cxx/syntax/toposort.rs

52 lines
1.4 KiB
Rust

use crate::syntax::map::{Entry, UnorderedMap as Map};
use crate::syntax::report::Errors;
use crate::syntax::{Api, Struct, Type, Types};
enum Mark {
Visiting,
Visited,
}
pub fn sort<'a>(cx: &mut Errors, apis: &'a [Api], types: &Types<'a>) -> Vec<&'a Struct> {
let mut sorted = Vec::new();
let ref mut marks = Map::new();
for api in apis {
if let Api::Struct(strct) = api {
let _ = visit(cx, strct, &mut sorted, marks, types);
}
}
sorted
}
fn visit<'a>(
cx: &mut Errors,
strct: &'a Struct,
sorted: &mut Vec<&'a Struct>,
marks: &mut Map<*const Struct, Mark>,
types: &Types<'a>,
) -> Result<(), ()> {
match marks.entry(strct) {
Entry::Occupied(entry) => match entry.get() {
Mark::Visiting => return Err(()), // not a DAG
Mark::Visited => return Ok(()),
},
Entry::Vacant(entry) => {
entry.insert(Mark::Visiting);
}
}
let mut result = Ok(());
for field in &strct.fields {
if let Type::Ident(ident) = &field.ty {
if let Some(inner) = types.structs.get(&ident.rust) {
if visit(cx, inner, sorted, marks, types).is_err() {
cx.error(field, "unsupported cyclic data structure");
result = Err(());
}
}
}
}
marks.insert(strct, Mark::Visited);
sorted.push(strct);
result
}