1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282
#[macro_use] extern crate quote; #[macro_use] extern crate syn; extern crate proc_macro; mod preprocess; use proc_macro2::{Span, TokenStream}; use serde_derive_internals::ast::{Container, Data, Field, Style, Variant}; use serde_derive_internals::attr::{self, Default as SerdeDefault, EnumTag}; use serde_derive_internals::{Ctxt, Derive}; use syn::spanned::Spanned; use syn::DeriveInput; #[proc_macro_derive(JsonSchema, attributes(schemars, serde))] pub fn derive_json_schema(input: proc_macro::TokenStream) -> proc_macro::TokenStream { let mut input = parse_macro_input!(input as DeriveInput); preprocess::add_trait_bounds(&mut input.generics); preprocess::rename_schemars_attrs(&mut input); let ctxt = Ctxt::new(); let cont = Container::from_ast(&ctxt, &input, Derive::Deserialize); if let Err(e) = ctxt.check() { return compile_error(input.span(), e).into(); } let schema = match cont.data { Data::Struct(Style::Unit, _) => schema_for_unit_struct(), Data::Struct(Style::Newtype, ref fields) => schema_for_newtype_struct(&fields[0]), Data::Struct(Style::Tuple, ref fields) => schema_for_tuple_struct(fields), Data::Struct(Style::Struct, ref fields) => schema_for_struct(fields, &cont.attrs), Data::Enum(ref variants) => schema_for_enum(variants, &cont.attrs), }; let type_name = cont.ident; let type_params: Vec<_> = cont.generics.type_params().map(|ty| &ty.ident).collect(); let schema_base_name = cont.attrs.name().deserialize_name(); let schema_name = if type_params.is_empty() { quote! { #schema_base_name.to_owned() } } else if type_name == schema_base_name { let mut schema_name_fmt = schema_base_name; schema_name_fmt.push_str("_For_{}"); schema_name_fmt.push_str(&"_And_{}".repeat(type_params.len() - 1)); quote! { format!(#schema_name_fmt #(,#type_params::schema_name())*) } } else { let mut schema_name_fmt = schema_base_name; for tp in &type_params { schema_name_fmt.push_str(&format!("{{{}:.0}}", tp)); } let fmt_param_names = &type_params; let type_params = &type_params; quote! { format!(#schema_name_fmt #(,#fmt_param_names=#type_params::schema_name())*) } }; let (impl_generics, ty_generics, where_clause) = cont.generics.split_for_impl(); let impl_block = quote! { #[automatically_derived] impl #impl_generics schemars::JsonSchema for #type_name #ty_generics #where_clause { fn schema_name() -> String { #schema_name } fn json_schema(gen: &mut schemars::gen::SchemaGenerator) -> schemars::Result { Ok(#schema) } }; }; proc_macro::TokenStream::from(impl_block) } fn wrap_schema_fields(schema_contents: TokenStream) -> TokenStream { quote! { schemars::schema::Schema::Object( schemars::schema::SchemaObject { #schema_contents ..Default::default() }) } } fn compile_error(span: Span, message: String) -> TokenStream { quote_spanned! {span=> compile_error!(#message); } } fn is_unit_variant(v: &Variant) -> bool { match v.style { Style::Unit => true, _ => false, } } fn schema_for_enum(variants: &[Variant], cattrs: &attr::Container) -> TokenStream { match cattrs.tag() { EnumTag::External => schema_for_external_tagged_enum(variants, cattrs), EnumTag::None => schema_for_untagged_enum(variants, cattrs), EnumTag::Internal { tag } => schema_for_internal_tagged_enum(variants, cattrs, tag), EnumTag::Adjacent { .. } => unimplemented!("Adjacent tagged enums not yet supported."), } } fn schema_for_external_tagged_enum(variants: &[Variant], cattrs: &attr::Container) -> TokenStream { let (unit_variants, complex_variants): (Vec<_>, Vec<_>) = variants.iter().partition(|v| is_unit_variant(v)); let unit_count = unit_variants.len(); let unit_names = unit_variants .into_iter() .map(|v| v.attrs.name().deserialize_name()); let unit_schema = wrap_schema_fields(quote! { enum_values: Some(vec![#(#unit_names.into()),*]), }); if complex_variants.is_empty() { return unit_schema; } let mut schemas = Vec::new(); if unit_count > 0 { schemas.push(unit_schema); } schemas.extend(complex_variants.into_iter().map(|variant| { let name = variant.attrs.name().deserialize_name(); let sub_schema = schema_for_untagged_enum_variant(variant, cattrs); wrap_schema_fields(quote! { instance_type: Some(schemars::schema::InstanceType::Object.into()), properties: { let mut props = schemars::Map::new(); props.insert(#name.to_owned(), #sub_schema); props }, required: { let mut required = schemars::Set::new(); required.insert(#name.to_owned()); required }, }) })); wrap_schema_fields(quote! { any_of: Some(vec![#(#schemas),*]), }) } fn schema_for_internal_tagged_enum( variants: &[Variant], cattrs: &attr::Container, tag_name: &str, ) -> TokenStream { let schemas = variants.iter().map(|variant| { let name = variant.attrs.name().deserialize_name(); let type_schema = wrap_schema_fields(quote! { instance_type: Some(schemars::schema::InstanceType::String.into()), enum_values: Some(vec![#name.into()]), }); let schema = wrap_schema_fields(quote! { instance_type: Some(schemars::schema::InstanceType::Object.into()), properties: { let mut props = schemars::Map::new(); props.insert(#tag_name.to_owned(), #type_schema); props }, required: { let mut required = schemars::Set::new(); required.insert(#tag_name.to_owned()); required }, }); if is_unit_variant(&variant) { schema } else { let sub_schema = schema_for_untagged_enum_variant(variant, cattrs); quote! { #schema.flatten(#sub_schema)? } } }); wrap_schema_fields(quote! { any_of: Some(vec![#(#schemas),*]), }) } fn schema_for_untagged_enum(variants: &[Variant], cattrs: &attr::Container) -> TokenStream { let schemas = variants .iter() .map(|v| schema_for_untagged_enum_variant(v, cattrs)); wrap_schema_fields(quote! { any_of: Some(vec![#(#schemas),*]), }) } fn schema_for_untagged_enum_variant(variant: &Variant, cattrs: &attr::Container) -> TokenStream { match variant.style { Style::Unit => schema_for_unit_struct(), Style::Newtype => schema_for_newtype_struct(&variant.fields[0]), Style::Tuple => schema_for_tuple_struct(&variant.fields), Style::Struct => schema_for_struct(&variant.fields, cattrs), } } fn schema_for_unit_struct() -> TokenStream { quote! { gen.subschema_for::<()>()? } } fn schema_for_newtype_struct(field: &Field) -> TokenStream { let ty = field.ty; quote_spanned! {field.original.span()=> gen.subschema_for::<#ty>()? } } fn schema_for_tuple_struct(fields: &[Field]) -> TokenStream { let types = fields.iter().map(|f| f.ty); quote! { gen.subschema_for::<(#(#types),*)>()? } } fn schema_for_struct(fields: &[Field], cattrs: &attr::Container) -> TokenStream { let (nested, flat): (Vec<_>, Vec<_>) = fields.iter().partition(|f| !f.attrs.flatten()); let container_has_default = has_default(cattrs.default()); let mut required = Vec::new(); let recurse = nested.iter().map(|f| { let name = f.attrs.name().deserialize_name(); if !container_has_default && !has_default(f.attrs.default()) { required.push(name.clone()); } let ty = f.ty; quote_spanned! {f.original.span()=> props.insert(#name.to_owned(), gen.subschema_for::<#ty>()?); } }); let schema = wrap_schema_fields(quote! { instance_type: Some(schemars::schema::InstanceType::Object.into()), properties: { let mut props = schemars::Map::new(); #(#recurse)* props }, required: { let mut required = schemars::Set::new(); #(required.insert(#required.to_owned());)* required }, }); let flattens = flat.iter().map(|f| { let ty = f.ty; quote_spanned! {f.original.span()=> .flatten(<#ty>::json_schema(gen)?)? } }); quote! { #schema #(#flattens)* } } fn has_default(d: &SerdeDefault) -> bool { match d { SerdeDefault::None => false, _ => true, } }