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use crate::attr::{self, Attrs};
use crate::generics::ParamsInScope;
use proc_macro2::Span;
use syn::{
Data, DataEnum, DataStruct, DeriveInput, Error, Fields, Generics, Ident, Index, Member, Result,
Type,
};
pub enum Input<'a> {
Struct(Struct<'a>),
Enum(Enum<'a>),
}
pub struct Struct<'a> {
pub attrs: Attrs<'a>,
pub ident: Ident,
pub generics: &'a Generics,
pub fields: Vec<Field<'a>>,
}
pub struct Enum<'a> {
pub attrs: Attrs<'a>,
pub ident: Ident,
pub generics: &'a Generics,
pub variants: Vec<Variant<'a>>,
}
pub struct Variant<'a> {
pub original: &'a syn::Variant,
pub attrs: Attrs<'a>,
pub ident: Ident,
pub fields: Vec<Field<'a>>,
}
pub struct Field<'a> {
pub original: &'a syn::Field,
pub attrs: Attrs<'a>,
pub member: Member,
pub ty: &'a Type,
pub contains_generic: bool,
}
impl<'a> Input<'a> {
pub fn from_syn(node: &'a DeriveInput) -> Result<Self> {
match &node.data {
Data::Struct(data) => Struct::from_syn(node, data).map(Input::Struct),
Data::Enum(data) => Enum::from_syn(node, data).map(Input::Enum),
Data::Union(_) => Err(Error::new_spanned(
node,
"union as errors are not supported",
)),
}
}
}
impl<'a> Struct<'a> {
fn from_syn(node: &'a DeriveInput, data: &'a DataStruct) -> Result<Self> {
let mut attrs = attr::get(&node.attrs)?;
let scope = ParamsInScope::new(&node.generics);
let span = attrs.span().unwrap_or_else(Span::call_site);
let fields = Field::multiple_from_syn(&data.fields, &scope, span)?;
if let Some(display) = &mut attrs.display {
display.expand_shorthand(&fields);
}
Ok(Struct {
attrs,
ident: node.ident.clone(),
generics: &node.generics,
fields,
})
}
}
impl<'a> Enum<'a> {
fn from_syn(node: &'a DeriveInput, data: &'a DataEnum) -> Result<Self> {
let attrs = attr::get(&node.attrs)?;
let scope = ParamsInScope::new(&node.generics);
let span = attrs.span().unwrap_or_else(Span::call_site);
let variants = data
.variants
.iter()
.map(|node| {
let mut variant = Variant::from_syn(node, &scope, span)?;
if let display @ None = &mut variant.attrs.display {
display.clone_from(&attrs.display);
}
if let Some(display) = &mut variant.attrs.display {
display.expand_shorthand(&variant.fields);
} else if variant.attrs.transparent.is_none() {
variant.attrs.transparent = attrs.transparent;
}
Ok(variant)
})
.collect::<Result<_>>()?;
Ok(Enum {
attrs,
ident: node.ident.clone(),
generics: &node.generics,
variants,
})
}
}
impl<'a> Variant<'a> {
fn from_syn(node: &'a syn::Variant, scope: &ParamsInScope<'a>, span: Span) -> Result<Self> {
let attrs = attr::get(&node.attrs)?;
let span = attrs.span().unwrap_or(span);
Ok(Variant {
original: node,
attrs,
ident: node.ident.clone(),
fields: Field::multiple_from_syn(&node.fields, scope, span)?,
})
}
}
impl<'a> Field<'a> {
fn multiple_from_syn(
fields: &'a Fields,
scope: &ParamsInScope<'a>,
span: Span,
) -> Result<Vec<Self>> {
fields
.iter()
.enumerate()
.map(|(i, field)| Field::from_syn(i, field, scope, span))
.collect()
}
fn from_syn(
i: usize,
node: &'a syn::Field,
scope: &ParamsInScope<'a>,
span: Span,
) -> Result<Self> {
Ok(Field {
original: node,
attrs: attr::get(&node.attrs)?,
member: node.ident.clone().map(Member::Named).unwrap_or_else(|| {
Member::Unnamed(Index {
index: i as u32,
span,
})
}),
ty: &node.ty,
contains_generic: scope.intersects(&node.ty),
})
}
}
impl Attrs<'_> {
pub fn span(&self) -> Option<Span> {
if let Some(display) = &self.display {
Some(display.fmt.span())
} else if let Some(transparent) = &self.transparent {
Some(transparent.span)
} else {
None
}
}
}