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, 89 insertions, 97 deletions

diff --git a/sway/tree/root.c b/sway/tree/root.c
index b42371de..ecc04ddb 100644
--- a/sway/tree/root.c
+++ b/sway/tree/root.c
@@ -14,54 +14,45 @@
 #include "log.h"
 #include "util.h"
 
-struct sway_container root_container;
+struct sway_root *root;
 
 static void output_layout_handle_change(struct wl_listener *listener,
                 void *data) {
-        arrange_windows(&root_container);
+        arrange_root();
         transaction_commit_dirty();
 }
 
-void root_create(void) {
-        root_container.id = 0; // normally assigned in new_swayc()
-        root_container.type = C_ROOT;
-        root_container.layout = L_NONE;
-        root_container.name = strdup("root");
-        root_container.children = create_list();
-        root_container.current.children = create_list();
-        wl_signal_init(&root_container.events.destroy);
-
-        root_container.sway_root = calloc(1, sizeof(*root_container.sway_root));
-        root_container.sway_root->output_layout = wlr_output_layout_create();
-        wl_list_init(&root_container.sway_root->all_outputs);
+struct sway_root *root_create(void) {
+        struct sway_root *root = calloc(1, sizeof(struct sway_root));
+        if (!root) {
+                wlr_log(WLR_ERROR, "Unable to allocate sway_root");
+                return NULL;
+        }
+        node_init(&root->node, N_ROOT, root);
+        root->output_layout = wlr_output_layout_create();
+        wl_list_init(&root->all_outputs);
 #ifdef HAVE_XWAYLAND
-        wl_list_init(&root_container.sway_root->xwayland_unmanaged);
+        wl_list_init(&root->xwayland_unmanaged);
 #endif
-        wl_list_init(&root_container.sway_root->drag_icons);
-        wl_signal_init(&root_container.sway_root->events.new_container);
-        root_container.sway_root->scratchpad = create_list();
-        root_container.sway_root->saved_workspaces = create_list();
-
-        root_container.sway_root->output_layout_change.notify =
-                output_layout_handle_change;
-        wl_signal_add(&root_container.sway_root->output_layout->events.change,
-                &root_container.sway_root->output_layout_change);
+        wl_list_init(&root->drag_icons);
+        wl_signal_init(&root->events.new_node);
+        root->outputs = create_list();
+        root->scratchpad = create_list();
+        root->saved_workspaces = create_list();
+
+        root->output_layout_change.notify = output_layout_handle_change;
+        wl_signal_add(&root->output_layout->events.change,
+                &root->output_layout_change);
+        return root;
 }
 
-void root_destroy(void) {
-        // sway_root
-        wl_list_remove(&root_container.sway_root->output_layout_change.link);
-        list_free(root_container.sway_root->scratchpad);
-        list_free(root_container.sway_root->saved_workspaces);
-        wlr_output_layout_destroy(root_container.sway_root->output_layout);
-        free(root_container.sway_root);
-
-        // root_container
-        list_free(root_container.children);
-        list_free(root_container.current.children);
-        free(root_container.name);
-
-        memset(&root_container, 0, sizeof(root_container));
+void root_destroy(struct sway_root *root) {
+        wl_list_remove(&root->output_layout_change.link);
+        list_free(root->scratchpad);
+        list_free(root->saved_workspaces);
+        list_free(root->outputs);
+        wlr_output_layout_destroy(root->output_layout);
+        free(root);
 }
 
 void root_scratchpad_add_container(struct sway_container *con) {
@@ -69,15 +60,21 @@ void root_scratchpad_add_container(struct sway_container *con) {
                 return;
         }
         con->scratchpad = true;
-        list_add(root_container.sway_root->scratchpad, con);
+        list_add(root->scratchpad, con);
 
         struct sway_container *parent = con->parent;
+        struct sway_workspace *workspace = con->workspace;
         container_set_floating(con, true);
-        container_remove_child(con);
-        arrange_windows(parent);
+        container_detach(con);
 
         struct sway_seat *seat = input_manager_current_seat(input_manager);
-        seat_set_focus(seat, seat_get_focus_inactive(seat, parent));
+        if (parent) {
+                arrange_container(parent);
+                seat_set_focus(seat, seat_get_focus_inactive(seat, &parent->node));
+        } else {
+                arrange_workspace(workspace);
+                seat_set_focus(seat, seat_get_focus_inactive(seat, &workspace->node));
+        }
 }
 
 void root_scratchpad_remove_container(struct sway_container *con) {
@@ -85,28 +82,25 @@ void root_scratchpad_remove_container(struct sway_container *con) {
                 return;
         }
         con->scratchpad = false;
-        int index = list_find(root_container.sway_root->scratchpad, con);
+        int index = list_find(root->scratchpad, con);
         if (index != -1) {
-                list_del(root_container.sway_root->scratchpad, index);
+                list_del(root->scratchpad, index);
         }
 }
 
 void root_scratchpad_show(struct sway_container *con) {
         struct sway_seat *seat = input_manager_current_seat(input_manager);
-        struct sway_container *ws = seat_get_focus(seat);
-        if (ws->type != C_WORKSPACE) {
-                ws = container_parent(ws, C_WORKSPACE);
-        }
+        struct sway_workspace *ws = seat_get_focused_workspace(seat);
 
     // If the current con or any of its parents are in fullscreen mode, we
     // first need to disable it before showing the scratchpad con.
-        if (ws->sway_workspace->fullscreen) {
-                container_set_fullscreen(ws->sway_workspace->fullscreen, false);
+        if (ws->fullscreen) {
+                container_set_fullscreen(ws->fullscreen, false);
         }
 
         // Show the container
-        if (con->parent) {
-                container_remove_child(con);
+        if (con->workspace) {
+                container_detach(con);
         }
         workspace_add_floating(ws, con);
 
@@ -115,7 +109,7 @@ void root_scratchpad_show(struct sway_container *con) {
         double center_ly = con->y + con->height / 2;
 
         struct wlr_box workspace_box;
-        container_get_box(ws, &workspace_box);
+        workspace_get_box(ws, &workspace_box);
         if (!wlr_box_contains_point(&workspace_box, center_lx, center_ly)) {
                 // Maybe resize it
                 if (con->width > ws->width || con->height > ws->height) {
@@ -128,23 +122,21 @@ void root_scratchpad_show(struct sway_container *con) {
                 container_floating_move_to(con, new_lx, new_ly);
         }
 
-        arrange_windows(ws);
-        seat_set_focus(seat, seat_get_focus_inactive(seat, con));
-
-        container_set_dirty(con->parent);
+        arrange_workspace(ws);
+        seat_set_focus(seat, seat_get_focus_inactive(seat, &con->node));
 }
 
 void root_scratchpad_hide(struct sway_container *con) {
         struct sway_seat *seat = input_manager_current_seat(input_manager);
-        struct sway_container *focus = seat_get_focus(seat);
-        struct sway_container *ws = container_parent(con, C_WORKSPACE);
+        struct sway_node *focus = seat_get_focus(seat);
+        struct sway_workspace *ws = con->workspace;
 
-        container_remove_child(con);
-        arrange_windows(ws);
-        if (con == focus) {
-                seat_set_focus(seat, seat_get_focus_inactive(seat, ws));
+        container_detach(con);
+        arrange_workspace(ws);
+        if (&con->node == focus) {
+                seat_set_focus(seat, seat_get_focus_inactive(seat, &ws->node));
         }
-        list_move_to_end(root_container.sway_root->scratchpad, con);
+        list_move_to_end(root->scratchpad, con);
 }
 
 struct pid_workspace {
@@ -152,7 +144,7 @@ struct pid_workspace {
         char *workspace;
         struct timespec time_added;
 
-        struct sway_container *output;
+        struct sway_output *output;
         struct wl_listener output_destroy;
 
         struct wl_list link;
@@ -160,13 +152,13 @@ struct pid_workspace {
 
 static struct wl_list pid_workspaces;
 
-struct sway_container *root_workspace_for_pid(pid_t pid) {
+struct sway_workspace *root_workspace_for_pid(pid_t pid) {
         if (!pid_workspaces.prev && !pid_workspaces.next) {
                 wl_list_init(&pid_workspaces);
                 return NULL;
         }
 
-        struct sway_container *ws = NULL;
+        struct sway_workspace *ws = NULL;
         struct pid_workspace *pw = NULL;
 
         wlr_log(WLR_DEBUG, "Looking up workspace for pid %d", pid);
@@ -219,16 +211,12 @@ void root_record_workspace_pid(pid_t pid) {
         }
 
         struct sway_seat *seat = input_manager_current_seat(input_manager);
-        struct sway_container *ws =
-                seat_get_focus_inactive(seat, &root_container);
-        if (ws && ws->type != C_WORKSPACE) {
-                ws = container_parent(ws, C_WORKSPACE);
-        }
+        struct sway_workspace *ws = seat_get_focused_workspace(seat);
         if (!ws) {
                 wlr_log(WLR_DEBUG, "Bailing out, no workspace");
                 return;
         }
-        struct sway_container *output = ws->parent;
+        struct sway_output *output = ws->output;
         if (!output) {
                 wlr_log(WLR_DEBUG, "Bailing out, no output");
                 return;
@@ -255,30 +243,28 @@ void root_record_workspace_pid(pid_t pid) {
         pw->pid = pid;
         memcpy(&pw->time_added, &now, sizeof(struct timespec));
         pw->output_destroy.notify = pw_handle_output_destroy;
-        wl_signal_add(&output->sway_output->wlr_output->events.destroy,
-                        &pw->output_destroy);
+        wl_signal_add(&output->wlr_output->events.destroy, &pw->output_destroy);
         wl_list_insert(&pid_workspaces, &pw->link);
 }
 
-void root_for_each_workspace(void (*f)(struct sway_container *con, void *data),
+void root_for_each_workspace(void (*f)(struct sway_workspace *ws, void *data),
                 void *data) {
-        for (int i = 0; i < root_container.children->length; ++i) {
-                struct sway_container *output = root_container.children->items[i];
+        for (int i = 0; i < root->outputs->length; ++i) {
+                struct sway_output *output = root->outputs->items[i];
                 output_for_each_workspace(output, f, data);
         }
 }
 
 void root_for_each_container(void (*f)(struct sway_container *con, void *data),
                 void *data) {
-        for (int i = 0; i < root_container.children->length; ++i) {
-                struct sway_container *output = root_container.children->items[i];
+        for (int i = 0; i < root->outputs->length; ++i) {
+                struct sway_output *output = root->outputs->items[i];
                 output_for_each_container(output, f, data);
         }
 
         // Scratchpad
-        for (int i = 0; i < root_container.sway_root->scratchpad->length; ++i) {
-                struct sway_container *container =
-                        root_container.sway_root->scratchpad->items[i];
+        for (int i = 0; i < root->scratchpad->length; ++i) {
+                struct sway_container *container = root->scratchpad->items[i];
                 // If the container has a parent then it's visible on a workspace
                 // and will have been iterated in the previous for loop. So we only
                 // iterate the hidden scratchpad containers here.
@@ -289,10 +275,10 @@ void root_for_each_container(void (*f)(struct sway_container *con, void *data),
         }
 }
 
-struct sway_container *root_find_output(
-                bool (*test)(struct sway_container *con, void *data), void *data) {
-        for (int i = 0; i < root_container.children->length; ++i) {
-                struct sway_container *output = root_container.children->items[i];
+struct sway_output *root_find_output(
+                bool (*test)(struct sway_output *output, void *data), void *data) {
+        for (int i = 0; i < root->outputs->length; ++i) {
+                struct sway_output *output = root->outputs->items[i];
                 if (test(output, data)) {
                         return output;
                 }
@@ -300,11 +286,11 @@ struct sway_container *root_find_output(
         return NULL;
 }
 
-struct sway_container *root_find_workspace(
-                bool (*test)(struct sway_container *con, void *data), void *data) {
-        struct sway_container *result = NULL;
-        for (int i = 0; i < root_container.children->length; ++i) {
-                struct sway_container *output = root_container.children->items[i];
+struct sway_workspace *root_find_workspace(
+                bool (*test)(struct sway_workspace *ws, void *data), void *data) {
+        struct sway_workspace *result = NULL;
+        for (int i = 0; i < root->outputs->length; ++i) {
+                struct sway_output *output = root->outputs->items[i];
                 if ((result = output_find_workspace(output, test, data))) {
                         return result;
                 }
@@ -315,17 +301,16 @@ struct sway_container *root_find_workspace(
 struct sway_container *root_find_container(
                 bool (*test)(struct sway_container *con, void *data), void *data) {
         struct sway_container *result = NULL;
-        for (int i = 0; i < root_container.children->length; ++i) {
-                struct sway_container *output = root_container.children->items[i];
+        for (int i = 0; i < root->outputs->length; ++i) {
+                struct sway_output *output = root->outputs->items[i];
                 if ((result = output_find_container(output, test, data))) {
                         return result;
                 }
         }
 
         // Scratchpad
-        for (int i = 0; i < root_container.sway_root->scratchpad->length; ++i) {
-                struct sway_container *container =
-                        root_container.sway_root->scratchpad->items[i];
+        for (int i = 0; i < root->scratchpad->length; ++i) {
+                struct sway_container *container = root->scratchpad->items[i];
                 if (!container->parent) {
                         if (test(container, data)) {
                                 return container;
@@ -337,3 +322,10 @@ struct sway_container *root_find_container(
         }
         return NULL;
 }
+
+void root_get_box(struct sway_root *root, struct wlr_box *box) {
+        box->x = root->x;
+        box->y = root->y;
+        box->width = root->width;
+        box->height = root->height;
+}