diff options
Diffstat (limited to 'third_party/rust/serde_derive/src/de.rs')
| -rw-r--r-- | third_party/rust/serde_derive/src/de.rs | 3148 |
1 files changed, 3148 insertions, 0 deletions
diff --git a/third_party/rust/serde_derive/src/de.rs b/third_party/rust/serde_derive/src/de.rs new file mode 100644 index 0000000000..e3b737c61c --- /dev/null +++ b/third_party/rust/serde_derive/src/de.rs @@ -0,0 +1,3148 @@ +use crate::fragment::{Expr, Fragment, Match, Stmts}; +use crate::internals::ast::{Container, Data, Field, Style, Variant}; +use crate::internals::{attr, replace_receiver, ungroup, Ctxt, Derive}; +use crate::{bound, dummy, pretend, this}; +use proc_macro2::{Literal, Span, TokenStream}; +use quote::{quote, quote_spanned, ToTokens}; +use std::collections::BTreeSet; +use std::ptr; +use syn::punctuated::Punctuated; +use syn::spanned::Spanned; +use syn::{parse_quote, Ident, Index, Member}; + +pub fn expand_derive_deserialize(input: &mut syn::DeriveInput) -> syn::Result<TokenStream> { + replace_receiver(input); + + let ctxt = Ctxt::new(); + let cont = match Container::from_ast(&ctxt, input, Derive::Deserialize) { + Some(cont) => cont, + None => return Err(ctxt.check().unwrap_err()), + }; + precondition(&ctxt, &cont); + ctxt.check()?; + + let ident = &cont.ident; + let params = Parameters::new(&cont); + let (de_impl_generics, _, ty_generics, where_clause) = split_with_de_lifetime(¶ms); + let body = Stmts(deserialize_body(&cont, ¶ms)); + let delife = params.borrowed.de_lifetime(); + let serde = cont.attrs.serde_path(); + + let impl_block = if let Some(remote) = cont.attrs.remote() { + let vis = &input.vis; + let used = pretend::pretend_used(&cont, params.is_packed); + quote! { + impl #de_impl_generics #ident #ty_generics #where_clause { + #vis fn deserialize<__D>(__deserializer: __D) -> #serde::__private::Result<#remote #ty_generics, __D::Error> + where + __D: #serde::Deserializer<#delife>, + { + #used + #body + } + } + } + } else { + let fn_deserialize_in_place = deserialize_in_place_body(&cont, ¶ms); + + quote! { + #[automatically_derived] + impl #de_impl_generics #serde::Deserialize<#delife> for #ident #ty_generics #where_clause { + fn deserialize<__D>(__deserializer: __D) -> #serde::__private::Result<Self, __D::Error> + where + __D: #serde::Deserializer<#delife>, + { + #body + } + + #fn_deserialize_in_place + } + } + }; + + Ok(dummy::wrap_in_const( + cont.attrs.custom_serde_path(), + impl_block, + )) +} + +fn precondition(cx: &Ctxt, cont: &Container) { + precondition_sized(cx, cont); + precondition_no_de_lifetime(cx, cont); +} + +fn precondition_sized(cx: &Ctxt, cont: &Container) { + if let Data::Struct(_, fields) = &cont.data { + if let Some(last) = fields.last() { + if let syn::Type::Slice(_) = ungroup(last.ty) { + cx.error_spanned_by( + cont.original, + "cannot deserialize a dynamically sized struct", + ); + } + } + } +} + +fn precondition_no_de_lifetime(cx: &Ctxt, cont: &Container) { + if let BorrowedLifetimes::Borrowed(_) = borrowed_lifetimes(cont) { + for param in cont.generics.lifetimes() { + if param.lifetime.to_string() == "'de" { + cx.error_spanned_by( + ¶m.lifetime, + "cannot deserialize when there is a lifetime parameter called 'de", + ); + return; + } + } + } +} + +struct Parameters { + /// Name of the type the `derive` is on. + local: syn::Ident, + + /// Path to the type the impl is for. Either a single `Ident` for local + /// types (does not include generic parameters) or `some::remote::Path` for + /// remote types. + this_type: syn::Path, + + /// Same as `this_type` but using `::<T>` for generic parameters for use in + /// expression position. + this_value: syn::Path, + + /// Generics including any explicit and inferred bounds for the impl. + generics: syn::Generics, + + /// Lifetimes borrowed from the deserializer. These will become bounds on + /// the `'de` lifetime of the deserializer. + borrowed: BorrowedLifetimes, + + /// At least one field has a serde(getter) attribute, implying that the + /// remote type has a private field. + has_getter: bool, + + /// Type has a repr(packed) attribute. + is_packed: bool, +} + +impl Parameters { + fn new(cont: &Container) -> Self { + let local = cont.ident.clone(); + let this_type = this::this_type(cont); + let this_value = this::this_value(cont); + let borrowed = borrowed_lifetimes(cont); + let generics = build_generics(cont, &borrowed); + let has_getter = cont.data.has_getter(); + let is_packed = cont.attrs.is_packed(); + + Parameters { + local, + this_type, + this_value, + generics, + borrowed, + has_getter, + is_packed, + } + } + + /// Type name to use in error messages and `&'static str` arguments to + /// various Deserializer methods. + fn type_name(&self) -> String { + self.this_type.segments.last().unwrap().ident.to_string() + } +} + +// All the generics in the input, plus a bound `T: Deserialize` for each generic +// field type that will be deserialized by us, plus a bound `T: Default` for +// each generic field type that will be set to a default value. +fn build_generics(cont: &Container, borrowed: &BorrowedLifetimes) -> syn::Generics { + let generics = bound::without_defaults(cont.generics); + + let generics = bound::with_where_predicates_from_fields(cont, &generics, attr::Field::de_bound); + + let generics = + bound::with_where_predicates_from_variants(cont, &generics, attr::Variant::de_bound); + + match cont.attrs.de_bound() { + Some(predicates) => bound::with_where_predicates(&generics, predicates), + None => { + let generics = match *cont.attrs.default() { + attr::Default::Default => bound::with_self_bound( + cont, + &generics, + &parse_quote!(_serde::__private::Default), + ), + attr::Default::None | attr::Default::Path(_) => generics, + }; + + let delife = borrowed.de_lifetime(); + let generics = bound::with_bound( + cont, + &generics, + needs_deserialize_bound, + &parse_quote!(_serde::Deserialize<#delife>), + ); + + bound::with_bound( + cont, + &generics, + requires_default, + &parse_quote!(_serde::__private::Default), + ) + } + } +} + +// Fields with a `skip_deserializing` or `deserialize_with` attribute, or which +// belong to a variant with a `skip_deserializing` or `deserialize_with` +// attribute, are not deserialized by us so we do not generate a bound. Fields +// with a `bound` attribute specify their own bound so we do not generate one. +// All other fields may need a `T: Deserialize` bound where T is the type of the +// field. +fn needs_deserialize_bound(field: &attr::Field, variant: Option<&attr::Variant>) -> bool { + !field.skip_deserializing() + && field.deserialize_with().is_none() + && field.de_bound().is_none() + && variant.map_or(true, |variant| { + !variant.skip_deserializing() + && variant.deserialize_with().is_none() + && variant.de_bound().is_none() + }) +} + +// Fields with a `default` attribute (not `default=...`), and fields with a +// `skip_deserializing` attribute that do not also have `default=...`. +fn requires_default(field: &attr::Field, _variant: Option<&attr::Variant>) -> bool { + if let attr::Default::Default = *field.default() { + true + } else { + false + } +} + +enum BorrowedLifetimes { + Borrowed(BTreeSet<syn::Lifetime>), + Static, +} + +impl BorrowedLifetimes { + fn de_lifetime(&self) -> syn::Lifetime { + match *self { + BorrowedLifetimes::Borrowed(_) => syn::Lifetime::new("'de", Span::call_site()), + BorrowedLifetimes::Static => syn::Lifetime::new("'static", Span::call_site()), + } + } + + fn de_lifetime_param(&self) -> Option<syn::LifetimeParam> { + match self { + BorrowedLifetimes::Borrowed(bounds) => Some(syn::LifetimeParam { + attrs: Vec::new(), + lifetime: syn::Lifetime::new("'de", Span::call_site()), + colon_token: None, + bounds: bounds.iter().cloned().collect(), + }), + BorrowedLifetimes::Static => None, + } + } +} + +// The union of lifetimes borrowed by each field of the container. +// +// These turn into bounds on the `'de` lifetime of the Deserialize impl. If +// lifetimes `'a` and `'b` are borrowed but `'c` is not, the impl is: +// +// impl<'de: 'a + 'b, 'a, 'b, 'c> Deserialize<'de> for S<'a, 'b, 'c> +// +// If any borrowed lifetime is `'static`, then `'de: 'static` would be redundant +// and we use plain `'static` instead of `'de`. +fn borrowed_lifetimes(cont: &Container) -> BorrowedLifetimes { + let mut lifetimes = BTreeSet::new(); + for field in cont.data.all_fields() { + if !field.attrs.skip_deserializing() { + lifetimes.extend(field.attrs.borrowed_lifetimes().iter().cloned()); + } + } + if lifetimes.iter().any(|b| b.to_string() == "'static") { + BorrowedLifetimes::Static + } else { + BorrowedLifetimes::Borrowed(lifetimes) + } +} + +fn deserialize_body(cont: &Container, params: &Parameters) -> Fragment { + if cont.attrs.transparent() { + deserialize_transparent(cont, params) + } else if let Some(type_from) = cont.attrs.type_from() { + deserialize_from(type_from) + } else if let Some(type_try_from) = cont.attrs.type_try_from() { + deserialize_try_from(type_try_from) + } else if let attr::Identifier::No = cont.attrs.identifier() { + match &cont.data { + Data::Enum(variants) => deserialize_enum(params, variants, &cont.attrs), + Data::Struct(Style::Struct, fields) => { + deserialize_struct(params, fields, &cont.attrs, StructForm::Struct) + } + Data::Struct(Style::Tuple, fields) | Data::Struct(Style::Newtype, fields) => { + deserialize_tuple(params, fields, &cont.attrs, TupleForm::Tuple) + } + Data::Struct(Style::Unit, _) => deserialize_unit_struct(params, &cont.attrs), + } + } else { + match &cont.data { + Data::Enum(variants) => deserialize_custom_identifier(params, variants, &cont.attrs), + Data::Struct(_, _) => unreachable!("checked in serde_derive_internals"), + } + } +} + +#[cfg(feature = "deserialize_in_place")] +fn deserialize_in_place_body(cont: &Container, params: &Parameters) -> Option<Stmts> { + // Only remote derives have getters, and we do not generate + // deserialize_in_place for remote derives. + assert!(!params.has_getter); + + if cont.attrs.transparent() + || cont.attrs.type_from().is_some() + || cont.attrs.type_try_from().is_some() + || cont.attrs.identifier().is_some() + || cont + .data + .all_fields() + .all(|f| f.attrs.deserialize_with().is_some()) + { + return None; + } + + let code = match &cont.data { + Data::Struct(Style::Struct, fields) => { + deserialize_struct_in_place(params, fields, &cont.attrs)? + } + Data::Struct(Style::Tuple, fields) | Data::Struct(Style::Newtype, fields) => { + deserialize_tuple_in_place(params, fields, &cont.attrs) + } + Data::Enum(_) | Data::Struct(Style::Unit, _) => { + return None; + } + }; + + let delife = params.borrowed.de_lifetime(); + let stmts = Stmts(code); + + let fn_deserialize_in_place = quote_block! { + fn deserialize_in_place<__D>(__deserializer: __D, __place: &mut Self) -> _serde::__private::Result<(), __D::Error> + where + __D: _serde::Deserializer<#delife>, + { + #stmts + } + }; + + Some(Stmts(fn_deserialize_in_place)) +} + +#[cfg(not(feature = "deserialize_in_place"))] +fn deserialize_in_place_body(_cont: &Container, _params: &Parameters) -> Option<Stmts> { + None +} + +fn deserialize_transparent(cont: &Container, params: &Parameters) -> Fragment { + let fields = match &cont.data { + Data::Struct(_, fields) => fields, + Data::Enum(_) => unreachable!(), + }; + + let this_value = ¶ms.this_value; + let transparent_field = fields.iter().find(|f| f.attrs.transparent()).unwrap(); + + let path = match transparent_field.attrs.deserialize_with() { + Some(path) => quote!(#path), + None => { + let span = transparent_field.original.span(); + quote_spanned!(span=> _serde::Deserialize::deserialize) + } + }; + + let assign = fields.iter().map(|field| { + let member = &field.member; + if ptr::eq(field, transparent_field) { + quote!(#member: __transparent) + } else { + let value = match field.attrs.default() { + attr::Default::Default => quote!(_serde::__private::Default::default()), + attr::Default::Path(path) => quote!(#path()), + attr::Default::None => quote!(_serde::__private::PhantomData), + }; + quote!(#member: #value) + } + }); + + quote_block! { + _serde::__private::Result::map( + #path(__deserializer), + |__transparent| #this_value { #(#assign),* }) + } +} + +fn deserialize_from(type_from: &syn::Type) -> Fragment { + quote_block! { + _serde::__private::Result::map( + <#type_from as _serde::Deserialize>::deserialize(__deserializer), + _serde::__private::From::from) + } +} + +fn deserialize_try_from(type_try_from: &syn::Type) -> Fragment { + quote_block! { + _serde::__private::Result::and_then( + <#type_try_from as _serde::Deserialize>::deserialize(__deserializer), + |v| _serde::__private::TryFrom::try_from(v).map_err(_serde::de::Error::custom)) + } +} + +fn deserialize_unit_struct(params: &Parameters, cattrs: &attr::Container) -> Fragment { + let this_type = ¶ms.this_type; + let this_value = ¶ms.this_value; + let type_name = cattrs.name().deserialize_name(); + let (de_impl_generics, de_ty_generics, ty_generics, where_clause) = + split_with_de_lifetime(params); + let delife = params.borrowed.de_lifetime(); + + let expecting = format!("unit struct {}", params.type_name()); + let expecting = cattrs.expecting().unwrap_or(&expecting); + + quote_block! { + #[doc(hidden)] + struct __Visitor #de_impl_generics #where_clause { + marker: _serde::__private::PhantomData<#this_type #ty_generics>, + lifetime: _serde::__private::PhantomData<&#delife ()>, + } + + impl #de_impl_generics _serde::de::Visitor<#delife> for __Visitor #de_ty_generics #where_clause { + type Value = #this_type #ty_generics; + + fn expecting(&self, __formatter: &mut _serde::__private::Formatter) -> _serde::__private::fmt::Result { + _serde::__private::Formatter::write_str(__formatter, #expecting) + } + + #[inline] + fn visit_unit<__E>(self) -> _serde::__private::Result<Self::Value, __E> + where + __E: _serde::de::Error, + { + _serde::__private::Ok(#this_value) + } + } + + _serde::Deserializer::deserialize_unit_struct( + __deserializer, + #type_name, + __Visitor { + marker: _serde::__private::PhantomData::<#this_type #ty_generics>, + lifetime: _serde::__private::PhantomData, + }, + ) + } +} + +enum TupleForm<'a> { + Tuple, + /// Contains a variant name + ExternallyTagged(&'a syn::Ident), + /// Contains a variant name and an intermediate deserializer from which actual + /// deserialization will be performed + Untagged(&'a syn::Ident, TokenStream), +} + +fn deserialize_tuple( + params: &Parameters, + fields: &[Field], + cattrs: &attr::Container, + form: TupleForm, +) -> Fragment { + assert!(!cattrs.has_flatten()); + + let field_count = fields + .iter() + .filter(|field| !field.attrs.skip_deserializing()) + .count(); + + let this_type = ¶ms.this_type; + let this_value = ¶ms.this_value; + let (de_impl_generics, de_ty_generics, ty_generics, where_clause) = + split_with_de_lifetime(params); + let delife = params.borrowed.de_lifetime(); + + // If there are getters (implying private fields), construct the local type + // and use an `Into` conversion to get the remote type. If there are no + // getters then construct the target type directly. + let construct = if params.has_getter { + let local = ¶ms.local; + quote!(#local) + } else { + quote!(#this_value) + }; + + let type_path = match form { + TupleForm::Tuple => construct, + TupleForm::ExternallyTagged(variant_ident) | TupleForm::Untagged(variant_ident, _) => { + quote!(#construct::#variant_ident) + } + }; + let expecting = match form { + TupleForm::Tuple => format!("tuple struct {}", params.type_name()), + TupleForm::ExternallyTagged(variant_ident) | TupleForm::Untagged(variant_ident, _) => { + format!("tuple variant {}::{}", params.type_name(), variant_ident) + } + }; + let expecting = cattrs.expecting().unwrap_or(&expecting); + + let nfields = fields.len(); + + let visit_newtype_struct = match form { + TupleForm::Tuple if nfields == 1 => { + Some(deserialize_newtype_struct(&type_path, params, &fields[0])) + } + _ => None, + }; + + let visit_seq = Stmts(deserialize_seq( + &type_path, params, fields, false, cattrs, expecting, + )); + + let visitor_expr = quote! { + __Visitor { + marker: _serde::__private::PhantomData::<#this_type #ty_generics>, + lifetime: _serde::__private::PhantomData, + } + }; + let dispatch = match form { + TupleForm::Tuple if nfields == 1 => { + let type_name = cattrs.name().deserialize_name(); + quote! { + _serde::Deserializer::deserialize_newtype_struct(__deserializer, #type_name, #visitor_expr) + } + } + TupleForm::Tuple => { + let type_name = cattrs.name().deserialize_name(); + quote! { + _serde::Deserializer::deserialize_tuple_struct(__deserializer, #type_name, #field_count, #visitor_expr) + } + } + TupleForm::ExternallyTagged(_) => quote! { + _serde::de::VariantAccess::tuple_variant(__variant, #field_count, #visitor_expr) + }, + TupleForm::Untagged(_, deserializer) => quote! { + _serde::Deserializer::deserialize_tuple(#deserializer, #field_count, #visitor_expr) + }, + }; + + let visitor_var = if field_count == 0 { + quote!(_) + } else { + quote!(mut __seq) + }; + + quote_block! { + #[doc(hidden)] + struct __Visitor #de_impl_generics #where_clause { + marker: _serde::__private::PhantomData<#this_type #ty_generics>, + lifetime: _serde::__private::PhantomData<&#delife ()>, + } + + impl #de_impl_generics _serde::de::Visitor<#delife> for __Visitor #de_ty_generics #where_clause { + type Value = #this_type #ty_generics; + + fn expecting(&self, __formatter: &mut _serde::__private::Formatter) -> _serde::__private::fmt::Result { + _serde::__private::Formatter::write_str(__formatter, #expecting) + } + + #visit_newtype_struct + + #[inline] + fn visit_seq<__A>(self, #visitor_var: __A) -> _serde::__private::Result<Self::Value, __A::Error> + where + __A: _serde::de::SeqAccess<#delife>, + { + #visit_seq + } + } + + #dispatch + } +} + +#[cfg(feature = "deserialize_in_place")] +fn deserialize_tuple_in_place( + params: &Parameters, + fields: &[Field], + cattrs: &attr::Container, +) -> Fragment { + assert!(!cattrs.has_flatten()); + + let field_count = fields + .iter() + .filter(|field| !field.attrs.skip_deserializing()) + .count(); + + let this_type = ¶ms.this_type; + let (de_impl_generics, de_ty_generics, ty_generics, where_clause) = + split_with_de_lifetime(params); + let delife = params.borrowed.de_lifetime(); + + let expecting = format!("tuple struct {}", params.type_name()); + let expecting = cattrs.expecting().unwrap_or(&expecting); + + let nfields = fields.len(); + + let visit_newtype_struct = if nfields == 1 { + // We do not generate deserialize_in_place if every field has a + // deserialize_with. + assert!(fields[0].attrs.deserialize_with().is_none()); + + Some(quote! { + #[inline] + fn visit_newtype_struct<__E>(self, __e: __E) -> _serde::__private::Result<Self::Value, __E::Error> + where + __E: _serde::Deserializer<#delife>, + { + _serde::Deserialize::deserialize_in_place(__e, &mut self.place.0) + } + }) + } else { + None + }; + + let visit_seq = Stmts(deserialize_seq_in_place(params, fields, cattrs, expecting)); + + let visitor_expr = quote! { + __Visitor { + place: __place, + lifetime: _serde::__private::PhantomData, + } + }; + + let type_name = cattrs.name().deserialize_name(); + let dispatch = if nfields == 1 { + quote!(_serde::Deserializer::deserialize_newtype_struct(__deserializer, #type_name, #visitor_expr)) + } else { + quote!(_serde::Deserializer::deserialize_tuple_struct(__deserializer, #type_name, #field_count, #visitor_expr)) + }; + + let visitor_var = if field_count == 0 { + quote!(_) + } else { + quote!(mut __seq) + }; + + let in_place_impl_generics = de_impl_generics.in_place(); + let in_place_ty_generics = de_ty_generics.in_place(); + let place_life = place_lifetime(); + + quote_block! { + #[doc(hidden)] + struct __Visitor #in_place_impl_generics #where_clause { + place: &#place_life mut #this_type #ty_generics, + lifetime: _serde::__private::PhantomData<&#delife ()>, + } + + impl #in_place_impl_generics _serde::de::Visitor<#delife> for __Visitor #in_place_ty_generics #where_clause { + type Value = (); + + fn expecting(&self, __formatter: &mut _serde::__private::Formatter) -> _serde::__private::fmt::Result { + _serde::__private::Formatter::write_str(__formatter, #expecting) + } + + #visit_newtype_struct + + #[inline] + fn visit_seq<__A>(self, #visitor_var: __A) -> _serde::__private::Result<Self::Value, __A::Error> + where + __A: _serde::de::SeqAccess<#delife>, + { + #visit_seq + } + } + + #dispatch + } +} + +fn deserialize_seq( + type_path: &TokenStream, + params: &Parameters, + fields: &[Field], + is_struct: bool, + cattrs: &attr::Container, + expecting: &str, +) -> Fragment { + let vars = (0..fields.len()).map(field_i as fn(_) -> _); + + let deserialized_count = fields + .iter() + .filter(|field| !field.attrs.skip_deserializing()) + .count(); + let expecting = if deserialized_count == 1 { + format!("{} with 1 element", expecting) + } else { + format!("{} with {} elements", expecting, deserialized_count) + }; + let expecting = cattrs.expecting().unwrap_or(&expecting); + + let mut index_in_seq = 0_usize; + let let_values = vars.clone().zip(fields).map(|(var, field)| { + if field.attrs.skip_deserializing() { + let default = Expr(expr_is_missing(field, cattrs)); + quote! { + let #var = #default; + } + } else { + let visit = match field.attrs.deserialize_with() { + None => { + let field_ty = field.ty; + let span = field.original.span(); + let func = + quote_spanned!(span=> _serde::de::SeqAccess::next_element::<#field_ty>); + quote!(#func(&mut __seq)?) + } + Some(path) => { + let (wrapper, wrapper_ty) = wrap_deserialize_field_with(params, field.ty, path); + quote!({ + #wrapper + _serde::__private::Option::map( + _serde::de::SeqAccess::next_element::<#wrapper_ty>(&mut __seq)?, + |__wrap| __wrap.value) + }) + } + }; + let value_if_none = expr_is_missing_seq(None, index_in_seq, field, cattrs, expecting); + let assign = quote! { + let #var = match #visit { + _serde::__private::Some(__value) => __value, + _serde::__private::None => #value_if_none, + }; + }; + index_in_seq += 1; + assign + } + }); + + let mut result = if is_struct { + let names = fields.iter().map(|f| &f.member); + quote! { + #type_path { #( #names: #vars ),* } + } + } else { + quote! { + #type_path ( #(#vars),* ) + } + }; + + if params.has_getter { + let this_type = ¶ms.this_type; + let (_, ty_generics, _) = params.generics.split_for_impl(); + result = quote! { + _serde::__private::Into::<#this_type #ty_generics>::into(#result) + }; + } + + let let_default = match cattrs.default() { + attr::Default::Default => Some(quote!( + let __default: Self::Value = _serde::__private::Default::default(); + )), + attr::Default::Path(path) => Some(quote!( + let __default: Self::Value = #path(); + )), + attr::Default::None => { + // We don't need the default value, to prevent an unused variable warning + // we'll leave the line empty. + None + } + }; + + quote_block! { + #let_default + #(#let_values)* + _serde::__private::Ok(#result) + } +} + +#[cfg(feature = "deserialize_in_place")] +fn deserialize_seq_in_place( + params: &Parameters, + fields: &[Field], + cattrs: &attr::Container, + expecting: &str, +) -> Fragment { + let deserialized_count = fields + .iter() + .filter(|field| !field.attrs.skip_deserializing()) + .count(); + let expecting = if deserialized_count == 1 { + format!("{} with 1 element", expecting) + } else { + format!("{} with {} elements", expecting, deserialized_count) + }; + let expecting = cattrs.expecting().unwrap_or(&expecting); + + let mut index_in_seq = 0usize; + let write_values = fields.iter().map(|field| { + let member = &field.member; + + if field.attrs.skip_deserializing() { + let default = Expr(expr_is_missing(field, cattrs)); + quote! { + self.place.#member = #default; + } + } else { + let value_if_none = expr_is_missing_seq(Some(quote!(self.place.#member = )), index_in_seq, field, cattrs, expecting); + let write = match field.attrs.deserialize_with() { + None => { + quote! { + if let _serde::__private::None = _serde::de::SeqAccess::next_element_seed(&mut __seq, + _serde::__private::de::InPlaceSeed(&mut self.place.#member))? + { + #value_if_none; + } + } + } + Some(path) => { + let (wrapper, wrapper_ty) = wrap_deserialize_field_with(params, field.ty, path); + quote!({ + #wrapper + match _serde::de::SeqAccess::next_element::<#wrapper_ty>(&mut __seq)? { + _serde::__private::Some(__wrap) => { + self.place.#member = __wrap.value; + } + _serde::__private::None => { + #value_if_none; + } + } + }) + } + }; + index_in_seq += 1; + write + } + }); + + let this_type = ¶ms.this_type; + let (_, ty_generics, _) = params.generics.split_for_impl(); + let let_default = match cattrs.default() { + attr::Default::Default => Some(quote!( + let __default: #this_type #ty_generics = _serde::__private::Default::default(); + )), + attr::Default::Path(path) => Some(quote!( + let __default: #this_type #ty_generics = #path(); + )), + attr::Default::None => { + // We don't need the default value, to prevent an unused variable warning + // we'll leave the line empty. + None + } + }; + + quote_block! { + #let_default + #(#write_values)* + _serde::__private::Ok(()) + } +} + +fn deserialize_newtype_struct( + type_path: &TokenStream, + params: &Parameters, + field: &Field, +) -> TokenStream { + let delife = params.borrowed.de_lifetime(); + let field_ty = field.ty; + + let value = match field.attrs.deserialize_with() { + None => { + let span = field.original.span(); + let func = quote_spanned!(span=> <#field_ty as _serde::Deserialize>::deserialize); + quote! { + #func(__e)? + } + } + Some(path) => { + quote! { + #path(__e)? + } + } + }; + + let mut result = quote!(#type_path(__field0)); + if params.has_getter { + let this_type = ¶ms.this_type; + let (_, ty_generics, _) = params.generics.split_for_impl(); + result = quote! { + _serde::__private::Into::<#this_type #ty_generics>::into(#result) + }; + } + + quote! { + #[inline] + fn visit_newtype_struct<__E>(self, __e: __E) -> _serde::__private::Result<Self::Value, __E::Error> + where + __E: _serde::Deserializer<#delife>, + { + let __field0: #field_ty = #value; + _serde::__private::Ok(#result) + } + } +} + +enum StructForm<'a> { + Struct, + /// Contains a variant name + ExternallyTagged(&'a syn::Ident), + /// Contains a variant name and an intermediate deserializer from which actual + /// deserialization will be performed + InternallyTagged(&'a syn::Ident, TokenStream), + /// Contains a variant name and an intermediate deserializer from which actual + /// deserialization will be performed + Untagged(&'a syn::Ident, TokenStream), +} + +fn deserialize_struct( + params: &Parameters, + fields: &[Field], + cattrs: &attr::Container, + form: StructForm, +) -> Fragment { + let this_type = ¶ms.this_type; + let this_value = ¶ms.this_value; + let (de_impl_generics, de_ty_generics, ty_generics, where_clause) = + split_with_de_lifetime(params); + let delife = params.borrowed.de_lifetime(); + + // If there are getters (implying private fields), construct the local type + // and use an `Into` conversion to get the remote type. If there are no + // getters then construct the target type directly. + let construct = if params.has_getter { + let local = ¶ms.local; + quote!(#local) + } else { + quote!(#this_value) + }; + + let type_path = match form { + StructForm::Struct => construct, + StructForm::ExternallyTagged(variant_ident) + | StructForm::InternallyTagged(variant_ident, _) + | StructForm::Untagged(variant_ident, _) => quote!(#construct::#variant_ident), + }; + let expecting = match form { + StructForm::Struct => format!("struct {}", params.type_name()), + StructForm::ExternallyTagged(variant_ident) + | StructForm::InternallyTagged(variant_ident, _) + | StructForm::Untagged(variant_ident, _) => { + format!("struct variant {}::{}", params.type_name(), variant_ident) + } + }; + let expecting = cattrs.expecting().unwrap_or(&expecting); + + let field_names_idents: Vec<_> = fields + .iter() + .enumerate() + // Skip fields that shouldn't be deserialized or that were flattened, + // so they don't appear in the storage in their literal form + .filter(|&(_, field)| !field.attrs.skip_deserializing() && !field.attrs.flatten()) + .map(|(i, field)| { + ( + field.attrs.name().deserialize_name(), + field_i(i), + field.attrs.aliases(), + ) + }) + .collect(); + let field_visitor = deserialize_field_identifier(&field_names_idents, cattrs); + + // untagged struct variants do not get a visit_seq method. The same applies to + // structs that only have a map representation. + let visit_seq = match form { + StructForm::Untagged(..) => None, + _ if cattrs.has_flatten() => None, + _ => { + let mut_seq = if field_names_idents.is_empty() { + quote!(_) + } else { + quote!(mut __seq) + }; + + let visit_seq = Stmts(deserialize_seq( + &type_path, params, fields, true, cattrs, expecting, + )); + + Some(quote! { + #[inline] + fn visit_seq<__A>(self, #mut_seq: __A) -> _serde::__private::Result<Self::Value, __A::Error> + where + __A: _serde::de::SeqAccess<#delife>, + { + #visit_seq + } + }) + } + }; + let visit_map = Stmts(deserialize_map(&type_path, params, fields, cattrs)); + + let visitor_seed = match form { + StructForm::ExternallyTagged(..) if cattrs.has_flatten() => Some(quote! { + impl #de_impl_generics _serde::de::DeserializeSeed<#delife> for __Visitor #de_ty_generics #where_clause { + type Value = #this_type #ty_generics; + + fn deserialize<__D>(self, __deserializer: __D) -> _serde::__private::Result<Self::Value, __D::Error> + where + __D: _serde::Deserializer<#delife>, + { + _serde::Deserializer::deserialize_map(__deserializer, self) + } + } + }), + _ => None, + }; + + let fields_stmt = if cattrs.has_flatten() { + None + } else { + let field_names = field_names_idents + .iter() + .flat_map(|&(_, _, aliases)| aliases); + + Some(quote! { + #[doc(hidden)] + const FIELDS: &'static [&'static str] = &[ #(#field_names),* ]; + }) + }; + + let visitor_expr = quote! { + __Visitor { + marker: _serde::__private::PhantomData::<#this_type #ty_generics>, + lifetime: _serde::__private::PhantomData, + } + }; + let dispatch = match form { + StructForm::Struct if cattrs.has_flatten() => quote! { + _serde::Deserializer::deserialize_map(__deserializer, #visitor_expr) + }, + StructForm::Struct => { + let type_name = cattrs.name().deserialize_name(); + quote! { + _serde::Deserializer::deserialize_struct(__deserializer, #type_name, FIELDS, #visitor_expr) + } + } + StructForm::ExternallyTagged(_) if cattrs.has_flatten() => quote! { + _serde::de::VariantAccess::newtype_variant_seed(__variant, #visitor_expr) + }, + StructForm::ExternallyTagged(_) => quote! { + _serde::de::VariantAccess::struct_variant(__variant, FIELDS, #visitor_expr) + }, + StructForm::InternallyTagged(_, deserializer) => quote! { + _serde::Deserializer::deserialize_any(#deserializer, #visitor_expr) + }, + StructForm::Untagged(_, deserializer) => quote! { + _serde::Deserializer::deserialize_any(#deserializer, #visitor_expr) + }, + }; + + quote_block! { + #field_visitor + + #[doc(hidden)] + struct __Visitor #de_impl_generics #where_clause { + marker: _serde::__private::PhantomData<#this_type #ty_generics>, + lifetime: _serde::__private::PhantomData<&#delife ()>, + } + + impl #de_impl_generics _serde::de::Visitor<#delife> for __Visitor #de_ty_generics #where_clause { + type Value = #this_type #ty_generics; + + fn expecting(&self, __formatter: &mut _serde::__private::Formatter) -> _serde::__private::fmt::Result { + _serde::__private::Formatter::write_str(__formatter, #expecting) + } + + #visit_seq + + #[inline] + fn visit_map<__A>(self, mut __map: __A) -> _serde::__private::Result<Self::Value, __A::Error> + where + __A: _serde::de::MapAccess<#delife>, + { + #visit_map + } + } + + #visitor_seed + + #fields_stmt + + #dispatch + } +} + +#[cfg(feature = "deserialize_in_place")] +fn deserialize_struct_in_place( + params: &Parameters, + fields: &[Field], + cattrs: &attr::Container, +) -> Option<Fragment> { + // for now we do not support in_place deserialization for structs that + // are represented as map. + if cattrs.has_flatten() { + return None; + } + + let this_type = ¶ms.this_type; + let (de_impl_generics, de_ty_generics, ty_generics, where_clause) = + split_with_de_lifetime(params); + let delife = params.borrowed.de_lifetime(); + + let expecting = format!("struct {}", params.type_name()); + let expecting = cattrs.expecting().unwrap_or(&expecting); + + let field_names_idents: Vec<_> = fields + .iter() + .enumerate() + .filter(|&(_, field)| !field.attrs.skip_deserializing()) + .map(|(i, field)| { + ( + field.attrs.name().deserialize_name(), + field_i(i), + field.attrs.aliases(), + ) + }) + .collect(); + + let field_visitor = deserialize_field_identifier(&field_names_idents, cattrs); + + let mut_seq = if field_names_idents.is_empty() { + quote!(_) + } else { + quote!(mut __seq) + }; + let visit_seq = Stmts(deserialize_seq_in_place(params, fields, cattrs, expecting)); + let visit_map = Stmts(deserialize_map_in_place(params, fields, cattrs)); + let field_names = field_names_idents + .iter() + .flat_map(|&(_, _, aliases)| aliases); + let type_name = cattrs.name().deserialize_name(); + + let in_place_impl_generics = de_impl_generics.in_place(); + let in_place_ty_generics = de_ty_generics.in_place(); + let place_life = place_lifetime(); + + Some(quote_block! { + #field_visitor + + #[doc(hidden)] + struct __Visitor #in_place_impl_generics #where_clause { + place: &#place_life mut #this_type #ty_generics, + lifetime: _serde::__private::PhantomData<&#delife ()>, + } + + impl #in_place_impl_generics _serde::de::Visitor<#delife> for __Visitor #in_place_ty_generics #where_clause { + type Value = (); + + fn expecting(&self, __formatter: &mut _serde::__private::Formatter) -> _serde::__private::fmt::Result { + _serde::__private::Formatter::write_str(__formatter, #expecting) + } + + #[inline] + fn visit_seq<__A>(self, #mut_seq: __A) -> _serde::__private::Result<Self::Value, __A::Error> + where + __A: _serde::de::SeqAccess<#delife>, + { + #visit_seq + } + + #[inline] + fn visit_map<__A>(self, mut __map: __A) -> _serde::__private::Result<Self::Value, __A::Error> + where + __A: _serde::de::MapAccess<#delife>, + { + #visit_map + } + } + + #[doc(hidden)] + const FIELDS: &'static [&'static str] = &[ #(#field_names),* ]; + + _serde::Deserializer::deserialize_struct(__deserializer, #type_name, FIELDS, __Visitor { + place: __place, + lifetime: _serde::__private::PhantomData, + }) + }) +} + +fn deserialize_enum( + params: &Parameters, + variants: &[Variant], + cattrs: &attr::Container, +) -> Fragment { + // The variants have already been checked (in ast.rs) that all untagged variants appear at the end + match variants.iter().position(|var| var.attrs.untagged()) { + Some(variant_idx) => { + let (tagged, untagged) = variants.split_at(variant_idx); + let tagged_frag = Expr(deserialize_homogeneous_enum(params, tagged, cattrs)); + deserialize_untagged_enum_after(params, untagged, cattrs, Some(tagged_frag)) + } + None => deserialize_homogeneous_enum(params, variants, cattrs), + } +} + +fn deserialize_homogeneous_enum( + params: &Parameters, + variants: &[Variant], + cattrs: &attr::Container, +) -> Fragment { + match cattrs.tag() { + attr::TagType::External => deserialize_externally_tagged_enum(params, variants, cattrs), + attr::TagType::Internal { tag } => { + deserialize_internally_tagged_enum(params, variants, cattrs, tag) + } + attr::TagType::Adjacent { tag, content } => { + deserialize_adjacently_tagged_enum(params, variants, cattrs, tag, content) + } + attr::TagType::None => deserialize_untagged_enum(params, variants, cattrs), + } +} + +fn prepare_enum_variant_enum( + variants: &[Variant], + cattrs: &attr::Container, +) -> (TokenStream, Stmts) { + let mut deserialized_variants = variants + .iter() + .enumerate() + .filter(|&(_, variant)| !variant.attrs.skip_deserializing()); + + let variant_names_idents: Vec<_> = deserialized_variants + .clone() + .map(|(i, variant)| { + ( + variant.attrs.name().deserialize_name(), + field_i(i), + variant.attrs.aliases(), + ) + }) + .collect(); + + let fallthrough = deserialized_variants + .position(|(_, variant)| variant.attrs.other()) + .map(|other_idx| { + let ignore_variant = variant_names_idents[other_idx].1.clone(); + quote!(_serde::__private::Ok(__Field::#ignore_variant)) + }); + + let variants_stmt = { + let variant_names = variant_names_idents.iter().map(|(name, _, _)| name); + quote! { + #[doc(hidden)] + const VARIANTS: &'static [&'static str] = &[ #(#variant_names),* ]; + } + }; + + let variant_visitor = Stmts(deserialize_generated_identifier( + &variant_names_idents, + cattrs, + true, + None, + fallthrough, + )); + + (variants_stmt, variant_visitor) +} + +fn deserialize_externally_tagged_enum( + params: &Parameters, + variants: &[Variant], + cattrs: &attr::Container, +) -> Fragment { + let this_type = ¶ms.this_type; + let (de_impl_generics, de_ty_generics, ty_generics, where_clause) = + split_with_de_lifetime(params); + let delife = params.borrowed.de_lifetime(); + + let type_name = cattrs.name().deserialize_name(); + let expecting = format!("enum {}", params.type_name()); + let expecting = cattrs.expecting().unwrap_or(&expecting); + + let (variants_stmt, variant_visitor) = prepare_enum_variant_enum(variants, cattrs); + + // Match arms to extract a variant from a string + let variant_arms = variants + .iter() + .enumerate() + .filter(|&(_, variant)| !variant.attrs.skip_deserializing()) + .map(|(i, variant)| { + let variant_name = field_i(i); + + let block = Match(deserialize_externally_tagged_variant( + params, variant, cattrs, + )); + + quote! { + (__Field::#variant_name, __variant) => #block + } + }); + + let all_skipped = variants + .iter() + .all(|variant| variant.attrs.skip_deserializing()); + let match_variant = if all_skipped { + // This is an empty enum like `enum Impossible {}` or an enum in which + // all variants have `#[serde(skip_deserializing)]`. + quote! { + // FIXME: Once feature(exhaustive_patterns) is stable: + // let _serde::__private::Err(__err) = _serde::de::EnumAccess::variant::<__Field>(__data); + // _serde::__private::Err(__err) + _serde::__private::Result::map( + _serde::de::EnumAccess::variant::<__Field>(__data), + |(__impossible, _)| match __impossible {}) + } + } else { + quote! { + match _serde::de::EnumAccess::variant(__data)? { + #(#variant_arms)* + } + } + }; + + quote_block! { + #variant_visitor + + #[doc(hidden)] + struct __Visitor #de_impl_generics #where_clause { + marker: _serde::__private::PhantomData<#this_type #ty_generics>, + lifetime: _serde::__private::PhantomData<&#delife ()>, + } + + impl #de_impl_generics _serde::de::Visitor<#delife> for __Visitor #de_ty_generics #where_clause { + type Value = #this_type #ty_generics; + + fn expecting(&self, __formatter: &mut _serde::__private::Formatter) -> _serde::__private::fmt::Result { + _serde::__private::Formatter::write_str(__formatter, #expecting) + } + + fn visit_enum<__A>(self, __data: __A) -> _serde::__private::Result<Self::Value, __A::Error> + where + __A: _serde::de::EnumAccess<#delife>, + { + #match_variant + } + } + + #variants_stmt + + _serde::Deserializer::deserialize_enum( + __deserializer, + #type_name, + VARIANTS, + __Visitor { + marker: _serde::__private::PhantomData::<#this_type #ty_generics>, + lifetime: _serde::__private::PhantomData, + }, + ) + } +} + +fn deserialize_internally_tagged_enum( + params: &Parameters, + variants: &[Variant], + cattrs: &attr::Container, + tag: &str, +) -> Fragment { + let (variants_stmt, variant_visitor) = prepare_enum_variant_enum(variants, cattrs); + + // Match arms to extract a variant from a string + let variant_arms = variants + .iter() + .enumerate() + .filter(|&(_, variant)| !variant.attrs.skip_deserializing()) + .map(|(i, variant)| { + let variant_name = field_i(i); + + let block = Match(deserialize_internally_tagged_variant( + params, + variant, + cattrs, + quote!(__deserializer), + )); + + quote! { + __Field::#variant_name => #block + } + }); + + let expecting = format!("internally tagged enum {}", params.type_name()); + let expecting = cattrs.expecting().unwrap_or(&expecting); + + quote_block! { + #variant_visitor + + #variants_stmt + + let (__tag, __content) = _serde::Deserializer::deserialize_any( + __deserializer, + _serde::__private::de::TaggedContentVisitor::<__Field>::new(#tag, #expecting))?; + let __deserializer = _serde::__private::de::ContentDeserializer::<__D::Error>::new(__content); + + match __tag { + #(#variant_arms)* + } + } +} + +fn deserialize_adjacently_tagged_enum( + params: &Parameters, + variants: &[Variant], + cattrs: &attr::Container, + tag: &str, + content: &str, +) -> Fragment { + let this_type = ¶ms.this_type; + let this_value = ¶ms.this_value; + let (de_impl_generics, de_ty_generics, ty_generics, where_clause) = + split_with_de_lifetime(params); + let delife = params.borrowed.de_lifetime(); + + let (variants_stmt, variant_visitor) = prepare_enum_variant_enum(variants, cattrs); + + let variant_arms: &Vec<_> = &variants + .iter() + .enumerate() + .filter(|&(_, variant)| !variant.attrs.skip_deserializing()) + .map(|(i, variant)| { + let variant_index = field_i(i); + + let block = Match(deserialize_untagged_variant( + params, + variant, + cattrs, + quote!(__deserializer), + )); + + quote! { + __Field::#variant_index => #block + } + }) + .collect(); + + let rust_name = params.type_name(); + let expecting = format!("adjacently tagged enum {}", rust_name); + let expecting = cattrs.expecting().unwrap_or(&expecting); + let type_name = cattrs.name().deserialize_name(); + let deny_unknown_fields = cattrs.deny_unknown_fields(); + + // If unknown fields are allowed, we pick the visitor that can step over + // those. Otherwise we pick the visitor that fails on unknown keys. + let field_visitor_ty = if deny_unknown_fields { + quote! { _serde::__private::de::TagOrContentFieldVisitor } + } else { + quote! { _serde::__private::de::TagContentOtherFieldVisitor } + }; + + let tag_or_content = quote! { + #field_visitor_ty { + tag: #tag, + content: #content, + } + }; + + let variant_seed = quote! { + _serde::__private::de::AdjacentlyTaggedEnumVariantSeed::<__Field> { + enum_name: #rust_name, + variants: VARIANTS, + fields_enum: _serde::__private::PhantomData + } + }; + + let mut missing_content = quote! { + _serde::__private::Err(<__A::Error as _serde::de::Error>::missing_field(#content)) + }; + let mut missing_content_fallthrough = quote!(); + let missing_content_arms = variants + .iter() + .enumerate() + .filter(|&(_, variant)| !variant.attrs.skip_deserializing()) + .filter_map(|(i, variant)| { + let variant_index = field_i(i); + let variant_ident = &variant.ident; + + let arm = match variant.style { + Style::Unit => quote! { + _serde::__private::Ok(#this_value::#variant_ident) + }, + Style::Newtype if variant.attrs.deserialize_with().is_none() => { + let span = variant.original.span(); + let func = quote_spanned!(span=> _serde::__private::de::missing_field); + quote! { + #func(#content).map(#this_value::#variant_ident) + } + } + _ => { + missing_content_fallthrough = quote!(_ => #missing_content); + return None; + } + }; + Some(quote! { + __Field::#variant_index => #arm, + }) + }) + .collect::<Vec<_>>(); + if !missing_content_arms.is_empty() { + missing_content = quote! { + match __field { + #(#missing_content_arms)* + #missing_content_fallthrough + } + }; + } + + // Advance the map by one key, returning early in case of error. + let next_key = quote! { + _serde::de::MapAccess::next_key_seed(&mut __map, #tag_or_content)? + }; + + let variant_from_map = quote! { + _serde::de::MapAccess::next_value_seed(&mut __map, #variant_seed)? + }; + + // When allowing unknown fields, we want to transparently step through keys + // we don't care about until we find `tag`, `content`, or run out of keys. + let next_relevant_key = if deny_unknown_fields { + next_key + } else { + quote!({ + let mut __rk : _serde::__private::Option<_serde::__private::de::TagOrContentField> = _serde::__private::None; + while let _serde::__private::Some(__k) = #next_key { + match __k { + _serde::__private::de::TagContentOtherField::Other => { + let _ = _serde::de::MapAccess::next_value::<_serde::de::IgnoredAny>(&mut __map)?; + continue; + }, + _serde::__private::de::TagContentOtherField::Tag => { + __rk = _serde::__private::Some(_serde::__private::de::TagOrContentField::Tag); + break; + } + _serde::__private::de::TagContentOtherField::Content => { + __rk = _serde::__private::Some(_serde::__private::de::TagOrContentField::Content); + break; + } + } + } + + __rk + }) + }; + + // Step through remaining keys, looking for duplicates of previously-seen + // keys. When unknown fields are denied, any key that isn't a duplicate will + // at this point immediately produce an error. + let visit_remaining_keys = quote! { + match #next_relevant_key { + _serde::__private::Some(_serde::__private::de::TagOrContentField::Tag) => { + _serde::__private::Err(<__A::Error as _serde::de::Error>::duplicate_field(#tag)) + } + _serde::__private::Some(_serde::__private::de::TagOrContentField::Content) => { + _serde::__private::Err(<__A::Error as _serde::de::Error>::duplicate_field(#content)) + } + _serde::__private::None => _serde::__private::Ok(__ret), + } + }; + + let finish_content_then_tag = if variant_arms.is_empty() { + quote! { + match #variant_from_map {} + } + } else { + quote! { + let __ret = match #variant_from_map { + // Deserialize the buffered content now that we know the variant. + #(#variant_arms)* + }?; + // Visit remaining keys, looking for duplicates. + #visit_remaining_keys + } + }; + + quote_block! { + #variant_visitor + + #variants_stmt + + #[doc(hidden)] + struct __Seed #de_impl_generics #where_clause { + field: __Field, + marker: _serde::__private::PhantomData<#this_type #ty_generics>, + lifetime: _serde::__private::PhantomData<&#delife ()>, + } + + impl #de_impl_generics _serde::de::DeserializeSeed<#delife> for __Seed #de_ty_generics #where_clause { + type Value = #this_type #ty_generics; + + fn deserialize<__D>(self, __deserializer: __D) -> _serde::__private::Result<Self::Value, __D::Error> + where + __D: _serde::Deserializer<#delife>, + { + match self.field { + #(#variant_arms)* + } + } + } + + #[doc(hidden)] + struct __Visitor #de_impl_generics #where_clause { + marker: _serde::__private::PhantomData<#this_type #ty_generics>, + lifetime: _serde::__private::PhantomData<&#delife ()>, + } + + impl #de_impl_generics _serde::de::Visitor<#delife> for __Visitor #de_ty_generics #where_clause { + type Value = #this_type #ty_generics; + + fn expecting(&self, __formatter: &mut _serde::__private::Formatter) -> _serde::__private::fmt::Result { + _serde::__private::Formatter::write_str(__formatter, #expecting) + } + + fn visit_map<__A>(self, mut __map: __A) -> _serde::__private::Result<Self::Value, __A::Error> + where + __A: _serde::de::MapAccess<#delife>, + { + // Visit the first relevant key. + match #next_relevant_key { + // First key is the tag. + _serde::__private::Some(_serde::__private::de::TagOrContentField::Tag) => { + // Parse the tag. + let __field = #variant_from_map; + // Visit the second key. + match #next_relevant_key { + // Second key is a duplicate of the tag. + _serde::__private::Some(_serde::__private::de::TagOrContentField::Tag) => { + _serde::__private::Err(<__A::Error as _serde::de::Error>::duplicate_field(#tag)) + } + // Second key is the content. + _serde::__private::Some(_serde::__private::de::TagOrContentField::Content) => { + let __ret = _serde::de::MapAccess::next_value_seed(&mut __map, + __Seed { + field: __field, + marker: _serde::__private::PhantomData, + lifetime: _serde::__private::PhantomData, + })?; + // Visit remaining keys, looking for duplicates. + #visit_remaining_keys + } + // There is no second key; might be okay if the we have a unit variant. + _serde::__private::None => #missing_content + } + } + // First key is the content. + _serde::__private::Some(_serde::__private::de::TagOrContentField::Content) => { + // Buffer up the content. + let __content = _serde::de::MapAccess::next_value::<_serde::__private::de::Content>(&mut __map)?; + // Visit the second key. + match #next_relevant_key { + // Second key is the tag. + _serde::__private::Some(_serde::__private::de::TagOrContentField::Tag) => { + let __deserializer = _serde::__private::de::ContentDeserializer::<__A::Error>::new(__content); + #finish_content_then_tag + } + // Second key is a duplicate of the content. + _serde::__private::Some(_serde::__private::de::TagOrContentField::Content) => { + _serde::__private::Err(<__A::Error as _serde::de::Error>::duplicate_field(#content)) + } + // There is no second key. + _serde::__private::None => { + _serde::__private::Err(<__A::Error as _serde::de::Error>::missing_field(#tag)) + } + } + } + // There is no first key. + _serde::__private::None => { + _serde::__private::Err(<__A::Error as _serde::de::Error>::missing_field(#tag)) + } + } + } + + fn visit_seq<__A>(self, mut __seq: __A) -> _serde::__private::Result<Self::Value, __A::Error> + where + __A: _serde::de::SeqAccess<#delife>, + { + // Visit the first element - the tag. + match _serde::de::SeqAccess::next_element(&mut __seq)? { + _serde::__private::Some(__field) => { + // Visit the second element - the content. + match _serde::de::SeqAccess::next_element_seed( + &mut __seq, + __Seed { + field: __field, + marker: _serde::__private::PhantomData, + lifetime: _serde::__private::PhantomData, + }, + )? { + _serde::__private::Some(__ret) => _serde::__private::Ok(__ret), + // There is no second element. + _serde::__private::None => { + _serde::__private::Err(_serde::de::Error::invalid_length(1, &self)) + } + } + } + // There is no first element. + _serde::__private::None => { + _serde::__private::Err(_serde::de::Error::invalid_length(0, &self)) + } + } + } + } + + #[doc(hidden)] + const FIELDS: &'static [&'static str] = &[#tag, #content]; + _serde::Deserializer::deserialize_struct( + __deserializer, + #type_name, + FIELDS, + __Visitor { + marker: _serde::__private::PhantomData::<#this_type #ty_generics>, + lifetime: _serde::__private::PhantomData, + }, + ) + } +} + +fn deserialize_untagged_enum( + params: &Parameters, + variants: &[Variant], + cattrs: &attr::Container, +) -> Fragment { + let first_attempt = None; + deserialize_untagged_enum_after(params, variants, cattrs, first_attempt) +} + +fn deserialize_untagged_enum_after( + params: &Parameters, + variants: &[Variant], + cattrs: &attr::Container, + first_attempt: Option<Expr>, +) -> Fragment { + let attempts = variants + .iter() + .filter(|variant| !variant.attrs.skip_deserializing()) + .map(|variant| { + Expr(deserialize_untagged_variant( + params, + variant, + cattrs, + quote!(__deserializer), + )) + }); + // TODO this message could be better by saving the errors from the failed + // attempts. The heuristic used by TOML was to count the number of fields + // processed before an error, and use the error that happened after the + // largest number of fields. I'm not sure I like that. Maybe it would be + // better to save all the errors and combine them into one message that + // explains why none of the variants matched. + let fallthrough_msg = format!( + "data did not match any variant of untagged enum {}", + params.type_name() + ); + let fallthrough_msg = cattrs.expecting().unwrap_or(&fallthrough_msg); + + // Ignore any error associated with non-untagged deserialization so that we + // can fall through to the untagged variants. This may be infallible so we + // need to provide the error type. + let first_attempt = first_attempt.map(|expr| { + quote! { + if let _serde::__private::Result::<_, __D::Error>::Ok(__ok) = (|| #expr)() { + return _serde::__private::Ok(__ok); + } + } + }); + + quote_block! { + let __content = <_serde::__private::de::Content as _serde::Deserialize>::deserialize(__deserializer)?; + let __deserializer = _serde::__private::de::ContentRefDeserializer::<__D::Error>::new(&__content); + + #first_attempt + + #( + if let _serde::__private::Ok(__ok) = #attempts { + return _serde::__private::Ok(__ok); + } + )* + + _serde::__private::Err(_serde::de::Error::custom(#fallthrough_msg)) + } +} + +fn deserialize_externally_tagged_variant( + params: &Parameters, + variant: &Variant, + cattrs: &attr::Container, +) -> Fragment { + if let Some(path) = variant.attrs.deserialize_with() { + let (wrapper, wrapper_ty, unwrap_fn) = wrap_deserialize_variant_with(params, variant, path); + return quote_block! { + #wrapper + _serde::__private::Result::map( + _serde::de::VariantAccess::newtype_variant::<#wrapper_ty>(__variant), #unwrap_fn) + }; + } + + let variant_ident = &variant.ident; + + match variant.style { + Style::Unit => { + let this_value = ¶ms.this_value; + quote_block! { + _serde::de::VariantAccess::unit_variant(__variant)?; + _serde::__private::Ok(#this_value::#variant_ident) + } + } + Style::Newtype => deserialize_externally_tagged_newtype_variant( + variant_ident, + params, + &variant.fields[0], + cattrs, + ), + Style::Tuple => deserialize_tuple( + params, + &variant.fields, + cattrs, + TupleForm::ExternallyTagged(variant_ident), + ), + Style::Struct => deserialize_struct( + params, + &variant.fields, + cattrs, + StructForm::ExternallyTagged(variant_ident), + ), + } +} + +// Generates significant part of the visit_seq and visit_map bodies of visitors +// for the variants of internally tagged enum. +fn deserialize_internally_tagged_variant( + params: &Parameters, + variant: &Variant, + cattrs: &attr::Container, + deserializer: TokenStream, +) -> Fragment { + if variant.attrs.deserialize_with().is_some() { + return deserialize_untagged_variant(params, variant, cattrs, deserializer); + } + + let variant_ident = &variant.ident; + + match effective_style(variant) { + Style::Unit => { + let this_value = ¶ms.this_value; + let type_name = params.type_name(); + let variant_name = variant.ident.to_string(); + let default = variant.fields.first().map(|field| { + let default = Expr(expr_is_missing(field, cattrs)); + quote!((#default)) + }); + quote_block! { + _serde::Deserializer::deserialize_any(#deserializer, _serde::__private::de::InternallyTaggedUnitVisitor::new(#type_name, #variant_name))?; + _serde::__private::Ok(#this_value::#variant_ident #default) + } + } + Style::Newtype => deserialize_untagged_newtype_variant( + variant_ident, + params, + &variant.fields[0], + &deserializer, + ), + Style::Struct => deserialize_struct( + params, + &variant.fields, + cattrs, + StructForm::InternallyTagged(variant_ident, deserializer), + ), + Style::Tuple => unreachable!("checked in serde_derive_internals"), + } +} + +fn deserialize_untagged_variant( + params: &Parameters, + variant: &Variant, + cattrs: &attr::Container, + deserializer: TokenStream, +) -> Fragment { + if let Some(path) = variant.attrs.deserialize_with() { + let unwrap_fn = unwrap_to_variant_closure(params, variant, false); + return quote_block! { + _serde::__private::Result::map(#path(#deserializer), #unwrap_fn) + }; + } + + let variant_ident = &variant.ident; + + match effective_style(variant) { + Style::Unit => { + let this_value = ¶ms.this_value; + let type_name = params.type_name(); + let variant_name = variant.ident.to_string(); + let default = variant.fields.first().map(|field| { + let default = Expr(expr_is_missing(field, cattrs)); + quote!((#default)) + }); + quote_expr! { + match _serde::Deserializer::deserialize_any( + #deserializer, + _serde::__private::de::UntaggedUnitVisitor::new(#type_name, #variant_name) + ) { + _serde::__private::Ok(()) => _serde::__private::Ok(#this_value::#variant_ident #default), + _serde::__private::Err(__err) => _serde::__private::Err(__err), + } + } + } + Style::Newtype => deserialize_untagged_newtype_variant( + variant_ident, + params, + &variant.fields[0], + &deserializer, + ), + Style::Tuple => deserialize_tuple( + params, + &variant.fields, + cattrs, + TupleForm::Untagged(variant_ident, deserializer), + ), + Style::Struct => deserialize_struct( + params, + &variant.fields, + cattrs, + StructForm::Untagged(variant_ident, deserializer), + ), + } +} + +fn deserialize_externally_tagged_newtype_variant( + variant_ident: &syn::Ident, + params: &Parameters, + field: &Field, + cattrs: &attr::Container, +) -> Fragment { + let this_value = ¶ms.this_value; + + if field.attrs.skip_deserializing() { + let default = Expr(expr_is_missing(field, cattrs)); + return quote_block! { + _serde::de::VariantAccess::unit_variant(__variant)?; + _serde::__private::Ok(#this_value::#variant_ident(#default)) + }; + } + + match field.attrs.deserialize_with() { + None => { + let field_ty = field.ty; + let span = field.original.span(); + let func = + quote_spanned!(span=> _serde::de::VariantAccess::newtype_variant::<#field_ty>); + quote_expr! { + _serde::__private::Result::map(#func(__variant), #this_value::#variant_ident) + } + } + Some(path) => { + let (wrapper, wrapper_ty) = wrap_deserialize_field_with(params, field.ty, path); + quote_block! { + #wrapper + _serde::__private::Result::map( + _serde::de::VariantAccess::newtype_variant::<#wrapper_ty>(__variant), + |__wrapper| #this_value::#variant_ident(__wrapper.value)) + } + } + } +} + +fn deserialize_untagged_newtype_variant( + variant_ident: &syn::Ident, + params: &Parameters, + field: &Field, + deserializer: &TokenStream, +) -> Fragment { + let this_value = ¶ms.this_value; + let field_ty = field.ty; + match field.attrs.deserialize_with() { + None => { + let span = field.original.span(); + let func = quote_spanned!(span=> <#field_ty as _serde::Deserialize>::deserialize); + quote_expr! { + _serde::__private::Result::map(#func(#deserializer), #this_value::#variant_ident) + } + } + Some(path) => { + quote_block! { + let __value: _serde::__private::Result<#field_ty, _> = #path(#deserializer); + _serde::__private::Result::map(__value, #this_value::#variant_ident) + } + } + } +} + +fn deserialize_generated_identifier( + fields: &[(&str, Ident, &BTreeSet<String>)], + cattrs: &attr::Container, + is_variant: bool, + ignore_variant: Option<TokenStream>, + fallthrough: Option<TokenStream>, +) -> Fragment { + let this_value = quote!(__Field); + let field_idents: &Vec<_> = &fields.iter().map(|(_, ident, _)| ident).collect(); + + let visitor_impl = Stmts(deserialize_identifier( + &this_value, + fields, + is_variant, + fallthrough, + None, + !is_variant && cattrs.has_flatten(), + None, + )); + + let lifetime = if !is_variant && cattrs.has_flatten() { + Some(quote!(<'de>)) + } else { + None + }; + + quote_block! { + #[allow(non_camel_case_types)] + #[doc(hidden)] + enum __Field #lifetime { + #(#field_idents,)* + #ignore_variant + } + + #[doc(hidden)] + struct __FieldVisitor; + + impl<'de> _serde::de::Visitor<'de> for __FieldVisitor { + type Value = __Field #lifetime; + + #visitor_impl + } + + impl<'de> _serde::Deserialize<'de> for __Field #lifetime { + #[inline] + fn deserialize<__D>(__deserializer: __D) -> _serde::__private::Result<Self, __D::Error> + where + __D: _serde::Deserializer<'de>, + { + _serde::Deserializer::deserialize_identifier(__deserializer, __FieldVisitor) + } + } + } +} + +/// Generates enum and its `Deserialize` implementation that represents each +/// non-skipped field of the struct +fn deserialize_field_identifier( + fields: &[(&str, Ident, &BTreeSet<String>)], + cattrs: &attr::Container, +) -> Stmts { + let (ignore_variant, fallthrough) = if cattrs.has_flatten() { + let ignore_variant = quote!(__other(_serde::__private::de::Content<'de>),); + let fallthrough = quote!(_serde::__private::Ok(__Field::__other(__value))); + (Some(ignore_variant), Some(fallthrough)) + } else if cattrs.deny_unknown_fields() { + (None, None) + } else { + let ignore_variant = quote!(__ignore,); + let fallthrough = quote!(_serde::__private::Ok(__Field::__ignore)); + (Some(ignore_variant), Some(fallthrough)) + }; + + Stmts(deserialize_generated_identifier( + fields, + cattrs, + false, + ignore_variant, + fallthrough, + )) +} + +// Generates `Deserialize::deserialize` body for an enum with +// `serde(field_identifier)` or `serde(variant_identifier)` attribute. +fn deserialize_custom_identifier( + params: &Parameters, + variants: &[Variant], + cattrs: &attr::Container, +) -> Fragment { + let is_variant = match cattrs.identifier() { + attr::Identifier::Variant => true, + attr::Identifier::Field => false, + attr::Identifier::No => unreachable!(), + }; + + let this_type = params.this_type.to_token_stream(); + let this_value = params.this_value.to_token_stream(); + + let (ordinary, fallthrough, fallthrough_borrowed) = if let Some(last) = variants.last() { + let last_ident = &last.ident; + if last.attrs.other() { + // Process `serde(other)` attribute. It would always be found on the + // last variant (checked in `check_identifier`), so all preceding + // are ordinary variants. + let ordinary = &variants[..variants.len() - 1]; + let fallthrough = quote!(_serde::__private::Ok(#this_value::#last_ident)); + (ordinary, Some(fallthrough), None) + } else if let Style::Newtype = last.style { + let ordinary = &variants[..variants.len() - 1]; + let fallthrough = |value| { + quote! { + _serde::__private::Result::map( + _serde::Deserialize::deserialize( + _serde::__private::de::IdentifierDeserializer::from(#value) + ), + #this_value::#last_ident) + } + }; + ( + ordinary, + Some(fallthrough(quote!(__value))), + Some(fallthrough(quote!(_serde::__private::de::Borrowed( + __value + )))), + ) + } else { + (variants, None, None) + } + } else { + (variants, None, None) + }; + + let names_idents: Vec<_> = ordinary + .iter() + .map(|variant| { + ( + variant.attrs.name().deserialize_name(), + variant.ident.clone(), + variant.attrs.aliases(), + ) + }) + .collect(); + + let names = names_idents.iter().flat_map(|&(_, _, aliases)| aliases); + + let names_const = if fallthrough.is_some() { + None + } else if is_variant { + let variants = quote! { + #[doc(hidden)] + const VARIANTS: &'static [&'static str] = &[ #(#names),* ]; + }; + Some(variants) + } else { + let fields = quote! { + #[doc(hidden)] + const FIELDS: &'static [&'static str] = &[ #(#names),* ]; + }; + Some(fields) + }; + + let (de_impl_generics, de_ty_generics, ty_generics, where_clause) = + split_with_de_lifetime(params); + let delife = params.borrowed.de_lifetime(); + let visitor_impl = Stmts(deserialize_identifier( + &this_value, + &names_idents, + is_variant, + fallthrough, + fallthrough_borrowed, + false, + cattrs.expecting(), + )); + + quote_block! { + #names_const + + #[doc(hidden)] + struct __FieldVisitor #de_impl_generics #where_clause { + marker: _serde::__private::PhantomData<#this_type #ty_generics>, + lifetime: _serde::__private::PhantomData<&#delife ()>, + } + + impl #de_impl_generics _serde::de::Visitor<#delife> for __FieldVisitor #de_ty_generics #where_clause { + type Value = #this_type #ty_generics; + + #visitor_impl + } + + let __visitor = __FieldVisitor { + marker: _serde::__private::PhantomData::<#this_type #ty_generics>, + lifetime: _serde::__private::PhantomData, + }; + _serde::Deserializer::deserialize_identifier(__deserializer, __visitor) + } +} + +fn deserialize_identifier( + this_value: &TokenStream, + fields: &[(&str, Ident, &BTreeSet<String>)], + is_variant: bool, + fallthrough: Option<TokenStream>, + fallthrough_borrowed: Option<TokenStream>, + collect_other_fields: bool, + expecting: Option<&str>, +) -> Fragment { + let str_mapping = fields.iter().map(|(_, ident, aliases)| { + // `aliases` also contains a main name + quote!(#(#aliases)|* => _serde::__private::Ok(#this_value::#ident)) + }); + let bytes_mapping = fields.iter().map(|(_, ident, aliases)| { + // `aliases` also contains a main name + let aliases = aliases + .iter() + .map(|alias| Literal::byte_string(alias.as_bytes())); + quote!(#(#aliases)|* => _serde::__private::Ok(#this_value::#ident)) + }); + + let expecting = expecting.unwrap_or(if is_variant { + "variant identifier" + } else { + "field identifier" + }); + + let bytes_to_str = if fallthrough.is_some() || collect_other_fields { + None + } else { + Some(quote! { + let __value = &_serde::__private::from_utf8_lossy(__value); + }) + }; + + let ( + value_as_str_content, + value_as_borrowed_str_content, + value_as_bytes_content, + value_as_borrowed_bytes_content, + ) = if collect_other_fields { + ( + Some(quote! { + let __value = _serde::__private::de::Content::String(_serde::__private::ToString::to_string(__value)); + }), + Some(quote! { + let __value = _serde::__private::de::Content::Str(__value); + }), + Some(quote! { + let __value = _serde::__private::de::Content::ByteBuf(__value.to_vec()); + }), + Some(quote! { + let __value = _serde::__private::de::Content::Bytes(__value); + }), + ) + } else { + (None, None, None, None) + }; + + let fallthrough_arm_tokens; + let fallthrough_arm = if let Some(fallthrough) = &fallthrough { + fallthrough + } else if is_variant { + fallthrough_arm_tokens = quote! { + _serde::__private::Err(_serde::de::Error::unknown_variant(__value, VARIANTS)) + }; + &fallthrough_arm_tokens + } else { + fallthrough_arm_tokens = quote! { + _serde::__private::Err(_serde::de::Error::unknown_field(__value, FIELDS)) + }; + &fallthrough_arm_tokens + }; + + let visit_other = if collect_other_fields { + quote! { + fn visit_bool<__E>(self, __value: bool) -> _serde::__private::Result<Self::Value, __E> + where + __E: _serde::de::Error, + { + _serde::__private::Ok(__Field::__other(_serde::__private::de::Content::Bool(__value))) + } + + fn visit_i8<__E>(self, __value: i8) -> _serde::__private::Result<Self::Value, __E> + where + __E: _serde::de::Error, + { + _serde::__private::Ok(__Field::__other(_serde::__private::de::Content::I8(__value))) + } + + fn visit_i16<__E>(self, __value: i16) -> _serde::__private::Result<Self::Value, __E> + where + __E: _serde::de::Error, + { + _serde::__private::Ok(__Field::__other(_serde::__private::de::Content::I16(__value))) + } + + fn visit_i32<__E>(self, __value: i32) -> _serde::__private::Result<Self::Value, __E> + where + __E: _serde::de::Error, + { + _serde::__private::Ok(__Field::__other(_serde::__private::de::Content::I32(__value))) + } + + fn visit_i64<__E>(self, __value: i64) -> _serde::__private::Result<Self::Value, __E> + where + __E: _serde::de::Error, + { + _serde::__private::Ok(__Field::__other(_serde::__private::de::Content::I64(__value))) + } + + fn visit_u8<__E>(self, __value: u8) -> _serde::__private::Result<Self::Value, __E> + where + __E: _serde::de::Error, + { + _serde::__private::Ok(__Field::__other(_serde::__private::de::Content::U8(__value))) + } + + fn visit_u16<__E>(self, __value: u16) -> _serde::__private::Result<Self::Value, __E> + where + __E: _serde::de::Error, + { + _serde::__private::Ok(__Field::__other(_serde::__private::de::Content::U16(__value))) + } + + fn visit_u32<__E>(self, __value: u32) -> _serde::__private::Result<Self::Value, __E> + where + __E: _serde::de::Error, + { + _serde::__private::Ok(__Field::__other(_serde::__private::de::Content::U32(__value))) + } + + fn visit_u64<__E>(self, __value: u64) -> _serde::__private::Result<Self::Value, __E> + where + __E: _serde::de::Error, + { + _serde::__private::Ok(__Field::__other(_serde::__private::de::Content::U64(__value))) + } + + fn visit_f32<__E>(self, __value: f32) -> _serde::__private::Result<Self::Value, __E> + where + __E: _serde::de::Error, + { + _serde::__private::Ok(__Field::__other(_serde::__private::de::Content::F32(__value))) + } + + fn visit_f64<__E>(self, __value: f64) -> _serde::__private::Result<Self::Value, __E> + where + __E: _serde::de::Error, + { + _serde::__private::Ok(__Field::__other(_serde::__private::de::Content::F64(__value))) + } + + fn visit_char<__E>(self, __value: char) -> _serde::__private::Result<Self::Value, __E> + where + __E: _serde::de::Error, + { + _serde::__private::Ok(__Field::__other(_serde::__private::de::Content::Char(__value))) + } + + fn visit_unit<__E>(self) -> _serde::__private::Result<Self::Value, __E> + where + __E: _serde::de::Error, + { + _serde::__private::Ok(__Field::__other(_serde::__private::de::Content::Unit)) + } + } + } else { + let u64_mapping = fields.iter().enumerate().map(|(i, (_, ident, _))| { + let i = i as u64; + quote!(#i => _serde::__private::Ok(#this_value::#ident)) + }); + + let u64_fallthrough_arm_tokens; + let u64_fallthrough_arm = if let Some(fallthrough) = &fallthrough { + fallthrough + } else { + let index_expecting = if is_variant { "variant" } else { "field" }; + let fallthrough_msg = format!("{} index 0 <= i < {}", index_expecting, fields.len()); + u64_fallthrough_arm_tokens = quote! { + _serde::__private::Err(_serde::de::Error::invalid_value( + _serde::de::Unexpected::Unsigned(__value), + &#fallthrough_msg, + )) + }; + &u64_fallthrough_arm_tokens + }; + + quote! { + fn visit_u64<__E>(self, __value: u64) -> _serde::__private::Result<Self::Value, __E> + where + __E: _serde::de::Error, + { + match __value { + #(#u64_mapping,)* + _ => #u64_fallthrough_arm, + } + } + } + }; + + let visit_borrowed = if fallthrough_borrowed.is_some() || collect_other_fields { + let str_mapping = str_mapping.clone(); + let bytes_mapping = bytes_mapping.clone(); + let fallthrough_borrowed_arm = fallthrough_borrowed.as_ref().unwrap_or(fallthrough_arm); + Some(quote! { + fn visit_borrowed_str<__E>(self, __value: &'de str) -> _serde::__private::Result<Self::Value, __E> + where + __E: _serde::de::Error, + { + match __value { + #(#str_mapping,)* + _ => { + #value_as_borrowed_str_content + #fallthrough_borrowed_arm + } + } + } + + fn visit_borrowed_bytes<__E>(self, __value: &'de [u8]) -> _serde::__private::Result<Self::Value, __E> + where + __E: _serde::de::Error, + { + match __value { + #(#bytes_mapping,)* + _ => { + #bytes_to_str + #value_as_borrowed_bytes_content + #fallthrough_borrowed_arm + } + } + } + }) + } else { + None + }; + + quote_block! { + fn expecting(&self, __formatter: &mut _serde::__private::Formatter) -> _serde::__private::fmt::Result { + _serde::__private::Formatter::write_str(__formatter, #expecting) + } + + #visit_other + + fn visit_str<__E>(self, __value: &str) -> _serde::__private::Result<Self::Value, __E> + where + __E: _serde::de::Error, + { + match __value { + #(#str_mapping,)* + _ => { + #value_as_str_content + #fallthrough_arm + } + } + } + + fn visit_bytes<__E>(self, __value: &[u8]) -> _serde::__private::Result<Self::Value, __E> + where + __E: _serde::de::Error, + { + match __value { + #(#bytes_mapping,)* + _ => { + #bytes_to_str + #value_as_bytes_content + #fallthrough_arm + } + } + } + + #visit_borrowed + } +} + +fn deserialize_map( + struct_path: &TokenStream, + params: &Parameters, + fields: &[Field], + cattrs: &attr::Container, +) -> Fragment { + // Create the field names for the fields. + let fields_names: Vec<_> = fields + .iter() + .enumerate() + .map(|(i, field)| (field, field_i(i))) + .collect(); + + // Declare each field that will be deserialized. + let let_values = fields_names + .iter() + .filter(|&&(field, _)| !field.attrs.skip_deserializing() && !field.attrs.flatten()) + .map(|(field, name)| { + let field_ty = field.ty; + quote! { + let mut #name: _serde::__private::Option<#field_ty> = _serde::__private::None; + } + }); + + // Collect contents for flatten fields into a buffer + let let_collect = if cattrs.has_flatten() { + Some(quote! { + let mut __collect = _serde::__private::Vec::<_serde::__private::Option<( + _serde::__private::de::Content, + _serde::__private::de::Content + )>>::new(); + }) + } else { + None + }; + + // Match arms to extract a value for a field. + let value_arms = fields_names + .iter() + .filter(|&&(field, _)| !field.attrs.skip_deserializing() && !field.attrs.flatten()) + .map(|(field, name)| { + let deser_name = field.attrs.name().deserialize_name(); + + let visit = match field.attrs.deserialize_with() { + None => { + let field_ty = field.ty; + let span = field.original.span(); + let func = + quote_spanned!(span=> _serde::de::MapAccess::next_value::<#field_ty>); + quote! { + #func(&mut __map)? + } + } + Some(path) => { + let (wrapper, wrapper_ty) = wrap_deserialize_field_with(params, field.ty, path); + quote!({ + #wrapper + match _serde::de::MapAccess::next_value::<#wrapper_ty>(&mut __map) { + _serde::__private::Ok(__wrapper) => __wrapper.value, + _serde::__private::Err(__err) => { + return _serde::__private::Err(__err); + } + } + }) + } + }; + quote! { + __Field::#name => { + if _serde::__private::Option::is_some(&#name) { + return _serde::__private::Err(<__A::Error as _serde::de::Error>::duplicate_field(#deser_name)); + } + #name = _serde::__private::Some(#visit); + } + } + }); + + // Visit ignored values to consume them + let ignored_arm = if cattrs.has_flatten() { + Some(quote! { + __Field::__other(__name) => { + __collect.push(_serde::__private::Some(( + __name, + _serde::de::MapAccess::next_value(&mut __map)?))); + } + }) + } else if cattrs.deny_unknown_fields() { + None + } else { + Some(quote! { + _ => { let _ = _serde::de::MapAccess::next_value::<_serde::de::IgnoredAny>(&mut __map)?; } + }) + }; + + let all_skipped = fields.iter().all(|field| field.attrs.skip_deserializing()); + let match_keys = if cattrs.deny_unknown_fields() && all_skipped { + quote! { + // FIXME: Once feature(exhaustive_patterns) is stable: + // let _serde::__private::None::<__Field> = _serde::de::MapAccess::next_key(&mut __map)?; + _serde::__private::Option::map( + _serde::de::MapAccess::next_key::<__Field>(&mut __map)?, + |__impossible| match __impossible {}); + } + } else { + quote! { + while let _serde::__private::Some(__key) = _serde::de::MapAccess::next_key::<__Field>(&mut __map)? { + match __key { + #(#value_arms)* + #ignored_arm + } + } + } + }; + + let extract_values = fields_names + .iter() + .filter(|&&(field, _)| !field.attrs.skip_deserializing() && !field.attrs.flatten()) + .map(|(field, name)| { + let missing_expr = Match(expr_is_missing(field, cattrs)); + + quote! { + let #name = match #name { + _serde::__private::Some(#name) => #name, + _serde::__private::None => #missing_expr + }; + } + }); + + let extract_collected = fields_names + .iter() + .filter(|&&(field, _)| field.attrs.flatten() && !field.attrs.skip_deserializing()) + .map(|(field, name)| { + let field_ty = field.ty; + let func = match field.attrs.deserialize_with() { + None => { + let span = field.original.span(); + quote_spanned!(span=> _serde::de::Deserialize::deserialize) + } + Some(path) => quote!(#path), + }; + quote! { + let #name: #field_ty = #func( + _serde::__private::de::FlatMapDeserializer( + &mut __collect, + _serde::__private::PhantomData))?; + } + }); + + let collected_deny_unknown_fields = if cattrs.has_flatten() && cattrs.deny_unknown_fields() { + Some(quote! { + if let _serde::__private::Some(_serde::__private::Some((__key, _))) = + __collect.into_iter().filter(_serde::__private::Option::is_some).next() + { + if let _serde::__private::Some(__key) = __key.as_str() { + return _serde::__private::Err( + _serde::de::Error::custom(format_args!("unknown field `{}`", &__key))); + } else { + return _serde::__private::Err( + _serde::de::Error::custom(format_args!("unexpected map key"))); + } + } + }) + } else { + None + }; + + let result = fields_names.iter().map(|(field, name)| { + let member = &field.member; + if field.attrs.skip_deserializing() { + let value = Expr(expr_is_missing(field, cattrs)); + quote!(#member: #value) + } else { + quote!(#member: #name) + } + }); + + let let_default = match cattrs.default() { + attr::Default::Default => Some(quote!( + let __default: Self::Value = _serde::__private::Default::default(); + )), + attr::Default::Path(path) => Some(quote!( + let __default: Self::Value = #path(); + )), + attr::Default::None => { + // We don't need the default value, to prevent an unused variable warning + // we'll leave the line empty. + None + } + }; + + let mut result = quote!(#struct_path { #(#result),* }); + if params.has_getter { + let this_type = ¶ms.this_type; + let (_, ty_generics, _) = params.generics.split_for_impl(); + result = quote! { + _serde::__private::Into::<#this_type #ty_generics>::into(#result) + }; + } + + quote_block! { + #(#let_values)* + + #let_collect + + #match_keys + + #let_default + + #(#extract_values)* + + #(#extract_collected)* + + #collected_deny_unknown_fields + + _serde::__private::Ok(#result) + } +} + +#[cfg(feature = "deserialize_in_place")] +fn deserialize_map_in_place( + params: &Parameters, + fields: &[Field], + cattrs: &attr::Container, +) -> Fragment { + assert!(!cattrs.has_flatten()); + + // Create the field names for the fields. + let fields_names: Vec<_> = fields + .iter() + .enumerate() + .map(|(i, field)| (field, field_i(i))) + .collect(); + + // For deserialize_in_place, declare booleans for each field that will be + // deserialized. + let let_flags = fields_names + .iter() + .filter(|&&(field, _)| !field.attrs.skip_deserializing()) + .map(|(_, name)| { + quote! { + let mut #name: bool = false; + } + }); + + // Match arms to extract a value for a field. + let value_arms_from = fields_names + .iter() + .filter(|&&(field, _)| !field.attrs.skip_deserializing()) + .map(|(field, name)| { + let deser_name = field.attrs.name().deserialize_name(); + let member = &field.member; + + let visit = match field.attrs.deserialize_with() { + None => { + quote! { + _serde::de::MapAccess::next_value_seed(&mut __map, _serde::__private::de::InPlaceSeed(&mut self.place.#member))? + } + } + Some(path) => { + let (wrapper, wrapper_ty) = wrap_deserialize_field_with(params, field.ty, path); + quote!({ + #wrapper + self.place.#member = match _serde::de::MapAccess::next_value::<#wrapper_ty>(&mut __map) { + _serde::__private::Ok(__wrapper) => __wrapper.value, + _serde::__private::Err(__err) => { + return _serde::__private::Err(__err); + } + }; + }) + } + }; + quote! { + __Field::#name => { + if #name { + return _serde::__private::Err(<__A::Error as _serde::de::Error>::duplicate_field(#deser_name)); + } + #visit; + #name = true; + } + } + }); + + // Visit ignored values to consume them + let ignored_arm = if cattrs.deny_unknown_fields() { + None + } else { + Some(quote! { + _ => { let _ = _serde::de::MapAccess::next_value::<_serde::de::IgnoredAny>(&mut __map)?; } + }) + }; + + let all_skipped = fields.iter().all(|field| field.attrs.skip_deserializing()); + + let match_keys = if cattrs.deny_unknown_fields() && all_skipped { + quote! { + // FIXME: Once feature(exhaustive_patterns) is stable: + // let _serde::__private::None::<__Field> = _serde::de::MapAccess::next_key(&mut __map)?; + _serde::__private::Option::map( + _serde::de::MapAccess::next_key::<__Field>(&mut __map)?, + |__impossible| match __impossible {}); + } + } else { + quote! { + while let _serde::__private::Some(__key) = _serde::de::MapAccess::next_key::<__Field>(&mut __map)? { + match __key { + #(#value_arms_from)* + #ignored_arm + } + } + } + }; + + let check_flags = fields_names + .iter() + .filter(|&&(field, _)| !field.attrs.skip_deserializing()) + .map(|(field, name)| { + let missing_expr = expr_is_missing(field, cattrs); + // If missing_expr unconditionally returns an error, don't try + // to assign its value to self.place. + if field.attrs.default().is_none() + && cattrs.default().is_none() + && field.attrs.deserialize_with().is_some() + { + let missing_expr = Stmts(missing_expr); + quote! { + if !#name { + #missing_expr; + } + } + } else { + let member = &field.member; + let missing_expr = Expr(missing_expr); + quote! { + if !#name { + self.place.#member = #missing_expr; + }; + } + } + }); + + let this_type = ¶ms.this_type; + let (_, _, ty_generics, _) = split_with_de_lifetime(params); + + let let_default = match cattrs.default() { + attr::Default::Default => Some(quote!( + let __default: #this_type #ty_generics = _serde::__private::Default::default(); + )), + attr::Default::Path(path) => Some(quote!( + let __default: #this_type #ty_generics = #path(); + )), + attr::Default::None => { + // We don't need the default value, to prevent an unused variable warning + // we'll leave the line empty. + None + } + }; + + quote_block! { + #(#let_flags)* + + #match_keys + + #let_default + + #(#check_flags)* + + _serde::__private::Ok(()) + } +} + +fn field_i(i: usize) -> Ident { + Ident::new(&format!("__field{}", i), Span::call_site()) +} + +/// This function wraps the expression in `#[serde(deserialize_with = "...")]` +/// in a trait to prevent it from accessing the internal `Deserialize` state. +fn wrap_deserialize_with( + params: &Parameters, + value_ty: &TokenStream, + deserialize_with: &syn::ExprPath, +) -> (TokenStream, TokenStream) { + let this_type = ¶ms.this_type; + let (de_impl_generics, de_ty_generics, ty_generics, where_clause) = + split_with_de_lifetime(params); + let delife = params.borrowed.de_lifetime(); + + let wrapper = quote! { + #[doc(hidden)] + struct __DeserializeWith #de_impl_generics #where_clause { + value: #value_ty, + phantom: _serde::__private::PhantomData<#this_type #ty_generics>, + lifetime: _serde::__private::PhantomData<&#delife ()>, + } + + impl #de_impl_generics _serde::Deserialize<#delife> for __DeserializeWith #de_ty_generics #where_clause { + fn deserialize<__D>(__deserializer: __D) -> _serde::__private::Result<Self, __D::Error> + where + __D: _serde::Deserializer<#delife>, + { + _serde::__private::Ok(__DeserializeWith { + value: #deserialize_with(__deserializer)?, + phantom: _serde::__private::PhantomData, + lifetime: _serde::__private::PhantomData, + }) + } + } + }; + + let wrapper_ty = quote!(__DeserializeWith #de_ty_generics); + + (wrapper, wrapper_ty) +} + +fn wrap_deserialize_field_with( + params: &Parameters, + field_ty: &syn::Type, + deserialize_with: &syn::ExprPath, +) -> (TokenStream, TokenStream) { + wrap_deserialize_with(params, "e!(#field_ty), deserialize_with) +} + +fn wrap_deserialize_variant_with( + params: &Parameters, + variant: &Variant, + deserialize_with: &syn::ExprPath, +) -> (TokenStream, TokenStream, TokenStream) { + let field_tys = variant.fields.iter().map(|field| field.ty); + let (wrapper, wrapper_ty) = + wrap_deserialize_with(params, "e!((#(#field_tys),*)), deserialize_with); + + let unwrap_fn = unwrap_to_variant_closure(params, variant, true); + + (wrapper, wrapper_ty, unwrap_fn) +} + +// Generates closure that converts single input parameter to the final value. +fn unwrap_to_variant_closure( + params: &Parameters, + variant: &Variant, + with_wrapper: bool, +) -> TokenStream { + let this_value = ¶ms.this_value; + let variant_ident = &variant.ident; + + let (arg, wrapper) = if with_wrapper { + (quote! { __wrap }, quote! { __wrap.value }) + } else { + let field_tys = variant.fields.iter().map(|field| field.ty); + (quote! { __wrap: (#(#field_tys),*) }, quote! { __wrap }) + }; + + let field_access = (0..variant.fields.len()).map(|n| { + Member::Unnamed(Index { + index: n as u32, + span: Span::call_site(), + }) + }); + + match variant.style { + Style::Struct if variant.fields.len() == 1 => { + let member = &variant.fields[0].member; + quote! { + |#arg| #this_value::#variant_ident { #member: #wrapper } + } + } + Style::Struct => { + let members = variant.fields.iter().map(|field| &field.member); + quote! { + |#arg| #this_value::#variant_ident { #(#members: #wrapper.#field_access),* } + } + } + Style::Tuple => quote! { + |#arg| #this_value::#variant_ident(#(#wrapper.#field_access),*) + }, + Style::Newtype => quote! { + |#arg| #this_value::#variant_ident(#wrapper) + }, + Style::Unit => quote! { + |#arg| #this_value::#variant_ident + }, + } +} + +fn expr_is_missing(field: &Field, cattrs: &attr::Container) -> Fragment { + match field.attrs.default() { + attr::Default::Default => { + let span = field.original.span(); + let func = quote_spanned!(span=> _serde::__private::Default::default); + return quote_expr!(#func()); + } + attr::Default::Path(path) => { + return quote_expr!(#path()); + } + attr::Default::None => { /* below */ } + } + + match *cattrs.default() { + attr::Default::Default | attr::Default::Path(_) => { + let member = &field.member; + return quote_expr!(__default.#member); + } + attr::Default::None => { /* below */ } + } + + let name = field.attrs.name().deserialize_name(); + match field.attrs.deserialize_with() { + None => { + let span = field.original.span(); + let func = quote_spanned!(span=> _serde::__private::de::missing_field); + quote_expr! { + #func(#name)? + } + } + Some(_) => { + quote_expr! { + return _serde::__private::Err(<__A::Error as _serde::de::Error>::missing_field(#name)) + } + } + } +} + +fn expr_is_missing_seq( + assign_to: Option<TokenStream>, + index: usize, + field: &Field, + cattrs: &attr::Container, + expecting: &str, +) -> TokenStream { + match field.attrs.default() { + attr::Default::Default => { + let span = field.original.span(); + return quote_spanned!(span=> #assign_to _serde::__private::Default::default()); + } + attr::Default::Path(path) => { + return quote_spanned!(path.span()=> #assign_to #path()); + } + attr::Default::None => { /* below */ } + } + + match *cattrs.default() { + attr::Default::Default | attr::Default::Path(_) => { + let member = &field.member; + quote!(#assign_to __default.#member) + } + attr::Default::None => quote!( + return _serde::__private::Err(_serde::de::Error::invalid_length(#index, &#expecting)) + ), + } +} + +fn effective_style(variant: &Variant) -> Style { + match variant.style { + Style::Newtype if variant.fields[0].attrs.skip_deserializing() => Style::Unit, + other => other, + } +} + +struct DeImplGenerics<'a>(&'a Parameters); +#[cfg(feature = "deserialize_in_place")] +struct InPlaceImplGenerics<'a>(&'a Parameters); + +impl<'a> ToTokens for DeImplGenerics<'a> { + fn to_tokens(&self, tokens: &mut TokenStream) { + let mut generics = self.0.generics.clone(); + if let Some(de_lifetime) = self.0.borrowed.de_lifetime_param() { + generics.params = Some(syn::GenericParam::Lifetime(de_lifetime)) + .into_iter() + .chain(generics.params) + .collect(); + } + let (impl_generics, _, _) = generics.split_for_impl(); + impl_generics.to_tokens(tokens); + } +} + +#[cfg(feature = "deserialize_in_place")] +impl<'a> ToTokens for InPlaceImplGenerics<'a> { + fn to_tokens(&self, tokens: &mut TokenStream) { + let place_lifetime = place_lifetime(); + let mut generics = self.0.generics.clone(); + + // Add lifetime for `&'place mut Self, and `'a: 'place` + for param in &mut generics.params { + match param { + syn::GenericParam::Lifetime(param) => { + param.bounds.push(place_lifetime.lifetime.clone()); + } + syn::GenericParam::Type(param) => { + param.bounds.push(syn::TypeParamBound::Lifetime( + place_lifetime.lifetime.clone(), + )); + } + syn::GenericParam::Const(_) => {} + } + } + generics.params = Some(syn::GenericParam::Lifetime(place_lifetime)) + .into_iter() + .chain(generics.params) + .collect(); + if let Some(de_lifetime) = self.0.borrowed.de_lifetime_param() { + generics.params = Some(syn::GenericParam::Lifetime(de_lifetime)) + .into_iter() + .chain(generics.params) + .collect(); + } + let (impl_generics, _, _) = generics.split_for_impl(); + impl_generics.to_tokens(tokens); + } +} + +#[cfg(feature = "deserialize_in_place")] +impl<'a> DeImplGenerics<'a> { + fn in_place(self) -> InPlaceImplGenerics<'a> { + InPlaceImplGenerics(self.0) + } +} + +struct DeTypeGenerics<'a>(&'a Parameters); +#[cfg(feature = "deserialize_in_place")] +struct InPlaceTypeGenerics<'a>(&'a Parameters); + +fn de_type_generics_to_tokens( + mut generics: syn::Generics, + borrowed: &BorrowedLifetimes, + tokens: &mut TokenStream, +) { + if borrowed.de_lifetime_param().is_some() { + let def = syn::LifetimeParam { + attrs: Vec::new(), + lifetime: syn::Lifetime::new("'de", Span::call_site()), + colon_token: None, + bounds: Punctuated::new(), + }; + // Prepend 'de lifetime to list of generics + generics.params = Some(syn::GenericParam::Lifetime(def)) + .into_iter() + .chain(generics.params) + .collect(); + } + let (_, ty_generics, _) = generics.split_for_impl(); + ty_generics.to_tokens(tokens); +} + +impl<'a> ToTokens for DeTypeGenerics<'a> { + fn to_tokens(&self, tokens: &mut TokenStream) { + de_type_generics_to_tokens(self.0.generics.clone(), &self.0.borrowed, tokens); + } +} + +#[cfg(feature = "deserialize_in_place")] +impl<'a> ToTokens for InPlaceTypeGenerics<'a> { + fn to_tokens(&self, tokens: &mut TokenStream) { + let mut generics = self.0.generics.clone(); + generics.params = Some(syn::GenericParam::Lifetime(place_lifetime())) + .into_iter() + .chain(generics.params) + .collect(); + + de_type_generics_to_tokens(generics, &self.0.borrowed, tokens); + } +} + +#[cfg(feature = "deserialize_in_place")] +impl<'a> DeTypeGenerics<'a> { + fn in_place(self) -> InPlaceTypeGenerics<'a> { + InPlaceTypeGenerics(self.0) + } +} + +#[cfg(feature = "deserialize_in_place")] +fn place_lifetime() -> syn::LifetimeParam { + syn::LifetimeParam { + attrs: Vec::new(), + lifetime: syn::Lifetime::new("'place", Span::call_site()), + colon_token: None, + bounds: Punctuated::new(), + } +} + +fn split_with_de_lifetime( + params: &Parameters, +) -> ( + DeImplGenerics, + DeTypeGenerics, + syn::TypeGenerics, + Option<&syn::WhereClause>, +) { + let de_impl_generics = DeImplGenerics(params); + let de_ty_generics = DeTypeGenerics(params); + let (_, ty_generics, where_clause) = params.generics.split_for_impl(); + (de_impl_generics, de_ty_generics, ty_generics, where_clause) +} |