Merge #5969

5969: Propose module name completion options r=jonas-schievink a=SomeoneToIgnore

<img width="539" alt="image" src="https://user-images.githubusercontent.com/2690773/92663009-cb0aec00-f308-11ea-9ef5-1faa91518031.png">

Currently traverses the whole file set every time we try to complete the module, as discussed in https://rust-lang.zulipchat.com/#narrow/stream/185405-t-compiler.2Fwg-rls-2.2E0/topic/mod.3C.7C.3E.20completion

Co-authored-by: Kirill Bulatov <[email protected]>

1 files changed, 11 insertions, 2 deletions

diff --git a/crates/vfs/src/file_set.rs b/crates/vfs/src/file_set.rs
index e9196fcd2..4aa2d6526 100644
--- a/crates/vfs/src/file_set.rs
+++ b/crates/vfs/src/file_set.rs
@@ -23,13 +23,22 @@ impl FileSet {
         let mut base = self.paths[&anchor].clone();
         base.pop();
         let path = base.join(path)?;
-        let res = self.files.get(&path).copied();
-        res
+        self.files.get(&path).copied()
+    }
+
+    pub fn file_for_path(&self, path: &VfsPath) -> Option<&FileId> {
+        self.files.get(path)
     }
+
+    pub fn path_for_file(&self, file: &FileId) -> Option<&VfsPath> {
+        self.paths.get(file)
+    }
+
     pub fn insert(&mut self, file_id: FileId, path: VfsPath) {
         self.files.insert(path.clone(), file_id);
         self.paths.insert(file_id, path);
     }
+
     pub fn iter(&self) -> impl Iterator<Item = FileId> + '_ {
         self.paths.keys().copied()
     }