rust/src/librustdoc/passes/propagate_doc_cfg.rs
2018-07-24 16:44:52 -04:00

47 lines
1.4 KiB
Rust

// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use std::sync::Arc;
use clean::{Crate, Item};
use clean::cfg::Cfg;
use fold::DocFolder;
pub fn propagate_doc_cfg(cr: Crate) -> Crate {
CfgPropagator { parent_cfg: None }.fold_crate(cr)
}
struct CfgPropagator {
parent_cfg: Option<Arc<Cfg>>,
}
impl DocFolder for CfgPropagator {
fn fold_item(&mut self, mut item: Item) -> Option<Item> {
let old_parent_cfg = self.parent_cfg.clone();
let new_cfg = match (self.parent_cfg.take(), item.attrs.cfg.take()) {
(None, None) => None,
(Some(rc), None) | (None, Some(rc)) => Some(rc),
(Some(mut a), Some(b)) => {
let b = Arc::try_unwrap(b).unwrap_or_else(|rc| Cfg::clone(&rc));
*Arc::make_mut(&mut a) &= b;
Some(a)
}
};
self.parent_cfg = new_cfg.clone();
item.attrs.cfg = new_cfg;
let result = self.fold_item_recur(item);
self.parent_cfg = old_parent_cfg;
result
}
}