Checkpoint: preserve all uncommitted rust-rewrite worktree work

Safety commit before reconciling this worktree with main, which has
diverged with its own separate fixes today. Nothing here is reviewed
or curated yet - this exists purely so none of this work can be lost
to a git operation, disk issue, or worktree cleanup while that
reconciliation happens.

1 files changed, 63 insertions, 0 deletions

diff --git a/crates/wayland/src/protocols/xdg_decoration.rs b/crates/wayland/src/protocols/xdg_decoration.rs
new file mode 100644
index 0000000..25973c0
--- /dev/null
+++ b/crates/wayland/src/protocols/xdg_decoration.rs
@@ -0,0 +1,63 @@
+//! `zxdg_decoration_manager_v1`: negotiates whether a toplevel draws its own
+//! (client-side) chrome or lets us draw it (server-side).
+
+use smithay::reexports::wayland_protocols::xdg::decoration::zv1::server::zxdg_toplevel_decoration_v1::Mode as DecorationMode;
+use smithay::wayland::shell::xdg::decoration::XdgDecorationHandler;
+use smithay::wayland::shell::xdg::ToplevelSurface;
+
+use crate::state::CompState;
+
+impl XdgDecorationHandler for CompState {
+    /// Offers whichever mode `theme.decorations.default_mode`/`srd set
+    /// decoration_mode` currently prefers - a client with a real opinion
+    /// of its own still overrides this via `request_mode` below regardless
+    /// of what's offered here; this only decides what a client with *no*
+    /// preference ends up with. See `srdwm_core::ThemeConfig::
+    /// default_decorated`'s own doc comment for why this is configurable
+    /// rather than hardcoded to one mode.
+    fn new_decoration(&mut self, toplevel: ToplevelSurface) {
+        let offer = if self.wm.borrow().theme.default_decorated { DecorationMode::ServerSide } else { DecorationMode::ClientSide };
+        toplevel.with_pending_state(|state| {
+            state.decoration_mode = Some(offer);
+        });
+    }
+
+    /// Honors whichever mode the client actually asked for, rather than
+    /// always forcing server-side - and mirrors the result into our own
+    /// `Window.decorated`, so a client drawing its own titlebar doesn't
+    /// *also* get one drawn on top of it by us.
+    ///
+    /// Always forcing `ServerSide` (what this used to do) is why some
+    /// clients ended up with two sets of window buttons: Firefox requests
+    /// client-side decoration when its own "use system titlebar" setting
+    /// is off, and draws its own close/minimize/maximize row regardless of
+    /// what the compositor grants - so forcing server-side just added
+    /// srdwm's row on top of the one Firefox was drawing anyway, instead
+    /// of preventing it. Respecting the request means srdwm steps out of
+    /// the way for exactly those clients, while everything that accepts
+    /// (or has no preference and gets offered) server-side still gets our
+    /// titlebar as before.
+    fn request_mode(&mut self, toplevel: ToplevelSurface, mode: DecorationMode) {
+        toplevel.with_pending_state(|state| {
+            state.decoration_mode = Some(mode);
+        });
+        toplevel.send_configure();
+        self.set_decorated_from_mode(toplevel.wl_surface(), mode == DecorationMode::ServerSide);
+    }
+
+    /// The client dropped its decoration-mode preference. `new_decoration`
+    /// already offers the configured default as the mode the next
+    /// configure will carry, so mirror that same default here rather than
+    /// leaving whatever mode was negotiated before this - otherwise a
+    /// client that requests one mode, then later unsets it expecting the
+    /// default back, would stay stuck in that mode forever.
+    fn unset_mode(&mut self, toplevel: ToplevelSurface) {
+        let default_decorated = self.wm.borrow().theme.default_decorated;
+        let mode = if default_decorated { DecorationMode::ServerSide } else { DecorationMode::ClientSide };
+        toplevel.with_pending_state(|state| {
+            state.decoration_mode = Some(mode);
+        });
+        toplevel.send_configure();
+        self.set_decorated_from_mode(toplevel.wl_surface(), default_decorated);
+    }
+}