3 files changed, 271 insertions, 0 deletions

diff --git a/crates/ra_hir/src/lib.rs b/crates/ra_hir/src/lib.rs
index f13f0107e..e7b6a81f4 100644
--- a/crates/ra_hir/src/lib.rs
+++ b/crates/ra_hir/src/lib.rs
@@ -15,6 +15,8 @@ macro_rules! ctry {
 }
 
 pub mod db;
+#[cfg(test)]
+mod mock;
 mod query_definitions;
 mod function;
 mod module;
diff --git a/crates/ra_hir/src/mock.rs b/crates/ra_hir/src/mock.rs
new file mode 100644
index 000000000..8e256b89f
--- /dev/null
+++ b/crates/ra_hir/src/mock.rs
@@ -0,0 +1,172 @@
+use std::sync::Arc;
+
+use parking_lot::Mutex;
+use salsa::{self, Database};
+use ra_db::{LocationIntener, BaseDatabase, FilePosition, mock::FileMap, FileId, WORKSPACE};
+use relative_path::RelativePathBuf;
+use test_utils::{parse_fixture, CURSOR_MARKER, extract_offset};
+
+use crate::{db, DefId, DefLoc, FnId, SourceItemId};
+
+#[derive(Debug)]
+pub(crate) struct MockDatabase {
+    events: Mutex<Option<Vec<salsa::Event<MockDatabase>>>>,
+    runtime: salsa::Runtime<MockDatabase>,
+    id_maps: Arc<IdMaps>,
+}
+
+impl MockDatabase {
+    pub(crate) fn with_position(fixture: &str) -> (MockDatabase, FilePosition) {
+        let mut db = MockDatabase::default();
+
+        let mut position = None;
+        let mut file_map = FileMap::default();
+        for entry in parse_fixture(fixture) {
+            if entry.text.contains(CURSOR_MARKER) {
+                assert!(
+                    position.is_none(),
+                    "only one marker (<|>) per fixture is allowed"
+                );
+                position = Some(db.add_file_with_position(&mut file_map, &entry.meta, &entry.text));
+            } else {
+                db.add_file(&mut file_map, &entry.meta, &entry.text);
+            }
+        }
+        let position = position.expect("expected a marker (<|>)");
+        let source_root = file_map.into_source_root();
+        db.query_mut(ra_db::SourceRootQuery)
+            .set(WORKSPACE, Arc::new(source_root));
+        (db, position)
+    }
+
+    fn add_file(&mut self, file_map: &mut FileMap, path: &str, text: &str) -> FileId {
+        assert!(path.starts_with('/'));
+        let path = RelativePathBuf::from_path(&path[1..]).unwrap();
+
+        let file_id = file_map.add(path);
+        let text = Arc::new(text.to_string());
+        self.query_mut(ra_db::FileTextQuery).set(file_id, text);
+        self.query_mut(ra_db::FileSourceRootQuery)
+            .set(file_id, WORKSPACE);
+        file_id
+    }
+
+    fn add_file_with_position(
+        &mut self,
+        file_map: &mut FileMap,
+        path: &str,
+        text: &str,
+    ) -> FilePosition {
+        let (offset, text) = extract_offset(text);
+        let file_id = self.add_file(file_map, path, &text);
+        FilePosition { file_id, offset }
+    }
+}
+
+#[derive(Debug, Default)]
+struct IdMaps {
+    fns: LocationIntener<SourceItemId, FnId>,
+    defs: LocationIntener<DefLoc, DefId>,
+}
+
+impl salsa::Database for MockDatabase {
+    fn salsa_runtime(&self) -> &salsa::Runtime<MockDatabase> {
+        &self.runtime
+    }
+
+    fn salsa_event(&self, event: impl Fn() -> salsa::Event<MockDatabase>) {
+        let mut events = self.events.lock();
+        if let Some(events) = &mut *events {
+            events.push(event());
+        }
+    }
+}
+
+impl Default for MockDatabase {
+    fn default() -> MockDatabase {
+        let mut db = MockDatabase {
+            events: Default::default(),
+            runtime: salsa::Runtime::default(),
+            id_maps: Default::default(),
+        };
+        db.query_mut(ra_db::SourceRootQuery)
+            .set(ra_db::WORKSPACE, Default::default());
+        db.query_mut(ra_db::CrateGraphQuery)
+            .set((), Default::default());
+        db.query_mut(ra_db::LibrariesQuery)
+            .set((), Default::default());
+        db
+    }
+}
+
+impl salsa::ParallelDatabase for MockDatabase {
+    fn snapshot(&self) -> salsa::Snapshot<MockDatabase> {
+        salsa::Snapshot::new(MockDatabase {
+            events: Default::default(),
+            runtime: self.runtime.snapshot(self),
+            id_maps: self.id_maps.clone(),
+        })
+    }
+}
+
+impl BaseDatabase for MockDatabase {}
+
+impl AsRef<LocationIntener<DefLoc, DefId>> for MockDatabase {
+    fn as_ref(&self) -> &LocationIntener<DefLoc, DefId> {
+        &self.id_maps.defs
+    }
+}
+
+impl AsRef<LocationIntener<SourceItemId, FnId>> for MockDatabase {
+    fn as_ref(&self) -> &LocationIntener<SourceItemId, FnId> {
+        &self.id_maps.fns
+    }
+}
+
+impl MockDatabase {
+    pub(crate) fn log(&self, f: impl FnOnce()) -> Vec<salsa::Event<MockDatabase>> {
+        *self.events.lock() = Some(Vec::new());
+        f();
+        let events = self.events.lock().take().unwrap();
+        events
+    }
+
+    pub(crate) fn log_executed(&self, f: impl FnOnce()) -> Vec<String> {
+        let events = self.log(f);
+        events
+            .into_iter()
+            .filter_map(|e| match e.kind {
+                // This pretty horrible, but `Debug` is the only way to inspect
+                // QueryDescriptor at the moment.
+                salsa::EventKind::WillExecute { descriptor } => Some(format!("{:?}", descriptor)),
+                _ => None,
+            })
+            .collect()
+    }
+}
+
+salsa::database_storage! {
+    pub(crate) struct MockDatabaseStorage for MockDatabase {
+        impl ra_db::FilesDatabase {
+            fn file_text() for ra_db::FileTextQuery;
+            fn file_source_root() for ra_db::FileSourceRootQuery;
+            fn source_root() for ra_db::SourceRootQuery;
+            fn libraries() for ra_db::LibrariesQuery;
+            fn crate_graph() for ra_db::CrateGraphQuery;
+        }
+        impl ra_db::SyntaxDatabase {
+            fn source_file() for ra_db::SourceFileQuery;
+            fn file_lines() for ra_db::FileLinesQuery;
+        }
+        impl db::HirDatabase {
+            fn module_tree() for db::ModuleTreeQuery;
+            fn fn_scopes() for db::FnScopesQuery;
+            fn file_items() for db::SourceFileItemsQuery;
+            fn file_item() for db::FileItemQuery;
+            fn input_module_items() for db::InputModuleItemsQuery;
+            fn item_map() for db::ItemMapQuery;
+            fn fn_syntax() for db::FnSyntaxQuery;
+            fn submodules() for db::SubmodulesQuery;
+        }
+    }
+}
diff --git a/crates/ra_hir/src/module/nameres.rs b/crates/ra_hir/src/module/nameres.rs
index 837a8d5ae..de13835b2 100644
--- a/crates/ra_hir/src/module/nameres.rs
+++ b/crates/ra_hir/src/module/nameres.rs
@@ -336,3 +336,100 @@ where
         f(module_items)
     }
 }
+
+//TODO: move to hir
+#[cfg(test)]
+mod tests {
+    use std::sync::Arc;
+
+    use salsa::Database;
+    use ra_db::FilesDatabase;
+    use ra_syntax::SmolStr;
+
+    use crate::{
+        self as hir,
+        db::HirDatabase,
+        mock::MockDatabase,
+};
+
+    fn item_map(fixture: &str) -> (Arc<hir::ItemMap>, hir::ModuleId) {
+        let (db, pos) = MockDatabase::with_position(fixture);
+        let source_root = db.file_source_root(pos.file_id);
+        let module = hir::Module::guess_from_position(&db, pos).unwrap().unwrap();
+        let module_id = module.module_id;
+        (db.item_map(source_root).unwrap(), module_id)
+    }
+
+    #[test]
+    fn test_item_map() {
+        let (item_map, module_id) = item_map(
+            "
+            //- /lib.rs
+            mod foo;
+
+            use crate::foo::bar::Baz;
+            <|>
+
+            //- /foo/mod.rs
+            pub mod bar;
+
+            //- /foo/bar.rs
+            pub struct Baz;
+        ",
+        );
+        let name = SmolStr::from("Baz");
+        let resolution = &item_map.per_module[&module_id].items[&name];
+        assert!(resolution.def_id.is_some());
+    }
+
+    #[test]
+    fn typing_inside_a_function_should_not_invalidate_item_map() {
+        let (mut db, pos) = MockDatabase::with_position(
+            "
+            //- /lib.rs
+            mod foo;<|>
+
+            use crate::foo::bar::Baz;
+
+            fn foo() -> i32 {
+                1 + 1
+            }
+            //- /foo/mod.rs
+            pub mod bar;
+
+            //- /foo/bar.rs
+            pub struct Baz;
+        ",
+        );
+        let source_root = db.file_source_root(pos.file_id);
+        {
+            let events = db.log_executed(|| {
+                db.item_map(source_root).unwrap();
+            });
+            assert!(format!("{:?}", events).contains("item_map"))
+        }
+
+        let new_text = "
+            mod foo;
+
+            use crate::foo::bar::Baz;
+
+            fn foo() -> i32 { 92 }
+        "
+        .to_string();
+
+        db.query_mut(ra_db::FileTextQuery)
+            .set(pos.file_id, Arc::new(new_text));
+
+        {
+            let events = db.log_executed(|| {
+                db.item_map(source_root).unwrap();
+            });
+            assert!(
+                !format!("{:?}", events).contains("_item_map"),
+                "{:#?}",
+                events
+            )
+        }
+    }
+}