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|
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)
}
#[allow(clippy::match_wildcard_for_single_variants)]
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())
}
}
|
