Implement explicit unmapped window state tracking

8 files changed, 308 insertions, 153 deletions

diff --git a/niri-visual-tests/src/cases/layout.rs b/niri-visual-tests/src/cases/layout.rs
index ca8edcec..be611cc5 100644
--- a/niri-visual-tests/src/cases/layout.rs
+++ b/niri-visual-tests/src/cases/layout.rs
@@ -145,8 +145,7 @@ impl Layout {
     }
 
     fn add_window(&mut self, window: TestWindow, width: Option<ColumnWidth>) {
-        self.layout
-            .add_window(window.clone(), width.map(Some), false);
+        self.layout.add_window(window.clone(), width, false);
         if window.communicate() {
             self.layout.update_window(&window);
         }
@@ -160,7 +159,7 @@ impl Layout {
         width: Option<ColumnWidth>,
     ) {
         self.layout
-            .add_window_right_of(right_of, window.clone(), width.map(Some), false);
+            .add_window_right_of(right_of, window.clone(), width, false);
         if window.communicate() {
             self.layout.update_window(&window);
         }
diff --git a/src/handlers/compositor.rs b/src/handlers/compositor.rs
index 2d6a6406..a8ef5e2c 100644
--- a/src/handlers/compositor.rs
+++ b/src/handlers/compositor.rs
@@ -16,9 +16,9 @@ use smithay::wayland::dmabuf::get_dmabuf;
 use smithay::wayland::shm::{ShmHandler, ShmState};
 use smithay::{delegate_compositor, delegate_shm};
 
-use super::xdg_shell::{initial_configure_sent, resolve_window_rules};
 use crate::niri::{ClientState, State};
 use crate::utils::clone2;
+use crate::window::{InitialConfigureState, Unmapped};
 
 impl CompositorHandler for State {
     fn compositor_state(&mut self) -> &mut CompositorState {
@@ -105,29 +105,41 @@ impl CompositorHandler for State {
 
                 if is_mapped {
                     // The toplevel got mapped.
-                    let window = entry.remove();
+                    let Unmapped { window, state } = entry.remove();
+
                     window.on_commit();
 
+                    let (width, output) =
+                        if let InitialConfigureState::Configured { width, output, .. } = state {
+                            // Check that the output is still connected.
+                            let output =
+                                output.filter(|o| self.niri.layout.monitor_for_output(o).is_some());
+
+                            (width, output)
+                        } else {
+                            error!("window map must happen after initial configure");
+                            (None, None)
+                        };
+
                     let parent = window
                         .toplevel()
                         .parent()
                         .and_then(|parent| self.niri.layout.find_window_and_output(&parent))
-                        .map(|(win, _)| win.clone());
-
-                    let (width, output) = {
-                        let config = self.niri.config.borrow();
-                        let rules = resolve_window_rules(&config.window_rules, window.toplevel());
-                        let output = rules
-                            .open_on_output
-                            .and_then(|name| self.niri.output_by_name.get(name))
-                            .cloned();
-                        (rules.default_width, output)
-                    };
+                        // Only consider the parent if we configured the window for the same
+                        // output.
+                        //
+                        // Normally when we're following the parent, the configured output will be
+                        // None. If the configured output is set, that means it was set explicitly
+                        // by a window rule or a fullscreen request.
+                        .filter(|(_, parent_output)| {
+                            output.is_none() || output.as_ref() == Some(*parent_output)
+                        })
+                        .map(|(window, _)| window.clone());
 
                     let win = window.clone();
 
-                    // Open dialogs immediately to the right of their parent window.
                     let output = if let Some(p) = parent {
+                        // Open dialogs immediately to the right of their parent window.
                         self.niri.layout.add_window_right_of(&p, win, width, false)
                     } else if let Some(output) = &output {
                         self.niri
@@ -146,17 +158,10 @@ impl CompositorHandler for State {
                 }
 
                 // The toplevel remains unmapped.
-                let window = entry.get().clone();
-
-                // Send the initial configure in an idle, in case the client sent some more info
-                // after the initial commit.
-                if !initial_configure_sent(window.toplevel()) {
-                    self.niri.event_loop.insert_idle(move |state| {
-                        if !window.toplevel().alive() {
-                            return;
-                        }
-                        state.send_initial_configure_if_needed(&window);
-                    });
+                let unmapped = entry.get();
+                if unmapped.needs_initial_configure() {
+                    let toplevel = unmapped.window.toplevel().clone();
+                    self.queue_initial_configure(toplevel);
                 }
                 return;
             }
@@ -178,7 +183,12 @@ impl CompositorHandler for State {
                 if !is_mapped {
                     // The toplevel got unmapped.
                     self.niri.layout.remove_window(&window);
-                    self.niri.unmapped_windows.insert(surface.clone(), window);
+
+                    // Newly-unmapped toplevels must perform the initial commit-configure sequence
+                    // afresh.
+                    let unmapped = Unmapped::new(window);
+                    self.niri.unmapped_windows.insert(surface.clone(), unmapped);
+
                     self.niri.queue_redraw(output);
                     return;
                 }
diff --git a/src/handlers/xdg_shell.rs b/src/handlers/xdg_shell.rs
index c4ac6a06..04d4cc50 100644
--- a/src/handlers/xdg_shell.rs
+++ b/src/handlers/xdg_shell.rs
@@ -27,19 +27,7 @@ use smithay::{delegate_kde_decoration, delegate_xdg_decoration, delegate_xdg_she
 use crate::layout::workspace::ColumnWidth;
 use crate::niri::{PopupGrabState, State};
 use crate::utils::clone2;
-
-#[derive(Debug, Default)]
-pub struct ResolvedWindowRule<'a> {
-    /// Default width for this window.
-    ///
-    /// - `None`: unset.
-    /// - `Some(None)`: set to empty.
-    /// - `Some(Some(width))`: set to a particular width.
-    pub default_width: Option<Option<ColumnWidth>>,
-
-    /// Output to open this window on.
-    pub open_on_output: Option<&'a str>,
-}
+use crate::window::{InitialConfigureState, ResolvedWindowRules, Unmapped};
 
 fn window_matches(role: &XdgToplevelSurfaceRoleAttributes, m: &Match) -> bool {
     if let Some(app_id_re) = &m.app_id {
@@ -63,13 +51,13 @@ fn window_matches(role: &XdgToplevelSurfaceRoleAttributes, m: &Match) -> bool {
     true
 }
 
-pub fn resolve_window_rules<'a>(
-    rules: &'a [WindowRule],
+pub fn resolve_window_rules(
+    rules: &[WindowRule],
     toplevel: &ToplevelSurface,
-) -> ResolvedWindowRule<'a> {
+) -> ResolvedWindowRules {
     let _span = tracy_client::span!("resolve_window_rules");
 
-    let mut resolved = ResolvedWindowRule::default();
+    let mut resolved = ResolvedWindowRules::default();
 
     with_states(toplevel.wl_surface(), |states| {
         let role = states
@@ -79,6 +67,8 @@ pub fn resolve_window_rules<'a>(
             .lock()
             .unwrap();
 
+        let mut open_on_output = None;
+
         for rule in rules {
             if !(rule.matches.is_empty() || rule.matches.iter().any(|m| window_matches(&role, m))) {
                 continue;
@@ -97,9 +87,11 @@ pub fn resolve_window_rules<'a>(
             }
 
             if let Some(x) = rule.open_on_output.as_deref() {
-                resolved.open_on_output = Some(x);
+                open_on_output = Some(x);
             }
         }
+
+        resolved.open_on_output = open_on_output.map(|x| x.to_owned());
     });
 
     resolved
@@ -112,10 +104,8 @@ impl XdgShellHandler for State {
 
     fn new_toplevel(&mut self, surface: ToplevelSurface) {
         let wl_surface = surface.wl_surface().clone();
-        let window = Window::new(surface);
-
-        // At the moment of creation, xdg toplevels must have no buffer.
-        let existing = self.niri.unmapped_windows.insert(wl_surface, window);
+        let unmapped = Unmapped::new(Window::new(surface));
+        let existing = self.niri.unmapped_windows.insert(wl_surface, unmapped);
         assert!(existing.is_none());
     }
 
@@ -273,53 +263,42 @@ impl XdgShellHandler for State {
         surface: ToplevelSurface,
         wl_output: Option<wl_output::WlOutput>,
     ) {
-        if surface
-            .current_state()
-            .capabilities
-            .contains(xdg_toplevel::WmCapabilities::Fullscreen)
+        if let Some((window, current_output)) = self
+            .niri
+            .layout
+            .find_window_and_output(surface.wl_surface())
         {
-            if let Some((window, current_output)) = self
-                .niri
-                .layout
-                .find_window_and_output(surface.wl_surface())
-            {
-                let window = window.clone();
+            let window = window.clone();
 
-                if let Some(requested_output) = wl_output.as_ref().and_then(Output::from_resource) {
-                    if &requested_output != current_output {
-                        self.niri
-                            .layout
-                            .move_window_to_output(window.clone(), &requested_output);
-                    }
+            if let Some(requested_output) = wl_output.as_ref().and_then(Output::from_resource) {
+                if &requested_output != current_output {
+                    self.niri
+                        .layout
+                        .move_window_to_output(window.clone(), &requested_output);
                 }
+            }
 
-                self.niri.layout.set_fullscreen(&window, true);
-            } else if let Some(window) = self.niri.unmapped_windows.get(surface.wl_surface()) {
-                let config = self.niri.config.borrow();
-                let rules = resolve_window_rules(&config.window_rules, window.toplevel());
-
-                // FIXME: take requested output into account (will need to thread this through to
-                // send_initial_configure_if_needed and commit handler).
-                let output = rules
-                    .open_on_output
-                    .and_then(|name| self.niri.output_by_name.get(name));
-                let mon = output.map(|o| self.niri.layout.monitor_for_output(o).unwrap());
-                let ws = mon
-                    .map(|mon| mon.active_workspace_ref())
-                    .or_else(|| self.niri.layout.active_workspace());
-
-                if let Some(ws) = ws {
-                    window.toplevel().with_pending_state(|state| {
-                        state.size = Some(ws.view_size());
-                        state.states.set(xdg_toplevel::State::Fullscreen);
-                    });
+            self.niri.layout.set_fullscreen(&window, true);
+
+            // A configure is required in response to this event regardless if there are pending
+            // changes.
+            surface.send_configure();
+        } else if let Some(unmapped) = self.niri.unmapped_windows.get_mut(surface.wl_surface()) {
+            match &mut unmapped.state {
+                InitialConfigureState::NotConfigured { wants_fullscreen } => {
+                    *wants_fullscreen = Some(wl_output.as_ref().and_then(Output::from_resource));
+
+                    // The required configure will be the initial configure.
                 }
-            }
-        }
+                InitialConfigureState::Configured { .. } => {
+                    // FIXME: implement this once I figure out a good way without code duplication.
 
-        // A configure is required in response to this event. However, if an initial configure
-        // wasn't sent, then we will send this as part of the initial configure later.
-        if initial_configure_sent(&surface) {
+                    // We already sent the initial configure, so we need to reconfigure.
+                    surface.send_configure();
+                }
+            }
+        } else {
+            error!("couldn't find the toplevel in fullscreen_request()");
             surface.send_configure();
         }
     }
@@ -332,24 +311,27 @@ impl XdgShellHandler for State {
         {
             let window = window.clone();
             self.niri.layout.set_fullscreen(&window, false);
-        } else if let Some(window) = self.niri.unmapped_windows.get(surface.wl_surface()) {
-            let config = self.niri.config.borrow();
-            let rules = resolve_window_rules(&config.window_rules, window.toplevel());
-
-            let output = rules
-                .open_on_output
-                .and_then(|name| self.niri.output_by_name.get(name));
-            let mon = output.map(|o| self.niri.layout.monitor_for_output(o).unwrap());
-            let ws = mon
-                .map(|mon| mon.active_workspace_ref())
-                .or_else(|| self.niri.layout.active_workspace());
-
-            if let Some(ws) = ws {
-                window.toplevel().with_pending_state(|state| {
-                    state.size = Some(ws.new_window_size(rules.default_width));
-                    state.states.unset(xdg_toplevel::State::Fullscreen);
-                });
+
+            // A configure is required in response to this event regardless if there are pending
+            // changes.
+            surface.send_configure();
+        } else if let Some(unmapped) = self.niri.unmapped_windows.get_mut(surface.wl_surface()) {
+            match &mut unmapped.state {
+                InitialConfigureState::NotConfigured { wants_fullscreen } => {
+                    *wants_fullscreen = None;
+
+                    // The required configure will be the initial configure.
+                }
+                InitialConfigureState::Configured { .. } => {
+                    // FIXME: implement this once I figure out a good way without code duplication.
+
+                    // We already sent the initial configure, so we need to reconfigure.
+                    surface.send_configure();
+                }
             }
+        } else {
+            error!("couldn't find the toplevel in unfullscreen_request()");
+            surface.send_configure();
         }
     }
 
@@ -385,6 +367,14 @@ impl XdgShellHandler for State {
             self.niri.queue_redraw(output.clone());
         }
     }
+
+    fn app_id_changed(&mut self, toplevel: ToplevelSurface) {
+        self.update_window_rules(&toplevel);
+    }
+
+    fn title_changed(&mut self, toplevel: ToplevelSurface) {
+        self.update_window_rules(&toplevel);
+    }
 }
 
 delegate_xdg_shell!(State);
@@ -440,7 +430,7 @@ impl KdeDecorationHandler for State {
 
 delegate_kde_decoration!(State);
 
-pub fn initial_configure_sent(toplevel: &ToplevelSurface) -> bool {
+fn initial_configure_sent(toplevel: &ToplevelSurface) -> bool {
     with_states(toplevel.wl_surface(), |states| {
         states
             .data_map
@@ -453,28 +443,82 @@ pub fn initial_configure_sent(toplevel: &ToplevelSurface) -> bool {
 }
 
 impl State {
-    pub fn send_initial_configure_if_needed(&mut self, window: &Window) {
-        let toplevel = window.toplevel();
-        if initial_configure_sent(toplevel) {
+    pub fn send_initial_configure(&mut self, toplevel: &ToplevelSurface) {
+        let _span = tracy_client::span!("State::send_initial_configure");
+
+        let Some(unmapped) = self.niri.unmapped_windows.get_mut(toplevel.wl_surface()) else {
+            error!("window must be present in unmapped_windows in send_initial_configure()");
             return;
-        }
+        };
 
-        let _span = tracy_client::span!("State::send_initial_configure_if_needed");
+        let Unmapped { window, state } = unmapped;
+
+        let InitialConfigureState::NotConfigured { wants_fullscreen } = state else {
+            error!("window must not be already configured in send_initial_configure()");
+            return;
+        };
 
         let config = self.niri.config.borrow();
         let rules = resolve_window_rules(&config.window_rules, toplevel);
 
-        let output = rules
+        // Pick the target monitor. First, check if we had an output set in the window rules.
+        let mon = rules
             .open_on_output
-            .and_then(|name| self.niri.output_by_name.get(name));
-        let mon = output.map(|o| self.niri.layout.monitor_for_output(o).unwrap());
+            .as_deref()
+            .and_then(|name| self.niri.output_by_name.get(name))
+            .and_then(|o| self.niri.layout.monitor_for_output(o));
+
+        // If not, check if the window requested one for fullscreen.
+        let mon = mon.or_else(|| {
+            wants_fullscreen
+                .as_ref()
+                .and_then(|x| x.as_ref())
+                // The monitor might not exist if the output was disconnected.
+                .and_then(|o| self.niri.layout.monitor_for_output(o))
+        });
+
+        // If not, check if this is a dialog with a parent, to place it next to the parent.
+        let mon = mon.map(|mon| (mon, false)).or_else(|| {
+            toplevel
+                .parent()
+                .and_then(|parent| self.niri.layout.find_window_and_output(&parent))
+                .map(|(_win, output)| output)
+                .and_then(|o| self.niri.layout.monitor_for_output(o))
+                .map(|mon| (mon, true))
+        });
+
+        // If not, use the active monitor.
+        let mon = mon.or_else(|| {
+            self.niri
+                .layout
+                .active_monitor_ref()
+                .map(|mon| (mon, false))
+        });
+
+        // If we're following the parent, don't set the target output, so that when the window is
+        // mapped, it fetches the possibly changed parent's output again, and shows up there.
+        let output = mon
+            .filter(|(_, parent)| !parent)
+            .map(|(mon, _)| mon.output.clone());
+        let mon = mon.map(|(mon, _)| mon);
+
+        let mut width = None;
+
+        // Tell the surface the preferred size and bounds for its likely output.
         let ws = mon
             .map(|mon| mon.active_workspace_ref())
             .or_else(|| self.niri.layout.active_workspace());
 
-        // Tell the surface the preferred size and bounds for its likely output.
         if let Some(ws) = ws {
-            ws.configure_new_window(window, rules.default_width);
+            // Set a fullscreen state if requested.
+            if wants_fullscreen.is_some() {
+                toplevel.with_pending_state(|state| {
+                    state.states.set(xdg_toplevel::State::Fullscreen);
+                });
+            }
+
+            width = ws.resolve_default_width(rules.default_width);
+            ws.configure_new_window(window, width);
         }
 
         // If the user prefers no CSD, it's a reasonable assumption that they would prefer to get
@@ -488,9 +532,32 @@ impl State {
             });
         }
 
+        // Set the configured settings.
+        *state = InitialConfigureState::Configured {
+            rules,
+            width,
+            output,
+        };
+
         toplevel.send_configure();
     }
 
+    pub fn queue_initial_configure(&self, toplevel: ToplevelSurface) {
+        // Send the initial configure in an idle, in case the client sent some more info after the
+        // initial commit.
+        self.niri.event_loop.insert_idle(move |state| {
+            if !toplevel.alive() {
+                return;
+            }
+
+            if let Some(unmapped) = state.niri.unmapped_windows.get(toplevel.wl_surface()) {
+                if unmapped.needs_initial_configure() {
+                    state.send_initial_configure(&toplevel);
+                }
+            }
+        });
+    }
+
     /// Should be called on `WlSurface::commit`
     pub fn popups_handle_commit(&mut self, surface: &WlSurface) {
         self.niri.popups.commit(surface);
@@ -611,6 +678,16 @@ impl State {
             }
         }
     }
+
+    pub fn update_window_rules(&mut self, toplevel: &ToplevelSurface) {
+        let resolve = || resolve_window_rules(&self.niri.config.borrow().window_rules, toplevel);
+
+        if let Some(unmapped) = self.niri.unmapped_windows.get_mut(toplevel.wl_surface()) {
+            if let InitialConfigureState::Configured { rules, .. } = &mut unmapped.state {
+                *rules = resolve();
+            }
+        }
+    }
 }
 
 fn unconstrain_with_padding(
diff --git a/src/layout/mod.rs b/src/layout/mod.rs
index edc0d9de..c7239a2b 100644
--- a/src/layout/mod.rs
+++ b/src/layout/mod.rs
@@ -531,15 +531,10 @@ impl<W: LayoutElement> Layout<W> {
     pub fn add_window(
         &mut self,
         window: W,
-        width: Option<Option<ColumnWidth>>,
+        width: Option<ColumnWidth>,
         is_full_width: bool,
     ) -> Option<&Output> {
-        let width = match width {
-            Some(Some(width)) => Some(width),
-            Some(None) => None,
-            None => self.options.default_width,
-        }
-        .unwrap_or_else(|| ColumnWidth::Fixed(window.size().w));
+        let width = width.unwrap_or_else(|| ColumnWidth::Fixed(window.size().w));
 
         match &mut self.monitor_set {
             MonitorSet::Normal {
@@ -587,15 +582,10 @@ impl<W: LayoutElement> Layout<W> {
         &mut self,
         right_of: &W,
         window: W,
-        width: Option<Option<ColumnWidth>>,
+        width: Option<ColumnWidth>,
         is_full_width: bool,
     ) -> Option<&Output> {
-        let width = match width {
-            Some(Some(width)) => Some(width),
-            Some(None) => None,
-            None => self.options.default_width,
-        }
-        .unwrap_or_else(|| ColumnWidth::Fixed(window.size().w));
+        let width = width.unwrap_or_else(|| ColumnWidth::Fixed(window.size().w));
 
         match &mut self.monitor_set {
             MonitorSet::Normal { monitors, .. } => {
@@ -623,15 +613,10 @@ impl<W: LayoutElement> Layout<W> {
         &mut self,
         output: &Output,
         window: W,
-        width: Option<Option<ColumnWidth>>,
+        width: Option<ColumnWidth>,
         is_full_width: bool,
     ) {
-        let width = match width {
-            Some(Some(width)) => Some(width),
-            Some(None) => None,
-            None => self.options.default_width,
-        }
-        .unwrap_or_else(|| ColumnWidth::Fixed(window.size().w));
+        let width = width.unwrap_or_else(|| ColumnWidth::Fixed(window.size().w));
 
         let MonitorSet::Normal {
             monitors,
@@ -931,6 +916,19 @@ impl<W: LayoutElement> Layout<W> {
         Some(&mut monitors[*active_monitor_idx])
     }
 
+    pub fn active_monitor_ref(&self) -> Option<&Monitor<W>> {
+        let MonitorSet::Normal {
+            monitors,
+            active_monitor_idx,
+            ..
+        } = &self.monitor_set
+        else {
+            return None;
+        };
+
+        Some(&monitors[*active_monitor_idx])
+    }
+
     pub fn monitor_for_output(&self, output: &Output) -> Option<&Monitor<W>> {
         let MonitorSet::Normal { monitors, .. } = &self.monitor_set else {
             return None;
diff --git a/src/layout/workspace.rs b/src/layout/workspace.rs
index b9016098..79889ef2 100644
--- a/src/layout/workspace.rs
+++ b/src/layout/workspace.rs
@@ -322,17 +322,19 @@ impl<W: LayoutElement> Workspace<W> {
         ))
     }
 
-    pub fn new_window_size(
+    pub fn resolve_default_width(
         &self,
         default_width: Option<Option<ColumnWidth>>,
-    ) -> Size<i32, Logical> {
-        let default_width = match default_width {
+    ) -> Option<ColumnWidth> {
+        match default_width {
             Some(Some(width)) => Some(width),
             Some(None) => None,
             None => self.options.default_width,
-        };
+        }
+    }
 
-        let width = if let Some(width) = default_width {
+    pub fn new_window_size(&self, width: Option<ColumnWidth>) -> Size<i32, Logical> {
+        let width = if let Some(width) = width {
             let mut width = width.resolve(&self.options, self.working_area.size.w);
             if !self.options.border.off {
                 width -= self.options.border.width as i32 * 2;
@@ -350,11 +352,7 @@ impl<W: LayoutElement> Workspace<W> {
         Size::from((width, max(height, 1)))
     }
 
-    pub fn configure_new_window(
-        &self,
-        window: &Window,
-        default_width: Option<Option<ColumnWidth>>,
-    ) {
+    pub fn configure_new_window(&self, window: &Window, width: Option<ColumnWidth>) {
         if let Some(output) = self.output.as_ref() {
             set_preferred_scale_transform(window, output);
         }
@@ -363,7 +361,7 @@ impl<W: LayoutElement> Workspace<W> {
             if state.states.contains(xdg_toplevel::State::Fullscreen) {
                 state.size = Some(self.view_size);
             } else {
-                state.size = Some(self.new_window_size(default_width));
+                state.size = Some(self.new_window_size(width));
             }
 
             state.bounds = Some(self.toplevel_bounds());
diff --git a/src/lib.rs b/src/lib.rs
index 26f1277b..fdf588b3 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -17,6 +17,7 @@ pub mod protocols;
 pub mod render_helpers;
 pub mod ui;
 pub mod utils;
+pub mod window;
 
 #[cfg(not(feature = "xdp-gnome-screencast"))]
 pub mod dummy_pw_utils;
diff --git a/src/niri.rs b/src/niri.rs
index 4e89e269..ed52a2ae 100644
--- a/src/niri.rs
+++ b/src/niri.rs
@@ -107,6 +107,7 @@ use crate::ui::screenshot_ui::{ScreenshotUi, ScreenshotUiRenderElement};
 use crate::utils::{
     center, get_monotonic_time, make_screenshot_path, output_size, write_png_rgba8,
 };
+use crate::window::Unmapped;
 use crate::{animation, niri_render_elements};
 
 const CLEAR_COLOR: [f32; 4] = [0.2, 0.2, 0.2, 1.];
@@ -132,7 +133,7 @@ pub struct Niri {
     pub global_space: Space<Window>,
 
     // Windows which don't have a buffer attached yet.
-    pub unmapped_windows: HashMap<WlSurface, Window>,
+    pub unmapped_windows: HashMap<WlSurface, Unmapped>,
 
     pub output_state: HashMap<Output, OutputState>,
     pub output_by_name: HashMap<String, Output>,
diff --git a/src/window.rs b/src/window.rs
new file mode 100644
index 00000000..68d1e3a0
--- /dev/null
+++ b/src/window.rs
@@ -0,0 +1,71 @@
+use smithay::desktop::Window;
+use smithay::output::Output;
+
+use crate::layout::workspace::ColumnWidth;
+
+#[derive(Debug)]
+pub struct Unmapped {
+    pub window: Window,
+    pub state: InitialConfigureState,
+}
+
+#[derive(Debug)]
+pub enum InitialConfigureState {
+    /// The window has not been initially configured yet.
+    NotConfigured {
+        /// Whether the window requested to be fullscreened, and the requested output, if any.
+        wants_fullscreen: Option<Option<Output>>,
+    },
+    /// The window has been configured.
+    Configured {
+        /// Up-to-date rules.
+        ///
+        /// We start tracking window rules when sending the initial configure, since they don't
+        /// affect anything before that.
+        rules: ResolvedWindowRules,
+
+        /// Resolved default width for this window.
+        ///
+        /// `None` means that the window will pick its own width.
+        width: Option<ColumnWidth>,
+
+        /// Output to open this window on.
+        ///
+        /// This can be `None` in cases like:
+        ///
+        /// - There are no outputs connected.
+        /// - This is a dialog with a parent, and there was no explicit output set, so this dialog
+        ///   should fetch the parent's current output again upon mapping.
+        output: Option<Output>,
+    },
+}
+
+/// Rules fully resolved for a window.
+#[derive(Debug, Default)]
+pub struct ResolvedWindowRules {
+    /// Default width for this window.
+    ///
+    /// - `None`: unset (global default should be used).
+    /// - `Some(None)`: set to empty (window picks its own width).
+    /// - `Some(Some(width))`: set to a particular width.
+    pub default_width: Option<Option<ColumnWidth>>,
+
+    /// Output to open this window on.
+    pub open_on_output: Option<String>,
+}
+
+impl Unmapped {
+    /// Wraps a newly created window that hasn't been initially configured yet.
+    pub fn new(window: Window) -> Self {
+        Self {
+            window,
+            state: InitialConfigureState::NotConfigured {
+                wants_fullscreen: None,
+            },
+        }
+    }
+
+    pub fn needs_initial_configure(&self) -> bool {
+        matches!(self.state, InitialConfigureState::NotConfigured { .. })
+    }
+}