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, 75 insertions, 83 deletions

diff --git a/sway/input/cursor.c b/sway/input/cursor.c
index 00240e84..15993265 100644
--- a/sway/input/cursor.c
+++ b/sway/input/cursor.c
@@ -20,6 +20,7 @@
 #include "sway/layers.h"
 #include "sway/output.h"
 #include "sway/tree/arrange.h"
+#include "sway/tree/container.h"
 #include "sway/tree/root.h"
 #include "sway/tree/view.h"
 #include "sway/tree/workspace.h"
@@ -50,15 +51,15 @@ static struct wlr_surface *layer_surface_at(struct sway_output *output,
 }
 
 /**
- * Returns the container at the cursor's position. If there is a surface at that
+ * Returns the node at the cursor's position. If there is a surface at that
  * location, it is stored in **surface (it may not be a view).
  */
-static struct sway_container *container_at_coords(
+static struct sway_node *node_at_coords(
                 struct sway_seat *seat, double lx, double ly,
                 struct wlr_surface **surface, double *sx, double *sy) {
         // check for unmanaged views first
 #ifdef HAVE_XWAYLAND
-        struct wl_list *unmanaged = &root_container.sway_root->xwayland_unmanaged;
+        struct wl_list *unmanaged = &root->xwayland_unmanaged;
         struct sway_xwayland_unmanaged *unmanaged_surface;
         wl_list_for_each_reverse(unmanaged_surface, unmanaged, link) {
                 struct wlr_xwayland_surface *xsurface =
@@ -75,67 +76,64 @@ static struct sway_container *container_at_coords(
         }
 #endif
         // find the output the cursor is on
-        struct wlr_output_layout *output_layout =
-                root_container.sway_root->output_layout;
         struct wlr_output *wlr_output = wlr_output_layout_output_at(
-                        output_layout, lx, ly);
+                        root->output_layout, lx, ly);
         if (wlr_output == NULL) {
                 return NULL;
         }
         struct sway_output *output = wlr_output->data;
         double ox = lx, oy = ly;
-        wlr_output_layout_output_coords(output_layout, wlr_output, &ox, &oy);
+        wlr_output_layout_output_coords(root->output_layout, wlr_output, &ox, &oy);
 
         // find the focused workspace on the output for this seat
-        struct sway_container *ws = seat_get_focus_inactive(seat, output->swayc);
-        if (ws && ws->type != C_WORKSPACE) {
-                ws = container_parent(ws, C_WORKSPACE);
-        }
-        if (!ws) {
-                return output->swayc;
-        }
+        struct sway_workspace *ws = output_get_active_workspace(output);
 
         if ((*surface = layer_surface_at(output,
                                 &output->layers[ZWLR_LAYER_SHELL_V1_LAYER_OVERLAY],
                                 ox, oy, sx, sy))) {
-                return ws;
+                return &ws->node;
         }
-        if (ws->sway_workspace->fullscreen) {
-                return tiling_container_at(ws->sway_workspace->fullscreen, lx, ly,
-                                surface, sx, sy);
+        if (ws->fullscreen) {
+                struct sway_container *con =
+                        tiling_container_at(&ws->fullscreen->node, lx, ly, surface, sx, sy);
+                if (con) {
+                        return &con->node;
+                }
+                return NULL;
         }
         if ((*surface = layer_surface_at(output,
                                 &output->layers[ZWLR_LAYER_SHELL_V1_LAYER_TOP],
                                 ox, oy, sx, sy))) {
-                return ws;
+                return &ws->node;
         }
 
         struct sway_container *c;
         if ((c = container_at(ws, lx, ly, surface, sx, sy))) {
-                return c;
+                return &c->node;
         }
 
         if ((*surface = layer_surface_at(output,
                                 &output->layers[ZWLR_LAYER_SHELL_V1_LAYER_BOTTOM],
                                 ox, oy, sx, sy))) {
-                return ws;
+                return &ws->node;
         }
         if ((*surface = layer_surface_at(output,
                                 &output->layers[ZWLR_LAYER_SHELL_V1_LAYER_BACKGROUND],
                                 ox, oy, sx, sy))) {
-                return ws;
+                return &ws->node;
         }
 
-        c = seat_get_active_child(seat, output->swayc);
-        if (c) {
-                return c;
-        }
-        if (!c && output->swayc->children->length) {
-                c = output->swayc->children->items[0];
-                return c;
-        }
+        return &ws->node;
+}
 
-        return output->swayc;
+static struct sway_container *container_at_coords(struct sway_seat *seat,
+                double lx, double ly,
+                struct wlr_surface **surface, double *sx, double *sy) {
+        struct sway_node *node = node_at_coords(seat, lx, ly, surface, sx, sy);
+        if (node && node->type == N_CONTAINER) {
+                return node->sway_container;
+        }
+        return NULL;
 }
 
 /**
@@ -160,13 +158,14 @@ static bool edge_is_external(struct sway_container *cont, enum wlr_edges edge) {
 
         // Iterate the parents until we find one with the layout we want,
         // then check if the child has siblings between it and the edge.
-        while (cont->type != C_OUTPUT) {
-                if (cont->parent->layout == layout) {
-                        int index = list_find(cont->parent->children, cont);
+        while (cont) {
+                if (container_parent_layout(cont) == layout) {
+                        list_t *siblings = container_get_siblings(cont);
+                        int index = list_find(siblings, cont);
                         if (index > 0 && (edge == WLR_EDGE_LEFT || edge == WLR_EDGE_TOP)) {
                                 return false;
                         }
-                        if (index < cont->parent->children->length - 1 &&
+                        if (index < siblings->length - 1 &&
                                         (edge == WLR_EDGE_RIGHT || edge == WLR_EDGE_BOTTOM)) {
                                 return false;
                         }
@@ -178,10 +177,10 @@ static bool edge_is_external(struct sway_container *cont, enum wlr_edges edge) {
 
 static enum wlr_edges find_edge(struct sway_container *cont,
                 struct sway_cursor *cursor) {
-        if (cont->type != C_VIEW) {
+        if (!cont->view) {
                 return WLR_EDGE_NONE;
         }
-        struct sway_view *view = cont->sway_view;
+        struct sway_view *view = cont->view;
         if (view->border == B_NONE || !view->border_thickness || view->using_csd) {
                 return WLR_EDGE_NONE;
         }
@@ -219,7 +218,7 @@ static enum wlr_edges find_resize_edge(struct sway_container *cont,
 static void handle_down_motion(struct sway_seat *seat,
                 struct sway_cursor *cursor, uint32_t time_msec) {
         struct sway_container *con = seat->op_container;
-        if (seat_is_input_allowed(seat, con->sway_view->surface)) {
+        if (seat_is_input_allowed(seat, con->view->surface)) {
                 double moved_x = cursor->cursor->x - seat->op_ref_lx;
                 double moved_y = cursor->cursor->y - seat->op_ref_ly;
                 double sx = seat->op_ref_con_lx + moved_x;
@@ -260,8 +259,7 @@ static void calculate_floating_constraints(struct sway_container *con,
         if (config->floating_maximum_width == -1) { // no maximum
                 *max_width = INT_MAX;
         } else if (config->floating_maximum_width == 0) { // automatic
-                struct sway_container *ws = container_parent(con, C_WORKSPACE);
-                *max_width = ws->width;
+                *max_width = con->workspace->width;
         } else {
                 *max_width = config->floating_maximum_width;
         }
@@ -269,8 +267,7 @@ static void calculate_floating_constraints(struct sway_container *con,
         if (config->floating_maximum_height == -1) { // no maximum
                 *max_height = INT_MAX;
         } else if (config->floating_maximum_height == 0) { // automatic
-                struct sway_container *ws = container_parent(con, C_WORKSPACE);
-                *max_height = ws->height;
+                *max_height = con->workspace->height;
         } else {
                 *max_height = config->floating_maximum_height;
         }
@@ -314,9 +311,9 @@ static void handle_resize_floating_motion(struct sway_seat *seat,
         height = fmax(min_height, fmin(height, max_height));
 
         // Apply the view's min/max size
-        if (con->type == C_VIEW) {
+        if (con->view) {
                 double view_min_width, view_max_width, view_min_height, view_max_height;
-                view_get_constraints(con->sway_view, &view_min_width, &view_max_width,
+                view_get_constraints(con->view, &view_min_width, &view_max_width,
                                 &view_min_height, &view_max_height);
                 width = fmax(view_min_width, fmin(width, view_max_width));
                 height = fmax(view_min_height, fmin(height, view_max_height));
@@ -357,15 +354,15 @@ static void handle_resize_floating_motion(struct sway_seat *seat,
         con->width += relative_grow_width;
         con->height += relative_grow_height;
 
-        if (con->type == C_VIEW) {
-                struct sway_view *view = con->sway_view;
+        if (con->view) {
+                struct sway_view *view = con->view;
                 view->x += relative_grow_x;
                 view->y += relative_grow_y;
                 view->width += relative_grow_width;
                 view->height += relative_grow_height;
         }
 
-        arrange_windows(con);
+        arrange_container(con);
 }
 
 static void handle_resize_tiling_motion(struct sway_seat *seat,
@@ -435,44 +432,40 @@ void cursor_send_pointer_motion(struct sway_cursor *cursor, uint32_t time_msec,
         struct wlr_surface *surface = NULL;
         double sx, sy;
 
-        // Find the container beneath the pointer's previous position
-        struct sway_container *prev_c = container_at_coords(seat,
+        // Find the node beneath the pointer's previous position
+        struct sway_node *prev_node = node_at_coords(seat,
                         cursor->previous.x, cursor->previous.y, &surface, &sx, &sy);
         // Update the stored previous position
         cursor->previous.x = cursor->cursor->x;
         cursor->previous.y = cursor->cursor->y;
 
-        struct sway_container *c = container_at_coords(seat,
+        struct sway_node *node = node_at_coords(seat,
                         cursor->cursor->x, cursor->cursor->y, &surface, &sx, &sy);
-        if (c && config->focus_follows_mouse && allow_refocusing) {
-                struct sway_container *focus = seat_get_focus(seat);
-                if (focus && c->type == C_WORKSPACE) {
+        if (node && config->focus_follows_mouse && allow_refocusing) {
+                struct sway_node *focus = seat_get_focus(seat);
+                if (focus && node->type == N_WORKSPACE) {
                         // Only follow the mouse if it would move to a new output
                         // Otherwise we'll focus the workspace, which is probably wrong
-                        if (focus->type != C_OUTPUT) {
-                                focus = container_parent(focus, C_OUTPUT);
-                        }
-                        struct sway_container *output = c;
-                        if (output->type != C_OUTPUT) {
-                                output = container_parent(c, C_OUTPUT);
-                        }
-                        if (output != focus) {
-                                seat_set_focus_warp(seat, c, false, true);
+                        struct sway_output *focused_output = node_get_output(focus);
+                        struct sway_output *output = node_get_output(node);
+                        if (output != focused_output) {
+                                seat_set_focus_warp(seat, node, false, true);
                         }
-                } else if (c->type == C_VIEW) {
-                        // Focus c if the following are true:
+                } else if (node->type == N_CONTAINER && node->sway_container->view) {
+                        // Focus node if the following are true:
                         // - cursor is over a new view, i.e. entered a new window; and
                         // - the new view is visible, i.e. not hidden in a stack or tab; and
                         // - the seat does not have a keyboard grab
                         if (!wlr_seat_keyboard_has_grab(cursor->seat->wlr_seat) &&
-                                        c != prev_c &&
-                                        view_is_visible(c->sway_view)) {
-                                seat_set_focus_warp(seat, c, false, true);
+                                        node != prev_node &&
+                                        view_is_visible(node->sway_container->view)) {
+                                seat_set_focus_warp(seat, node, false, true);
                         } else {
-                                struct sway_container *next_focus =
-                                        seat_get_focus_inactive(seat, &root_container);
-                                if (next_focus && next_focus->type == C_VIEW &&
-                                                view_is_visible(next_focus->sway_view)) {
+                                struct sway_node *next_focus =
+                                        seat_get_focus_inactive(seat, &root->node);
+                                if (next_focus && next_focus->type == N_CONTAINER &&
+                                                node->sway_container->view &&
+                                                view_is_visible(next_focus->sway_container->view)) {
                                         seat_set_focus_warp(seat, next_focus, false, true);
                                 }
                         }
@@ -486,12 +479,12 @@ void cursor_send_pointer_motion(struct sway_cursor *cursor, uint32_t time_msec,
                 if (client != cursor->image_client) {
                         cursor_set_image(cursor, "left_ptr", client);
                 }
-        } else if (c) {
-                // Try a container's resize edge
-                enum wlr_edges edge = find_resize_edge(c, cursor);
+        } else if (node && node->type == N_CONTAINER) {
+                // Try a node's resize edge
+                enum wlr_edges edge = find_resize_edge(node->sway_container, cursor);
                 if (edge == WLR_EDGE_NONE) {
                         cursor_set_image(cursor, "left_ptr", NULL);
-                } else if (container_is_floating(c)) {
+                } else if (container_is_floating(node->sway_container)) {
                         cursor_set_image(cursor, wlr_xcursor_get_resize_name(edge), NULL);
                 } else {
                         if (edge & (WLR_EDGE_LEFT | WLR_EDGE_RIGHT)) {
@@ -684,7 +677,7 @@ void dispatch_cursor_button(struct sway_cursor *cursor,
         // Handle tiling resize via border
         if (resize_edge && button == BTN_LEFT && state == WLR_BUTTON_PRESSED &&
                         !is_floating) {
-                seat_set_focus(seat, cont);
+                seat_set_focus(seat, &cont->node);
                 seat_begin_resize_tiling(seat, cont, button, edge);
                 return;
         }
@@ -713,7 +706,7 @@ void dispatch_cursor_button(struct sway_cursor *cursor,
                                 image = "sw-resize";
                         }
                         cursor_set_image(seat->cursor, image, NULL);
-                        seat_set_focus(seat, cont);
+                        seat_set_focus(seat, &cont->node);
                         seat_begin_resize_tiling(seat, cont, button, edge);
                         return;
                 }
@@ -725,7 +718,7 @@ void dispatch_cursor_button(struct sway_cursor *cursor,
                 uint32_t btn_move = config->floating_mod_inverse ? BTN_RIGHT : BTN_LEFT;
                 if (button == btn_move && state == WLR_BUTTON_PRESSED &&
                                 (mod_pressed || on_titlebar)) {
-                        while (cont->parent->type != C_WORKSPACE) {
+                        while (cont->parent) {
                                 cont = cont->parent;
                         }
                         seat_begin_move(seat, cont, button);
@@ -747,7 +740,7 @@ void dispatch_cursor_button(struct sway_cursor *cursor,
                         BTN_LEFT : BTN_RIGHT;
                 if (mod_pressed && button == btn_resize) {
                         struct sway_container *floater = cont;
-                        while (floater->parent->type != C_WORKSPACE) {
+                        while (floater->parent) {
                                 floater = floater->parent;
                         }
                         edge = 0;
@@ -762,7 +755,7 @@ void dispatch_cursor_button(struct sway_cursor *cursor,
 
         // Handle mousedown on a container surface
         if (surface && cont && state == WLR_BUTTON_PRESSED) {
-                seat_set_focus(seat, cont);
+                seat_set_focus(seat, &cont->node);
                 seat_pointer_notify_button(seat, time_msec, button, state);
                 seat_begin_down(seat, cont, button, sx, sy);
                 return;
@@ -770,7 +763,7 @@ void dispatch_cursor_button(struct sway_cursor *cursor,
 
         // Handle clicking a container surface
         if (cont) {
-                seat_set_focus(seat, cont);
+                seat_set_focus(seat, &cont->node);
                 seat_pointer_notify_button(seat, time_msec, button, state);
                 return;
         }
@@ -1025,8 +1018,7 @@ struct sway_cursor *sway_cursor_create(struct sway_seat *seat) {
         cursor->previous.y = wlr_cursor->y;
 
         cursor->seat = seat;
-        wlr_cursor_attach_output_layout(wlr_cursor,
-                root_container.sway_root->output_layout);
+        wlr_cursor_attach_output_layout(wlr_cursor, root->output_layout);
 
         // input events
         wl_signal_add(&wlr_cursor->events.motion, &cursor->motion);