juniper_codegen/graphql_enum/mod.rs
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//! Code generation for [GraphQL enums][0].
//!
//! [0]: https://spec.graphql.org/October2021#sec-Enums
pub(crate) mod derive;
use proc_macro2::TokenStream;
use quote::{format_ident, quote, ToTokens};
use syn::{
ext::IdentExt as _,
parse::{Parse, ParseStream},
parse_quote,
spanned::Spanned as _,
token,
};
use crate::common::{
deprecation, filter_attrs,
parse::{
attr::{err, OptionExt as _},
ParseBufferExt as _,
},
rename, scalar, Description, SpanContainer,
};
/// Available arguments behind `#[graphql]` attribute placed on a Rust enum
/// definition, when generating code for a [GraphQL enum][0].
///
/// [0]: https://spec.graphql.org/October2021#sec-Enums
#[derive(Debug, Default)]
struct ContainerAttr {
/// Explicitly specified name of this [GraphQL enum][0].
///
/// If [`None`], then Rust enum name will be used by default.
///
/// [0]: https://spec.graphql.org/October2021#sec-Enums
name: Option<SpanContainer<String>>,
/// Explicitly specified [description][2] of this [GraphQL enum][0].
///
/// If [`None`], then Rust doc comment will be used as the [description][2],
/// if any.
///
/// [0]: https://spec.graphql.org/October2021#sec-Enums
/// [2]: https://spec.graphql.org/October2021#sec-Descriptions
description: Option<SpanContainer<Description>>,
/// Explicitly specified type of [`Context`] to use for resolving this
/// [GraphQL enum][0] type with.
///
/// If [`None`], then unit type `()` is assumed as a type of [`Context`].
///
/// [`Context`]: juniper::Context
/// [0]: https://spec.graphql.org/October2021#sec-Enums
context: Option<SpanContainer<syn::Type>>,
/// Explicitly specified type (or type parameter with its bounds) of
/// [`ScalarValue`] to resolve this [GraphQL enum][0] type with.
///
/// If [`None`], then generated code will be generic over any
/// [`ScalarValue`] type.
///
/// [`GraphQLType`]: juniper::GraphQLType
/// [`ScalarValue`]: juniper::ScalarValue
/// [0]: https://spec.graphql.org/October2021#sec-Enums
scalar: Option<SpanContainer<scalar::AttrValue>>,
/// Explicitly specified [`rename::Policy`] for all [values][1] of this
/// [GraphQL enum][0].
///
/// If [`None`], then the [`rename::Policy::ScreamingSnakeCase`] will be
/// applied by default.
///
/// [0]: https://spec.graphql.org/October2021#sec-Enums
/// [1]: https://spec.graphql.org/October2021#EnumValuesDefinition
rename_values: Option<SpanContainer<rename::Policy>>,
/// Indicator whether the generated code is intended to be used only inside
/// the [`juniper`] library.
is_internal: bool,
}
impl Parse for ContainerAttr {
fn parse(input: ParseStream<'_>) -> syn::Result<Self> {
let mut out = Self::default();
while !input.is_empty() {
let ident = input.parse_any_ident()?;
match ident.to_string().as_str() {
"name" => {
input.parse::<token::Eq>()?;
let name = input.parse::<syn::LitStr>()?;
out.name
.replace(SpanContainer::new(
ident.span(),
Some(name.span()),
name.value(),
))
.none_or_else(|_| err::dup_arg(&ident))?
}
"desc" | "description" => {
input.parse::<token::Eq>()?;
let desc = input.parse::<Description>()?;
out.description
.replace(SpanContainer::new(ident.span(), Some(desc.span()), desc))
.none_or_else(|_| err::dup_arg(&ident))?
}
"ctx" | "context" | "Context" => {
input.parse::<token::Eq>()?;
let ctx = input.parse::<syn::Type>()?;
out.context
.replace(SpanContainer::new(ident.span(), Some(ctx.span()), ctx))
.none_or_else(|_| err::dup_arg(&ident))?
}
"scalar" | "Scalar" | "ScalarValue" => {
input.parse::<token::Eq>()?;
let scl = input.parse::<scalar::AttrValue>()?;
out.scalar
.replace(SpanContainer::new(ident.span(), Some(scl.span()), scl))
.none_or_else(|_| err::dup_arg(&ident))?
}
"rename_all" => {
input.parse::<token::Eq>()?;
let val = input.parse::<syn::LitStr>()?;
out.rename_values
.replace(SpanContainer::new(
ident.span(),
Some(val.span()),
val.try_into()?,
))
.none_or_else(|_| err::dup_arg(&ident))?;
}
"internal" => {
out.is_internal = true;
}
name => {
return Err(err::unknown_arg(&ident, name));
}
}
input.try_parse::<token::Comma>()?;
}
Ok(out)
}
}
impl ContainerAttr {
/// Tries to merge two [`ContainerAttr`]s into a single one, reporting about
/// duplicates, if any.
fn try_merge(self, mut another: Self) -> syn::Result<Self> {
Ok(Self {
name: try_merge_opt!(name: self, another),
description: try_merge_opt!(description: self, another),
context: try_merge_opt!(context: self, another),
scalar: try_merge_opt!(scalar: self, another),
rename_values: try_merge_opt!(rename_values: self, another),
is_internal: self.is_internal || another.is_internal,
})
}
/// Parses [`ContainerAttr`] from the given multiple `name`d
/// [`syn::Attribute`]s placed on a trait definition.
fn from_attrs(name: &str, attrs: &[syn::Attribute]) -> syn::Result<Self> {
let mut attr = filter_attrs(name, attrs)
.map(|attr| attr.parse_args())
.try_fold(Self::default(), |prev, curr| prev.try_merge(curr?))?;
if attr.description.is_none() {
attr.description = Description::parse_from_doc_attrs(attrs)?;
}
Ok(attr)
}
}
/// Available arguments behind `#[graphql]` attribute when generating code for
/// a [GraphQL enum][0]'s [value][1].
///
/// [0]: https://spec.graphql.org/October2021#sec-Enums
/// [1]: https://spec.graphql.org/October2021#sec-Enum-Value
#[derive(Debug, Default)]
struct VariantAttr {
/// Explicitly specified name of this [GraphQL enum value][1].
///
/// If [`None`], then Rust enum variant's name will be used by default.
///
/// [1]: https://spec.graphql.org/October2021#sec-Enum-Value
name: Option<SpanContainer<String>>,
/// Explicitly specified [description][2] of this [GraphQL enum value][1].
///
/// If [`None`], then Rust doc comment will be used as the [description][2],
/// if any.
///
/// [1]: https://spec.graphql.org/October2021#sec-Enum-Value
/// [2]: https://spec.graphql.org/October2021#sec-Descriptions
description: Option<SpanContainer<Description>>,
/// Explicitly specified [deprecation][2] of this [GraphQL enum value][1].
///
/// If [`None`], then Rust `#[deprecated]` attribute will be used as the
/// [deprecation][2], if any.
///
/// [1]: https://spec.graphql.org/October2021#sec-Enum-Value
/// [2]: https://spec.graphql.org/October2021#sec--deprecated
/// [3]: https://spec.graphql.org/October2021#sel-GAHnBZDACEDDGAA_6L
deprecated: Option<SpanContainer<deprecation::Directive>>,
/// Explicitly specified marker for the Rust enum variant to be ignored and
/// not included into the code generated for a [GraphQL enum][0]
/// implementation.
///
/// [0]: https://spec.graphql.org/October20210#sec-Enums
ignore: Option<SpanContainer<syn::Ident>>,
}
impl Parse for VariantAttr {
fn parse(input: ParseStream<'_>) -> syn::Result<Self> {
let mut out = Self::default();
while !input.is_empty() {
let ident = input.parse_any_ident()?;
match ident.to_string().as_str() {
"name" => {
input.parse::<token::Eq>()?;
let name = input.parse::<syn::LitStr>()?;
out.name
.replace(SpanContainer::new(
ident.span(),
Some(name.span()),
name.value(),
))
.none_or_else(|_| err::dup_arg(&ident))?
}
"desc" | "description" => {
input.parse::<token::Eq>()?;
let desc = input.parse::<Description>()?;
out.description
.replace(SpanContainer::new(ident.span(), Some(desc.span()), desc))
.none_or_else(|_| err::dup_arg(&ident))?
}
"deprecated" => {
let directive = input.parse::<deprecation::Directive>()?;
out.deprecated
.replace(SpanContainer::new(
ident.span(),
directive.reason.as_ref().map(|r| r.span()),
directive,
))
.none_or_else(|_| err::dup_arg(&ident))?
}
"ignore" | "skip" => out
.ignore
.replace(SpanContainer::new(ident.span(), None, ident.clone()))
.none_or_else(|_| err::dup_arg(&ident))?,
name => {
return Err(err::unknown_arg(&ident, name));
}
}
input.try_parse::<token::Comma>()?;
}
Ok(out)
}
}
impl VariantAttr {
/// Tries to merge two [`VariantAttr`]s into a single one, reporting about
/// duplicates, if any.
fn try_merge(self, mut another: Self) -> syn::Result<Self> {
Ok(Self {
name: try_merge_opt!(name: self, another),
description: try_merge_opt!(description: self, another),
deprecated: try_merge_opt!(deprecated: self, another),
ignore: try_merge_opt!(ignore: self, another),
})
}
/// Parses [`VariantAttr`] from the given multiple `name`d
/// [`syn::Attribute`]s placed on a trait definition.
fn from_attrs(name: &str, attrs: &[syn::Attribute]) -> syn::Result<Self> {
let mut attr = filter_attrs(name, attrs)
.map(|attr| attr.parse_args())
.try_fold(Self::default(), |prev, curr| prev.try_merge(curr?))?;
if attr.description.is_none() {
attr.description = Description::parse_from_doc_attrs(attrs)?;
}
if attr.deprecated.is_none() {
attr.deprecated = deprecation::Directive::parse_from_deprecated_attr(attrs)?;
}
Ok(attr)
}
}
/// Representation of a [GraphQL enum value][1] for code generation.
///
/// [1]: https://spec.graphql.org/October2021#sec-Enum-Value
#[derive(Debug)]
struct ValueDefinition {
/// [`Ident`] of the Rust enum variant behind this [GraphQL enum value][1].
///
/// [`Ident`]: syn::Ident
/// [1]: https://spec.graphql.org/October2021#sec-Enum-Value
ident: syn::Ident,
/// Name of this [GraphQL enum value][1] in GraphQL schema.
///
/// [1]: https://spec.graphql.org/October2021#sec-Enum-Value
name: Box<str>,
/// [Description][2] of this [GraphQL enum value][1] to put into GraphQL
/// schema.
///
/// [1]: https://spec.graphql.org/October2021#sec-Enum-Value
/// [2]: https://spec.graphql.org/October2021#sec-Descriptions
description: Option<Description>,
/// [Deprecation][2] of this [GraphQL enum value][1] to put into GraphQL
/// schema.
///
/// [1]: https://spec.graphql.org/October2021#sec-Enum-Value
/// [2]: https://spec.graphql.org/October2021#sec--deprecated
deprecated: Option<deprecation::Directive>,
}
/// Representation of a [GraphQL enum][0] for code generation.
///
/// [0]: https://spec.graphql.org/October2021#sec-Enums
struct Definition {
/// [`Ident`] of the Rust enum behind this [GraphQL enum][0].
///
/// [0]: https://spec.graphql.org/October2021#sec-Enums
ident: syn::Ident,
/// [`Generics`] of the Rust enum behind this [GraphQL enum][0].
///
/// [`Generics`]: syn::Generics
/// [0]: https://spec.graphql.org/October2021#sec-Enums
generics: syn::Generics,
/// Name of this [GraphQL enum][0] in GraphQL schema.
///
/// [0]: https://spec.graphql.org/October2021#sec-Enums
name: Box<str>,
/// [Description][2] of this [GraphQL enum][0] to put into GraphQL schema.
///
/// [0]: https://spec.graphql.org/October2021#sec-Enums
/// [2]: https://spec.graphql.org/October2021#sec-Descriptions
description: Option<Description>,
/// Rust type of [`Context`] to generate [`GraphQLType`] implementation with
/// for this [GraphQL enum][0].
///
/// [`GraphQLType`]: juniper::GraphQLType
/// [`Context`]: juniper::Context
/// [0]: https://spec.graphql.org/October2021#sec-Enums
context: syn::Type,
/// [`ScalarValue`] parametrization to generate [`GraphQLType`]
/// implementation with for this [GraphQL enum][0].
///
/// [`GraphQLType`]: juniper::GraphQLType
/// [`ScalarValue`]: juniper::ScalarValue
/// [0]: https://spec.graphql.org/October2021#sec-Enums
scalar: scalar::Type,
/// [Values][1] of this [GraphQL enum][0].
///
/// [0]: https://spec.graphql.org/October2021#sec-Enums
/// [1]: https://spec.graphql.org/October2021#EnumValuesDefinition
values: Vec<ValueDefinition>,
/// Indicates whether the Rust enum behind this [GraphQL enum][0] contains
/// ignored variants.
///
/// [0]: https://spec.graphql.org/October2021#sec-Enums
has_ignored_variants: bool,
}
impl ToTokens for Definition {
fn to_tokens(&self, into: &mut TokenStream) {
self.impl_input_and_output_type_tokens().to_tokens(into);
self.impl_graphql_type_tokens().to_tokens(into);
self.impl_graphql_value_tokens().to_tokens(into);
self.impl_graphql_value_async_tokens().to_tokens(into);
self.impl_from_input_value_tokens().to_tokens(into);
self.impl_to_input_value_tokens().to_tokens(into);
self.impl_reflection_traits_tokens().to_tokens(into);
}
}
impl Definition {
/// Returns generated code implementing [`marker::IsOutputType`] trait for
/// this [GraphQL enum][0].
///
/// [`marker::IsOutputType`]: juniper::marker::IsOutputType
/// [0]: https://spec.graphql.org/October2021#sec-Enums
fn impl_input_and_output_type_tokens(&self) -> TokenStream {
let ident = &self.ident;
let scalar = &self.scalar;
let generics = self.impl_generics(false);
let (impl_generics, _, where_clause) = generics.split_for_impl();
let (_, ty_generics, _) = self.generics.split_for_impl();
quote! {
#[automatically_derived]
impl #impl_generics ::juniper::marker::IsInputType<#scalar>
for #ident #ty_generics
#where_clause {}
#[automatically_derived]
impl #impl_generics ::juniper::marker::IsOutputType<#scalar>
for #ident #ty_generics
#where_clause {}
}
}
/// Returns generated code implementing [`GraphQLType`] trait for this
/// [GraphQL enum][0].
///
/// [`GraphQLType`]: juniper::GraphQLType
/// [0]: https://spec.graphql.org/October2021#sec-Enums
fn impl_graphql_type_tokens(&self) -> TokenStream {
let ident = &self.ident;
let scalar = &self.scalar;
let generics = self.impl_generics(false);
let (impl_generics, _, where_clause) = generics.split_for_impl();
let (_, ty_generics, _) = self.generics.split_for_impl();
let name = &self.name;
let description = &self.description;
let variants_meta = self.values.iter().map(|v| {
let v_name = &v.name;
let v_description = &v.description;
let v_deprecation = &v.deprecated;
quote! {
::juniper::meta::EnumValue::new(#v_name)
#v_description
#v_deprecation
}
});
quote! {
#[automatically_derived]
impl #impl_generics ::juniper::GraphQLType<#scalar>
for #ident #ty_generics
#where_clause
{
fn name(
_ : &Self::TypeInfo,
) -> ::core::option::Option<&'static ::core::primitive::str> {
::core::option::Option::Some(#name)
}
fn meta<'r>(
info: &Self::TypeInfo,
registry: &mut ::juniper::Registry<'r, #scalar>
) -> ::juniper::meta::MetaType<'r, #scalar>
where #scalar: 'r,
{
let variants = [#( #variants_meta ),*];
registry.build_enum_type::<#ident #ty_generics>(info, &variants)
#description
.into_meta()
}
}
}
}
/// Returns generated code implementing [`GraphQLValue`] trait for this
/// [GraphQL enum][0].
///
/// [`GraphQLValue`]: juniper::GraphQLValue
/// [0]: https://spec.graphql.org/October2021#sec-Enums
fn impl_graphql_value_tokens(&self) -> TokenStream {
let ident = &self.ident;
let scalar = &self.scalar;
let context = &self.context;
let generics = self.impl_generics(false);
let (impl_generics, _, where_clause) = generics.split_for_impl();
let (_, ty_generics, _) = self.generics.split_for_impl();
let variants = self.values.iter().map(|v| {
let ident = &v.ident;
let name = &v.name;
quote! {
Self::#ident => ::core::result::Result::Ok(::juniper::Value::scalar(
::std::string::String::from(#name),
)),
}
});
let ignored = self.has_ignored_variants.then(|| {
quote! {
_ => ::core::result::Result::Err(::juniper::FieldError::<#scalar>::from(
"Cannot resolve ignored enum variant",
)),
}
});
quote! {
impl #impl_generics ::juniper::GraphQLValue<#scalar>
for #ident #ty_generics
#where_clause
{
type Context = #context;
type TypeInfo = ();
fn type_name<'__i>(
&self,
info: &'__i Self::TypeInfo,
) -> ::core::option::Option<&'__i ::core::primitive::str> {
<Self as ::juniper::GraphQLType<#scalar>>::name(info)
}
fn resolve(
&self,
_: &(),
_: ::core::option::Option<&[::juniper::Selection<#scalar>]>,
_: &::juniper::Executor<Self::Context, #scalar>,
) -> ::juniper::ExecutionResult<#scalar> {
match self {
#( #variants )*
#ignored
}
}
}
}
}
/// Returns generated code implementing [`GraphQLValueAsync`] trait for this
/// [GraphQL enum][0].
///
/// [`GraphQLValueAsync`]: juniper::GraphQLValueAsync
/// [0]: https://spec.graphql.org/October2021#sec-Enums
fn impl_graphql_value_async_tokens(&self) -> TokenStream {
let ident = &self.ident;
let scalar = &self.scalar;
let generics = self.impl_generics(true);
let (impl_generics, _, where_clause) = generics.split_for_impl();
let (_, ty_generics, _) = self.generics.split_for_impl();
quote! {
impl #impl_generics ::juniper::GraphQLValueAsync<#scalar>
for #ident #ty_generics
#where_clause
{
fn resolve_async<'__a>(
&'__a self,
info: &'__a Self::TypeInfo,
selection_set: ::core::option::Option<&'__a [::juniper::Selection<#scalar>]>,
executor: &'__a ::juniper::Executor<Self::Context, #scalar>,
) -> ::juniper::BoxFuture<'__a, ::juniper::ExecutionResult<#scalar>> {
let v = ::juniper::GraphQLValue::resolve(self, info, selection_set, executor);
::std::boxed::Box::pin(::juniper::futures::future::ready(v))
}
}
}
}
/// Returns generated code implementing [`FromInputValue`] trait for this
/// [GraphQL enum][0].
///
/// [`FromInputValue`]: juniper::FromInputValue
/// [0]: https://spec.graphql.org/October2021#sec-Enums
fn impl_from_input_value_tokens(&self) -> TokenStream {
let ident = &self.ident;
let scalar = &self.scalar;
let generics = self.impl_generics(false);
let (impl_generics, _, where_clause) = generics.split_for_impl();
let (_, ty_generics, _) = self.generics.split_for_impl();
let variants = self.values.iter().map(|v| {
let ident = &v.ident;
let name = &v.name;
quote! {
::core::option::Option::Some(#name) => ::core::result::Result::Ok(Self::#ident),
}
});
quote! {
impl #impl_generics ::juniper::FromInputValue<#scalar>
for #ident #ty_generics
#where_clause
{
type Error = ::std::string::String;
fn from_input_value(
v: &::juniper::InputValue<#scalar>,
) -> ::core::result::Result<Self, Self::Error> {
match v.as_enum_value().or_else(|| v.as_string_value()) {
#( #variants )*
_ => ::core::result::Result::Err(
::std::format!("Unknown enum value: {}", v),
),
}
}
}
}
}
/// Returns generated code implementing [`ToInputValue`] trait for this
/// [GraphQL enum][0].
///
/// [`ToInputValue`]: juniper::ToInputValue
/// [0]: https://spec.graphql.org/October2021#sec-Enums
fn impl_to_input_value_tokens(&self) -> TokenStream {
let ident = &self.ident;
let scalar = &self.scalar;
let generics = self.impl_generics(false);
let (impl_generics, _, where_clause) = generics.split_for_impl();
let (_, ty_generics, _) = self.generics.split_for_impl();
let variants = self.values.iter().map(|v| {
let var_ident = &v.ident;
let name = &v.name;
quote! {
#ident::#var_ident => ::juniper::InputValue::<#scalar>::scalar(
::std::string::String::from(#name),
),
}
});
let ignored = self.has_ignored_variants.then(|| {
quote! {
_ => ::core::panic!("Cannot resolve ignored enum variant"),
}
});
quote! {
impl #impl_generics ::juniper::ToInputValue<#scalar>
for #ident #ty_generics
#where_clause
{
fn to_input_value(&self) -> ::juniper::InputValue<#scalar> {
match self {
#( #variants )*
#ignored
}
}
}
}
}
/// Returns generated code implementing [`BaseType`], [`BaseSubTypes`] and
/// [`WrappedType`] traits for this [GraphQL enum][0].
///
/// [`BaseSubTypes`]: juniper::macros::reflect::BaseSubTypes
/// [`BaseType`]: juniper::macros::reflect::BaseType
/// [`WrappedType`]: juniper::macros::reflect::WrappedType
/// [0]: https://spec.graphql.org/October2021#sec-Enums
fn impl_reflection_traits_tokens(&self) -> TokenStream {
let ident = &self.ident;
let name = &self.name;
let scalar = &self.scalar;
let generics = self.impl_generics(false);
let (impl_generics, _, where_clause) = generics.split_for_impl();
let (_, ty_generics, _) = self.generics.split_for_impl();
quote! {
impl #impl_generics ::juniper::macros::reflect::BaseType<#scalar>
for #ident #ty_generics
#where_clause
{
const NAME: ::juniper::macros::reflect::Type = #name;
}
impl #impl_generics ::juniper::macros::reflect::BaseSubTypes<#scalar>
for #ident #ty_generics
#where_clause
{
const NAMES: ::juniper::macros::reflect::Types =
&[<Self as ::juniper::macros::reflect::BaseType<#scalar>>::NAME];
}
impl #impl_generics ::juniper::macros::reflect::WrappedType<#scalar>
for #ident #ty_generics
#where_clause
{
const VALUE: ::juniper::macros::reflect::WrappedValue = 1;
}
}
}
/// Returns prepared [`syn::Generics`] for [`GraphQLType`] trait (and
/// similar) implementation of this enum.
///
/// If `for_async` is `true`, then additional predicates are added to suit
/// the [`GraphQLAsyncValue`] trait (and similar) requirements.
///
/// [`GraphQLAsyncValue`]: juniper::GraphQLAsyncValue
/// [`GraphQLType`]: juniper::GraphQLType
fn impl_generics(&self, for_async: bool) -> syn::Generics {
let mut generics = self.generics.clone();
let scalar = &self.scalar;
if scalar.is_implicit_generic() {
generics.params.push(parse_quote! { #scalar });
}
if scalar.is_generic() {
generics
.make_where_clause()
.predicates
.push(parse_quote! { #scalar: ::juniper::ScalarValue });
}
if let Some(bound) = scalar.bounds() {
generics.make_where_clause().predicates.push(bound);
}
if for_async {
let self_ty = if self.generics.lifetimes().next().is_some() {
// Modify lifetime names to omit "lifetime name `'a` shadows a
// lifetime name that is already in scope" error.
let mut generics = self.generics.clone();
for lt in generics.lifetimes_mut() {
let ident = lt.lifetime.ident.unraw();
lt.lifetime.ident = format_ident!("__fa__{ident}");
}
let lifetimes = generics.lifetimes().map(|lt| <.lifetime);
let ident = &self.ident;
let (_, ty_generics, _) = generics.split_for_impl();
quote! { for<#( #lifetimes ),*> #ident #ty_generics }
} else {
quote! { Self }
};
generics
.make_where_clause()
.predicates
.push(parse_quote! { #self_ty: ::core::marker::Sync });
if scalar.is_generic() {
generics
.make_where_clause()
.predicates
.push(parse_quote! { #scalar: ::core::marker::Send + ::core::marker::Sync });
}
}
generics
}
}