From 385ba6bf3a37ebf462cacdfb46501b7e6170570f Mon Sep 17 00:00:00 2001
From: Adrien Prokopowicz <adrien.prokopowicz@gmail.com>
Date: Wed, 27 Mar 2024 19:20:40 +0100
Subject: [PATCH] wip

---
 src/x11/visual_info.rs    |  2 +-
 src/x11/window.rs         | 25 +++++++++++++------------
 src/x11/xcb_connection.rs | 13 +++++++++----
 3 files changed, 23 insertions(+), 17 deletions(-)

diff --git a/src/x11/visual_info.rs b/src/x11/visual_info.rs
index 602b2f0..3f1be38 100644
--- a/src/x11/visual_info.rs
+++ b/src/x11/visual_info.rs
@@ -63,7 +63,7 @@ impl WindowVisualConfig {
 
 // For this 32-bit depth to work, you also need to define a color map and set a border
 // pixel: https://cgit.freedesktop.org/xorg/xserver/tree/dix/window.c#n818
-pub fn create_color_map(
+fn create_color_map(
     connection: &XcbConnection, visual_id: Visualid,
 ) -> Result<Colormap, Box<dyn Error>> {
     let colormap = connection.conn.generate_id()?;
diff --git a/src/x11/window.rs b/src/x11/window.rs
index 86af03c..7658d7e 100644
--- a/src/x11/window.rs
+++ b/src/x11/window.rs
@@ -1,3 +1,4 @@
+use std::cell::Cell;
 use std::error::Error;
 use std::ffi::c_void;
 use std::os::fd::AsRawFd;
@@ -101,11 +102,11 @@ struct WindowInner {
     window_id: XWindow,
     window_info: WindowInfo,
     visual_id: Visualid,
-    mouse_cursor: MouseCursor,
+    mouse_cursor: Cell<MouseCursor>,
 
     frame_interval: Duration,
     event_loop_running: bool,
-    close_requested: bool,
+    close_requested: Cell<bool>,
 
     new_physical_size: Option<PhySize>,
     parent_handle: Option<ParentHandle>,
@@ -115,7 +116,7 @@ struct WindowInner {
 }
 
 pub struct Window<'a> {
-    inner: &'a mut WindowInner,
+    inner: &'a WindowInner,
 }
 
 // Hack to allow sending a RawWindowHandle between threads. Do not make public
@@ -284,11 +285,11 @@ impl<'a> Window<'a> {
             window_id,
             window_info,
             visual_id: visual_info.visual_id,
-            mouse_cursor: MouseCursor::default(),
+            mouse_cursor: Cell::new(MouseCursor::default()),
 
             frame_interval: Duration::from_millis(15),
             event_loop_running: false,
-            close_requested: false,
+            close_requested: Cell::new(false),
 
             new_physical_size: None,
             parent_handle,
@@ -312,8 +313,8 @@ impl<'a> Window<'a> {
         Ok(())
     }
 
-    pub fn set_mouse_cursor(&mut self, mouse_cursor: MouseCursor) {
-        if self.inner.mouse_cursor == mouse_cursor {
+    pub fn set_mouse_cursor(&self, mouse_cursor: MouseCursor) {
+        if self.inner.mouse_cursor.get() == mouse_cursor {
             return;
         }
 
@@ -327,11 +328,11 @@ impl<'a> Window<'a> {
             let _ = self.inner.xcb_connection.conn.flush();
         }
 
-        self.inner.mouse_cursor = mouse_cursor;
+        self.inner.mouse_cursor.set(mouse_cursor);
     }
 
     pub fn close(&mut self) {
-        self.inner.close_requested = true;
+        self.inner.close_requested.set(true);
     }
 
     pub fn has_focus(&mut self) -> bool {
@@ -444,14 +445,14 @@ impl WindowInner {
             if let Some(parent_handle) = &self.parent_handle {
                 if parent_handle.parent_did_drop() {
                     self.handle_must_close(handler);
-                    self.close_requested = false;
+                    self.close_requested.set(false);
                 }
             }
 
             // Check if the user has requested the window to close
-            if self.close_requested {
+            if self.close_requested.get() {
                 self.handle_must_close(handler);
-                self.close_requested = false;
+                self.close_requested.set(false);
             }
         }
 
diff --git a/src/x11/xcb_connection.rs b/src/x11/xcb_connection.rs
index b7ca188..518ed54 100644
--- a/src/x11/xcb_connection.rs
+++ b/src/x11/xcb_connection.rs
@@ -1,3 +1,4 @@
+use std::cell::RefCell;
 use std::collections::hash_map::{Entry, HashMap};
 use std::error::Error;
 
@@ -30,7 +31,7 @@ pub struct XcbConnection {
     pub(crate) atoms: Atoms,
     pub(crate) resources: resource_manager::Database,
     pub(crate) cursor_handle: CursorHandle,
-    pub(super) cursor_cache: HashMap<MouseCursor, u32>,
+    pub(super) cursor_cache: RefCell<HashMap<MouseCursor, u32>>,
 }
 
 impl XcbConnection {
@@ -56,7 +57,7 @@ impl XcbConnection {
             atoms,
             resources,
             cursor_handle,
-            cursor_cache: HashMap::new(),
+            cursor_cache: RefCell::new(HashMap::new()),
         })
     }
 
@@ -103,8 +104,12 @@ impl XcbConnection {
     }
 
     #[inline]
-    pub fn get_cursor(&mut self, cursor: MouseCursor) -> Result<Cursor, Box<dyn Error>> {
-        match self.cursor_cache.entry(cursor) {
+    pub fn get_cursor(&self, cursor: MouseCursor) -> Result<Cursor, Box<dyn Error>> {
+        // PANIC: this function is the only point where we access the cache, and we never call
+        // external functions that may make a reentrant call to this function
+        let mut cursor_cache = self.cursor_cache.borrow_mut();
+
+        match cursor_cache.entry(cursor) {
             Entry::Occupied(entry) => Ok(*entry.get()),
             Entry::Vacant(entry) => {
                 let cursor =