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low_luajit/lua/
state.rs

1use core::ptr;
2
3use crate::{LuaState, ffi::{self, lua_State}};
4
5/// State handling functions.
6impl LuaState {
7	/* Not yet...
8	/// Creates a new valid and independent Lua state.
9	///
10	/// This state will use the standard C `realloc` function as its allocator.
11	///
12	/// # Safety
13	///
14	/// While there is nothing inherently unsafe about creating a new `LuaState`,
15	/// using the state without a protected environment could end badly in case a Lua error is triggered:
16	/// at best, Rust simply aborts abruptly...but I've had segmentation faults happen sometimes too.
17	#[inline]
18	pub unsafe fn new_unchecked() -> Self {
19		let ptr = unsafe { luaL_newstate() };
20		assert!(!ptr.is_null(), "cannot create new Lua state: memory allocation error");
21		Self(ptr)
22	}*/
23
24	/// Wraps a pre-existing raw [`lua_State`] pointer.
25	///
26	/// # Safety
27	///
28	/// `ptr` **must** be a valid pointer of an already existing state, as all other methods will assume it to be so.
29	///
30	/// Additionally, there must not be an existing `LuaState` that is already using this pointer.
31	#[must_use]
32	pub const unsafe fn from_ptr(ptr: *mut lua_State) -> Self {
33		Self(ptr)
34	}
35
36	/// Returns the wrapped raw [`lua_State`] pointer.
37	///
38	/// The caller must ensure that the `LuaState` outlives the pointer this function returns, or else it will end up dangling.
39	///
40	/// The returned pointer should also not be passed to functions that might invalidate the `LuaState` (like [`lua_close`]).
41	///
42	/// [`lua_close`]: ./ffi/fn.lua_close.html
43	#[must_use]
44	pub const fn as_ptr(&self) -> *mut lua_State {
45		self.0
46	}
47
48	/// Destroys all objects and frees all dynamic memory of the state.
49	///
50	/// # Safety
51	///
52	/// Can only be called if this `LuaState` is not being used anywhere else.
53	///
54	/// If your crate is a Lua module, this function must *not* return back to the Lua interpreter (as it would no longer exist).
55	#[inline]
56	pub unsafe fn close(self) {
57		// SAFETY: self.0 is always valid and the caller must make sure that the LuaState is not used anywhere else.
58		unsafe { ffi::lua_close(self.0); }
59	}
60
61	/// Returns a reference to a number that represents the version of Lua.
62	///
63	/// For LuaJIT, this should always returns `501` (which represents 5.1, the Lua version LuaJIT is based on).
64	#[inline]
65	pub fn version() -> &'static f64 {
66		// SAFETY: lua_version doesn't actually use the pointer given to it and always returns a valid pointer to a static f64.
67		unsafe { &*ffi::lua_version(ptr::null_mut()) }
68	}
69}