diff options
author | Joel Galenson <jgalenson@google.com> | 2021-09-22 11:19:44 -0700 |
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committer | Joel Galenson <jgalenson@google.com> | 2021-09-22 11:19:44 -0700 |
commit | 0efbd40678185898855d20949f214d7c55e075ba (patch) | |
tree | 9767e8ee4aefab4b6992d8cbc27f9ac98220a93f /src/pretend.rs | |
parent | b3ad500f0e2eb2022859078339a8b2b4bb42332f (diff) | |
download | serde_derive-0efbd40678185898855d20949f214d7c55e075ba.tar.gz |
Upgrade rust/crates/serde_derive to 1.0.130
Test: make
Change-Id: I2357003e23ca7a9582ebc171da5673f3e2be9a0d
Diffstat (limited to 'src/pretend.rs')
-rw-r--r-- | src/pretend.rs | 137 |
1 files changed, 98 insertions, 39 deletions
diff --git a/src/pretend.rs b/src/pretend.rs index 955ce3d..c4e5874 100644 --- a/src/pretend.rs +++ b/src/pretend.rs @@ -1,7 +1,7 @@ -use proc_macro2::{Span, TokenStream}; -use syn::Ident; +use proc_macro2::TokenStream; +use quote::format_ident; -use internals::ast::{Container, Data, Field, Style}; +use internals::ast::{Container, Data, Field, Style, Variant}; // Suppress dead_code warnings that would otherwise appear when using a remote // derive. Other than this pretend code, a struct annotated with remote derive @@ -20,8 +20,8 @@ use internals::ast::{Container, Data, Field, Style}; // 8 | enum EnumDef { V } // | ^ // -pub fn pretend_used(cont: &Container) -> TokenStream { - let pretend_fields = pretend_fields_used(cont); +pub fn pretend_used(cont: &Container, is_packed: bool) -> TokenStream { + let pretend_fields = pretend_fields_used(cont, is_packed); let pretend_variants = pretend_variants_used(cont); quote! { @@ -32,49 +32,115 @@ pub fn pretend_used(cont: &Container) -> TokenStream { // For structs with named fields, expands to: // +// match None::<&T> { +// Some(T { a: __v0, b: __v1 }) => {} +// _ => {} +// } +// +// For packed structs on sufficiently new rustc, expands to: +// +// match None::<&T> { +// Some(__v @ T { a: _, b: _ }) => { +// let _ = addr_of!(__v.a); +// let _ = addr_of!(__v.b); +// } +// _ => {} +// } +// +// For packed structs on older rustc, we assume Sized and !Drop, and expand to: +// // match None::<T> { -// Some(T { a: ref __v0, b: ref __v1 }) => {} +// Some(T { a: __v0, b: __v1 }) => {} // _ => {} // } // // For enums, expands to the following but only including struct variants: // -// match None::<T> { -// Some(T::A { a: ref __v0 }) => {} -// Some(T::B { b: ref __v0 }) => {} +// match None::<&T> { +// Some(T::A { a: __v0 }) => {} +// Some(T::B { b: __v0 }) => {} // _ => {} // } // -// The `ref` is important in case the user has written a Drop impl on their -// type. Rust does not allow destructuring a struct or enum that has a Drop -// impl. -fn pretend_fields_used(cont: &Container) -> TokenStream { +fn pretend_fields_used(cont: &Container, is_packed: bool) -> TokenStream { + match &cont.data { + Data::Enum(variants) => pretend_fields_used_enum(cont, variants), + Data::Struct(Style::Struct, fields) => if is_packed { + pretend_fields_used_struct_packed(cont, fields) + } else { + pretend_fields_used_struct(cont, fields) + }, + Data::Struct(_, _) => quote!(), + } +} + +fn pretend_fields_used_struct(cont: &Container, fields: &[Field]) -> TokenStream { let type_ident = &cont.ident; let (_, ty_generics, _) = cont.generics.split_for_impl(); - let patterns = match &cont.data { - Data::Enum(variants) => variants - .iter() - .filter_map(|variant| match variant.style { - Style::Struct => { - let variant_ident = &variant.ident; - let pat = struct_pattern(&variant.fields); - Some(quote!(#type_ident::#variant_ident #pat)) + let members = fields.iter().map(|field| &field.member); + let placeholders = (0usize..).map(|i| format_ident!("__v{}", i)); + + quote! { + match _serde::__private::None::<&#type_ident #ty_generics> { + _serde::__private::Some(#type_ident { #(#members: #placeholders),* }) => {} + _ => {} + } + } +} + +fn pretend_fields_used_struct_packed(cont: &Container, fields: &[Field]) -> TokenStream { + let type_ident = &cont.ident; + let (_, ty_generics, _) = cont.generics.split_for_impl(); + + let members = fields.iter().map(|field| &field.member).collect::<Vec<_>>(); + + #[cfg(ptr_addr_of)] + { + quote! { + match _serde::__private::None::<&#type_ident #ty_generics> { + _serde::__private::Some(__v @ #type_ident { #(#members: _),* }) => { + #( + let _ = _serde::__private::ptr::addr_of!(__v.#members); + )* } - _ => None, - }) - .collect::<Vec<_>>(), - Data::Struct(Style::Struct, fields) => { - let pat = struct_pattern(fields); - vec![quote!(#type_ident #pat)] + _ => {} + } } - Data::Struct(_, _) => { - return quote!(); + } + + #[cfg(not(ptr_addr_of))] + { + let placeholders = (0usize..).map(|i| format_ident!("__v{}", i)); + + quote! { + match _serde::__private::None::<#type_ident #ty_generics> { + _serde::__private::Some(#type_ident { #(#members: #placeholders),* }) => {} + _ => {} + } } - }; + } +} + +fn pretend_fields_used_enum(cont: &Container, variants: &[Variant]) -> TokenStream { + let type_ident = &cont.ident; + let (_, ty_generics, _) = cont.generics.split_for_impl(); + + let patterns = variants + .iter() + .filter_map(|variant| match variant.style { + Style::Struct => { + let variant_ident = &variant.ident; + let members = variant.fields.iter().map(|field| &field.member); + let placeholders = (0usize..).map(|i| format_ident!("__v{}", i)); + Some(quote!(#type_ident::#variant_ident { #(#members: #placeholders),* })) + } + _ => None, + }) + .collect::<Vec<_>>(); quote! { - match _serde::__private::None::<#type_ident #ty_generics> { + match _serde::__private::None::<&#type_ident #ty_generics> { #( _serde::__private::Some(#patterns) => {} )* @@ -107,7 +173,7 @@ fn pretend_variants_used(cont: &Container) -> TokenStream { let cases = variants.iter().map(|variant| { let variant_ident = &variant.ident; let placeholders = &(0..variant.fields.len()) - .map(|i| Ident::new(&format!("__v{}", i), Span::call_site())) + .map(|i| format_ident!("__v{}", i)) .collect::<Vec<_>>(); let pat = match variant.style { @@ -131,10 +197,3 @@ fn pretend_variants_used(cont: &Container) -> TokenStream { quote!(#(#cases)*) } - -fn struct_pattern(fields: &[Field]) -> TokenStream { - let members = fields.iter().map(|field| &field.member); - let placeholders = - (0..fields.len()).map(|i| Ident::new(&format!("__v{}", i), Span::call_site())); - quote!({ #(#members: ref #placeholders),* }) -} |