layer-shell: allow surfaces larger than the output

The motivation for this change is to simplify the implementation
and remove a massive footgun that is currently present and causing
UB/crashes. If a layer surface is destroyed in arrangeLayers() then
the code in LayerSurface.handleCommit() after the arrangeLayers()
call accesses free'd memory. This is of course possible to fix,
but it's far simpler to loosen up the protocol implementation a bit.

The new implementation is also in line with what sway and the new
wlroots layer shell helper do and is perfectly valid according to
the protocol.

1 files changed, 2 insertions, 22 deletions

diff --git a/river/Output.zig b/river/Output.zig
index 4ec4d0d..6f7a76a 100644
--- a/river/Output.zig
+++ b/river/Output.zig
@@ -308,17 +308,7 @@ fn arrangeLayer(
         var new_box: Box = undefined;
 
         // Horizontal alignment
-        const horizontal_margin_size = current_state.margin.left + current_state.margin.right;
-        if (horizontal_margin_size + current_state.desired_width > bounds.width) {
-            std.log.scoped(.layer_shell).warn(
-                "margins of layer surface '{s}' are too large to be reasonably handled. Closing.",
-                .{layer_surface.wlr_layer_surface.namespace},
-            );
-            // This will cause the output to be rearranged, so it's fine to
-            // stop this attempt early.
-            layer_surface.wlr_layer_surface.destroy();
-            return;
-        } else if (current_state.desired_width == 0) {
+        if (current_state.desired_width == 0) {
             assert(current_state.anchor.right and current_state.anchor.left);
             new_box.x = bounds.x + @intCast(i32, current_state.margin.left);
             new_box.width = bounds.width - (current_state.margin.left + current_state.margin.right);
@@ -336,17 +326,7 @@ fn arrangeLayer(
         }
 
         // Vertical alignment
-        const vertical_margin_size = current_state.margin.bottom + current_state.margin.top;
-        if (vertical_margin_size + current_state.desired_height > bounds.height) {
-            std.log.scoped(.layer_shell).warn(
-                "margins of layer surface '{s}' are too large to be reasonably handled. Closing.",
-                .{layer_surface.wlr_layer_surface.namespace},
-            );
-            layer_surface.wlr_layer_surface.destroy();
-            // This will cause the output to be rearranged, so it's fine to
-            // stop this attempt early.
-            return;
-        } else if (current_state.desired_height == 0) {
+        if (current_state.desired_height == 0) {
             assert(current_state.anchor.top and current_state.anchor.bottom);
             new_box.y = bounds.y + @intCast(i32, current_state.margin.top);
             new_box.height = bounds.height - (current_state.margin.top + current_state.margin.bottom);