error handling and refactoring unsafe code

Cargo.lock

@@ -94,6 +94,7 @@ dependencies = [
  "as-raw-xcb-connection",
  "tiny-xlib",
  "x11rb",
+ "x11rb-protocol",
 ]
 
 [[package]]

Cargo.toml

@@ -9,4 +9,5 @@ edition = "2021"
 tiny-xlib = "0.2.2"
 as-raw-xcb-connection = "1.0.1"
 x11rb = { version = "0.13.0", features = ["extra-traits", "allow-unsafe-code"] }
+x11rb-protocol = { version = "0.13.0", features = ["std"] }
 anyhow = "1.0.79"

src/main.rs

@@ -4,6 +4,15 @@ use as_raw_xcb_connection::AsRawXcbConnection;
 use tiny_xlib::Display;
 use x11rb::xcb_ffi::XCBConnection;
 
+fn xcb_connection_from_display(display: &Display) -> anyhow::Result<XCBConnection> {
+    let xcb_conn = display.as_raw_xcb_connection();
+
+    // Safety: taking a pointer straight from the safe tiny_x11 to the safe x11rb
+    unsafe {
+        XCBConnection::from_raw_xcb_connection(xcb_conn.cast(), false).map_err(|e| anyhow!(e))
+    }
+}
+
 fn main() -> anyhow::Result<()> {
     let mut args = std::env::args().skip(1);
     if let Some(arg) = args.next() {
@@ -19,8 +28,14 @@ fn main() -> anyhow::Result<()> {
 
     // Here we open a display and get an x11rb connection, we could also just use xcb I think
     let display = Display::new(None).context("Failed to open display")?;
-    let xcb_conn = display.as_raw_xcb_connection();
+
-    let xcb_conn = unsafe { XCBConnection::from_raw_xcb_connection(xcb_conn.cast(), false)? };
+    let _conn = xcb_connection_from_display(&display)?;
+
+    // Registering a baby error handler for now
+    tiny_xlib::register_error_handler(Box::new(|_, error| {
+        println!("X11 error: {:?}", error);
+        false
+    }))?;
 
     // TODO: Check if there are other wms running