Add better userdata api and type coercion, add Vector and Angle types

gmod/src/lib.rs

@@ -16,6 +16,9 @@ pub mod msgc;
 /// Advanced dark magic utilities
 pub mod hax;
 
+/// Userdata types
+pub mod userdata;
+
 /// Returns whether this client is running the x86-64 branch
 ///
 /// Current implementation checks the contents of the bin/ directory, so this is a blocking operation and requires syscalls, use sparingly

gmod/src/lua/lua_state.rs

@@ -2,6 +2,8 @@ use std::{mem::MaybeUninit, borrow::Cow, ffi::c_void};
 
 use crate::lua::*;
 
+use crate::userdata::UserData;
+
 #[repr(transparent)]
 #[derive(Clone, Copy, Debug)]
 pub struct LuaState(pub *mut std::ffi::c_void);

gmod/src/lua/mod.rs

@@ -6,14 +6,6 @@ pub use import::*;
 mod lua_state;
 pub use lua_state::LuaState as State;
 
-#[repr(C)]
-#[derive(Debug)]
-pub struct UserData
-{
-	pub data: *mut core::ffi::c_void,
-	pub r#type: u8
-}
-
 #[derive(Debug, Clone)]
 pub enum LuaError {
 	/// Out of memory

gmod/src/userdata.rs

@@ -0,0 +1,112 @@
+#[repr(u8)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord)]
+pub enum UserData {
+	None = 255,
+
+	Nil = 0,
+	Bool,
+	LightUserData,
+	Number,
+	String,
+	Table,
+	Function,
+	UserData,
+	Thread,
+
+	// GMod Types
+	Entity,
+	Vector,
+	Angle,
+	PhysObj,
+	Save,
+	Restore,
+	DamageInfo,
+	EffectData,
+	MoveData,
+	RecipientFilter,
+	UserCmd,
+	ScriptedVehicle,
+	Material,
+	Panel,
+	Particle,
+	ParticleEmitter,
+	Texture,
+	UserMsg,
+	ConVar,
+	IMesh,
+	Matrix,
+	Sound,
+	PixelVisHandle,
+	DLight,
+	Video,
+	File,
+	Locomotion,
+	Path,
+	NavArea,
+	SoundHandle,
+	NavLadder,
+	ParticleSystem,
+	ProjectedTexture,
+	PhysCollide,
+	SurfaceInfo,
+
+	MAX
+}
+
+#[derive(Clone, Copy, Debug, Default, PartialEq, PartialOrd)]
+#[repr(C)]
+pub struct Vector {
+	x: f32,
+	y: f32,
+	z: f32
+}
+
+#[derive(Clone, Copy, Debug, Default, PartialEq, PartialOrd)]
+#[repr(C)]
+pub struct Angle {
+	p: f32,
+	y: f32,
+	r: f32
+}
+
+#[repr(C)]
+#[derive(Debug, Clone, Copy, Eq, PartialEq, Hash)]
+pub struct TaggedUserData
+{
+	pub data: *mut core::ffi::c_void,
+	pub r#type: UserData
+}
+
+pub trait CoercibleUserData {}
+
+macro_rules! userdata {
+	($(UserData::$enum:ident => $struct:ident),+) => {
+		$(impl CoercibleUserData for $struct {})+
+
+		impl TaggedUserData {
+			/// Coerce this tagged UserData into its corresponding Rust struct, if possible.
+			///
+			/// This will perform a type check to ensure that the tagged userdata matches the user data you are coercing to.
+			pub fn coerce<'a, T: CoercibleUserData>(&self) -> Result<&mut T, UserData> {
+				match self.r#type {
+					$(UserData::$enum => Ok(unsafe { &mut *(self.data as *mut T) }),)+
+					_ => Err(self.r#type)
+				}
+			}
+
+			/// Coerce this tagged UserData into its corresponding Rust struct, if possible.
+			///
+			/// # Safety
+			/// This will NOT perform a type check to ensure that the tagged userdata matches the user data you are coercing to.
+			///
+			/// Coercing to the wrong type is undefined behaviour and is likely to crash your program.
+			pub unsafe fn coerce_unchecked<T: CoercibleUserData>(&self) -> &mut T {
+				&mut *(self.data as *mut T)
+			}
+		}
+	};
+}
+userdata! {
+	UserData::Vector => Vector,
+	UserData::Angle => Angle
+}