use proc_macro::TokenStream;
use quote::quote;
use syn::ext::IdentExt;
use syn::{Block, Error, FnArg, ImplItem, ItemImpl, Pat, ReturnType, Type, TypeReference};
use crate::args::{self, ComplexityType, RenameRuleExt, RenameTarget};
use crate::output_type::OutputType;
use crate::utils::{
gen_deprecation, generate_default, generate_guards, generate_validator, get_cfg_attrs,
get_crate_name, get_param_getter_ident, get_rustdoc, get_type_path_and_name,
parse_complexity_expr, parse_graphql_attrs, remove_graphql_attrs, visible_fn, GeneratorResult,
};
pub fn generate(
object_args: &args::ComplexObject,
item_impl: &mut ItemImpl,
) -> GeneratorResult<TokenStream> {
let crate_name = get_crate_name(object_args.internal);
let (self_ty, _) = get_type_path_and_name(item_impl.self_ty.as_ref())?;
let generics = &item_impl.generics;
let generics_params = &generics.params;
let where_clause = &item_impl.generics.where_clause;
let mut resolvers = Vec::new();
let mut schema_fields = Vec::new();
for item in &mut item_impl.items {
if let ImplItem::Method(method) = item {
let method_args: args::ObjectField =
parse_graphql_attrs(&method.attrs)?.unwrap_or_default();
if method_args.skip {
continue;
}
let field_name = method_args.name.clone().unwrap_or_else(|| {
object_args
.rename_fields
.rename(method.sig.ident.unraw().to_string(), RenameTarget::Field)
});
let field_desc = get_rustdoc(&method.attrs)?
.map(|s| quote! { ::std::option::Option::Some(#s) })
.unwrap_or_else(|| quote! {::std::option::Option::None});
let field_deprecation = gen_deprecation(&method_args.deprecation, &crate_name);
let external = method_args.external;
let requires = match &method_args.requires {
Some(requires) => quote! { ::std::option::Option::Some(#requires) },
None => quote! { ::std::option::Option::None },
};
let provides = match &method_args.provides {
Some(provides) => quote! { ::std::option::Option::Some(#provides) },
None => quote! { ::std::option::Option::None },
};
let ty = match &method.sig.output {
ReturnType::Type(_, ty) => OutputType::parse(ty)?,
ReturnType::Default => {
return Err(Error::new_spanned(
&method.sig.output,
"Resolver must have a return type",
)
.into())
}
};
let cache_control = {
let public = method_args.cache_control.is_public();
let max_age = method_args.cache_control.max_age;
quote! {
#crate_name::CacheControl {
public: #public,
max_age: #max_age,
}
}
};
let cfg_attrs = get_cfg_attrs(&method.attrs);
let mut create_ctx = true;
let mut args = Vec::new();
if method.sig.inputs.is_empty() {
return Err(Error::new_spanned(
&method.sig,
"The self receiver must be the first parameter.",
)
.into());
}
for (idx, arg) in method.sig.inputs.iter_mut().enumerate() {
if let FnArg::Receiver(receiver) = arg {
if idx != 0 {
return Err(Error::new_spanned(
receiver,
"The self receiver must be the first parameter.",
)
.into());
}
} else if let FnArg::Typed(pat) = arg {
if idx == 0 {
return Err(Error::new_spanned(
pat,
"The self receiver must be the first parameter.",
)
.into());
}
match (&*pat.pat, &*pat.ty) {
(Pat::Ident(arg_ident), Type::Path(arg_ty)) => {
args.push((
arg_ident.clone(),
arg_ty.clone(),
parse_graphql_attrs::<args::Argument>(&pat.attrs)?
.unwrap_or_default(),
));
remove_graphql_attrs(&mut pat.attrs);
}
(arg, Type::Reference(TypeReference { elem, .. })) => {
if let Type::Path(path) = elem.as_ref() {
if idx != 1 || path.path.segments.last().unwrap().ident != "Context"
{
return Err(Error::new_spanned(
arg,
"Only types that implement `InputType` can be used as input arguments.",
)
.into());
}
create_ctx = false;
}
}
_ => return Err(Error::new_spanned(arg, "Invalid argument type.").into()),
}
}
}
if create_ctx {
let arg = syn::parse2::<FnArg>(quote! { _: &#crate_name::Context<'_> }).unwrap();
method.sig.inputs.insert(1, arg);
}
let mut schema_args = Vec::new();
let mut use_params = Vec::new();
let mut get_params = Vec::new();
for (
ident,
ty,
args::Argument {
name,
desc,
default,
default_with,
validator,
visible,
..
},
) in &args
{
let name = name.clone().unwrap_or_else(|| {
object_args
.rename_args
.rename(ident.ident.unraw().to_string(), RenameTarget::Argument)
});
let desc = desc
.as_ref()
.map(|s| quote! {::std::option::Option::Some(#s)})
.unwrap_or_else(|| quote! {::std::option::Option::None});
let default = generate_default(&default, &default_with)?;
let schema_default = default
.as_ref()
.map(|value| {
quote! {
::std::option::Option::Some(::std::string::ToString::to_string(
&<#ty as #crate_name::InputType>::to_value(&#value)
))
}
})
.unwrap_or_else(|| quote! {::std::option::Option::None});
let validator = match &validator {
Some(meta) => {
let stream = generate_validator(&crate_name, meta)?;
quote!(::std::option::Option::Some(#stream))
}
None => quote!(::std::option::Option::None),
};
let visible = visible_fn(&visible);
schema_args.push(quote! {
args.insert(#name, #crate_name::registry::MetaInputValue {
name: #name,
description: #desc,
ty: <#ty as #crate_name::Type>::create_type_info(registry),
default_value: #schema_default,
validator: #validator,
visible: #visible,
});
});
let param_ident = &ident.ident;
use_params.push(quote! { #param_ident });
let default = match default {
Some(default) => {
quote! { ::std::option::Option::Some(|| -> #ty { #default }) }
}
None => quote! { ::std::option::Option::None },
};
let param_getter_name = get_param_getter_ident(&ident.ident.unraw().to_string());
get_params.push(quote! {
#[allow(non_snake_case)]
let #param_getter_name = || -> #crate_name::ServerResult<#ty> { ctx.param_value(#name, #default) };
#[allow(non_snake_case)]
let #ident: #ty = #param_getter_name()?;
});
}
let schema_ty = ty.value_type();
let visible = visible_fn(&method_args.visible);
let complexity = if let Some(complexity) = &method_args.complexity {
match complexity {
ComplexityType::Const(n) => {
quote! { ::std::option::Option::Some(#crate_name::registry::ComplexityType::Const(#n)) }
}
ComplexityType::Fn(s) => {
let (variables, expr) = parse_complexity_expr(s)?;
let mut parse_args = Vec::new();
for variable in variables {
if let Some((
ident,
ty,
args::Argument {
name,
default,
default_with,
..
},
)) = args
.iter()
.find(|(pat_ident, _, _)| pat_ident.ident == variable)
{
let default = match generate_default(&default, &default_with)? {
Some(default) => {
quote! { ::std::option::Option::Some(|| -> #ty { #default }) }
}
None => quote! { ::std::option::Option::None },
};
let name = name.clone().unwrap_or_else(|| {
object_args.rename_args.rename(
ident.ident.unraw().to_string(),
RenameTarget::Argument,
)
});
parse_args.push(quote! {
let #ident: #ty = __ctx.param_value(__variables_definition, __field, #name, #default)?;
});
}
}
quote! {
Some(#crate_name::registry::ComplexityType::Fn(|__ctx, __variables_definition, __field, child_complexity| {
#(#parse_args)*
Ok(#expr)
}))
}
}
}
} else {
quote! { ::std::option::Option::None }
};
schema_fields.push(quote! {
#(#cfg_attrs)*
fields.push((#field_name.to_string(), #crate_name::registry::MetaField {
name: ::std::borrow::ToOwned::to_owned(#field_name),
description: #field_desc,
args: {
let mut args = #crate_name::indexmap::IndexMap::new();
#(#schema_args)*
args
},
ty: <#schema_ty as #crate_name::Type>::create_type_info(registry),
deprecation: #field_deprecation,
cache_control: #cache_control,
external: #external,
provides: #provides,
requires: #requires,
visible: #visible,
compute_complexity: #complexity,
}));
});
let field_ident = &method.sig.ident;
if let OutputType::Value(inner_ty) = &ty {
let block = &method.block;
let new_block = quote!({
{
::std::result::Result::Ok(async move {
let value:#inner_ty = #block;
value
}.await)
}
});
method.block = syn::parse2::<Block>(new_block).expect("invalid block");
method.sig.output =
syn::parse2::<ReturnType>(quote! { -> #crate_name::Result<#inner_ty> })
.expect("invalid result type");
}
let resolve_obj = quote! {
{
let res = self.#field_ident(ctx, #(#use_params),*).await;
res.map_err(|err| ::std::convert::Into::<#crate_name::Error>::into(err).into_server_error().at(ctx.item.pos))?
}
};
let guard = match &method_args.guard {
Some(meta_list) => generate_guards(&crate_name, meta_list)?,
None => None,
};
let guard = guard.map(|guard| {
quote! {
#guard.check(ctx).await
.map_err(|err| err.into_server_error().at(ctx.item.pos))?;
}
});
resolvers.push(quote! {
#(#cfg_attrs)*
if ctx.item.node.name.node == #field_name {
#(#get_params)*
#guard
let ctx_obj = ctx.with_selection_set(&ctx.item.node.selection_set);
let res = #resolve_obj;
return #crate_name::OutputType::resolve(&res, &ctx_obj, ctx.item).await.map(::std::option::Option::Some);
}
});
remove_graphql_attrs(&mut method.attrs);
}
}
let expanded = quote! {
#item_impl
#[allow(clippy::all, clippy::pedantic)]
#[#crate_name::async_trait::async_trait]
impl #generics #crate_name::ComplexObject for #self_ty#generics_params #where_clause {
fn fields(registry: &mut #crate_name::registry::Registry) -> ::std::vec::Vec<(::std::string::String, #crate_name::registry::MetaField)> {
let mut fields = ::std::vec::Vec::new();
#(#schema_fields)*
fields
}
async fn resolve_field(&self, ctx: &#crate_name::Context<'_>) -> #crate_name::ServerResult<::std::option::Option<#crate_name::Value>> {
#(#resolvers)*
::std::result::Result::Ok(::std::option::Option::None)
}
}
};
Ok(expanded.into())
}