1 files changed, 48 insertions, 0 deletions

diff --git a/crates/ra_hir/src/krate.rs b/crates/ra_hir/src/krate.rs
new file mode 100644
index 000000000..1196dcef1
--- /dev/null
+++ b/crates/ra_hir/src/krate.rs
@@ -0,0 +1,48 @@
+use ra_syntax::SmolStr;
+pub use ra_db::CrateId;
+
+use crate::{HirDatabase, Module, Cancelable};
+
+/// hir::Crate describes a single crate. It's the main inteface with which
+/// crate's dependencies interact. Mostly, it should be just a proxy for the
+/// root module.
+#[derive(Debug)]
+pub struct Crate {
+    crate_id: CrateId,
+}
+
+#[derive(Debug)]
+pub struct CrateDependency {
+    pub krate: Crate,
+    pub name: SmolStr,
+}
+
+impl Crate {
+    pub(crate) fn new(crate_id: CrateId) -> Crate {
+        Crate { crate_id }
+    }
+    pub fn dependencies(&self, db: &impl HirDatabase) -> Vec<CrateDependency> {
+        let crate_graph = db.crate_graph();
+        crate_graph
+            .dependencies(self.crate_id)
+            .map(|dep| {
+                let krate = Crate::new(dep.crate_id());
+                let name = dep.name.clone();
+                CrateDependency { krate, name }
+            })
+            .collect()
+    }
+    pub fn root_module(&self, db: &impl HirDatabase) -> Cancelable<Option<Module>> {
+        let crate_graph = db.crate_graph();
+        let file_id = crate_graph.crate_root(self.crate_id);
+        let source_root_id = db.file_source_root(file_id);
+        let module_tree = db.module_tree(source_root_id)?;
+        // FIXME: teach module tree about crate roots instead of guessing
+        let (module_id, _) = ctry!(module_tree
+            .modules_with_sources()
+            .find(|(_, src)| src.file_id() == file_id));
+
+        let module = Module::new(db, source_root_id, module_id)?;
+        Ok(Some(module))
+    }
+}