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Add InsideCallback struct
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@tomaka
tomaka committed Jul 21, 2014
1 parent fcaea62 commit 3466c3d
Showing 1 changed file with 32 additions and 23 deletions.
55 changes: 32 additions & 23 deletions rust-hl-lua/src/functions_write.rs
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Original file line number Diff line number Diff line change
@@ -1,5 +1,6 @@
use super::ffi;
use { Lua, Push, CopyRead };
use {HasLua, Lua, Push, CopyRead};
use std::kinds::marker::ContravariantLifetime;

// this function is the main entry point when Lua wants to call one of our functions
extern fn wrapper1(lua: *mut ffi::lua_State) -> ::libc::c_int {
Expand All @@ -24,19 +25,31 @@ trait AnyCallable {
fn load_args_and_call(&mut self, lua: *mut ffi::lua_State) -> ::libc::c_int;
}

// lua context used inside callbacks
struct InsideCallback<'lua> {
lua: *mut ffi::lua_State,
marker: ContravariantLifetime<'lua>,
}

impl<'lua> HasLua<'lua> for InsideCallback<'lua> {
fn use_lua(&mut self) -> *mut ffi::lua_State {
self.lua
}
}

// should be implemented by objects that can be called
// this will be removed in favor of std::ops::Fn when it is widely supported
// "Args" should be a tuple containing the parameters
trait Callable<'lua, Args: CopyRead<Lua<'lua>>, Ret: Push<Lua<'lua>>> {
trait Callable<'lua, Args: CopyRead<InsideCallback<'lua>>, Ret: Push<InsideCallback<'lua>>> {
fn do_call(&mut self, args: Args) -> Ret;
}

impl<'lua, Args: CopyRead<Lua<'lua>>, Ret: Push<Lua<'lua>>, T: Callable<'lua, Args, Ret>> AnyCallable for T {
impl<'lua, Args: CopyRead<InsideCallback<'lua>>, Ret: Push<InsideCallback<'lua>>, T: Callable<'lua, Args, Ret>> AnyCallable for T {
fn load_args_and_call(&mut self, lua: *mut ffi::lua_State)
-> ::libc::c_int
{
// creating a temporary Lua context in order to pass it to push & read functions
let mut tmpLua = Lua { lua: lua, marker: ::std::kinds::marker::ContravariantLifetime, must_be_closed: false, inside_callback: true } ;
let mut tmpLua = InsideCallback { lua: lua, marker: ::std::kinds::marker::ContravariantLifetime } ;

// trying to read the arguments
let argumentsCount = unsafe { ffi::lua_gettop(lua) } as int;
Expand All @@ -62,51 +75,51 @@ impl<'lua, Args: CopyRead<Lua<'lua>>, Ret: Push<Lua<'lua>>, T: Callable<'lua, Ar
// this macro will allow us to handle multiple parameters count
macro_rules! Push_function(
($s:ident, $args:ident, $b:block | $($ty:ident),*) => (
impl<'lua, Ret: Push<Lua<'lua>> $(, $ty : CopyRead<Lua<'lua>>+Clone)*> Push<Lua<'lua>> for fn($($ty),*)->Ret {
fn push_to_lua(self, lua: &mut Lua) -> uint {
impl<'lua, L: HasLua<'lua>, Ret: Push<InsideCallback<'lua>> $(, $ty : CopyRead<InsideCallback<'lua>>+Clone)*> Push<L> for fn($($ty),*)->Ret {
fn push_to_lua(self, lua: &mut L) -> uint {
// pushing the function pointer as a userdata
let luaDataRaw = unsafe { ffi::lua_newuserdata(lua.lua, ::std::mem::size_of_val(&self) as ::libc::size_t) };
let luaDataRaw = unsafe { ffi::lua_newuserdata(lua.use_lua(), ::std::mem::size_of_val(&self) as ::libc::size_t) };
let luaData: *mut fn($($ty),*)->Ret = unsafe { ::std::mem::transmute(luaDataRaw) };
unsafe { ::std::ptr::write(luaData, self) };

// pushing wrapper2 as a lightuserdata
let wrapper2: fn(*mut ffi::lua_State)->::libc::c_int = wrapper2::<fn($($ty),*)->Ret>;
unsafe { ffi::lua_pushlightuserdata(lua.lua, ::std::mem::transmute(wrapper2)) };
unsafe { ffi::lua_pushlightuserdata(lua.use_lua(), ::std::mem::transmute(wrapper2)) };

// pushing wrapper1 as a closure
unsafe { ffi::lua_pushcclosure(lua.lua, ::std::mem::transmute(wrapper1), 2) };
unsafe { ffi::lua_pushcclosure(lua.use_lua(), ::std::mem::transmute(wrapper1), 2) };

1
}
}

#[allow(unused_variable)]
impl<'lua, Ret: Push<Lua<'lua>> $(, $ty : CopyRead<Lua<'lua>>+Clone)*> Callable<'lua,($($ty),*),Ret> for fn($($ty),*)->Ret {
impl<'lua, Ret: Push<InsideCallback<'lua>> $(, $ty : CopyRead<InsideCallback<'lua>>+Clone)*> Callable<'lua,($($ty),*),Ret> for fn($($ty),*)->Ret {
fn do_call(&mut $s, $args: ($($ty),*)) -> Ret {
$b
}
}

impl<'lua, Ret: Push<Lua<'lua>> $(, $ty : CopyRead<Lua<'lua>>+Clone)*> Push<Lua<'lua>> for |$($ty),*|:'lua->Ret {
fn push_to_lua(self, lua: &mut Lua) -> uint {
impl<'lua, L: HasLua<'lua>, Ret: Push<InsideCallback<'lua>> $(, $ty : CopyRead<InsideCallback<'lua>>+Clone)*> Push<L> for |$($ty),*|:'lua->Ret {
fn push_to_lua(self, lua: &mut L) -> uint {
// pushing the function pointer as a userdata
let luaDataRaw = unsafe { ffi::lua_newuserdata(lua.lua, ::std::mem::size_of_val(&self) as ::libc::size_t) };
let luaDataRaw = unsafe { ffi::lua_newuserdata(lua.use_lua(), ::std::mem::size_of_val(&self) as ::libc::size_t) };
let luaData: *mut |$($ty),*|->Ret = unsafe { ::std::mem::transmute(luaDataRaw) };
unsafe { ::std::ptr::write(luaData, self) };

// pushing wrapper2 as a lightuserdata
let wrapper2: fn(*mut ffi::lua_State)->::libc::c_int = wrapper2::<|$($ty),*|:'lua->Ret>;
unsafe { ffi::lua_pushlightuserdata(lua.lua, ::std::mem::transmute(wrapper2)) };
unsafe { ffi::lua_pushlightuserdata(lua.use_lua(), ::std::mem::transmute(wrapper2)) };

// pushing wrapper1 as a closure
unsafe { ffi::lua_pushcclosure(lua.lua, ::std::mem::transmute(wrapper1), 2) };
unsafe { ffi::lua_pushcclosure(lua.use_lua(), ::std::mem::transmute(wrapper1), 2) };

1
}
}

#[allow(unused_variable)]
impl<'lua, Ret: Push<Lua<'lua>> $(, $ty : CopyRead<Lua<'lua>>+Clone)*> Callable<'lua,($($ty),*),Ret> for |$($ty),*|:'lua->Ret {
impl<'lua, Ret: Push<InsideCallback<'lua>> $(, $ty : CopyRead<InsideCallback<'lua>>+Clone)*> Callable<'lua,($($ty),*),Ret> for |$($ty),*|:'lua->Ret {
fn do_call(&mut $s, $args: ($($ty),*)) -> Ret {
$b
}
Expand All @@ -124,18 +137,14 @@ Push_function!(self, args, { (*self)(args.ref0().clone(), args.ref1().clone(), a



impl<'lua, T: Push<Lua<'lua>>, E: ::std::fmt::Show> Push<Lua<'lua>> for Result<T,E> {
fn push_to_lua(self, lua: &mut Lua<'lua>) -> uint {
if !lua.inside_callback {
fail!("cannot push a Result object except as a function return type")
}

impl<'lua, T: Push<InsideCallback<'lua>>, E: ::std::fmt::Show> Push<InsideCallback<'lua>> for Result<T,E> {
fn push_to_lua(self, lua: &mut InsideCallback<'lua>) -> uint {
match self {
Ok(val) => val.push_to_lua(lua),
Err(val) => {
let msg = format!("{}", val);
msg.push_to_lua(lua);
unsafe { ffi::lua_error(lua.lua); }
unsafe { ffi::lua_error(lua.use_lua()); }
unreachable!()
}
}
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