Pin luaL_Buffer

Add `PhantomData<PhantomPinned>` to ensure that `luaL_Buffer` does not implement `Unpin`.

Fixes #741

Author: khvzak

mlua-sys/src/lua51/lauxlib.rs

@@ -1,5 +1,6 @@
 //! Contains definitions from `lauxlib.h`.
 
+use std::marker::{PhantomData, PhantomPinned};
 use std::os::raw::{c_char, c_int, c_void};
 use std::ptr;
 
@@ -169,6 +170,7 @@ pub struct luaL_Buffer {
     pub lvl: c_int,     // number of strings in the stack
     pub L: *mut lua_State,
     pub buffer: [c_char; LUAL_BUFFERSIZE],
+    _marker: PhantomData<PhantomPinned>,
 }
 
 #[cfg_attr(all(windows, raw_dylib), link(name = "lua51", kind = "raw-dylib"))]

mlua-sys/src/lua52/lauxlib.rs

@@ -1,5 +1,6 @@
 //! Contains definitions from `lauxlib.h`.
 
+use std::marker::{PhantomData, PhantomPinned};
 use std::os::raw::{c_char, c_int, c_void};
 use std::ptr;
 
@@ -205,6 +206,7 @@ pub struct luaL_Buffer {
     pub n: usize,       // number of characters in buffer
     pub L: *mut lua_State,
     pub initb: [c_char; LUAL_BUFFERSIZE], // initial buffer space
+    _marker: PhantomData<PhantomPinned>,
 }
 
 #[cfg_attr(all(windows, raw_dylib), link(name = "lua52", kind = "raw-dylib"))]

mlua-sys/src/lua53/lauxlib.rs

@@ -1,5 +1,6 @@
 //! Contains definitions from `lauxlib.h`.
 
+use std::marker::{PhantomData, PhantomPinned};
 use std::os::raw::{c_char, c_int, c_void};
 use std::{mem, ptr};
 
@@ -201,6 +202,7 @@ pub struct luaL_Buffer {
     pub n: usize,       // number of characters in buffer
     pub L: *mut lua_State,
     pub initb: [c_char; LUAL_BUFFERSIZE], // initial buffer space
+    _marker: PhantomData<PhantomPinned>,
 }
 
 #[cfg_attr(all(windows, raw_dylib), link(name = "lua53", kind = "raw-dylib"))]

mlua-sys/src/lua54/lauxlib.rs

@@ -1,5 +1,6 @@
 //! Contains definitions from `lauxlib.h`.
 
+use std::marker::{PhantomData, PhantomPinned};
 use std::os::raw::{c_char, c_double, c_int, c_long, c_void};
 use std::{mem, ptr};
 
@@ -230,6 +231,7 @@ pub struct luaL_Buffer {
     pub n: usize,       // number of characters in buffer
     pub L: *mut lua_State,
     pub init: luaL_BufferInit, // initial buffer (union with alignment)
+    _marker: PhantomData<PhantomPinned>,
 }
 
 #[cfg_attr(all(windows, raw_dylib), link(name = "lua54", kind = "raw-dylib"))]

mlua-sys/src/lua55/lauxlib.rs

@@ -1,5 +1,6 @@
 //! Contains definitions from `lauxlib.h`.
 
+use std::marker::{PhantomData, PhantomPinned};
 use std::os::raw::{c_char, c_double, c_int, c_long, c_uint, c_void};
 use std::{mem, ptr};
 
@@ -249,6 +250,7 @@ pub struct luaL_Buffer {
     pub n: usize,       // number of characters in buffer
     pub L: *mut lua_State,
     pub init: luaL_BufferInit, // initial buffer (union with alignment)
+    _marker: PhantomData<PhantomPinned>,
 }
 
 #[cfg_attr(all(windows, raw_dylib), link(name = "lua55", kind = "raw-dylib"))]

mlua-sys/src/luau/lauxlib.rs

@@ -1,5 +1,6 @@
 //! Contains definitions from `lualib.h`.
 
+use std::marker::{PhantomData, PhantomPinned};
 use std::os::raw::{c_char, c_float, c_int, c_void};
 use std::ptr;
 
@@ -206,6 +207,7 @@ pub struct luaL_Strbuf {
     L: *mut lua_State,
     storage: *mut c_void, // TString
     buffer: [c_char; LUA_BUFFERSIZE],
+    _marker: PhantomData<PhantomPinned>,
 }
 
 // For compatibility

tests/ffi.rs

@@ -0,0 +1,4 @@
+#[test]
+fn test_buffer_not_unpin() {
+    static_assertions::assert_not_impl_any!(mlua::ffi::luaL_Buffer: Unpin);
+}