 				child, child->type, width, scale);
+
+			if (child->type == C_VIEW) {
 				view_configure(child->sway_view, child_x, y, child->width,
 					child->height);
+			} else {
+				child->x = child_x;
+				child->y = y;
+			}
 
 			if (i == end - 1) {
 				double remaining_width = x + width - child_x;
@@ -400,8 +407,13 @@ void apply_vert_layout(struct sway_container *container,
 			wlr_log(L_DEBUG,
 				"Calculating arrangement for %p:%d (will scale %f by %f)",
 				child, child->type, height, scale);
+			if (child->type == C_VIEW) {
 				view_configure(child->sway_view, x, child_y, child->width,
 					child->height);
+			} else {
+				child->x = x;
+				child->y = child_y;
+			}
 
 			if (i == end - 1) {
 				double remaining_height = y + height - child_y;
@@ -533,9 +545,9 @@ static struct sway_container *sway_output_from_wlr(struct wlr_output *output) {
 	return NULL;
 }
 
-static struct sway_container *get_swayc_in_direction_under(
+struct sway_container *container_get_in_direction(
-		struct sway_container *container, enum movement_direction dir,
+		struct sway_container *container, struct sway_seat *seat,
-		struct sway_seat *seat, struct sway_container *limit) {
+		enum movement_direction dir) {
 	if (dir == MOVE_CHILD) {
 		return seat_get_focus_inactive(seat, container);
 	}
@@ -567,7 +579,6 @@ static struct sway_container *get_swayc_in_direction_under(
 
 	struct sway_container *wrap_candidate = NULL;
 	while (true) {
-		// Test if we can even make a difference here
 		bool can_move = false;
 		int desired;
 		int idx = index_child(container);
@@ -597,7 +608,7 @@ static struct sway_container *get_swayc_in_direction_under(
 			}
 			if (next->children && next->children->length) {
 				// TODO consider floating children as well
-				return seat_get_focus_inactive(seat, next);
+				return seat_get_focus_by_type(seat, next, C_VIEW);
 			} else {
 				return next;
 			}
@@ -627,21 +638,23 @@ static struct sway_container *get_swayc_in_direction_under(
 						wrap_candidate = parent->children->items[0];
 					}
 					if (config->force_focus_wrapping) {
-						return wrap_candidate;
+						 return seat_get_focus_by_type(seat,
+								 wrap_candidate, C_VIEW);
 					}
 				}
 			} else {
 				wlr_log(L_DEBUG,
 					"cont %d-%p dir %i sibling %d: %p", idx,
 					container, dir, desired, parent->children->items[desired]);
-				return parent->children->items[desired];
+				return seat_get_focus_by_type(seat,
+						parent->children->items[desired], C_VIEW);
 			}
 		}
 
 		if (!can_move) {
 			container = parent;
 			parent = parent->parent;
-			if (!parent || container == limit) {
+			if (!parent) {
 				// wrapping is the last chance
 				return wrap_candidate;
 			}
@@ -649,8 +662,70 @@ static struct sway_container *get_swayc_in_direction_under(
 	}
 }
 
-struct sway_container *container_get_in_direction(
+struct sway_container *container_replace_child(struct sway_container *child,
-		struct sway_container *container, struct sway_seat *seat,
+		struct sway_container *new_child) {
-		enum movement_direction dir) {
+	struct sway_container *parent = child->parent;
-	return get_swayc_in_direction_under(container, dir, seat, NULL);
+	if (parent == NULL) {
+		return NULL;
+	}
+	int i = index_child(child);
+
+	// TODO floating
+	parent->children->items[i] = new_child;
+	new_child->parent = parent;
+	child->parent = NULL;
+
+	// Set geometry for new child
+	new_child->x = child->x;
+	new_child->y = child->y;
+	new_child->width = child->width;
+	new_child->height = child->height;
+
+	// reset geometry for child
+	child->width = 0;
+	child->height = 0;
+
+	return parent;
+}
+
+struct sway_container *container_split(struct sway_container *child,
+		enum sway_container_layout layout) {
+	// TODO floating: cannot split a floating container
+	if (!sway_assert(child, "child cannot be null")) {
+		return NULL;
+	}
+	struct sway_container *cont = container_create(C_CONTAINER);
+
+	wlr_log(L_DEBUG, "creating container %p around %p", cont, child);
+
+	cont->prev_layout = L_NONE;
+	cont->width = child->width;
+	cont->height = child->height;
+	cont->x = child->x;
+	cont->y = child->y;
+
+	if (child->type == C_WORKSPACE) {
+		struct sway_seat *seat = input_manager_get_default_seat(input_manager);
+		struct sway_container *workspace = child;
+		bool set_focus = (seat_get_focus(seat) == workspace);
+
+		while (workspace->children->length) {
+			struct sway_container *ws_child = workspace->children->items[0];
+			container_remove_child(ws_child);
+			container_add_child(cont, ws_child);
+		}
+
+		container_add_child(workspace, cont);
+		container_set_layout(workspace, layout);
+
+		if (set_focus) {
+			seat_set_focus(seat, cont);
+		}
+	} else {
+		cont->layout = layout;
+		container_replace_child(child, cont);
+		container_add_child(cont, child);
+	}
+
+	return cont;
 }