From c27bf4d597294cee0d196c4fb4356e34659fa0dc Mon Sep 17 00:00:00 2001
From: Julian Orth <ju.orth@gmail.com>
Date: Thu, 25 Apr 2024 19:52:26 +0200
Subject: [PATCH] wayland: allow binding to removed outputs

---
 src/globals.rs                      | 21 +++++++++-
 src/ifs/wl_output.rs                |  6 ++-
 src/ifs/wl_output/removed_output.rs | 63 +++++++++++++++++++++++++++++
 src/state.rs                        |  4 +-
 4 files changed, 89 insertions(+), 5 deletions(-)
 create mode 100644 src/ifs/wl_output/removed_output.rs

diff --git a/src/globals.rs b/src/globals.rs
index e73fe0bf..41aeb925 100644
--- a/src/globals.rs
+++ b/src/globals.rs
@@ -127,6 +127,7 @@ pub trait Global: GlobalBase {
 pub struct Globals {
     next_name: NumCell<u32>,
     registry: CopyHashMap<GlobalName, Rc<dyn Global>>,
+    removed: CopyHashMap<GlobalName, Rc<dyn Global>>,
     pub outputs: CopyHashMap<GlobalName, Rc<WlOutputGlobal>>,
     pub seats: CopyHashMap<GlobalName, Rc<WlSeatGlobal>>,
 }
@@ -136,6 +137,7 @@ impl Globals {
         let slf = Self {
             next_name: NumCell::new(1),
             registry: CopyHashMap::new(),
+            removed: CopyHashMap::new(),
             outputs: Default::default(),
             seats: Default::default(),
         };
@@ -241,9 +243,17 @@ impl Globals {
         Ok(global)
     }
 
-    pub fn remove<T: WaylandGlobal>(&self, state: &State, global: &T) -> Result<(), GlobalsError> {
+    pub fn remove<T: RemovableWaylandGlobal>(
+        &self,
+        state: &State,
+        global: &T,
+    ) -> Result<(), GlobalsError> {
         let _global = self.take(global.name(), true)?;
         global.remove(self);
+        let replacement = global.create_replacement();
+        assert_eq!(global.name(), replacement.name());
+        assert_eq!(global.interface().0, replacement.interface().0);
+        self.removed.set(global.name(), replacement);
         self.broadcast(state, global.required_caps(), global.xwayland_only(), |r| {
             r.send_global_remove(global.name())
         });
@@ -295,7 +305,10 @@ impl Globals {
         let res = if remove {
             self.registry.remove(&name)
         } else {
-            self.registry.get(&name)
+            match self.registry.get(&name) {
+                Some(res) => Some(res),
+                _ => self.removed.get(&name),
+            }
         };
         match res {
             Some(g) => Ok(g),
@@ -330,3 +343,7 @@ pub trait WaylandGlobal: Global + 'static {
         let _ = globals;
     }
 }
+
+pub trait RemovableWaylandGlobal: WaylandGlobal {
+    fn create_replacement(&self) -> Rc<dyn Global>;
+}
diff --git a/src/ifs/wl_output.rs b/src/ifs/wl_output.rs
index 52cee8cd..0e9c5ea8 100644
--- a/src/ifs/wl_output.rs
+++ b/src/ifs/wl_output.rs
@@ -1,3 +1,5 @@
+mod removed_output;
+
 use {
     crate::{
         backend,
@@ -229,13 +231,15 @@ impl WlOutputGlobal {
 
 global_base!(WlOutputGlobal, WlOutput, WlOutputError);
 
+const OUTPUT_VERSION: u32 = 4;
+
 impl Global for WlOutputGlobal {
     fn singleton(&self) -> bool {
         false
     }
 
     fn version(&self) -> u32 {
-        4
+        OUTPUT_VERSION
     }
 
     fn break_loops(&self) {
diff --git a/src/ifs/wl_output/removed_output.rs b/src/ifs/wl_output/removed_output.rs
new file mode 100644
index 00000000..67072aec
--- /dev/null
+++ b/src/ifs/wl_output/removed_output.rs
@@ -0,0 +1,63 @@
+use {
+    crate::{
+        client::{Client, ClientError},
+        globals::{Global, GlobalName, RemovableWaylandGlobal},
+        ifs::wl_output::{WlOutput, WlOutputGlobal, OUTPUT_VERSION},
+        object::Version,
+        wire::WlOutputId,
+    },
+    std::rc::Rc,
+    thiserror::Error,
+};
+
+struct RemovedOutputGlobal {
+    name: GlobalName,
+}
+
+impl RemovedOutputGlobal {
+    fn bind_(
+        self: Rc<Self>,
+        id: WlOutputId,
+        client: &Rc<Client>,
+        version: Version,
+    ) -> Result<(), RemovedOutputError> {
+        let obj = Rc::new(WlOutput {
+            global: Default::default(),
+            id,
+            xdg_outputs: Default::default(),
+            client: client.clone(),
+            version,
+            tracker: Default::default(),
+        });
+        track!(client, obj);
+        client.add_client_obj(&obj)?;
+        Ok(())
+    }
+}
+
+global_base!(RemovedOutputGlobal, WlOutput, RemovedOutputError);
+
+impl Global for RemovedOutputGlobal {
+    fn singleton(&self) -> bool {
+        false
+    }
+
+    fn version(&self) -> u32 {
+        OUTPUT_VERSION
+    }
+}
+
+simple_add_global!(RemovedOutputGlobal);
+
+impl RemovableWaylandGlobal for WlOutputGlobal {
+    fn create_replacement(&self) -> Rc<dyn Global> {
+        Rc::new(RemovedOutputGlobal { name: self.name })
+    }
+}
+
+#[derive(Debug, Error)]
+enum RemovedOutputError {
+    #[error(transparent)]
+    ClientError(Box<ClientError>),
+}
+efrom!(RemovedOutputError, ClientError);
diff --git a/src/state.rs b/src/state.rs
index fe49b79e..be8797f7 100644
--- a/src/state.rs
+++ b/src/state.rs
@@ -22,7 +22,7 @@ use {
             SyncFile,
         },
         gfx_apis::create_gfx_context,
-        globals::{Globals, GlobalsError, WaylandGlobal},
+        globals::{Globals, GlobalsError, RemovableWaylandGlobal, WaylandGlobal},
         ifs::{
             ext_foreign_toplevel_list_v1::ExtForeignToplevelListV1,
             ext_session_lock_v1::ExtSessionLockV1,
@@ -511,7 +511,7 @@ impl State {
         self.globals.add_global(self, global)
     }
 
-    pub fn remove_global<T: WaylandGlobal>(&self, global: &T) -> Result<(), GlobalsError> {
+    pub fn remove_global<T: RemovableWaylandGlobal>(&self, global: &T) -> Result<(), GlobalsError> {
         self.globals.remove(self, global)
     }