Implement type safe arguments and demote sway_container

This commit changes the meaning of sway_container so that it only refers
to layout containers and view containers. Workspaces, outputs and the
root are no longer known as containers. Instead, root, outputs,
workspaces and containers are all a type of node, and containers come in
two types: layout containers and view containers.

In addition to the above, this implements type safe variables. This
means we use specific types such as sway_output and sway_workspace
instead of generic containers or nodes. However, it's worth noting that
in a few places places (eg. seat focus and transactions) referring to
them in a generic way is unavoidable which is why we still use nodes in
some places.

If you want a TL;DR, look at node.h, as well as the struct definitions
for root, output, workspace and container. Note that sway_output now
contains a workspaces list, and workspaces now contain a tiling and
floating list, and containers now contain a pointer back to the
workspace.

There are now functions for seat_get_focused_workspace and
seat_get_focused_container. The latter will return NULL if a workspace
itself is focused. Most other seat functions like seat_get_focus and
seat_set_focus now accept and return nodes.

In the config->handler_context struct, current_container has been
replaced with three pointers: node, container and workspace. node is the
same as what current_container was, while workspace is the workspace
that the node resides on and container is the actual container, which
may be NULL if a workspace itself is focused.

The global root_container variable has been replaced with one simply
called root, which is a pointer to the sway_root instance.

The way outputs are created, enabled, disabled and destroyed has
changed. Previously we'd wrap the sway_output in a container when it is
enabled, but as we don't have containers any more it needs a different
approach. The output_create and output_destroy functions previously
created/destroyed the container, but now they create/destroy the
sway_output. There is a new function output_disable to disable an output
without destroying it.

Containers have a new view property. If this is populated then the
container is a view container, otherwise it's a layout container. Like
before, this property is immutable for the life of the container.

Containers have both a `sway_container *parent` and
`sway_workspace *workspace`. As we use specific types now, parent cannot
point to a workspace so it'll be NULL for containers which are direct
children of the workspace. The workspace property is set for all
containers, except those which are hidden in the scratchpad as they have
no workspace.

In some cases we need to refer to workspaces in a container-like way.
For example, workspaces have layout and children, but when using
specific types this makes it difficult. Likewise, it's difficult for a
container to get its parent's layout when the parent could be another
container or a workspace. To make it easier, some helper functions have
been created: container_parent_layout and container_get_siblings.

container_remove_child has been renamed to container_detach and
container_replace_child has been renamed to container_replace.

`container_handle_fullscreen_reparent(con, old_parent)` has had the
old_parent removed. We now unfullscreen the workspace when detaching the
container, so this function is simplified and only needs one argument
now.

container_notify_subtree_changed has been renamed to
container_update_representation. This is more descriptive of its
purpose. I also wanted to be able to call it with whatever container was
changed rather than the container's parent, which makes bubbling up to
the workspace easier.

There are now state structs per node thing. ie. sway_output_state,
sway_workspace_state and sway_container_state.

The focus, move and layout commands have been completely refactored to
work with the specific types. I considered making these a separate PR,
but I'd be backporting my changes only to replace them again, and it's
easier just to test everything at once.

1 files changed, 235 insertions, 139 deletions

diff --git a/sway/desktop/transaction.c b/sway/desktop/transaction.c
index 145c5f92..b4eec933 100644
--- a/sway/desktop/transaction.c
+++ b/sway/desktop/transaction.c
@@ -12,6 +12,7 @@
 #include "sway/desktop/transaction.h"
 #include "sway/output.h"
 #include "sway/tree/container.h"
+#include "sway/tree/node.h"
 #include "sway/tree/view.h"
 #include "sway/tree/workspace.h"
 #include "list.h"
@@ -27,8 +28,12 @@ struct sway_transaction {
 
 struct sway_transaction_instruction {
 	struct sway_transaction *transaction;
-	struct sway_container *container;
-	struct sway_container_state state;
+	struct sway_node *node;
+	union {
+		struct sway_output_state *output_state;
+		struct sway_workspace_state *workspace_state;
+		struct sway_container_state *container_state;
+	};
 	uint32_t serial;
 };
 
@@ -47,26 +52,24 @@ static void transaction_destroy(struct sway_transaction *transaction) {
 	for (int i = 0; i < transaction->instructions->length; ++i) {
 		struct sway_transaction_instruction *instruction =
 			transaction->instructions->items[i];
-		struct sway_container *con = instruction->container;
-		con->ntxnrefs--;
-		if (con->instruction == instruction) {
-			con->instruction = NULL;
+		struct sway_node *node = instruction->node;
+		node->ntxnrefs--;
+		if (node->instruction == instruction) {
+			node->instruction = NULL;
 		}
-		if (con->destroying && con->ntxnrefs == 0) {
-			switch (con->type) {
-			case C_ROOT:
+		if (node->destroying && node->ntxnrefs == 0) {
+			switch (node->type) {
+			case N_ROOT:
+				sway_assert(false, "Never reached");
 				break;
-			case C_OUTPUT:
-				output_destroy(con);
+			case N_OUTPUT:
+				output_destroy(node->sway_output);
 				break;
-			case C_WORKSPACE:
-				workspace_destroy(con);
+			case N_WORKSPACE:
+				workspace_destroy(node->sway_workspace);
 				break;
-			case C_CONTAINER:
-			case C_VIEW:
-				container_destroy(con);
-				break;
-			case C_TYPES:
+			case N_CONTAINER:
+				container_destroy(node->sway_container);
 				break;
 			}
 		}
@@ -80,22 +83,79 @@ static void transaction_destroy(struct sway_transaction *transaction) {
 	free(transaction);
 }
 
-static void copy_pending_state(struct sway_container *container,
-		struct sway_container_state *state) {
+static void copy_output_state(struct sway_output *output,
+		struct sway_transaction_instruction *instruction) {
+	struct sway_output_state *state =
+		calloc(1, sizeof(struct sway_output_state));
+	if (!state) {
+		wlr_log(WLR_ERROR, "Could not allocate output state");
+		return;
+	}
+	instruction->output_state = state;
+
+	state->workspaces = create_list();
+	list_cat(state->workspaces, output->workspaces);
+
+	state->active_workspace = output_get_active_workspace(output);
+}
+
+static void copy_workspace_state(struct sway_workspace *ws,
+		struct sway_transaction_instruction *instruction) {
+	struct sway_workspace_state *state =
+		calloc(1, sizeof(struct sway_workspace_state));
+	if (!state) {
+		wlr_log(WLR_ERROR, "Could not allocate workspace state");
+		return;
+	}
+	instruction->workspace_state = state;
+
+	state->fullscreen = ws->fullscreen;
+	state->x = ws->x;
+	state->y = ws->y;
+	state->width = ws->width;
+	state->height = ws->height;
+	state->layout = ws->layout;
+
+	state->output = ws->output;
+	state->floating = create_list();
+	state->tiling = create_list();
+	list_cat(state->floating, ws->floating);
+	list_cat(state->tiling, ws->tiling);
+
+	struct sway_seat *seat = input_manager_current_seat(input_manager);
+	state->focused = seat_get_focus(seat) == &ws->node;
+
+	// Set focused_inactive_child to the direct tiling child
+	struct sway_container *focus = seat_get_focus_inactive_tiling(seat, ws);
+	if (focus) {
+		while (focus->parent) {
+			focus = focus->parent;
+		}
+	}
+	state->focused_inactive_child = focus;
+}
+
+static void copy_container_state(struct sway_container *container,
+		struct sway_transaction_instruction *instruction) {
+	struct sway_container_state *state =
+		calloc(1, sizeof(struct sway_container_state));
+	if (!state) {
+		wlr_log(WLR_ERROR, "Could not allocate container state");
+		return;
+	}
+	instruction->container_state = state;
+
 	state->layout = container->layout;
-	state->swayc_x = container->x;
-	state->swayc_y = container->y;
-	state->swayc_width = container->width;
-	state->swayc_height = container->height;
+	state->con_x = container->x;
+	state->con_y = container->y;
+	state->con_width = container->width;
+	state->con_height = container->height;
 	state->is_fullscreen = container->is_fullscreen;
-	state->has_gaps = container->has_gaps;
-	state->current_gaps = container->current_gaps;
-	state->gaps_inner = container->gaps_inner;
-	state->gaps_outer = container->gaps_outer;
 	state->parent = container->parent;
+	state->workspace = container->workspace;
 
-	if (container->type == C_VIEW) {
-		struct sway_view *view = container->sway_view;
+	if (container->view) {
+		struct sway_view *view = container->view;
 		state->view_x = view->x;
 		state->view_y = view->y;
 		state->view_width = view->width;
@@ -107,50 +167,111 @@ static void copy_pending_state(struct sway_container *container,
 		state->border_right = view->border_right;
 		state->border_bottom = view->border_bottom;
 		state->using_csd = view->using_csd;
-	} else if (container->type == C_WORKSPACE) {
-		state->ws_fullscreen = container->sway_workspace->fullscreen;
-		state->ws_floating = create_list();
-		state->children = create_list();
-		list_cat(state->ws_floating, container->sway_workspace->floating);
-		list_cat(state->children, container->children);
 	} else {
 		state->children = create_list();
 		list_cat(state->children, container->children);
 	}
 
 	struct sway_seat *seat = input_manager_current_seat(input_manager);
-	state->focused = seat_get_focus(seat) == container;
-
-	if (container->type == C_WORKSPACE) {
-		// Set focused_inactive_child to the direct tiling child
-		struct sway_container *focus =
-			seat_get_focus_inactive_tiling(seat, container);
-		if (focus && focus->type > C_WORKSPACE) {
-			while (focus->parent->type != C_WORKSPACE) {
-				focus = focus->parent;
-			}
-		}
-		state->focused_inactive_child = focus;
-	} else if (container->type != C_VIEW) {
-		state->focused_inactive_child =
-			seat_get_active_child(seat, container);
+	state->focused = seat_get_focus(seat) == &container->node;
+
+	if (!container->view) {
+		struct sway_node *focus = seat_get_active_child(seat, &container->node);
+		state->focused_inactive_child = focus ? focus->sway_container : NULL;
 	}
 }
 
-static void transaction_add_container(struct sway_transaction *transaction,
-		struct sway_container *container) {
+static void transaction_add_node(struct sway_transaction *transaction,
+		struct sway_node *node) {
 	struct sway_transaction_instruction *instruction =
 		calloc(1, sizeof(struct sway_transaction_instruction));
 	if (!sway_assert(instruction, "Unable to allocate instruction")) {
 		return;
 	}
 	instruction->transaction = transaction;
-	instruction->container = container;
-
-	copy_pending_state(container, &instruction->state);
+	instruction->node = node;
+
+	switch (node->type) {
+	case N_ROOT:
+		break;
+	case N_OUTPUT:
+		copy_output_state(node->sway_output, instruction);
+		break;
+	case N_WORKSPACE:
+		copy_workspace_state(node->sway_workspace, instruction);
+		break;
+	case N_CONTAINER:
+		copy_container_state(node->sway_container, instruction);
+		break;
+	}
 
 	list_add(transaction->instructions, instruction);
-	container->ntxnrefs++;
+	node->ntxnrefs++;
+}
+
+static void apply_output_state(struct sway_output *output,
+		struct sway_output_state *state) {
+	output_damage_whole(output);
+	list_free(output->current.workspaces);
+	memcpy(&output->current, state, sizeof(struct sway_output_state));
+	output_damage_whole(output);
+}
+
+static void apply_workspace_state(struct sway_workspace *ws,
+		struct sway_workspace_state *state) {
+	output_damage_whole(ws->current.output);
+	list_free(ws->current.floating);
+	list_free(ws->current.tiling);
+	memcpy(&ws->current, state, sizeof(struct sway_workspace_state));
+	output_damage_whole(ws->current.output);
+}
+
+static void apply_container_state(struct sway_container *container,
+		struct sway_container_state *state) {
+	struct sway_view *view = container->view;
+	// Damage the old location
+	desktop_damage_whole_container(container);
+	if (view && view->saved_buffer) {
+		struct wlr_box box = {
+			.x = container->current.view_x - view->saved_geometry.x,
+			.y = container->current.view_y - view->saved_geometry.y,
+			.width = view->saved_buffer_width,
+			.height = view->saved_buffer_height,
+		};
+		desktop_damage_box(&box);
+	}
+
+	// There are separate children lists for each instruction state, the
+	// container's current state and the container's pending state
+	// (ie. con->children). The list itself needs to be freed here.
+	// Any child containers which are being deleted will be cleaned up in
+	// transaction_destroy().
+	list_free(container->current.children);
+
+	memcpy(&container->current, state, sizeof(struct sway_container_state));
+
+	if (view && view->saved_buffer) {
+		if (!container->node.destroying || container->node.ntxnrefs == 1) {
+			view_remove_saved_buffer(view);
+		}
+	}
+
+	// Damage the new location
+	desktop_damage_whole_container(container);
+	if (view && view->surface) {
+		struct wlr_surface *surface = view->surface;
+		struct wlr_box box = {
+			.x = container->current.view_x - view->geometry.x,
+			.y = container->current.view_y - view->geometry.y,
+			.width = surface->current.width,
+			.height = surface->current.height,
+		};
+		desktop_damage_box(&box);
+	}
+
+	if (!container->node.destroying) {
+		container_discover_outputs(container);
+	}
 }
 
 /**
@@ -168,67 +289,36 @@ static void transaction_apply(struct sway_transaction *transaction) {
 				"(%.1f frames if 60Hz)", transaction, ms, ms / (1000.0f / 60));
 	}
 
-	// Apply the instruction state to the container's current state
+	// Apply the instruction state to the node's current state
 	for (int i = 0; i < transaction->instructions->length; ++i) {
 		struct sway_transaction_instruction *instruction =
 			transaction->instructions->items[i];
-		struct sway_container *container = instruction->container;
-
-		// Damage the old location
-		desktop_damage_whole_container(container);
-		if (container->type == C_VIEW && container->sway_view->saved_buffer) {
-			struct sway_view *view = container->sway_view;
-			struct wlr_box box = {
-				.x = container->current.view_x - view->saved_geometry.x,
-				.y = container->current.view_y - view->saved_geometry.y,
-				.width = view->saved_buffer_width,
-				.height = view->saved_buffer_height,
-			};
-			desktop_damage_box(&box);
-		}
-
-		// There are separate children lists for each instruction state, the
-		// container's current state and the container's pending state
-		// (ie. con->children). The list itself needs to be freed here.
-		// Any child containers which are being deleted will be cleaned up in
-		// transaction_destroy().
-		list_free(container->current.children);
-		list_free(container->current.ws_floating);
-
-		memcpy(&container->current, &instruction->state,
-				sizeof(struct sway_container_state));
-
-		if (container->type == C_VIEW && container->sway_view->saved_buffer) {
-			if (!container->destroying || container->ntxnrefs == 1) {
-				view_remove_saved_buffer(container->sway_view);
-			}
-		}
+		struct sway_node *node = instruction->node;
 
-		// Damage the new location
-		desktop_damage_whole_container(container);
-		if (container->type == C_VIEW && container->sway_view->surface) {
-			struct sway_view *view = container->sway_view;
-			struct wlr_surface *surface = view->surface;
-			struct wlr_box box = {
-				.x = container->current.view_x - view->geometry.x,
-				.y = container->current.view_y - view->geometry.y,
-				.width = surface->current.width,
-				.height = surface->current.height,
-			};
-			desktop_damage_box(&box);
+		switch (node->type) {
+		case N_ROOT:
+			break;
+		case N_OUTPUT:
+			apply_output_state(node->sway_output, instruction->output_state);
+			break;
+		case N_WORKSPACE:
+			apply_workspace_state(node->sway_workspace,
+					instruction->workspace_state);
+			break;
+		case N_CONTAINER:
+			apply_container_state(node->sway_container,
+					instruction->container_state);
+			break;
 		}
 
-		container->instruction = NULL;
-		if (container->type == C_CONTAINER || container->type == C_VIEW) {
-			container_discover_outputs(container);
-		}
+		node->instruction = NULL;
 	}
 }
 
 static void transaction_commit(struct sway_transaction *transaction);
 
-// Return true if both transactions operate on the same containers
-static bool transaction_same_containers(struct sway_transaction *a,
+// Return true if both transactions operate on the same nodes
+static bool transaction_same_nodes(struct sway_transaction *a,
 		struct sway_transaction *b) {
 	if (a->instructions->length != b->instructions->length) {
 		return false;
@@ -236,7 +326,7 @@ static bool transaction_same_containers(struct sway_transaction *a,
 	for (int i = 0; i < a->instructions->length; ++i) {
 		struct sway_transaction_instruction *a_inst = a->instructions->items[i];
 		struct sway_transaction_instruction *b_inst = b->instructions->items[i];
-		if (a_inst->container != b_inst->container) {
+		if (a_inst->node != b_inst->node) {
 			return false;
 		}
 	}
@@ -267,7 +357,7 @@ static void transaction_progress_queue() {
 	while (server.transactions->length >= 2) {
 		struct sway_transaction *a = server.transactions->items[0];
 		struct sway_transaction *b = server.transactions->items[1];
-		if (transaction_same_containers(a, b)) {
+		if (transaction_same_nodes(a, b)) {
 			list_del(server.transactions, 0);
 			transaction_destroy(a);
 		} else {
@@ -289,16 +379,18 @@ static int handle_timeout(void *data) {
 	return 0;
 }
 
-static bool should_configure(struct sway_container *con,
+static bool should_configure(struct sway_node *node,
 		struct sway_transaction_instruction *instruction) {
-	if (con->type != C_VIEW) {
+	if (!node_is_view(node)) {
 		return false;
 	}
-	if (con->destroying) {
+	if (node->destroying) {
 		return false;
 	}
-	if (con->current.view_width == instruction->state.view_width &&
-			con->current.view_height == instruction->state.view_height) {
+	struct sway_container_state *cstate = &node->sway_container->current;
+	struct sway_container_state *istate = instruction->container_state;
+	if (cstate->view_width == istate->view_width &&
+			cstate->view_height == istate->view_height) {
 		return false;
 	}
 	return true;
@@ -311,13 +403,13 @@ static void transaction_commit(struct sway_transaction *transaction) {
 	for (int i = 0; i < transaction->instructions->length; ++i) {
 		struct sway_transaction_instruction *instruction =
 			transaction->instructions->items[i];
-		struct sway_container *con = instruction->container;
-		if (should_configure(con, instruction)) {
-			instruction->serial = view_configure(con->sway_view,
-					instruction->state.view_x,
-					instruction->state.view_y,
-					instruction->state.view_width,
-					instruction->state.view_height);
+		struct sway_node *node = instruction->node;
+		if (should_configure(node, instruction)) {
+			instruction->serial = view_configure(node->sway_container->view,
+					instruction->container_state->view_x,
+					instruction->container_state->view_y,
+					instruction->container_state->view_width,
+					instruction->container_state->view_height);
 			++transaction->num_waiting;
 
 			// From here on we are rendering a saved buffer of the view, which
@@ -325,14 +417,16 @@ static void transaction_commit(struct sway_transaction *transaction) {
 			// as soon as possible. Additionally, this is required if a view is
 			// mapping and its default geometry doesn't intersect an output.
 			struct timespec when;
-			wlr_surface_send_frame_done(con->sway_view->surface, &when);
+			wlr_surface_send_frame_done(
+					node->sway_container->view->surface, &when);
 		}
-		if (con->type == C_VIEW && !con->sway_view->saved_buffer) {
-			view_save_buffer(con->sway_view);
-			memcpy(&con->sway_view->saved_geometry, &con->sway_view->geometry,
+		if (node_is_view(node) && !node->sway_container->view->saved_buffer) {
+			view_save_buffer(node->sway_container->view);
+			memcpy(&node->sway_container->view->saved_geometry,
+					&node->sway_container->view->geometry,
 					sizeof(struct wlr_box));
 		}
-		con->instruction = instruction;
+		node->instruction = instruction;
 	}
 	transaction->num_configures = transaction->num_waiting;
 	if (debug.txn_timings) {
@@ -381,7 +475,7 @@ static void set_instruction_ready(
 				transaction,
 				transaction->num_configures - transaction->num_waiting + 1,
 				transaction->num_configures, ms,
-				instruction->container->name);
+				instruction->node->sway_container->title);
 	}
 
 	// If the transaction has timed out then its num_waiting will be 0 already.
@@ -390,41 +484,43 @@ static void set_instruction_ready(
 		wl_event_source_timer_update(transaction->timer, 0);
 	}
 
-	instruction->container->instruction = NULL;
+	instruction->node->instruction = NULL;
 	transaction_progress_queue();
 }
 
 void transaction_notify_view_ready_by_serial(struct sway_view *view,
 		uint32_t serial) {
-	struct sway_transaction_instruction *instruction = view->swayc->instruction;
-	if (view->swayc->instruction->serial == serial) {
+	struct sway_transaction_instruction *instruction =
+		view->container->node.instruction;
+	if (instruction->serial == serial) {
 		set_instruction_ready(instruction);
 	}
 }
 
 void transaction_notify_view_ready_by_size(struct sway_view *view,
 		int width, int height) {
-	struct sway_transaction_instruction *instruction = view->swayc->instruction;
-	if (instruction->state.view_width == width &&
-			instruction->state.view_height == height) {
+	struct sway_transaction_instruction *instruction =
+		view->container->node.instruction;
+	if (instruction->container_state->view_width == width &&
+			instruction->container_state->view_height == height) {
 		set_instruction_ready(instruction);
 	}
 }
 
 void transaction_commit_dirty(void) {
-	if (!server.dirty_containers->length) {
+	if (!server.dirty_nodes->length) {
 		return;
 	}
 	struct sway_transaction *transaction = transaction_create();
 	if (!transaction) {
 		return;
 	}
-	for (int i = 0; i < server.dirty_containers->length; ++i) {
-		struct sway_container *container = server.dirty_containers->items[i];
-		transaction_add_container(transaction, container);
-		container->dirty = false;
+	for (int i = 0; i < server.dirty_nodes->length; ++i) {
+		struct sway_node *node = server.dirty_nodes->items[i];
+		transaction_add_node(transaction, node);
+		node->dirty = false;
 	}
-	server.dirty_containers->length = 0;
+	server.dirty_nodes->length = 0;
 
 	list_add(server.transactions, transaction);