Make WINGs configuration visible from Rust.

WINGs/wings-rs/src/configuration.rs

@@ -0,0 +1,66 @@
+//! Global WINGs configuration.
+//!
+//! Use [`Configuration::global`] to get a snapshot of current configuration
+//! settings.
+//!
+//! ## Rust rewrite notes
+//!
+//! This accesses a global that is defined in C code. Once more of WINGs is
+//! migrated to Rust, we should use a different approach that is more
+//! Rust-friendly. Threading a configuration object down the stack is a likely
+//! way to go.
+
+use crate::WINGsP::_WINGsConfiguration;
+
+use std::{ffi::CStr, ptr::NonNull};
+
+unsafe extern "C" {
+    static WINGsConfiguration: _WINGsConfiguration;
+}
+
+#[derive(Clone, Copy, Debug)]
+pub struct Configuration {
+    pub system_font: &'static CStr,
+    pub bold_system_font: &'static CStr,
+    pub default_font_size: u16,
+    pub antialiased_text: bool,
+    pub floppy_path: &'static CStr,
+    pub double_click_delay: u32,
+    pub mouse_wheel_up: u32,
+    pub mouse_wheel_down: u32,
+}
+
+impl Configuration {
+    /// Returns the current WINGs configuration. Returns `None` if the
+    /// configuration appears not to have been loaded.
+    ///
+    /// This should only be called after `W_ReadConfigurations` is called
+    /// (presumably when initializing WINGs in C code), but it should be safe to
+    /// call it at any time. (It may just contain nonsense values.)
+    ///
+    /// ## Rust rewrite notes
+    ///
+    /// We should migrate away from a static global and thread a configuration
+    /// object in some other way.
+    pub fn global() -> Option<Self> {
+        let c = unsafe { &WINGsConfiguration };
+        let system_font = unsafe { CStr::from_ptr(NonNull::new(c.systemFont)?.as_ptr()) };
+        let bold_system_font = unsafe { CStr::from_ptr(NonNull::new(c.boldSystemFont)?.as_ptr()) };
+        let default_font_size = u16::try_from(c.defaultFontSize).ok()?;
+        let antialiased_text = c.antialiasedText != 0;
+        let floppy_path = unsafe { CStr::from_ptr(NonNull::new(c.floppyPath)?.as_ptr()) };
+        let double_click_delay = u32::try_from(c.doubleClickDelay).ok()?;
+        let mouse_wheel_up = u32::try_from(c.mouseWheelUp).ok()?;
+        let mouse_wheel_down = u32::try_from(c.mouseWheelDown).ok()?;
+        Some(Configuration {
+            system_font,
+            bold_system_font,
+            default_font_size,
+            antialiased_text,
+            floppy_path,
+            double_click_delay,
+            mouse_wheel_up,
+            mouse_wheel_down,
+        })
+    }
+}

WINGs/wings-rs/src/lib.rs

@@ -2,3 +2,4 @@
 #[allow(non_snake_case)]
 #[allow(non_upper_case_globals)]
 pub mod WINGsP;
+pub mod configuration;