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/*
This file is part of jellything (https://codeberg.org/metamuffin/jellything)
which is licensed under the GNU Affero General Public License (version 3); see /COPYING.
Copyright (C) 2023 metamuffin <metamuffin.org>
*/
use proc_macro::{token_stream, Delimiter, Span, TokenStream, TokenTree};
use quote::quote;
use syn::{Fields, FieldsUnnamed, Ident, Variant};
struct Tag {
id: u64,
global: bool,
path: Vec<u64>,
name: Ident,
r#type: Option<String>, // None -> Master
}
#[proc_macro]
pub fn define_ebml(ts: TokenStream) -> TokenStream {
let mut ts = ts.into_iter();
let mut tags = vec![];
parse_kt(&mut tags, &mut ts, vec![]);
let enum_variants = tags
.iter()
.map(|e| Variant {
ident: e.name.clone(),
attrs: vec![],
fields: Fields::Unnamed(
syn::parse2::<FieldsUnnamed>(match e.r#type.clone() {
None => quote!((Master)),
Some(r#type) => match r#type.as_str() {
"Int" => quote!((i64)),
"Uint" => quote!((u64)),
"Float" => quote!((f64)),
"Utf8" => quote!((String)),
"Binary" => quote!((Vec<u8>)),
_ => panic!("unsupported type {type}"),
},
})
.expect("parse type"),
),
discriminant: None,
})
.collect::<Vec<_>>();
let path_match = tags
.iter()
.map(|e| {
let name = &e.name;
let path = e.path.clone();
if e.global {
quote! { Self::#name(_) => None }
} else {
quote! { Self::#name(_) => Some(&[#(#path),*]) }
}
})
.collect::<Vec<_>>();
let id_match = tags
.iter()
.map(|Tag { id, name, .. }| {
quote! { Self::#name(_) => #id }
})
.collect::<Vec<_>>();
let parse_match = tags
.iter()
.filter_map(
|Tag {
id, name, r#type, ..
}| {
if r#type.is_some() {
Some(quote! { #id => Self::#name(crate::ReadValue::from_buf(data)?) })
} else {
None
}
},
)
.collect::<Vec<_>>();
let write_match = tags
.iter()
.map(|Tag { name, .. }| quote! { Self::#name(v) => v.write_to(w) })
.collect::<Vec<_>>();
let cons_master_match = tags
.iter()
.filter_map(
|Tag {
id, name, r#type, ..
}| {
if r#type.is_none() {
Some(quote! { #id => Self::#name(kind) })
} else {
None
}
},
)
.collect::<Vec<_>>();
let is_master_match = tags
.iter()
.map(|Tag { id, r#type, .. }| match r#type {
None => quote!(#id => true),
Some(_) => quote!(#id => false),
})
.collect::<Vec<_>>();
quote! {
use crate::Master;
use crate::WriteValue;
#[derive(Debug, PartialEq, Clone)]
pub enum MatroskaTag {
#(#enum_variants),*
}
impl MatroskaTag {
/// returns path in **reverse** order or None if global.
pub fn path(&self) -> Option<&'static [u64]> {
match self { #(#path_match),* }
}
pub fn id(&self) -> u64 {
match self { #(#id_match),* }
}
pub fn is_master(id: u64) -> anyhow::Result<bool> {
Ok(match id { #(#is_master_match),*, _ => anyhow::bail!("unknown id") })
}
pub fn construct_master(id: u64, kind: Master) -> anyhow::Result<Self> {
Ok(match id { #(#cons_master_match),*, _ => anyhow::bail!("unknown id") })
}
pub fn parse(id: u64, data: &[u8]) -> anyhow::Result<Self> {
Ok(match id { #(#parse_match),*, _ => anyhow::bail!("unknown id or master") })
}
pub fn write(&self, w: &mut Vec<u8>) -> anyhow::Result<()> {
match self { #(#write_match),* }
}
}
}
.into()
}
fn parse_kt(tags: &mut Vec<Tag>, ts: &mut token_stream::IntoIter, path: Vec<u64>) {
let mut next_glob = false;
loop {
let global = next_glob;
next_glob = false;
let name = if let Some(tt) = ts.next() {
if let TokenTree::Ident(name) = tt {
if &name.to_string() == "global" {
next_glob = true;
continue;
}
name.to_string()
} else {
panic!("expected ident")
}
} else {
break;
};
let id = if let Some(TokenTree::Group(gr)) = ts.next() {
assert_eq!(gr.delimiter(), Delimiter::Bracket);
let mut ts = gr.stream().into_iter();
if let TokenTree::Literal(lit) = ts.next().unwrap() {
u64::from_str_radix(&lit.to_string()[2..], 16).unwrap()
} else {
panic!("literal expected")
}
} else {
panic!("group expected")
};
if let Some(TokenTree::Punct(p)) = ts.next() {
assert_eq!(p.as_char(), ':')
} else {
panic!("colon expected")
}
match ts.next() {
Some(TokenTree::Group(gr)) => {
// eprintln!("entering group");
let mut ts = gr.stream().into_iter();
tags.push(Tag {
global,
id,
name: Ident::new(&name, Span::call_site().into()),
path: path.clone(),
r#type: None,
});
let mut path = path.clone();
path.push(id);
parse_kt(tags, &mut ts, path);
// eprintln!("leaving group");
}
Some(TokenTree::Ident(r#type)) => {
let r#type = r#type.to_string();
// eprintln!("global={global} id={id}, type={}", r#type);
tags.push(Tag {
id,
name: Ident::new(&name, Span::call_site().into()),
path: path.clone(),
global,
r#type: Some(r#type),
})
}
_ => panic!("group or ident expected"),
}
if let Some(TokenTree::Punct(p)) = ts.next() {
assert_eq!(p.as_char(), ',')
} else {
panic!("colon expected")
}
}
}
|
