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Derivable Encode & Decode #509

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pepyakin merged 13 commits into from
Aug 8, 2018
Merged

Derivable Encode & Decode #509

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a44fd32
Derive macro for simple structs.
tomusdrw Aug 6, 2018
66f6424
Derive Encode/Decode wherever we can.
tomusdrw Aug 6, 2018
0aecc83
Derive for enums.
tomusdrw Aug 7, 2018
d21d09d
Support discriminant.
tomusdrw Aug 7, 2018
ac85a7f
Get rid of some repetition.
tomusdrw Aug 7, 2018
0729be8
Support custom indices.
tomusdrw Aug 7, 2018
252302c
Derive codec for enums wherever possible.
tomusdrw Aug 7, 2018
a558a62
Merge branch 'master' into td-codecderive
tomusdrw Aug 7, 2018
7f0c8e9
Fix no_std
tomusdrw Aug 7, 2018
68c93b3
WASM rebuilt
tomusdrw Aug 7, 2018
d3a5ccd
Avoid excessive import.
tomusdrw Aug 7, 2018
1588c86
Fix compilation.
tomusdrw Aug 8, 2018
cf6b46c
Address review grumbles.
tomusdrw Aug 8, 2018
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Get rid of some repetition.
  • Loading branch information
@tomusdrw
tomusdrw committed Aug 7, 2018
commit ac85a7fbd1e909332fcb9c0b9cac63b8a607a251
120 changes: 52 additions & 68 deletions substrate/codec/derive/src/decode.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -20,42 +20,19 @@ use syn::{
spanned::Spanned,
};

pub fn quote(data: &Data, type_name: &Ident, input_: &TokenStream) -> TokenStream {
pub fn quote(data: &Data, type_name: &Ident, input: &TokenStream) -> TokenStream {
let call_site = Span::call_site();
match *data {
Data::Struct(ref data) => match data.fields {
Fields::Named(ref fields) => {
let recurse = fields.named.iter().map(|f| {
let name = &f.ident;
let field = quote_spanned!(call_site => #name);

quote_spanned! { f.span() =>
#field: ::codec::Decode::decode(#input_)?
}
});

quote_spanned! {call_site =>
Some(Self {
#( #recurse, )*
})
}
},
Fields::Unnamed(ref fields) => {
let recurse = fields.unnamed.iter().map(|f| {
quote_spanned! { f.span() =>
::codec::Decode::decode(#input_)?
}
});

quote_spanned! {call_site =>
Some(#type_name (
#( #recurse, )*
))
}
},
Fields::Named(_) | Fields::Unnamed(_) => create_instance(
call_site,
quote! { #type_name },
input,
&data.fields,
),
Fields::Unit => {
quote_spanned! {call_site =>
drop(#input_);
drop(#input);
Some(#type_name)
}
},
Expand All @@ -70,42 +47,12 @@ pub fn quote(data: &Data, type_name: &Ident, input_: &TokenStream) -> TokenStrea
.map(|&(_, ref expr)| quote! { #expr })
.unwrap_or_else(|| quote! { #i });

let create = match v.fields {
Fields::Named(ref fields) => {
let recurse = fields.named.iter().map(|f| {
let name = &f.ident;
let field = quote_spanned!(call_site => #name);

quote_spanned! { f.span() =>
#field: ::codec::Decode::decode(#input_)?
}
});

quote_spanned! {call_site =>
Some(#type_name :: #name {
#( #recurse, )*
})
}
},
Fields::Unnamed(ref fields) => {
let recurse = fields.unnamed.iter().map(|f| {
quote_spanned! { f.span() =>
::codec::Decode::decode(#input_)?
}
});

quote_spanned! {call_site =>
Some(#type_name :: #name (
#( #recurse, )*
))
}
},
Fields::Unit => {
quote_spanned! {call_site =>
Some(#type_name :: #name)
}
},
};
let create = create_instance(
call_site,
quote! { #type_name :: #name },
input,
&v.fields,
);

quote_spanned! { v.span() =>
x if x == #index as u8 => {
Expand All @@ -115,7 +62,7 @@ pub fn quote(data: &Data, type_name: &Ident, input_: &TokenStream) -> TokenStrea
});

quote! {
match #input_.read_byte()? {
match #input.read_byte()? {
#( #recurse )*
_ => None,
}
Expand All @@ -128,4 +75,41 @@ pub fn quote(data: &Data, type_name: &Ident, input_: &TokenStream) -> TokenStrea
}
}

fn create_instance(call_site: Span, name: TokenStream, input: &TokenStream, fields: &Fields) -> TokenStream {
match *fields {
Fields::Named(ref fields) => {
let recurse = fields.named.iter().map(|f| {
let name = &f.ident;
let field = quote_spanned!(call_site => #name);

quote_spanned! { f.span() =>
#field: ::codec::Decode::decode(#input)?
}
});

quote_spanned! {call_site =>
Some(#name {
#( #recurse, )*
})
}
},
Fields::Unnamed(ref fields) => {
let recurse = fields.unnamed.iter().map(|f| {
quote_spanned! { f.span() =>
::codec::Decode::decode(#input)?
}
});

quote_spanned! {call_site =>
Some(#name (
#( #recurse, )*
))
}
},
Fields::Unit => {
quote_spanned! {call_site =>
Some(#name)
}
},
}
}
124 changes: 70 additions & 54 deletions substrate/codec/derive/src/encode.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -16,44 +16,53 @@

use proc_macro2::{Span, TokenStream};
use syn::{
Data, Fields, Ident, Index,
Data, Field, Fields, Ident, Index,
punctuated::Punctuated,
spanned::Spanned,
token::Comma,
};

pub fn quote(data: &Data, type_name: &Ident, self_: &TokenStream, dest_: &TokenStream) -> TokenStream {
type FieldsList = Punctuated<Field, Comma>;

fn encode_fields<F>(
dest: &TokenStream,
fields: &FieldsList,
field_name: F,
) -> TokenStream where
F: Fn(usize, &Option<Ident>) -> TokenStream,
{
let recurse = fields.iter().enumerate().map(|(i, f)| {
let field = field_name(i, &f.ident);

quote_spanned! { f.span() =>
#dest.push(#field);
}
});

quote! {
#( #recurse )*
}
}

pub fn quote(data: &Data, type_name: &Ident, self_: &TokenStream, dest: &TokenStream) -> TokenStream {
let call_site = Span::call_site();
match *data {
Data::Struct(ref data) => match data.fields {
Fields::Named(ref fields) => {
let recurse = fields.named.iter().map(|f| {
let name = &f.ident;
let field = quote_spanned!(call_site => #self_.#name);

quote_spanned! { f.span() =>
#dest_.push(&#field);
}
});

quote_spanned! { call_site =>
#( #recurse )*
}
},
Fields::Unnamed(ref fields) => {
let recurse = fields.unnamed.iter().enumerate().map(|(i, f)| {
Fields::Named(ref fields) => encode_fields(
dest,
&fields.named,
|_, name| quote_spanned!(call_site => &#self_.#name),
),
Fields::Unnamed(ref fields) => encode_fields(
dest,
&fields.unnamed,
|i, _| {
let index = Index { index: i as u32, span: call_site };
let field = quote_spanned!(call_site => #self_.#index);
quote_spanned! { f.span() =>
#dest_.push(&#field);
}
});

quote! {
#( #recurse )*
}
},
// Do nothing, we don't encode unit type and assume it's always decodable.
Fields::Unit => quote! {
drop(#dest_);
quote_spanned!(call_site => &#self_.#index)
},
),
Fields::Unit => quote_spanned! { call_site =>
drop(#dest);
},
},
Data::Enum(ref data) => {
Expand All @@ -68,45 +77,52 @@ pub fn quote(data: &Data, type_name: &Ident, self_: &TokenStream, dest_: &TokenS

match f.fields {
Fields::Named(ref fields) => {
let names = fields.named.iter().map(|f| {
let field_name = &f.ident;
quote_spanned!(call_site => #field_name)
}).collect::<Vec<_>>();

let fields = names.iter();
let encode_fields = names.iter().map(|f| {
quote_spanned! { call_site => #dest_.push(#f); }
});
let field_name = |_, ident: &Option<Ident>| quote_spanned!(call_site => #ident);
let names = fields.named
.iter()
.enumerate()
.map(|(i, f)| field_name(i, &f.ident));

let encode_fields = encode_fields(
dest,
&fields.named,
|a, b| field_name(a, b),
);

quote_spanned! { f.span() =>
#type_name :: #name { #( ref #fields, )* } => {
#dest_.push_byte(#index as u8);
#( #encode_fields )*
#type_name :: #name { #( ref #names, )* } => {
#dest.push_byte(#index as u8);
#encode_fields
}
}
},
Fields::Unnamed(ref fields) => {
let names = fields.unnamed.iter().enumerate().map(|(i, _f)| {
let field_name = |i, _: &Option<Ident>| {
let ident = Ident::new(&format!("f_{}", i), call_site);
quote_spanned!(call_site => #ident)
}).collect::<Vec<_>>();

let fields = names.iter();
let encode_fields = names.iter().map(|f| {
quote_spanned! { call_site => #dest_.push(#f); }
});
};
let names = fields.unnamed
.iter()
.enumerate()
.map(|(i, f)| field_name(i, &f.ident));

let encode_fields = encode_fields(
dest,
&fields.unnamed,
|a, b| field_name(a, b),
);

quote_spanned! { f.span() =>
#type_name :: #name ( #( ref #fields, )* ) => {
#dest_.push_byte(#index as u8);
#( #encode_fields )*
#type_name :: #name ( #( ref #names, )* ) => {
#dest.push_byte(#index as u8);
#encode_fields
}
}
},
Fields::Unit => {
quote_spanned! { f.span() =>
#type_name :: #name => {
#dest_.push_byte(#index as u8);
#dest.push_byte(#index as u8);
}
}
},
Expand Down
12 changes: 6 additions & 6 deletions substrate/codec/derive/src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -82,10 +82,10 @@ pub fn decode_derive(input: TokenStream) -> TokenStream {
}

fn add_trait_bounds(mut generics: Generics, bounds: syn::TypeParamBound) -> Generics {
for param in &mut generics.params {
if let GenericParam::Type(ref mut type_param) = *param {
type_param.bounds.push(bounds.clone());
}
}
generics
for param in &mut generics.params {
if let GenericParam::Type(ref mut type_param) = *param {
type_param.bounds.push(bounds.clone());
}
}
generics
}