Add workspace_overview_is_open function; put in a utils::quirks mod

This is increasingly not just related to screencopy, so it's weird to
add there. I don't see any other module that fits, so add one called
"quirks" (like the Linux kernel uses for device-specific handling in
generic drives).

src/backend/kms/surface/mod.rs

@@ -7,11 +7,9 @@ use crate::{
     },
     shell::Shell,
     state::SurfaceDmabufFeedback,
-    utils::prelude::*,
+    utils::{prelude::*, quirks::workspace_overview_is_open},
     wayland::{
-        handlers::screencopy::{
-            submit_buffer, FrameHolder, SessionData, WORKSPACE_OVERVIEW_NAMESPACE,
-        },
+        handlers::screencopy::{submit_buffer, FrameHolder, SessionData},
         protocols::screencopy::{
             FailureReason, Frame as ScreencopyFrame, Session as ScreencopySession,
         },
@@ -48,7 +46,7 @@ use smithay::{
             Bind, ImportDma, Offscreen, Renderer, Texture,
         },
     },
-    desktop::{layer_map_for_output, utils::OutputPresentationFeedback},
+    desktop::utils::OutputPresentationFeedback,
     output::{Output, OutputNoMode},
     reexports::{
         calloop::{
@@ -871,10 +869,7 @@ impl SurfaceThreadState {
 
             std::mem::drop(shell);
 
-            let element_filter = if layer_map_for_output(output)
-                .layers()
-                .any(|s| s.namespace() == WORKSPACE_OVERVIEW_NAMESPACE)
-            {
+            let element_filter = if workspace_overview_is_open(output) {
                 ElementFilter::LayerShellOnly
             } else {
                 ElementFilter::All

src/backend/render/mod.rs

@@ -20,11 +20,11 @@ use crate::{
         CosmicMappedRenderElement, OverviewMode, SeatExt, SessionLock, Trigger, WorkspaceDelta,
         WorkspaceRenderElement,
     },
-    utils::prelude::*,
+    utils::{prelude::*, quirks::WORKSPACE_OVERVIEW_NAMESPACE},
     wayland::{
         handlers::{
             data_device::get_dnd_icon,
-            screencopy::{render_session, FrameHolder, SessionData, WORKSPACE_OVERVIEW_NAMESPACE},
+            screencopy::{render_session, FrameHolder, SessionData},
         },
         protocols::workspace::WorkspaceHandle,
     },

src/shell/mod.rs

@@ -52,11 +52,11 @@ use smithay::{
 use crate::{
     backend::render::animations::spring::{Spring, SpringParams},
     config::Config,
-    utils::prelude::*,
+    utils::{prelude::*, quirks::WORKSPACE_OVERVIEW_NAMESPACE},
     wayland::{
         handlers::{
-            screencopy::WORKSPACE_OVERVIEW_NAMESPACE, toplevel_management::minimize_rectangle,
-            xdg_activation::ActivationContext, xdg_shell::popup::get_popup_toplevel,
+            toplevel_management::minimize_rectangle, xdg_activation::ActivationContext,
+            xdg_shell::popup::get_popup_toplevel,
         },
         protocols::{
             toplevel_info::{

src/utils/mod.rs

@@ -5,6 +5,7 @@ pub(crate) use self::ids::id_gen;
 pub mod geometry;
 pub mod iced;
 pub mod prelude;
+pub mod quirks;
 pub mod rlimit;
 pub mod screenshot;
 pub mod tween;

src/utils/quirks.rs

@@ -0,0 +1,14 @@
+// SPDX-License-Identifier: GPL-3.0-only
+
+use smithay::{desktop::layer_map_for_output, output::Output};
+
+/// Layer shell namespace used by `cosmic-workspaces`
+// TODO: Avoid special case, or add protocol to expose required behavior
+pub const WORKSPACE_OVERVIEW_NAMESPACE: &str = "cosmic-workspace-overview";
+
+/// Check if a workspace overview shell surface is open on the output
+pub fn workspace_overview_is_open(output: &Output) -> bool {
+    layer_map_for_output(output)
+        .layers()
+        .any(|s| s.namespace() == WORKSPACE_OVERVIEW_NAMESPACE)
+}

src/wayland/handlers/screencopy/mod.rs

@@ -39,8 +39,6 @@ pub use self::render::*;
 use self::user_data::*;
 pub use self::user_data::{FrameHolder, ScreencopySessions, SessionData, SessionHolder};
 
-pub const WORKSPACE_OVERVIEW_NAMESPACE: &str = "cosmic-workspace-overview";
-
 impl ScreencopyHandler for State {
     fn screencopy_state(&mut self) -> &mut ScreencopyState {
         &mut self.common.screencopy_state