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Diffstat (limited to 'syrette_macros/src/injectable_impl.rs')
| -rw-r--r-- | syrette_macros/src/injectable_impl.rs | 244 |
1 files changed, 244 insertions, 0 deletions
diff --git a/syrette_macros/src/injectable_impl.rs b/syrette_macros/src/injectable_impl.rs new file mode 100644 index 0000000..e7d1b54 --- /dev/null +++ b/syrette_macros/src/injectable_impl.rs @@ -0,0 +1,244 @@ +use quote::{quote, ToTokens}; +use syn::parse::{Parse, ParseStream}; +use syn::{ + parse_str, punctuated::Punctuated, token::Comma, ExprMethodCall, FnArg, + GenericArgument, Ident, ImplItem, ImplItemMethod, ItemImpl, Path, PathArguments, + Type, TypePath, +}; + +const DI_CONTAINER_VAR_NAME: &str = "di_container"; + +pub struct InjectableImpl +{ + pub dependency_types: Vec<Type>, + pub self_type: Type, + pub original_impl: ItemImpl, +} + +impl Parse for InjectableImpl +{ + fn parse(input: ParseStream) -> syn::Result<Self> + { + match input.parse::<ItemImpl>() { + Ok(impl_parsed_input) => { + match Self::_get_dependency_types(&impl_parsed_input) { + Ok(dependency_types) => Ok(Self { + dependency_types, + self_type: impl_parsed_input.self_ty.as_ref().clone(), + original_impl: impl_parsed_input, + }), + Err(error_msg) => Err(input.error(error_msg)), + } + } + Err(_) => Err(input.error("Expected an impl")), + } + } +} + +impl InjectableImpl +{ + pub fn expand(&self) -> proc_macro2::TokenStream + { + let original_impl = &self.original_impl; + let self_type = &self.self_type; + + let di_container_var: Ident = parse_str(DI_CONTAINER_VAR_NAME).unwrap(); + + let get_dependencies = Self::_create_get_dependencies(&self.dependency_types); + + quote! { + #original_impl + + impl syrette::interfaces::injectable::Injectable for #self_type { + fn resolve( + #di_container_var: &syrette::DIContainer + ) -> error_stack::Result< + syrette::ptr::InterfacePtr<Self>, + syrette::errors::injectable::ResolveError> + { + use error_stack::ResultExt; + + return Ok(syrette::ptr::InterfacePtr::new(Self::new( + #(#get_dependencies + .change_context(syrette::errors::injectable::ResolveError) + .attach_printable( + format!( + "Unable to resolve a dependency of {}", + std::any::type_name::<#self_type>() + ) + )? + ),* + ))); + } + } + } + } + + fn _create_get_dependencies(dependency_types: &[Type]) -> Vec<ExprMethodCall> + { + dependency_types + .iter() + .filter_map(|dep_type| match dep_type { + Type::TraitObject(dep_type_trait) => Some( + parse_str( + format!( + "{}.get::<{}>()", + DI_CONTAINER_VAR_NAME, + dep_type_trait.to_token_stream() + ) + .as_str(), + ) + .unwrap(), + ), + Type::Path(dep_type_path) => { + let dep_type_path_str = Self::_path_to_string(&dep_type_path.path); + + let get_method_name = if dep_type_path_str.ends_with("Factory") { + "get_factory" + } else { + "get" + }; + + Some( + parse_str( + format!( + "{}.{}::<{}>()", + DI_CONTAINER_VAR_NAME, get_method_name, dep_type_path_str + ) + .as_str(), + ) + .unwrap(), + ) + } + &_ => None, + }) + .collect() + } + + fn _find_method_by_name<'impl_lt>( + item_impl: &'impl_lt ItemImpl, + method_name: &'static str, + ) -> Option<&'impl_lt ImplItemMethod> + { + let impl_items = &item_impl.items; + + impl_items + .iter() + .filter_map(|impl_item| match impl_item { + ImplItem::Method(method_item) => Some(method_item), + &_ => None, + }) + .find(|method_item| method_item.sig.ident == method_name) + } + + fn get_has_fn_args_self(fn_args: &Punctuated<FnArg, Comma>) -> bool + { + fn_args.iter().any(|arg| match arg { + FnArg::Receiver(_) => true, + &_ => false, + }) + } + + fn _get_fn_arg_type_paths(fn_args: &Punctuated<FnArg, Comma>) -> Vec<&TypePath> + { + fn_args + .iter() + .filter_map(|arg| match arg { + FnArg::Typed(typed_fn_arg) => match typed_fn_arg.ty.as_ref() { + Type::Path(arg_type_path) => Some(arg_type_path), + Type::Reference(ref_type_path) => match ref_type_path.elem.as_ref() { + Type::Path(arg_type_path) => Some(arg_type_path), + &_ => None, + }, + &_ => None, + }, + FnArg::Receiver(_receiver_fn_arg) => None, + }) + .collect() + } + + fn _path_to_string(path: &Path) -> String + { + path.segments + .pairs() + .fold(String::new(), |mut acc, segment_pair| { + let segment_ident = &segment_pair.value().ident; + + acc.push_str(segment_ident.to_string().as_str()); + + let opt_colon_two = segment_pair.punct(); + + match opt_colon_two { + Some(colon_two) => { + acc.push_str(colon_two.to_token_stream().to_string().as_str()) + } + None => {} + } + + acc + }) + } + + fn _is_type_path_ptr(type_path: &TypePath) -> bool + { + let arg_type_path_string = Self::_path_to_string(&type_path.path); + + arg_type_path_string == "InterfacePtr" + || arg_type_path_string == "ptr::InterfacePtr" + || arg_type_path_string == "syrrete::ptr::InterfacePtr" + || arg_type_path_string == "FactoryPtr" + || arg_type_path_string == "ptr::FactoryPtr" + || arg_type_path_string == "syrrete::ptr::FactoryPtr" + } + + fn _get_dependency_types(item_impl: &ItemImpl) -> Result<Vec<Type>, &'static str> + { + let new_method_impl_item = match Self::_find_method_by_name(item_impl, "new") { + Some(method_item) => Ok(method_item), + None => Err("Missing a 'new' method"), + }?; + + let new_method_args = &new_method_impl_item.sig.inputs; + + if Self::get_has_fn_args_self(new_method_args) { + return Err("Unexpected self argument in 'new' method"); + } + + let new_method_arg_type_paths = Self::_get_fn_arg_type_paths(new_method_args); + + if new_method_arg_type_paths + .iter() + .any(|arg_type_path| !Self::_is_type_path_ptr(arg_type_path)) + { + return Err("All argument types in 'new' method must ptr types"); + } + + Ok(new_method_arg_type_paths + .iter() + .filter_map(|arg_type_path| { + // Assume the type path has a last segment. + let last_path_segment = arg_type_path.path.segments.last().unwrap(); + + match &last_path_segment.arguments { + PathArguments::AngleBracketed(angle_bracketed_generic_args) => { + let generic_args = &angle_bracketed_generic_args.args; + + let opt_first_generic_arg = generic_args.first(); + + // Assume a first generic argument exists because InterfacePtr and + // FactoryPtr requires one + let first_generic_arg = opt_first_generic_arg.as_ref().unwrap(); + + match first_generic_arg { + GenericArgument::Type(first_generic_arg_type) => { + Some(first_generic_arg_type.clone()) + } + &_ => None, + } + } + &_ => None, + } + }) + .collect()) + } +} |