Revert "Remove Xbase in Rust"

This reverts commit 333b3163d3.

rust-polytreewm/src/lib.rs

@@ -1,6 +1,7 @@
 mod api;
 mod atoms;
 mod constraints;
+mod xbase;
 
 pub mod geom;
 pub mod settings;
@@ -8,3 +9,4 @@ pub mod unit;
 
 pub use atoms::Atoms;
 pub use settings::Settings;
+pub use xbase::Xbase;

rust-polytreewm/src/xbase.rs

@@ -0,0 +1,77 @@
+use crate::geom;
+
+use std::os::raw::*;
+use std::ptr::null;
+
+use x11::xlib::{self, Display};
+
+pub type ErrorHandler =
+    unsafe extern "C" fn(*mut Display, *mut xlib::XErrorEvent) -> c_int;
+
+pub struct Xbase {
+    program_title: String,
+    x_display: *mut Display,
+    x_screen: c_int,
+    x_root: c_ulong,
+    screen_sizes: geom::Sizes,
+    x_error: Option<ErrorHandler>,
+}
+
+impl Xbase {
+    pub fn new(
+        program_title: String,
+        x_error_handler: ErrorHandler,
+    ) -> Result<Self, Box<dyn std::error::Error>> {
+        unsafe {
+            if xlib::XSupportsLocale() == 0 {
+                return Err("no locale support in X".into());
+            }
+
+            let x_display = xlib::XOpenDisplay(null());
+            if x_display.is_null() {
+                return Err("cannot open X display".into());
+            }
+
+            let x_screen = xlib::XDefaultScreen(x_display);
+            let x_root = xlib::XRootWindow(x_display, x_screen);
+
+            let screen_sizes = geom::Sizes::new(
+                xlib::XDisplayWidth(x_display, x_screen),
+                xlib::XDisplayHeight(x_display, x_screen),
+            );
+
+            let x_error = xlib::XSetErrorHandler(Some(x_error_wm_check));
+
+            xlib::XSelectInput(
+                x_display,
+                xlib::XDefaultRootWindow(x_display),
+                xlib::SubstructureRedirectMask,
+            );
+            xlib::XSync(x_display, xlib::False);
+            xlib::XSetErrorHandler(Some(x_error_handler));
+            xlib::XSync(x_display, xlib::False);
+
+            Ok(Self {
+                program_title,
+                x_display,
+                x_screen,
+                x_root,
+                screen_sizes,
+                x_error,
+            })
+        }
+    }
+}
+
+impl Drop for Xbase {
+    fn drop(&mut self) {
+        unsafe { xlib::XCloseDisplay(self.x_display) };
+    }
+}
+
+unsafe extern "C" fn x_error_wm_check(
+    _display: *mut Display,
+    _x_error_event: *mut xlib::XErrorEvent,
+) -> c_int {
+    panic!("another window manager is already running");
+}