1 files changed, 82 insertions, 0 deletions
diff --git a/src/librustdoc/visit_lib.rs b/src/librustdoc/visit_lib.rs
new file mode 100644
index 000000000..f01ec3866
--- /dev/null
+++ b/src/librustdoc/visit_lib.rs
@@ -0,0 +1,82 @@
+use rustc_data_structures::fx::FxHashSet;
+use rustc_hir::def::{DefKind, Res};
+use rustc_hir::def_id::{CrateNum, DefId};
+use rustc_middle::middle::privacy::{AccessLevel, AccessLevels};
+use rustc_middle::ty::TyCtxt;
+
+// FIXME: this may not be exhaustive, but is sufficient for rustdocs current uses
+
+/// Similar to `librustc_privacy::EmbargoVisitor`, but also takes
+/// specific rustdoc annotations into account (i.e., `doc(hidden)`)
+pub(crate) struct LibEmbargoVisitor<'a, 'tcx> {
+    tcx: TyCtxt<'tcx>,
+    // Accessibility levels for reachable nodes
+    access_levels: &'a mut AccessLevels<DefId>,
+    // Previous accessibility level, None means unreachable
+    prev_level: Option<AccessLevel>,
+    // Keeps track of already visited modules, in case a module re-exports its parent
+    visited_mods: FxHashSet<DefId>,
+}
+
+impl<'a, 'tcx> LibEmbargoVisitor<'a, 'tcx> {
+    pub(crate) fn new(cx: &'a mut crate::core::DocContext<'tcx>) -> LibEmbargoVisitor<'a, 'tcx> {
+        LibEmbargoVisitor {
+            tcx: cx.tcx,
+            access_levels: &mut cx.cache.access_levels,
+            prev_level: Some(AccessLevel::Public),
+            visited_mods: FxHashSet::default(),
+        }
+    }
+
+    pub(crate) fn visit_lib(&mut self, cnum: CrateNum) {
+        let did = cnum.as_def_id();
+        self.update(did, Some(AccessLevel::Public));
+        self.visit_mod(did);
+    }
+
+    // Updates node level and returns the updated level
+    fn update(&mut self, did: DefId, level: Option<AccessLevel>) -> Option<AccessLevel> {
+        let is_hidden = self.tcx.is_doc_hidden(did);
+
+        let old_level = self.access_levels.map.get(&did).cloned();
+        // Accessibility levels can only grow
+        if level > old_level && !is_hidden {
+            self.access_levels.map.insert(did, level.unwrap());
+            level
+        } else {
+            old_level
+        }
+    }
+
+    pub(crate) fn visit_mod(&mut self, def_id: DefId) {
+        if !self.visited_mods.insert(def_id) {
+            return;
+        }
+
+        for item in self.tcx.module_children(def_id).iter() {
+            if let Some(def_id) = item.res.opt_def_id() {
+                if self.tcx.def_key(def_id).parent.map_or(false, |d| d == def_id.index)
+                    || item.vis.is_public()
+                {
+                    self.visit_item(item.res);
+                }
+            }
+        }
+    }
+
+    fn visit_item(&mut self, res: Res<!>) {
+        let def_id = res.def_id();
+        let vis = self.tcx.visibility(def_id);
+        let inherited_item_level = if vis.is_public() { self.prev_level } else { None };
+
+        let item_level = self.update(def_id, inherited_item_level);
+
+        if let Res::Def(DefKind::Mod, _) = res {
+            let orig_level = self.prev_level;
+
+            self.prev_level = item_level;
+            self.visit_mod(def_id);
+            self.prev_level = orig_level;
+        }
+    }
+}