diff options
Diffstat (limited to 'src/codegen/dyngen.rs')
| -rw-r--r-- | src/codegen/dyngen.rs | 181 |
1 files changed, 181 insertions, 0 deletions
diff --git a/src/codegen/dyngen.rs b/src/codegen/dyngen.rs new file mode 100644 index 00000000..aab6cac9 --- /dev/null +++ b/src/codegen/dyngen.rs @@ -0,0 +1,181 @@ +use crate::ir::function::Abi; +use proc_macro2::Ident; + +/// Used to build the output tokens for dynamic bindings. +pub struct DynamicItems { + /// Tracks the tokens that will appears inside the library struct -- e.g.: + /// ```ignore + /// struct Lib { + /// __library: ::libloading::Library, + /// 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 tokens that will appear inside the struct used for checking if a symbol is + /// usable, e.g.: + /// ```ignore + /// pub fn f(&self) -> Result<(), &'a ::libloading::Error> { // <- tracks these + /// self.__library.f.as_ref().map(|_| ()) + /// } + /// ``` + runtime_checks: 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 Default for DynamicItems { + fn default() -> Self { + DynamicItems { + struct_members: vec![], + struct_implementation: vec![], + runtime_checks: vec![], + constructor_inits: vec![], + init_fields: vec![], + } + } +} + +impl DynamicItems { + pub fn new() -> Self { + Self::default() + } + + pub fn get_tokens( + &self, + lib_ident: Ident, + check_struct_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; + let runtime_checks = &self.runtime_checks; + 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: __library, + #( #init_fields ),* + } + ) + } + + pub fn can_call(&self) -> #check_struct_ident { + #check_struct_ident { __library: self } + } + + #( #struct_implementation )* + } + + pub struct #check_struct_ident<'a> { + __library: &'a #lib_ident, + } + + impl<'a> #check_struct_ident<'a> { + #( #runtime_checks )* + } + } + } + + pub fn add_function( + &mut self, + ident: Ident, + abi: Abi, + args: Vec<proc_macro2::TokenStream>, + args_identifiers: Vec<proc_macro2::TokenStream>, + ret: proc_macro2::TokenStream, + ret_ty: proc_macro2::TokenStream, + ) { + assert_eq!(args.len(), args_identifiers.len()); + + self.struct_members.push(quote!{ + #ident: Result<unsafe extern #abi fn ( #( #args ),* ) #ret, ::libloading::Error>, + }); + + 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 ),*) + } + }); + + self.runtime_checks.push(quote! { + pub fn #ident (&self) -> Result<(), &'a::libloading::Error> { + self.__library.#ident.as_ref().map(|_| ()) + } + }); + + let ident_str = ident.to_string(); + self.constructor_inits.push(quote! { + let #ident = __library.get(#ident_str.as_bytes()).map(|sym| *sym); + }); + + self.init_fields.push(quote! { + #ident + }); + } +} |