// Copyright 2012-2014 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 rustc::util::nodemap::DefIdSet;
use std::mem;

use clean::{self, AttributesExt, NestedAttributesExt};
use clean::Item;
use plugins;
use fold;
use fold::DocFolder;
use fold::FoldItem::Strip;
use passes::ImplStripper;

/// Strip items marked `#[doc(hidden)]`
pub fn strip_hidden(krate: clean::Crate) -> plugins::PluginResult {
    let mut retained = DefIdSet();

    // strip all #[doc(hidden)] items
    let krate = {
        let mut stripper = Stripper{ retained: &mut retained, update_retained: true };
        stripper.fold_crate(krate)
    };

    // strip all impls referencing stripped items
    let mut stripper = ImplStripper { retained: &retained };
    stripper.fold_crate(krate)
}

struct Stripper<'a> {
    retained: &'a mut DefIdSet,
    update_retained: bool,
}

impl<'a> fold::DocFolder for Stripper<'a> {
    fn fold_item(&mut self, i: Item) -> Option<Item> {
        if i.attrs.lists("doc").has_word("hidden") {
            debug!("found one in strip_hidden; removing");
            // use a dedicated hidden item for given item type if any
            match i.inner {
                clean::StructFieldItem(..) | clean::ModuleItem(..) => {
                    // We need to recurse into stripped modules to
                    // strip things like impl methods but when doing so
                    // we must not add any items to the `retained` set.
                    let old = mem::replace(&mut self.update_retained, false);
                    let ret = Strip(self.fold_item_recur(i).unwrap()).fold();
                    self.update_retained = old;
                    return ret;
                }
                _ => return None,
            }
        } else {
            if self.update_retained {
                self.retained.insert(i.def_id);
            }
        }
        self.fold_item_recur(i)
    }
}