/
merged_subscription.rs
91 lines (79 loc) · 3.54 KB
/
merged_subscription.rs
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use darling::ast::Data;
use proc_macro::TokenStream;
use proc_macro2::Span;
use quote::quote;
use syn::{Error, LitInt};
use crate::args::{self, RenameTarget};
use crate::utils::{get_crate_name, get_rustdoc, visible_fn, GeneratorResult};
pub fn generate(object_args: &args::MergedSubscription) -> GeneratorResult<TokenStream> {
let crate_name = get_crate_name(object_args.internal);
let ident = &object_args.ident;
let extends = object_args.extends;
let gql_typename = object_args
.name
.clone()
.unwrap_or_else(|| RenameTarget::Type.rename(ident.to_string()));
let desc = get_rustdoc(&object_args.attrs)
.map(|s| quote! { ::std::option::Option::Some(#s) })
.unwrap_or_else(|| quote! {::std::option::Option::None});
let s = match &object_args.data {
Data::Struct(e) => e,
_ => {
return Err(Error::new_spanned(
ident,
"MergedSubscription can only be applied to an struct.",
)
.into())
}
};
let types: Vec<_> = s.fields.iter().map(|field| &field.ty).collect();
let create_field_stream: proc_macro2::TokenStream = (0..types.len())
.map(|i| {
let n = LitInt::new(&i.to_string(), Span::call_site());
quote!(.or_else(|| #crate_name::SubscriptionType::create_field_stream(&self.#n, ctx)))
})
.collect();
let merged_type = types.iter().fold(
quote!(#crate_name::MergedObjectTail),
|obj, ty| quote!(#crate_name::MergedObject::<#ty, #obj>),
);
let visible = visible_fn(&object_args.visible);
let expanded = quote! {
#[allow(clippy::all, clippy::pedantic)]
impl #crate_name::SubscriptionType for #ident {
fn type_name() -> ::std::borrow::Cow<'static, ::std::primitive::str> {
::std::borrow::Cow::Borrowed(#gql_typename)
}
fn create_type_info(registry: &mut #crate_name::registry::Registry) -> #crate_name::registry::InputValueType {
registry.create_subscription_type::<Self, _>(|registry| {
let mut fields = ::std::default::Default::default();
if let #crate_name::registry::MetaType::Object {
fields: obj_fields,
..
} = registry.create_fake_subscription_type::<#merged_type>() {
fields = obj_fields;
}
#crate_name::registry::MetaType::Object(#crate_name::registry::ObjectType {
name: ::std::borrow::ToOwned::to_owned(#gql_typename),
description: #desc,
fields,
cache_control: ::std::default::Default::default(),
extends: #extends,
keys: ::std::option::Option::None,
visible: #visible,
is_subscription: true,
rust_typename: ::std::any::type_name::<Self>(),
constraints: vec![],
})
})
}
fn create_field_stream<'__life>(
&'__life self,
ctx: &'__life #crate_name::Context<'__life>
) -> ::std::option::Option<::std::pin::Pin<::std::boxed::Box<dyn #crate_name::futures_util::stream::Stream<Item = #crate_name::Response> + ::std::marker::Send + '__life>>> {
::std::option::Option::None #create_field_stream
}
}
};
Ok(expanded.into())
}