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use proc_macro::TokenStream;
use proc_macro2::{Ident, Span};
use quote::quote;
use syn::meta::ParseNestedMeta;
use syn::{parse_macro_input, ItemFn, LitStr, Result};
#[cfg(feature = "macros")]
use {
crate::chunk::Chunk, proc_macro::TokenTree, proc_macro2::TokenStream as TokenStream2,
proc_macro_error::proc_macro_error,
};
#[derive(Default)]
struct ModuleAttributes {
name: Option<Ident>,
skip_memory_check: bool,
}
impl ModuleAttributes {
fn parse(&mut self, meta: ParseNestedMeta) -> Result<()> {
if meta.path.is_ident("name") {
match meta.value() {
Ok(value) => {
self.name = Some(value.parse::<LitStr>()?.parse()?);
}
Err(_) => {
return Err(meta.error("`name` attribute must have a value"));
}
}
} else if meta.path.is_ident("skip_memory_check") {
if meta.value().is_ok() {
return Err(meta.error("`skip_memory_check` attribute have no values"));
}
self.skip_memory_check = true;
} else {
return Err(meta.error("unsupported module attribute"));
}
Ok(())
}
}
#[proc_macro_attribute]
pub fn lua_module(attr: TokenStream, item: TokenStream) -> TokenStream {
let mut args = ModuleAttributes::default();
if !attr.is_empty() {
let args_parser = syn::meta::parser(|meta| args.parse(meta));
parse_macro_input!(attr with args_parser);
}
let func = parse_macro_input!(item as ItemFn);
let func_name = &func.sig.ident;
let module_name = args.name.unwrap_or_else(|| func_name.clone());
let ext_entrypoint_name = Ident::new(&format!("luaopen_{module_name}"), Span::call_site());
let skip_memory_check = if args.skip_memory_check {
quote! { lua.skip_memory_check(true); }
} else {
quote! {}
};
let wrapped = quote! {
::mlua::require_module_feature!();
#func
#[no_mangle]
unsafe extern "C-unwind" fn #ext_entrypoint_name(state: *mut ::mlua::lua_State) -> ::std::os::raw::c_int {
let lua = ::mlua::Lua::init_from_ptr(state);
#skip_memory_check
lua.entrypoint1(state, #func_name)
}
};
wrapped.into()
}
#[cfg(feature = "macros")]
fn to_ident(tt: &TokenTree) -> TokenStream2 {
let s: TokenStream = tt.clone().into();
s.into()
}
#[cfg(feature = "macros")]
#[proc_macro]
#[proc_macro_error]
pub fn chunk(input: TokenStream) -> TokenStream {
let chunk = Chunk::new(input);
let source = chunk.source();
let caps_len = chunk.captures().len();
let caps = chunk.captures().iter().map(|cap| {
let cap_name = cap.as_rust().to_string();
let cap = to_ident(cap.as_rust());
quote! { env.raw_set(#cap_name, #cap)?; }
});
let wrapped_code = quote! {{
use ::mlua::{AsChunk, ChunkMode, Lua, Result, Table};
use ::std::borrow::Cow;
use ::std::cell::Cell;
use ::std::io::Result as IoResult;
use ::std::marker::PhantomData;
struct InnerChunk<'lua, F: FnOnce(&'lua Lua) -> Result<Table<'lua>>>(Cell<Option<F>>, PhantomData<&'lua ()>);
impl<'lua, F> AsChunk<'lua, 'static> for InnerChunk<'lua, F>
where
F: FnOnce(&'lua Lua) -> Result<Table<'lua>>,
{
fn environment(&self, lua: &'lua Lua) -> Result<Option<Table<'lua>>> {
if #caps_len > 0 {
if let Some(make_env) = self.0.take() {
return make_env(lua).map(Some);
}
}
Ok(None)
}
fn mode(&self) -> Option<ChunkMode> {
Some(ChunkMode::Text)
}
fn source(self) -> IoResult<Cow<'static, [u8]>> {
Ok(Cow::Borrowed((#source).as_bytes()))
}
}
fn annotate<'a, F: FnOnce(&'a Lua) -> Result<Table<'a>>>(f: F) -> F { f }
let make_env = annotate(move |lua: &Lua| -> Result<Table> {
let globals = lua.globals();
let env = lua.create_table()?;
let meta = lua.create_table()?;
meta.raw_set("__index", globals.clone())?;
meta.raw_set("__newindex", globals)?;
// Add captured variables
#(#caps)*
env.set_metatable(Some(meta));
Ok(env)
});
InnerChunk(Cell::new(Some(make_env)), PhantomData)
}};
wrapped_code.into()
}
#[cfg(feature = "macros")]
#[proc_macro_derive(FromLua)]
pub fn from_lua(input: TokenStream) -> TokenStream {
from_lua::from_lua(input)
}
#[cfg(feature = "macros")]
mod chunk;
#[cfg(feature = "macros")]
mod from_lua;
#[cfg(feature = "macros")]
mod token;
|
