tree/view: Send configure before mapping

Sending 0,0 as configure dimensions indicate that the client is free to
pick its own dimensions. When tiling, the client needs to strictly
adhere to the tile dimensions. Sway's handling of this has been to send
a the appropriate dimensions in a new configure when the surface is
mapped, leading to the first buffer most likely being incorrectly sized.

Move the majority of the mapping logic to view_premap, issued on the
initial role commit rather than when mapping the view. This allow the
first configure to be driven by a tree transaction with the appropriate
geometr, and allows container siblings to start preparing earlier as
well, reducing the new window latency.

Fixes: swaywm#2176

include/sway/tree/view.h

@@ -286,15 +286,29 @@ void view_destroy(struct sway_view *view);
 void view_begin_destroy(struct sway_view *view);
 
 /**
- * Map a view, ie. make it visible in the tree.
+ * Perform post-map setup like updating focus. view_setup must be called before
+ * calling view_map.
+ */
+void view_map(struct sway_view *view, struct wlr_surface *wlr_surface);
+
+/**
+ * Prepare the view for its upcoming mapping, sending the intended dimensions
+ * so that the first frame has a chance of being correct. If CSD preferences or
+ * floating tendency changes, this may turn out to be inaccurate but no worse
+ * than skipping the step.
+ *
+ * This may bail early for some views if the surface is not mapped, in which
+ * case it should be called again before view_map once the surface is mapped.
+ * It is safe to call view_setup adancegain even if the first call before
+ * surface map succeeded.
  *
  * `fullscreen` should be set to true (and optionally `fullscreen_output`
  * should be populated) if the view should be made fullscreen immediately.
  *
  * `decoration` should be set to true if the client prefers CSD. The client's
  * preference may be ignored.
  */
-void view_map(struct sway_view *view, struct wlr_surface *wlr_surface,
+void view_setup(struct sway_view *view, struct wlr_surface *wlr_surface,
 	bool fullscreen, struct wlr_output *fullscreen_output, bool decoration);
 
 void view_unmap(struct sway_view *view);

sway/desktop/xdg_shell.c

@@ -277,6 +277,20 @@ static const struct sway_view_impl view_impl = {
 	.destroy = destroy,
 };
 
+static bool view_wants_csd(struct sway_view *view) {
+	struct wlr_xdg_toplevel *toplevel = view->wlr_xdg_toplevel;
+	struct wlr_xdg_surface *xdg_surface = toplevel->base;
+	if (view->xdg_decoration) {
+		enum wlr_xdg_toplevel_decoration_v1_mode mode =
+			view->xdg_decoration->wlr_xdg_decoration->requested_mode;
+		return mode == WLR_XDG_TOPLEVEL_DECORATION_V1_MODE_CLIENT_SIDE;
+	}
+	struct sway_server_decoration *deco =
+			decoration_from_surface(xdg_surface->surface);
+	return !deco || deco->wlr_server_decoration->mode ==
+		WLR_SERVER_DECORATION_MANAGER_MODE_CLIENT;
+}
+
 static void handle_commit(struct wl_listener *listener, void *data) {
 	struct sway_xdg_shell_view *xdg_shell_view =
 		wl_container_of(listener, xdg_shell_view, commit);
@@ -287,10 +301,14 @@ static void handle_commit(struct wl_listener *listener, void *data) {
 		if (view->xdg_decoration != NULL) {
 			set_xdg_decoration_mode(view->xdg_decoration);
 		}
-		// XXX: https://github.com/swaywm/sway/issues/2176
+
 		wlr_xdg_surface_schedule_configure(xdg_surface);
 		wlr_xdg_toplevel_set_wm_capabilities(view->wlr_xdg_toplevel,
 			XDG_TOPLEVEL_WM_CAPABILITIES_FULLSCREEN);
+		view_setup(&xdg_shell_view->view, xdg_surface->surface, false, NULL,
+			view_wants_csd(&xdg_shell_view->view));
+		transaction_commit_dirty();
+
 		// TODO: wlr_xdg_toplevel_set_bounds()
 		return;
 	}
@@ -465,23 +483,8 @@ static void handle_map(struct wl_listener *listener, void *data) {
 	view->natural_width = toplevel->base->geometry.width;
 	view->natural_height = toplevel->base->geometry.height;
 
-	bool csd = false;
-
-	if (view->xdg_decoration) {
-		enum wlr_xdg_toplevel_decoration_v1_mode mode =
-			view->xdg_decoration->wlr_xdg_decoration->requested_mode;
-		csd = mode == WLR_XDG_TOPLEVEL_DECORATION_V1_MODE_CLIENT_SIDE;
-	} else {
-		struct sway_server_decoration *deco =
-				decoration_from_surface(toplevel->base->surface);
-		csd = !deco || deco->wlr_server_decoration->mode ==
-			WLR_SERVER_DECORATION_MANAGER_MODE_CLIENT;
-	}
-
-	view_map(view, toplevel->base->surface,
-		toplevel->requested.fullscreen,
-		toplevel->requested.fullscreen_output,
-		csd);
+	view_setup(view, toplevel->base->surface, false, NULL, view_wants_csd(view));
+	view_map(view, toplevel->base->surface);
 
 	transaction_commit_dirty();
 
@@ -518,7 +521,8 @@ static void handle_destroy(struct wl_listener *listener, void *data) {
 	struct sway_xdg_shell_view *xdg_shell_view =
 		wl_container_of(listener, xdg_shell_view, destroy);
 	struct sway_view *view = &xdg_shell_view->view;
-	if (!sway_assert(view->surface == NULL, "Tried to destroy a mapped view")) {
+	if (!sway_assert(view->surface == NULL ||
+			!view->surface->mapped, "Tried to destroy a mapped view")) {
 		return;
 	}
 	wl_list_remove(&xdg_shell_view->destroy.link);

sway/desktop/xwayland.c

@@ -526,7 +526,8 @@ static void handle_map(struct wl_listener *listener, void *data) {
 	xwayland_view->commit.notify = handle_commit;
 
 	// Put it back into the tree
-	view_map(view, xsurface->surface, xsurface->fullscreen, NULL, false);
+	view_setup(view, xsurface->surface, xsurface->fullscreen, NULL, false);
+	view_map(view, xsurface->surface);
 
 	xwayland_view->surface_tree = wlr_scene_subsurface_tree_create(
 		xwayland_view->view.content_tree, xsurface->surface);

sway/tree/view.c

@@ -714,12 +714,23 @@ static void handle_foreign_destroy(
 	wl_list_remove(&view->foreign_destroy.link);
 }
 
-void view_map(struct sway_view *view, struct wlr_surface *wlr_surface,
+void view_setup(struct sway_view *view, struct wlr_surface *wlr_surface,
 			  bool fullscreen, struct wlr_output *fullscreen_output,
 			  bool decoration) {
-	if (!sway_assert(view->surface == NULL, "cannot map mapped view")) {
+	if (view->surface) {
+		// Setup has already already completed
 		return;
 	}
+	if (!wlr_surface->mapped && view->impl->wants_floating &&
+			view->impl->wants_floating(view)) {
+		// Configuring floating containers before the surface is mapped lead to
+		// us accidentally sending the configured minimum dimensions, which we
+		// only want to send if the client comes up with unreasonably small
+		// dimensions. As a hack, just skip this scenario for now and have the
+		// caller call view_setup again after the surface has been mapped.
+		return;
+	}
+
 	view->surface = wlr_surface;
 	view_populate_pid(view);
 	view->container = container_create(view);
@@ -846,6 +857,24 @@ void view_map(struct sway_view *view, struct wlr_surface *wlr_surface,
 
 	view_execute_criteria(view);
 
+	const char *app_id;
+	const char *class;
+	if ((app_id = view_get_app_id(view)) != NULL) {
+		wlr_foreign_toplevel_handle_v1_set_app_id(view->foreign_toplevel, app_id);
+	} else if ((class = view_get_class(view)) != NULL) {
+		wlr_foreign_toplevel_handle_v1_set_app_id(view->foreign_toplevel, class);
+	}
+
+	if (view->ext_foreign_toplevel) {
+		update_ext_foreign_toplevel(view);
+	}
+}
+
+void view_map(struct sway_view *view, struct wlr_surface *wlr_surface) {
+	if (!sway_assert(view->surface != NULL, "cannot map view that has not been setup")) {
+		return;
+	}
+
 	bool set_focus = should_focus(view);
 
 #if WLR_HAS_XWAYLAND
@@ -859,18 +888,6 @@ void view_map(struct sway_view *view, struct wlr_surface *wlr_surface,
 	if (set_focus) {
 		input_manager_set_focus(&view->container->node);
 	}
-
-	if (view->ext_foreign_toplevel) {
-		update_ext_foreign_toplevel(view);
-	}
-
-	const char *app_id;
-	const char *class;
-	if ((app_id = view_get_app_id(view)) != NULL) {
-		wlr_foreign_toplevel_handle_v1_set_app_id(view->foreign_toplevel, app_id);
-	} else if ((class = view_get_class(view)) != NULL) {
-		wlr_foreign_toplevel_handle_v1_set_app_id(view->foreign_toplevel, class);
-	}
 }
 
 void view_unmap(struct sway_view *view) {