Add some support for the Lua API

src/lib.rs

@@ -9,6 +9,7 @@ pub mod display;
 pub mod file;
 pub mod geometry;
 pub mod graphics;
+pub mod lua;
 pub mod sound;
 pub mod sprite;
 pub mod system;
@@ -18,6 +19,7 @@ use {
         display::Display,
         file::FileSystem,
         graphics::{Graphics, PDRect},
+        lua::Lua,
         sound::Sound,
         sprite::{
             Sprite, SpriteCollideFunction, SpriteDrawFunction, SpriteManager, SpriteUpdateFunction,
@@ -48,6 +50,8 @@ impl Playdate {
         FileSystem::new(file);
         let graphics = unsafe { (*playdate).graphics };
         Graphics::new(graphics);
+        let lua = unsafe { (*playdate).lua };
+        Lua::new(lua);
         let sound = unsafe { (*playdate).sound };
         Sound::new(sound)?;
         let display = unsafe { (*playdate).display };

src/lua.rs

@@ -0,0 +1,45 @@
+use {
+    crate::pd_func_caller,
+    alloc::string::String,
+    anyhow::{anyhow, Error},
+    core::ptr,
+    crankstart_sys::{ctypes, lua_CFunction},
+    cstr_core::{CStr, CString},
+};
+
+static mut LUA: Lua = Lua(ptr::null_mut());
+
+#[derive(Clone, Debug)]
+pub struct Lua(*const crankstart_sys::playdate_lua);
+
+impl Lua {
+    pub(crate) fn new(file: *const crankstart_sys::playdate_lua) {
+        unsafe {
+            LUA = Lua(file);
+        }
+    }
+
+    pub fn get() -> Self {
+        unsafe { LUA.clone() }
+    }
+
+    pub fn add_function(&self, f: lua_CFunction, name: &str) -> Result<(), Error> {
+        let c_name = CString::new(name).map_err(Error::msg)?;
+        let mut out_err: *const crankstart_sys::ctypes::c_char = ptr::null_mut();
+        pd_func_caller!((*self.0).addFunction, f, c_name.as_ptr(), &mut out_err)?;
+        if out_err != ptr::null_mut() {
+            let err_msg = unsafe { CStr::from_ptr(out_err).to_string_lossy().into_owned() };
+            Err(anyhow!(err_msg))
+        } else {
+            Ok(())
+        }
+    }
+
+    pub fn get_arg_string(&self, pos: i32) -> Result<String, Error> {
+        let c_arg_string = pd_func_caller!((*self.0).getArgString, pos as ctypes::c_int)?;
+        unsafe {
+            let arg_string = CStr::from_ptr(c_arg_string).to_string_lossy().into_owned();
+            Ok(arg_string)
+        }
+    }
+}