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use std::collections::HashMap;
use proc_macro::TokenStream;
use proc_macro2::TokenStream as TokenStream2;
use quote::{format_ident, quote};
use syn::{
parse::{Parse, ParseStream, Result as ParseResult},
parse_macro_input,
punctuated::Punctuated,
Expr, Ident, ItemStruct, Lit, Token,
};
struct KeyValue {
key: Ident,
_eq: Token![=],
value: Expr,
}
impl Parse for KeyValue {
fn parse(input: ParseStream) -> ParseResult<Self> {
Ok(Self {
key: input.parse()?,
_eq: input.parse()?,
value: input.parse()?,
})
}
}
struct LintMeta(HashMap<Ident, Expr>);
impl Parse for LintMeta {
fn parse(input: ParseStream) -> ParseResult<Self> {
Ok(Self(
Punctuated::<KeyValue, Token![,]>::parse_terminated(input)?
.into_iter()
.map(|item| (item.key, item.value))
.collect(),
))
}
}
fn generate_self_impl(struct_name: &Ident) -> TokenStream2 {
quote! {
impl #struct_name {
pub fn new() -> Box<Self> {
Box::new(Self)
}
}
}
}
fn generate_meta_impl(struct_name: &Ident, meta: &LintMeta) -> TokenStream2 {
let name_fn = generate_name_fn(meta);
let note_fn = generate_note_fn(meta);
let match_with_fn = generate_match_with_fn(meta);
let match_kind = generate_match_kind(meta);
quote! {
impl Metadata for #struct_name {
#name_fn
#note_fn
#match_with_fn
#match_kind
}
}
}
fn generate_name_fn(meta: &LintMeta) -> TokenStream2 {
let name = meta
.0
.get(&format_ident!("name"))
.unwrap_or_else(|| panic!("`name` not present"));
if let syn::Expr::Lit(name_lit) = name {
if let Lit::Str(name_str) = &name_lit.lit {
return quote! {
fn name() -> &'static str {
#name_str
}
};
}
}
panic!("Invalid value for `name`");
}
fn generate_note_fn(meta: &LintMeta) -> TokenStream2 {
let note = meta
.0
.get(&format_ident!("note"))
.unwrap_or_else(|| panic!("`note` not present"));
if let syn::Expr::Lit(note_lit) = note {
if let Lit::Str(note_str) = ¬e_lit.lit {
return quote! {
fn note() -> &'static str {
#note_str
}
};
}
}
panic!("Invalid value for `note`");
}
fn generate_match_with_fn(meta: &LintMeta) -> TokenStream2 {
let match_with_lit = meta
.0
.get(&format_ident!("match_with"))
.unwrap_or_else(|| panic!("`match_with` not present"));
if let syn::Expr::Path(match_path) = match_with_lit {
quote! {
fn match_with(&self, with: &SyntaxKind) -> bool {
#match_path == *with
}
}
} else {
panic!("`match_with` has non-path value")
}
}
fn generate_match_kind(meta: &LintMeta) -> TokenStream2 {
let match_with_lit = meta
.0
.get(&format_ident!("match_with"))
.unwrap_or_else(|| panic!("`match_with` not present"));
if let syn::Expr::Path(match_path) = match_with_lit {
quote! {
fn match_kind(&self) -> SyntaxKind {
#match_path
}
}
} else {
panic!("`match_with` has non-path value")
}
}
#[proc_macro_attribute]
pub fn lint(attr: TokenStream, item: TokenStream) -> TokenStream {
let struct_item = parse_macro_input!(item as ItemStruct);
let meta = parse_macro_input!(attr as LintMeta);
let struct_name = &struct_item.ident;
let self_impl = generate_self_impl(struct_name);
let meta_impl = generate_meta_impl(struct_name, &meta);
(quote! {
#struct_item
::lazy_static::lazy_static! {
pub static ref LINT: Box<dyn crate::Lint> = #struct_name::new();
}
#self_impl
#meta_impl
impl Lint for #struct_name {}
})
.into()
}
|
