use crate::args;
use crate::args::{InterfaceField, InterfaceFieldArgument};
use crate::output_type::OutputType;
use crate::utils::{build_value_repr, check_reserved_name, get_crate_name, get_rustdoc};
use inflector::Inflector;
use proc_macro::TokenStream;
use proc_macro2::{Ident, Span};
use quote::quote;
use std::collections::HashSet;
use syn::{Data, DeriveInput, Error, Fields, Result, Type};
pub fn generate(interface_args: &args::Interface, input: &DeriveInput) -> Result<TokenStream> {
let crate_name = get_crate_name(interface_args.internal);
let ident = &input.ident;
let generics = &input.generics;
let s = match &input.data {
Data::Enum(s) => s,
_ => {
return Err(Error::new_spanned(
input,
"Interfaces can only be applied to an enum.",
))
}
};
let extends = interface_args.extends;
let mut enum_names = Vec::new();
let mut enum_items = HashSet::new();
let mut type_into_impls = Vec::new();
let gql_typename = interface_args
.name
.clone()
.unwrap_or_else(|| ident.to_string());
check_reserved_name(&gql_typename, interface_args.internal)?;
let desc = interface_args
.desc
.clone()
.or_else(|| get_rustdoc(&input.attrs).ok().flatten())
.map(|s| quote! { Some(#s) })
.unwrap_or_else(|| quote! {None});
let mut registry_types = Vec::new();
let mut possible_types = Vec::new();
let mut collect_inline_fields = Vec::new();
let mut get_introspection_typename = Vec::new();
for variant in s.variants.iter() {
let enum_name = &variant.ident;
let field = match &variant.fields {
Fields::Unnamed(fields) if fields.unnamed.len() == 1 => fields.unnamed.first().unwrap(),
Fields::Unnamed(_) => {
return Err(Error::new_spanned(
variant,
"Only single value variants are supported",
))
}
Fields::Unit => {
return Err(Error::new_spanned(
variant,
"Empty variants are not supported",
))
}
Fields::Named(_) => {
return Err(Error::new_spanned(
variant,
"Variants with named fields are not supported",
))
}
};
if let Type::Path(p) = &field.ty {
if !enum_items.insert(p) {
return Err(Error::new_spanned(
field,
"This type already used in another variant",
));
}
type_into_impls.push(quote! {
impl #generics From<#p> for #ident #generics {
fn from(obj: #p) -> Self {
#ident::#enum_name(obj)
}
}
});
enum_names.push(enum_name);
registry_types.push(quote! {
<#p as #crate_name::Type>::create_type_info(registry);
registry.add_implements(&<#p as #crate_name::Type>::type_name(), #gql_typename);
});
possible_types.push(quote! {
possible_types.insert(<#p as #crate_name::Type>::type_name().to_string());
});
collect_inline_fields.push(quote! {
if let #ident::#enum_name(obj) = self {
return obj.collect_inline_fields(name, ctx, futures);
}
});
get_introspection_typename.push(quote! {
#ident::#enum_name(obj) => <#p as #crate_name::Type>::type_name()
})
} else {
return Err(Error::new_spanned(field, "Invalid type"));
}
}
let mut methods = Vec::new();
let mut schema_fields = Vec::new();
let mut resolvers = Vec::new();
for InterfaceField {
name,
desc,
ty,
args,
deprecation,
external,
provides,
requires,
} in &interface_args.fields
{
let method_name = Ident::new(name, Span::call_site());
let name = name.to_camel_case();
let mut calls = Vec::new();
let mut use_params = Vec::new();
let mut decl_params = Vec::new();
let mut get_params = Vec::new();
let mut schema_args = Vec::new();
let requires = match &requires {
Some(requires) => quote! { Some(#requires) },
None => quote! { None },
};
let provides = match &provides {
Some(provides) => quote! { Some(#provides) },
None => quote! { None },
};
decl_params.push(quote! { ctx: &'ctx #crate_name::Context<'ctx> });
use_params.push(quote! { ctx });
for InterfaceFieldArgument {
name,
desc,
ty,
default,
} in args
{
let ident = Ident::new(name, Span::call_site());
let name = name.to_camel_case();
decl_params.push(quote! { #ident: #ty });
use_params.push(quote! { #ident });
let param_default = match &default {
Some(default) => {
let repr = build_value_repr(&crate_name, &default);
quote! {|| #repr }
}
None => quote! { || #crate_name::Value::Null },
};
get_params.push(quote! {
let #ident: #ty = ctx.param_value(#name, #param_default)?;
});
let desc = desc
.as_ref()
.map(|s| quote! {Some(#s)})
.unwrap_or_else(|| quote! {None});
let schema_default = default
.as_ref()
.map(|v| {
let s = v.to_string();
quote! {Some(#s)}
})
.unwrap_or_else(|| quote! {None});
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: None,
});
});
}
for enum_name in &enum_names {
calls.push(quote! {
#ident::#enum_name(obj) => obj.#method_name(#(#use_params),*).await
});
}
let desc = desc
.as_ref()
.map(|s| quote! {Some(#s)})
.unwrap_or_else(|| quote! {None});
let deprecation = deprecation
.as_ref()
.map(|s| quote! {Some(#s)})
.unwrap_or_else(|| quote! {None});
let oty = OutputType::parse(ty)?;
let ty = match oty {
OutputType::Value(ty) => ty,
OutputType::Result(_, ty) => ty,
};
let schema_ty = oty.value_type();
methods.push(quote! {
#[inline]
async fn #method_name <'ctx>(&self, #(#decl_params),*) -> #crate_name::FieldResult<#ty> {
match self {
#(#calls,)*
}
}
});
schema_fields.push(quote! {
fields.insert(#name.to_string(), #crate_name::registry::MetaField {
name: #name.to_string(),
description: #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: #deprecation,
cache_control: Default::default(),
external: #external,
provides: #provides,
requires: #requires,
});
});
let resolve_obj = quote! {
self.#method_name(#(#use_params),*).await.
map_err(|err| err.into_error_with_path(ctx.position(), ctx.path_node.as_ref().unwrap().to_json()))?
};
resolvers.push(quote! {
if ctx.name.node == #name {
#(#get_params)*
let ctx_obj = ctx.with_selection_set(&ctx.selection_set);
return #crate_name::OutputValueType::resolve(&#resolve_obj, &ctx_obj, ctx.position()).await;
}
});
}
let introspection_type_name = if get_introspection_typename.is_empty() {
quote! { unreachable!() }
} else {
quote! {
match self {
#(#get_introspection_typename),*
}
}
};
let expanded = quote! {
#input
#(#type_into_impls)*
impl #generics #ident #generics {
#(#methods)*
}
impl #generics #crate_name::Type for #ident #generics {
fn type_name() -> std::borrow::Cow<'static, str> {
std::borrow::Cow::Borrowed(#gql_typename)
}
fn introspection_type_name(&self) -> std::borrow::Cow<'static, str> {
#introspection_type_name
}
fn create_type_info(registry: &mut #crate_name::registry::Registry) -> String {
registry.create_type::<Self, _>(|registry| {
#(#registry_types)*
#crate_name::registry::MetaType::Interface {
name: #gql_typename.to_string(),
description: #desc,
fields: {
let mut fields = #crate_name::indexmap::IndexMap::new();
#(#schema_fields)*
fields
},
possible_types: {
let mut possible_types = #crate_name::indexmap::IndexSet::new();
#(#possible_types)*
possible_types
},
extends: #extends,
keys: None,
}
})
}
}
#[#crate_name::async_trait::async_trait]
impl #generics #crate_name::ObjectType for #ident #generics {
async fn resolve_field(&self, ctx: &#crate_name::Context<'_>) -> #crate_name::Result<#crate_name::serde_json::Value> {
#(#resolvers)*
Err(#crate_name::QueryError::FieldNotFound {
field_name: ctx.name.to_string(),
object: #gql_typename.to_string(),
}.into_error(ctx.position()))
}
fn collect_inline_fields<'a>(
&'a self,
name: &str,
ctx: &#crate_name::ContextSelectionSet<'a>,
futures: &mut Vec<#crate_name::BoxFieldFuture<'a>>,
) -> #crate_name::Result<()> {
#(#collect_inline_fields)*
Ok(())
}
}
#[#crate_name::async_trait::async_trait]
impl #generics #crate_name::OutputValueType for #ident #generics {
async fn resolve(&self, ctx: &#crate_name::ContextSelectionSet<'_>, pos: #crate_name::Pos) -> #crate_name::Result<#crate_name::serde_json::Value> {
#crate_name::do_resolve(ctx, self).await
}
}
};
Ok(expanded.into())
}