use syn::ext::IdentExt as _;
use crate::{macros::tokens::local, request::bodies, runtime::paths::Paths, types};
struct FieldAttr {
name: syn::LitStr,
default: Option<syn::LitStr>,
}
fn contains(attrs: &[syn::Attribute], name: &str) -> bool {
attrs.iter().any(|attr| attr.path().is_ident(name))
}
fn is_only(attrs: &[syn::Attribute], name: &str) -> bool {
contains(attrs, name)
&& [
"header",
"query",
"path",
"raw_body",
"body_len",
"authority",
]
.into_iter()
.filter(|source| contains(attrs, source))
.count()
== 1
}
fn parse(attrs: &[syn::Attribute], name: &str) -> syn::Result<Option<FieldAttr>> {
let mut found = None;
for attr in attrs {
use syn::{Expr, Lit, punctuated::Punctuated};
if !attr.path().is_ident(name) {
continue;
}
if found.is_some() {
return Err(syn::Error::new_spanned(
attr,
format!("a request field may have only one `#[{name}]` attribute"),
));
}
let args = attr.parse_args_with(Punctuated::<Expr, syn::Token![,]>::parse_terminated)?;
let Some(first) = args.first() else {
return Err(syn::Error::new_spanned(
attr,
format!("`#[{name}]` requires a string name"),
));
};
let Expr::Lit(first) = first else {
return Err(syn::Error::new_spanned(
first,
format!("`#[{name}]` name must be a string literal"),
));
};
let Lit::Str(base) = &first.lit else {
return Err(syn::Error::new_spanned(
first,
format!("`#[{name}]` name must be a string literal"),
));
};
let mut default = None;
for expr in args.iter().skip(1) {
let Expr::Assign(assign) = expr else {
return Err(syn::Error::new_spanned(
expr,
format!("`#[{name}]` options after the name must be assignments"),
));
};
let Expr::Path(option) = assign.left.as_ref() else {
return Err(syn::Error::new_spanned(
assign,
format!("`#[{name}]` accepts only `default = \"...\"` after the name"),
));
};
if !option.path.is_ident("default") {
return Err(syn::Error::new_spanned(
option,
format!("unknown `#[{name}]` option; expected `default`"),
));
}
if default.is_some() {
return Err(syn::Error::new_spanned(
assign,
format!("duplicate `#[{name}]` default"),
));
}
let Expr::Lit(value) = assign.right.as_ref() else {
return Err(syn::Error::new_spanned(
assign,
format!("`#[{name}]` default must be a string literal"),
));
};
let Lit::Str(value) = &value.lit else {
return Err(syn::Error::new_spanned(
value,
format!("`#[{name}]` default must be a string literal"),
));
};
default = Some(value.clone());
}
found = Some(FieldAttr {
name: base.clone(),
default,
});
}
Ok(found)
}
fn path(attrs: &[syn::Attribute], ident: &syn::Ident) -> syn::Result<Option<syn::LitStr>> {
let mut found = None;
for attr in attrs {
let path = match &attr.meta {
syn::Meta::Path(path) => path,
syn::Meta::List(options) => {
if !options.path.is_ident("path") {
continue;
}
return Err(syn::Error::new_spanned(
options,
"`#[path]` does not accept options; the route schema requires this capture",
));
}
syn::Meta::NameValue(option) => {
if !option.path.is_ident("path") {
continue;
}
return Err(syn::Error::new_spanned(
option,
"`#[path]` does not accept options; the route schema requires this capture",
));
}
};
if !path.is_ident("path") {
continue;
}
if found.is_some() {
return Err(syn::Error::new_spanned(
attr,
"a request field may have only one `#[path]` attribute",
));
}
let name = ident.unraw().to_string();
found = Some(syn::LitStr::new(&name, ident.span()));
}
Ok(found)
}
pub(super) struct Field {
pub(super) ident: syn::Ident,
pub(super) name: syn::LitStr,
pub(super) default: Option<syn::LitStr>,
pub(super) ty: syn::Type,
}
pub(super) struct Path {
pub(super) ident: syn::Ident,
pub(super) path: syn::LitStr,
pub(super) ty: syn::Type,
}
pub(super) struct Fields {
pub(super) headers: Vec<Field>,
pub(super) queries: Vec<Field>,
pub(super) paths: Vec<Path>,
pub(super) peer: Option<syn::Type>,
pub(super) init: Vec<proc_macro2::TokenStream>,
pub(super) body: bodies::Plan,
}
impl Fields {
pub(super) fn collect(
paths: &Paths,
named: &syn::FieldsNamed,
body: bodies::Plan,
) -> syn::Result<Self> {
let [v_heads, v_params, v_auth] = ["headers", "params", "__sark_authority"].map(local);
named.named.iter().try_for_each(|field| {
if !is_only(&field.attrs, "authority") {
return Ok(());
}
let invalid = || syn::Error::new_spanned(&field.ty, "#[authority] requires Shared");
let view = types::View::new(&field.ty);
if view.is_optional() {
return Err(invalid());
}
match view.kind()? {
types::ValueKind::Bytes => Ok(()),
_ => Err(invalid()),
}
})?;
let body =
named.named.iter().try_fold(body, |body, field| {
if is_only(&field.attrs, "raw_body") {
body.try_raw(
paths,
field.ident.clone().ok_or_else(|| {
syn::Error::new_spanned(field, "named field required")
})?,
&field.ty,
)
} else if is_only(&field.attrs, "body_len") {
body.try_len(
field.ident.clone().ok_or_else(|| {
syn::Error::new_spanned(field, "named field required")
})?,
&field.ty,
)
} else {
Ok(body)
}
})?;
let mut headers = Vec::new();
let mut queries = Vec::new();
let mut paths = Vec::new();
let mut peer = None;
let mut init = Vec::new();
for field in &named.named {
use syn::Error;
let ident = field.ident.clone().ok_or_else(|| {
use proc_macro2::Span;
Error::new(Span::call_site(), "named field required")
})?;
if ident.unraw() == "body" {
return Err(syn::Error::new_spanned(
&field.ident,
"#[sark_gen::request] reserves field name `body`",
));
}
let header = parse(&field.attrs, "header")?;
let query = parse(&field.attrs, "query")?;
let path = path(&field.attrs, &ident)?;
let view = types::View::new(&field.ty);
if types::View::new(view.value()).is_named("AcceptEncoding")
&& (!view.is_optional()
|| header.as_ref().is_none_or(|header| {
!header.name.value().eq_ignore_ascii_case("accept-encoding")
|| header.default.is_some()
}))
{
return Err(syn::Error::new_spanned(
field,
"AcceptEncoding requires Option and an accept-encoding header without default",
));
}
let raw = contains(&field.attrs, "raw_body");
let len = contains(&field.attrs, "body_len");
let auth = contains(&field.attrs, "authority");
let kinds = [
header.is_some(),
query.is_some(),
path.is_some(),
raw,
len,
auth,
]
.into_iter()
.filter(|value| *value)
.count();
if kinds > 1 {
return Err(syn::Error::new_spanned(
field,
"request field must have exactly one request source attribute",
));
}
if let Some(FieldAttr {
name: header,
default,
}) = header
{
if headers.iter().any(|field: &Field| {
field
.name
.value()
.eq_ignore_ascii_case(header.value().as_str())
}) {
return Err(syn::Error::new_spanned(
&header,
"duplicate request header name",
));
}
headers.push(Field {
ident: ident.clone(),
name: header,
default,
ty: field.ty.clone(),
});
init.push(quote::quote!(#ident: #v_heads.#ident));
} else if let Some(FieldAttr {
name: query,
default,
}) = query
{
if queries
.iter()
.any(|field: &Field| field.name.value() == query.value())
{
return Err(syn::Error::new_spanned(
&query,
"duplicate request query name",
));
}
queries.push(Field {
ident: ident.clone(),
name: query,
default,
ty: field.ty.clone(),
});
init.push(quote::quote!(#ident: #v_heads.#ident));
} else if let Some(path) = path {
paths.push(Path {
ident: ident.clone(),
path,
ty: field.ty.clone(),
});
init.push(quote::quote!(#ident: #v_params.#ident));
} else if raw || len {
} else if auth {
if let Some(first) = &peer {
let mut error = syn::Error::new_spanned(
field,
"request can contain only one #[authority] field",
);
error.combine(syn::Error::new_spanned(
first,
"first #[authority] field declared here",
));
return Err(error);
}
peer = Some(field.ty.clone());
init.push(quote::quote!(#ident: #v_auth));
} else {
return Err(syn::Error::new_spanned(
field,
"#[sark_gen::request] fields require a request source attribute",
));
}
}
paths.sort_by_key(|field| field.path.value());
for (left, right) in paths.iter().zip(paths.iter().skip(1)) {
if left.path.value() == right.path.value() {
return Err(syn::Error::new_spanned(
&right.ident,
"duplicate request path parameter name",
));
}
}
Ok(Self {
headers,
queries,
paths,
peer,
init,
body,
})
}
pub(super) fn commit(attrs: &mut Vec<syn::Attribute>, named: &mut syn::FieldsNamed) {
attrs.retain(|attr| !attr.path().is_ident("json_body"));
for field in &mut named.named {
field.attrs.retain(|attr| {
!attr.path().is_ident("header")
&& !attr.path().is_ident("query")
&& !attr.path().is_ident("path")
&& !attr.path().is_ident("raw_body")
&& !attr.path().is_ident("body_len")
&& !attr.path().is_ident("authority")
});
}
}
}