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, 102 insertions, 162 deletions

diff --git a/sway/commands/focus.c b/sway/commands/focus.c
index f342e524..e31898af 100644
--- a/sway/commands/focus.c
+++ b/sway/commands/focus.c
@@ -34,211 +34,139 @@ static bool parse_movement_direction(const char *name,
 }
 
 /**
- * Get swayc in the direction of newly entered output.
+ * Get node in the direction of newly entered output.
  */
-static struct sway_container *get_swayc_in_output_direction(
-                struct sway_container *output, enum movement_direction dir,
-                struct sway_seat *seat) {
-        if (!output) {
-                return NULL;
-        }
-
-        struct sway_container *ws = seat_get_focus_inactive(seat, output);
-        if (ws->type != C_WORKSPACE) {
-                ws = container_parent(ws, C_WORKSPACE);
-        }
-
-        if (ws == NULL) {
-                wlr_log(WLR_ERROR, "got an output without a workspace");
-                return NULL;
+static struct sway_node *get_node_in_output_direction(
+                struct sway_output *output, enum movement_direction dir) {
+        struct sway_seat *seat = config->handler_context.seat;
+        struct sway_workspace *ws = output_get_active_workspace(output);
+        if (ws->fullscreen) {
+                return seat_get_focus_inactive(seat, &ws->fullscreen->node);
         }
+        struct sway_container *container = NULL;
 
-        if (ws->children->length > 0) {
+        if (ws->tiling->length > 0) {
                 switch (dir) {
                 case MOVE_LEFT:
                         if (ws->layout == L_HORIZ || ws->layout == L_TABBED) {
                                 // get most right child of new output
-                                return ws->children->items[ws->children->length-1];
+                                container = ws->tiling->items[ws->tiling->length-1];
                         } else {
-                                return seat_get_focus_inactive(seat, ws);
+                                container = seat_get_focus_inactive_tiling(seat, ws);
                         }
+                        return &container->node;
                 case MOVE_RIGHT:
                         if (ws->layout == L_HORIZ || ws->layout == L_TABBED) {
                                 // get most left child of new output
-                                return ws->children->items[0];
+                                container = ws->tiling->items[0];
                         } else {
-                                return seat_get_focus_inactive(seat, ws);
+                                container = seat_get_focus_inactive_tiling(seat, ws);
                         }
+                        return &container->node;
                 case MOVE_UP:
+                        if (ws->layout == L_VERT || ws->layout == L_STACKED) {
+                                // get most bottom child of new output
+                                container = ws->tiling->items[ws->tiling->length-1];
+                        } else {
+                                container = seat_get_focus_inactive_tiling(seat, ws);
+                        }
+                        return &container->node;
                 case MOVE_DOWN: {
-                        struct sway_container *focused =
-                                seat_get_focus_inactive(seat, ws);
-                        if (focused && focused->parent) {
-                                struct sway_container *parent = focused->parent;
-                                if (parent->layout == L_VERT) {
-                                        if (dir == MOVE_UP) {
-                                                // get child furthest down on new output
-                                                int idx = parent->children->length - 1;
-                                                return parent->children->items[idx];
-                                        } else if (dir == MOVE_DOWN) {
-                                                // get child furthest up on new output
-                                                return parent->children->items[0];
-                                        }
-                                }
-                                return focused;
+                        if (ws->layout == L_VERT || ws->layout == L_STACKED) {
+                                // get most top child of new output
+                                container = ws->tiling->items[0];
+                        } else {
+                                container = seat_get_focus_inactive_tiling(seat, ws);
                         }
-                        break;
+                        return &container->node;
                 }
                 default:
                         break;
                 }
         }
 
-        return ws;
+        return &ws->node;
 }
 
-static struct sway_container *container_get_in_direction(
-                struct sway_container *container, struct sway_seat *seat,
-                enum movement_direction dir) {
-        struct sway_container *parent = container->parent;
-
+static struct sway_node *node_get_in_direction(struct sway_container *container,
+                struct sway_seat *seat, enum movement_direction dir) {
         if (dir == MOVE_CHILD) {
-                return seat_get_focus_inactive(seat, container);
+                return seat_get_active_child(seat, &container->node);
         }
         if (container->is_fullscreen) {
                 if (dir == MOVE_PARENT) {
                         return NULL;
                 }
-                container = container_parent(container, C_OUTPUT);
-                parent = container->parent;
-        } else {
-                if (dir == MOVE_PARENT) {
-                        if (parent->type == C_OUTPUT || container_is_floating(container)) {
-                                return NULL;
-                        } else {
-                                return parent;
-                        }
-                }
+                // Fullscreen container with a direction - go straight to outputs
+                struct sway_output *output = container->workspace->output;
+                struct sway_output *new_output = output_get_in_direction(output, dir);
+                return get_node_in_output_direction(new_output, dir);
+        }
+        if (dir == MOVE_PARENT) {
+                return node_get_parent(&container->node);
         }
 
         struct sway_container *wrap_candidate = NULL;
-        while (true) {
+        struct sway_container *current = container;
+        while (current) {
                 bool can_move = false;
                 int desired;
-                int idx = list_find(container->parent->children, container);
-                if (idx == -1) {
-                        return NULL;
-                }
-                if (parent->type == C_ROOT) {
-                        enum wlr_direction wlr_dir = 0;
-                        if (!sway_assert(sway_dir_to_wlr(dir, &wlr_dir),
-                                                "got invalid direction: %d", dir)) {
-                                return NULL;
-                        }
-                        int lx = container->x + container->width / 2;
-                        int ly = container->y + container->height / 2;
-                        struct wlr_output_layout *layout =
-                                root_container.sway_root->output_layout;
-                        struct wlr_output *wlr_adjacent =
-                                wlr_output_layout_adjacent_output(layout, wlr_dir,
-                                        container->sway_output->wlr_output, lx, ly);
-                        struct sway_container *adjacent =
-                                output_from_wlr_output(wlr_adjacent);
+                int idx = container_sibling_index(current);
+                enum sway_container_layout parent_layout =
+                        container_parent_layout(current);
+                list_t *siblings = container_get_siblings(current);
 
-                        if (!adjacent || adjacent == container) {
-                                if (!wrap_candidate) {
-                                        return NULL;
-                                }
-                                return seat_get_focus_inactive_view(seat, wrap_candidate);
-                        }
-                        struct sway_container *next =
-                                get_swayc_in_output_direction(adjacent, dir, seat);
-                        if (next == NULL) {
-                                return NULL;
-                        }
-                        struct sway_container *next_workspace = next;
-                        if (next_workspace->type != C_WORKSPACE) {
-                                next_workspace = container_parent(next_workspace, C_WORKSPACE);
-                        }
-                        sway_assert(next_workspace, "Next container has no workspace");
-                        if (next_workspace->sway_workspace->fullscreen) {
-                                return seat_get_focus_inactive(seat,
-                                                next_workspace->sway_workspace->fullscreen);
-                        }
-                        if (next->children && next->children->length) {
-                                // TODO consider floating children as well
-                                return seat_get_focus_inactive_view(seat, next);
-                        } else {
-                                return next;
+                if (dir == MOVE_LEFT || dir == MOVE_RIGHT) {
+                        if (parent_layout == L_HORIZ || parent_layout == L_TABBED) {
+                                can_move = true;
+                                desired = idx + (dir == MOVE_LEFT ? -1 : 1);
                         }
                 } else {
-                        if (dir == MOVE_LEFT || dir == MOVE_RIGHT) {
-                                if (parent->layout == L_HORIZ || parent->layout == L_TABBED) {
-                                        can_move = true;
-                                        desired = idx + (dir == MOVE_LEFT ? -1 : 1);
-                                }
-                        } else {
-                                if (parent->layout == L_VERT || parent->layout == L_STACKED) {
-                                        can_move = true;
-                                        desired = idx + (dir == MOVE_UP ? -1 : 1);
-                                }
+                        if (parent_layout == L_VERT || parent_layout == L_STACKED) {
+                                can_move = true;
+                                desired = idx + (dir == MOVE_UP ? -1 : 1);
                         }
                 }
 
                 if (can_move) {
-                        // TODO handle floating
-                        if (desired < 0 || desired >= parent->children->length) {
+                        if (desired < 0 || desired >= siblings->length) {
                                 can_move = false;
-                                int len = parent->children->length;
+                                int len = siblings->length;
                                 if (config->focus_wrapping != WRAP_NO && !wrap_candidate
                                                 && len > 1) {
                                         if (desired < 0) {
-                                                wrap_candidate = parent->children->items[len-1];
+                                                wrap_candidate = siblings->items[len-1];
                                         } else {
-                                                wrap_candidate = parent->children->items[0];
+                                                wrap_candidate = siblings->items[0];
                                         }
                                         if (config->focus_wrapping == WRAP_FORCE) {
-                                                return seat_get_focus_inactive_view(seat,
-                                                                wrap_candidate);
+                                                struct sway_container *c = seat_get_focus_inactive_view(
+                                                                seat, &wrap_candidate->node);
+                                                return &c->node;
                                         }
                                 }
                         } else {
-                                struct sway_container *desired_con =
-                                        parent->children->items[desired];
-                                wlr_log(WLR_DEBUG,
-                                        "cont %d-%p dir %i sibling %d: %p", idx,
-                                        container, dir, desired, desired_con);
-                                return seat_get_focus_inactive_view(seat, desired_con);
+                                struct sway_container *desired_con = siblings->items[desired];
+                                struct sway_container *c = seat_get_focus_inactive_view(
+                                                seat, &desired_con->node);
+                                return &c->node;
                         }
                 }
 
-                if (!can_move) {
-                        container = parent;
-                        parent = parent->parent;
-                        if (!parent) {
-                                // wrapping is the last chance
-                                if (!wrap_candidate) {
-                                        return NULL;
-                                }
-                                return seat_get_focus_inactive_view(seat, wrap_candidate);
-                        }
-                }
+                current = current->parent;
         }
-}
 
-static struct cmd_results *focus_mode(struct sway_container *con,
-                struct sway_seat *seat, bool floating) {
-        struct sway_container *ws = con->type == C_WORKSPACE ?
-                con : container_parent(con, C_WORKSPACE);
-
-        // If the container is in a floating split container,
-        // operate on the split container instead of the child.
-        if (container_is_floating_or_child(con)) {
-                while (con->parent->type != C_WORKSPACE) {
-                        con = con->parent;
-                }
+        // Check a different output
+        struct sway_output *output = container->workspace->output;
+        struct sway_output *new_output = output_get_in_direction(output, dir);
+        if (new_output) {
+                return get_node_in_output_direction(new_output, dir);
         }
+        return NULL;
+}
 
+static struct cmd_results *focus_mode(struct sway_workspace *ws,
+                struct sway_seat *seat, bool floating) {
         struct sway_container *new_focus = NULL;
         if (floating) {
                 new_focus = seat_get_focus_inactive_floating(seat, ws);
@@ -246,7 +174,7 @@ static struct cmd_results *focus_mode(struct sway_container *con,
                 new_focus = seat_get_focus_inactive_tiling(seat, ws);
         }
         if (new_focus) {
-                seat_set_focus(seat, new_focus);
+                seat_set_focus(seat, &new_focus->node);
         } else {
                 return cmd_results_new(CMD_FAILURE, "focus",
                                 "Failed to find a %s container in workspace",
@@ -255,14 +183,14 @@ static struct cmd_results *focus_mode(struct sway_container *con,
         return cmd_results_new(CMD_SUCCESS, NULL, NULL);
 }
 
-static struct cmd_results *focus_output(struct sway_container *con,
-                struct sway_seat *seat, int argc, char **argv) {
+static struct cmd_results *focus_output(struct sway_seat *seat,
+                int argc, char **argv) {
         if (!argc) {
                 return cmd_results_new(CMD_INVALID, "focus",
                         "Expected 'focus output <direction|name>'");
         }
         char *identifier = join_args(argv, argc);
-        struct sway_container *output = output_by_name(identifier);
+        struct sway_output *output = output_by_name(identifier);
 
         if (!output) {
                 enum movement_direction direction;
@@ -272,14 +200,13 @@ static struct cmd_results *focus_output(struct sway_container *con,
                         return cmd_results_new(CMD_INVALID, "focus",
                                 "There is no output with that name");
                 }
-                struct sway_container *focus = seat_get_focus(seat);
-                focus = container_parent(focus, C_OUTPUT);
-                output = container_get_in_direction(focus, seat, direction);
+                struct sway_workspace *ws = seat_get_focused_workspace(seat);
+                output = output_get_in_direction(ws->output, direction);
         }
 
         free(identifier);
         if (output) {
-                seat_set_focus(seat, seat_get_focus_inactive(seat, output));
+                seat_set_focus(seat, seat_get_focus_inactive(seat, &output->node));
         }
 
         return cmd_results_new(CMD_SUCCESS, NULL, NULL);
@@ -289,29 +216,32 @@ struct cmd_results *cmd_focus(int argc, char **argv) {
         if (config->reading || !config->active) {
                 return cmd_results_new(CMD_DEFER, NULL, NULL);
         }
-        struct sway_container *con = config->handler_context.current_container;
+        struct sway_node *node = config->handler_context.node;
+        struct sway_container *container = config->handler_context.container;
+        struct sway_workspace *workspace = config->handler_context.workspace;
         struct sway_seat *seat = config->handler_context.seat;
-        if (con->type < C_WORKSPACE) {
+        if (node->type < N_WORKSPACE) {
                 return cmd_results_new(CMD_FAILURE, "focus",
                         "Command 'focus' cannot be used above the workspace level");
         }
 
         if (argc == 0) {
-                seat_set_focus(seat, con);
+                seat_set_focus(seat, node);
                 return cmd_results_new(CMD_SUCCESS, NULL, NULL);
         }
 
         if (strcmp(argv[0], "floating") == 0) {
-                return focus_mode(con, seat, true);
+                return focus_mode(workspace, seat, true);
         } else if (strcmp(argv[0], "tiling") == 0) {
-                return focus_mode(con, seat, false);
+                return focus_mode(workspace, seat, false);
         } else if (strcmp(argv[0], "mode_toggle") == 0) {
-                return focus_mode(con, seat, !container_is_floating_or_child(con));
+                bool floating = container && container_is_floating_or_child(container);
+                return focus_mode(workspace, seat, !floating);
         }
 
         if (strcmp(argv[0], "output") == 0) {
                 argc--; argv++;
-                return focus_output(con, seat, argc, argv);
+                return focus_output(seat, argc, argv);
         }
 
         enum movement_direction direction = 0;
@@ -321,8 +251,18 @@ struct cmd_results *cmd_focus(int argc, char **argv) {
                         "or 'focus output <direction|name>'");
         }
 
-        struct sway_container *next_focus = container_get_in_direction(
-                        con, seat, direction);
+        if (node->type == N_WORKSPACE) {
+                // A workspace is focused, so just jump to the next output
+                struct sway_output *new_output =
+                        output_get_in_direction(workspace->output, direction);
+                struct sway_node *node =
+                        get_node_in_output_direction(new_output, direction);
+                seat_set_focus(seat, node);
+                return cmd_results_new(CMD_SUCCESS, NULL, NULL);
+        }
+
+        struct sway_node *next_focus =
+                node_get_in_direction(container, seat, direction);
         if (next_focus) {
                 seat_set_focus(seat, next_focus);
         }