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|
use crate::codegen;
use crate::ir::function::Abi;
use proc_macro2::Ident;
/// Used to build the output tokens for dynamic bindings.
#[derive(Default)]
pub struct DynamicItems {
/// Tracks the tokens that will appears inside the library struct -- e.g.:
/// ```ignore
/// struct Lib {
/// __library: ::libloading::Library,
/// pub x: Result<unsafe extern ..., ::libloading::Error>, // <- tracks these
/// ...
/// }
/// ```
struct_members: Vec<proc_macro2::TokenStream>,
/// Tracks the tokens that will appear inside the library struct's implementation, e.g.:
///
/// ```ignore
/// impl Lib {
/// ...
/// pub unsafe fn foo(&self, ...) { // <- tracks these
/// ...
/// }
/// }
/// ```
struct_implementation: Vec<proc_macro2::TokenStream>,
/// Tracks the initialization of the fields inside the `::new` constructor of the library
/// struct, e.g.:
/// ```ignore
/// impl Lib {
///
/// pub unsafe fn new<P>(path: P) -> Result<Self, ::libloading::Error>
/// where
/// P: AsRef<::std::ffi::OsStr>,
/// {
/// ...
/// let foo = __library.get(...) ...; // <- tracks these
/// ...
/// }
///
/// ...
/// }
/// ```
constructor_inits: Vec<proc_macro2::TokenStream>,
/// Tracks the information that is passed to the library struct at the end of the `::new`
/// constructor, e.g.:
/// ```ignore
/// impl LibFoo {
/// pub unsafe fn new<P>(path: P) -> Result<Self, ::libloading::Error>
/// where
/// P: AsRef<::std::ffi::OsStr>,
/// {
/// ...
/// Ok(LibFoo {
/// __library: __library,
/// foo,
/// bar, // <- tracks these
/// ...
/// })
/// }
/// }
/// ```
init_fields: Vec<proc_macro2::TokenStream>,
}
impl DynamicItems {
pub fn new() -> Self {
Self::default()
}
pub fn get_tokens(&self, lib_ident: Ident) -> proc_macro2::TokenStream {
let struct_members = &self.struct_members;
let constructor_inits = &self.constructor_inits;
let init_fields = &self.init_fields;
let struct_implementation = &self.struct_implementation;
quote! {
extern crate libloading;
pub struct #lib_ident {
__library: ::libloading::Library,
#(#struct_members)*
}
impl #lib_ident {
pub unsafe fn new<P>(
path: P
) -> Result<Self, ::libloading::Error>
where P: AsRef<::std::ffi::OsStr> {
let __library = ::libloading::Library::new(path)?;
#( #constructor_inits )*
Ok(
#lib_ident {
__library,
#( #init_fields ),*
}
)
}
#( #struct_implementation )*
}
}
}
pub fn push(
&mut self,
ident: Ident,
abi: Abi,
is_variadic: bool,
args: Vec<proc_macro2::TokenStream>,
args_identifiers: Vec<proc_macro2::TokenStream>,
ret: proc_macro2::TokenStream,
ret_ty: proc_macro2::TokenStream,
) {
if !is_variadic {
assert_eq!(args.len(), args_identifiers.len());
}
self.struct_members.push(quote! {
pub #ident: Result<unsafe extern #abi fn ( #( #args ),* ) #ret, ::libloading::Error>,
});
// We can't implement variadic functions from C easily, so we allow to
// access the function pointer so that the user can call it just fine.
if !is_variadic {
self.struct_implementation.push(quote! {
pub unsafe fn #ident ( &self, #( #args ),* ) -> #ret_ty {
let sym = self.#ident.as_ref().expect("Expected function, got error.");
(sym)(#( #args_identifiers ),*)
}
});
}
let ident_str = codegen::helpers::ast_ty::cstr_expr(ident.to_string());
self.constructor_inits.push(quote! {
let #ident = __library.get(#ident_str).map(|sym| *sym);
});
self.init_fields.push(quote! {
#ident
});
}
}
|
