use proc_macro::TokenStream;
use quote::quote;
use syn::ext::IdentExt;
use syn::{
Block, Error, FnArg, ImplItem, ItemImpl, Pat, ReturnType, Type, TypeImplTrait, TypeParamBound,
TypeReference,
};
use crate::args::{self, ComplexityType, RenameRuleExt, RenameTarget, SubscriptionField};
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(
subscription_args: &args::Subscription,
item_impl: &mut ItemImpl,
) -> GeneratorResult<TokenStream> {
let crate_name = get_crate_name(subscription_args.internal);
let (self_ty, self_name) = get_type_path_and_name(item_impl.self_ty.as_ref())?;
let generics = &item_impl.generics;
let where_clause = &item_impl.generics.where_clause;
let extends = subscription_args.extends;
let gql_typename = subscription_args
.name
.clone()
.unwrap_or_else(|| RenameTarget::Type.rename(self_name.clone()));
let desc = if subscription_args.use_type_description {
quote! { ::std::option::Option::Some(<Self as #crate_name::Description>::description()) }
} else {
get_rustdoc(&item_impl.attrs)?
.map(|s| quote!(::std::option::Option::Some(#s)))
.unwrap_or_else(|| quote!(::std::option::Option::None))
};
let mut create_stream = Vec::new();
let mut schema_fields = Vec::new();
for item in &mut item_impl.items {
if let ImplItem::Method(method) = item {
let field: SubscriptionField = parse_graphql_attrs(&method.attrs)?.unwrap_or_default();
if field.skip {
remove_graphql_attrs(&mut method.attrs);
continue;
}
let ident = &method.sig.ident;
let field_name = field.name.clone().unwrap_or_else(|| {
subscription_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(&field.deprecation, &crate_name);
let cfg_attrs = get_cfg_attrs(&method.attrs);
if method.sig.asyncness.is_none() {
return Err(Error::new_spanned(
&method,
"The subscription stream function must be asynchronous",
)
.into());
}
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 mut create_ctx = true;
let mut args = Vec::new();
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::SubscriptionFieldArgument>(&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());
} else {
create_ctx = false;
}
}
}
_ => {
return Err(Error::new_spanned(arg, "Incorrect argument type").into());
}
}
} else {
return Err(Error::new_spanned(arg, "Incorrect 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::SubscriptionFieldArgument {
name,
desc,
default,
default_with,
validator,
visible: arg_visible,
secret,
},
) in &args
{
let name = name.clone().unwrap_or_else(|| {
subscription_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 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 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 visible = visible_fn(&arg_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,
is_secret: #secret,
});
});
use_params.push(quote! { #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.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 = ctx.param_value(#name, #default)?;
});
}
let res_ty = ty.value_type();
let stream_ty = if let Type::ImplTrait(TypeImplTrait { bounds, .. }) = &res_ty {
let mut r = None;
for b in bounds {
if let TypeParamBound::Trait(b) = b {
r = Some(quote! { #b });
}
}
quote! { #r }
} else {
quote! { #res_ty }
};
if let OutputType::Value(inner_ty) = &ty {
let block = &method.block;
let new_block = quote!({
{
let value = (move || { async move #block })().await;
::std::result::Result::Ok(value)
}
});
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 visible = visible_fn(&field.visible);
let complexity = if let Some(complexity) = &field.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::SubscriptionFieldArgument {
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(|| {
subscription_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)*
::std::result::Result::Ok(#expr)
}))
}
}
}
} else {
quote! { ::std::option::Option::None }
};
schema_fields.push(quote! {
#(#cfg_attrs)*
fields.insert(::std::borrow::ToOwned::to_owned(#field_name), #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: <<#stream_ty as #crate_name::futures_util::stream::Stream>::Item as #crate_name::Type>::create_type_info(registry),
deprecation: #field_deprecation,
cache_control: ::std::default::Default::default(),
external: false,
requires: ::std::option::Option::None,
provides: ::std::option::Option::None,
visible: #visible,
compute_complexity: #complexity,
});
});
let create_field_stream = quote! {
self.#ident(ctx, #(#use_params),*)
.await
.map_err(|err| {
::std::convert::Into::<#crate_name::Error>::into(err).into_server_error()
.at(ctx.item.pos)
.path(#crate_name::PathSegment::Field(::std::borrow::ToOwned::to_owned(&*field_name)))
})?
};
let guard = match &field.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)
.path(#crate_name::PathSegment::Field(::std::borrow::ToOwned::to_owned(&*field_name)))
})?;
});
let stream_fn = quote! {
let field_name = ::std::clone::Clone::clone(&ctx.item.node.response_key().node);
let field = ::std::sync::Arc::new(::std::clone::Clone::clone(&ctx.item));
#(#get_params)*
#guard
let pos = ctx.item.pos;
let schema_env = ::std::clone::Clone::clone(&ctx.schema_env);
let query_env = ::std::clone::Clone::clone(&ctx.query_env);
let stream = #crate_name::futures_util::stream::StreamExt::then(#create_field_stream, {
let field_name = ::std::clone::Clone::clone(&field_name);
move |msg| {
let schema_env = ::std::clone::Clone::clone(&schema_env);
let query_env = ::std::clone::Clone::clone(&query_env);
let field = ::std::clone::Clone::clone(&field);
let field_name = ::std::clone::Clone::clone(&field_name);
async move {
let ctx_selection_set = query_env.create_context(
&schema_env,
::std::option::Option::Some(#crate_name::QueryPathNode {
parent: ::std::option::Option::None,
segment: #crate_name::QueryPathSegment::Name(&field_name),
}),
&field.node.selection_set,
);
let mut execute_fut = async {
#[allow(bare_trait_objects)]
let ri = #crate_name::extensions::ResolveInfo {
path_node: ctx_selection_set.path_node.as_ref().unwrap(),
parent_type: #gql_typename,
return_type: &<<#stream_ty as #crate_name::futures_util::stream::Stream>::Item as #crate_name::Type>::qualified_type_name(),
};
let resolve_fut = async {
#crate_name::OutputType::resolve(&msg, &ctx_selection_set, &*field)
.await
.map(::std::option::Option::Some)
};
#crate_name::futures_util::pin_mut!(resolve_fut);
query_env.extensions.resolve(ri, &mut resolve_fut).await
.map(|value| {
let mut map = ::std::collections::BTreeMap::new();
map.insert(::std::clone::Clone::clone(&field_name), value.unwrap_or_default());
#crate_name::Response::new(#crate_name::Value::Object(map))
})
.unwrap_or_else(|err| {
#crate_name::Response::from_errors(::std::vec![
err.path(#crate_name::PathSegment::Field(::std::borrow::ToOwned::to_owned(&*field_name)))
])
})
};
#crate_name::futures_util::pin_mut!(execute_fut);
::std::result::Result::Ok(query_env.extensions.execute(&mut execute_fut).await)
}
}
});
#crate_name::ServerResult::Ok(#crate_name::futures_util::stream::StreamExt::scan(
stream,
false,
|errored, item| {
if *errored {
return #crate_name::futures_util::future::ready(::std::option::Option::None);
}
match &item {
::std::result::Result::Err(_) => *errored = true,
::std::result::Result::Ok(resp) if resp.is_err() => *errored = true,
_ => {}
}
#crate_name::futures_util::future::ready(::std::option::Option::Some(item))
},
))
};
create_stream.push(quote! {
#(#cfg_attrs)*
if ctx.item.node.name.node == #field_name {
let stream = #crate_name::futures_util::stream::TryStreamExt::try_flatten(
#crate_name::futures_util::stream::once((move || async move { #stream_fn })())
);
let stream = #crate_name::futures_util::StreamExt::map(stream, |res| match res {
::std::result::Result::Ok(resp) => resp,
::std::result::Result::Err(err) => #crate_name::Response::from_errors(::std::vec![err]),
});
return ::std::option::Option::Some(::std::boxed::Box::pin(stream));
}
});
remove_graphql_attrs(&mut method.attrs);
}
}
if create_stream.is_empty() {
return Err(Error::new_spanned(
&self_ty,
"A GraphQL Object type must define one or more fields.",
)
.into());
}
let expanded = quote! {
#item_impl
#[allow(clippy::all, clippy::pedantic)]
impl #generics #crate_name::Type for #self_ty #where_clause {
fn type_name() -> ::std::borrow::Cow<'static, ::std::primitive::str> {
::std::borrow::Cow::Borrowed(#gql_typename)
}
#[allow(bare_trait_objects)]
fn create_type_info(registry: &mut #crate_name::registry::Registry) -> ::std::string::String {
registry.create_type::<Self, _>(|registry| #crate_name::registry::MetaType::Object {
name: ::std::borrow::ToOwned::to_owned(#gql_typename),
description: #desc,
fields: {
let mut fields = #crate_name::indexmap::IndexMap::new();
#(#schema_fields)*
fields
},
cache_control: ::std::default::Default::default(),
extends: #extends,
keys: ::std::option::Option::None,
visible: ::std::option::Option::None,
})
}
}
#[allow(clippy::all, clippy::pedantic)]
#[allow(unused_braces, unused_variables)]
impl #generics #crate_name::SubscriptionType for #self_ty #where_clause {
fn create_field_stream<'__life>(
&'__life self,
ctx: &'__life #crate_name::Context<'_>,
) -> ::std::option::Option<::std::pin::Pin<::std::boxed::Box<dyn #crate_name::futures_util::stream::Stream<Item = #crate_name::Response> + ::std::marker::Send + '__life>>> {
#(#create_stream)*
::std::option::Option::None
}
}
};
Ok(expanded.into())
}