4 files changed, 37 insertions, 19 deletions

diff --git a/crates/ra_analysis/src/db.rs b/crates/ra_analysis/src/db.rs
index 0773edcc1..c69577233 100644
--- a/crates/ra_analysis/src/db.rs
+++ b/crates/ra_analysis/src/db.rs
@@ -30,6 +30,20 @@ impl salsa::Database for RootDatabase {
     }
 }
 
+impl salsa::ParallelDatabase for RootDatabase {
+    fn fork(&self) -> Self {
+        RootDatabase {
+            runtime: self.runtime.fork(),
+        }
+    }
+}
+
+impl Clone for RootDatabase {
+    fn clone(&self) -> RootDatabase {
+        salsa::ParallelDatabase::fork(self)
+    }
+}
+
 salsa::database_storage! {
     pub(crate) struct RootDatabaseStorage for RootDatabase {
         impl FilesDatabase {
diff --git a/crates/ra_analysis/src/imp.rs b/crates/ra_analysis/src/imp.rs
index 0cf6db40d..d07d797d5 100644
--- a/crates/ra_analysis/src/imp.rs
+++ b/crates/ra_analysis/src/imp.rs
@@ -78,13 +78,13 @@ impl Default for FileResolverImp {
 
 #[derive(Debug)]
 pub(crate) struct AnalysisHostImpl {
-    data: Arc<WorldData>
+    data: WorldData
 }
 
 impl AnalysisHostImpl {
     pub fn new() -> AnalysisHostImpl {
         AnalysisHostImpl {
-            data: Arc::new(WorldData::default()),
+            data: WorldData::default(),
         }
     }
     pub fn analysis(&self) -> AnalysisImpl {
@@ -114,18 +114,18 @@ impl AnalysisHostImpl {
         self.data_mut().libs.push(Arc::new(root));
     }
     fn data_mut(&mut self) -> &mut WorldData {
-        Arc::make_mut(&mut self.data)
+        &mut self.data
     }
 }
 
 pub(crate) struct AnalysisImpl {
     needs_reindex: AtomicBool,
-    data: Arc<WorldData>,
+    data: WorldData,
 }
 
 impl fmt::Debug for AnalysisImpl {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        (&*self.data).fmt(f)
+        self.data.fmt(f)
     }
 }
 
@@ -133,7 +133,7 @@ impl Clone for AnalysisImpl {
     fn clone(&self) -> AnalysisImpl {
         AnalysisImpl {
             needs_reindex: AtomicBool::new(self.needs_reindex.load(SeqCst)),
-            data: Arc::clone(&self.data),
+            data: self.data.clone(),
         }
     }
 }
diff --git a/crates/ra_analysis/src/lib.rs b/crates/ra_analysis/src/lib.rs
index d49132513..c76e4f4fe 100644
--- a/crates/ra_analysis/src/lib.rs
+++ b/crates/ra_analysis/src/lib.rs
@@ -258,3 +258,9 @@ impl LibraryData {
         LibraryData { root }
     }
 }
+
+#[test]
+fn analysis_is_send() {
+    fn is_send<T: Send>() {}
+    is_send::<Analysis>();
+}
diff --git a/crates/ra_analysis/src/roots.rs b/crates/ra_analysis/src/roots.rs
index 42833af36..76bcecd38 100644
--- a/crates/ra_analysis/src/roots.rs
+++ b/crates/ra_analysis/src/roots.rs
@@ -2,7 +2,6 @@ use std::{
     sync::Arc,
     panic,
 };
-use parking_lot::RwLock;
 
 use once_cell::sync::OnceCell;
 use rayon::prelude::*;
@@ -30,7 +29,7 @@ pub(crate) trait SourceRoot {
 
 #[derive(Default, Debug, Clone)]
 pub(crate) struct WritableSourceRoot {
-    db: Arc<RwLock<db::RootDatabase>>,
+    db: db::RootDatabase,
 }
 
 impl WritableSourceRoot {
@@ -39,7 +38,6 @@ impl WritableSourceRoot {
         changes: &mut dyn Iterator<Item=(FileId, Option<String>)>,
         file_resolver: Option<FileResolverImp>,
     ) {
-        let db = self.db.write();
         let mut changed = FxHashSet::default();
         let mut removed = FxHashSet::default();
         for (file_id, text) in changes {
@@ -48,13 +46,13 @@ impl WritableSourceRoot {
                     removed.insert(file_id);
                 }
                 Some(text) => {
-                    db.query(db::FileTextQuery)
+                    self.db.query(db::FileTextQuery)
                         .set(file_id, Arc::new(text));
                     changed.insert(file_id);
                 }
             }
         }
-        let file_set = db.file_set(());
+        let file_set = self.db.file_set(());
         let mut files: FxHashSet<FileId> = file_set
             .files
             .clone();
@@ -63,28 +61,28 @@ impl WritableSourceRoot {
         }
         files.extend(changed);
         let resolver = file_resolver.unwrap_or_else(|| file_set.resolver.clone());
-        db.query(db::FileSetQuery)
+        self.db.query(db::FileSetQuery)
             .set((), Arc::new(db::FileSet { files, resolver }));
     }
 }
 
 impl SourceRoot for WritableSourceRoot {
     fn module_tree(&self) -> Arc<ModuleTreeDescriptor> {
-        self.db.read().module_tree(())
+        self.db.module_tree(())
     }
     fn contains(&self, file_id: FileId) -> bool {
-        let db = self.db.read();
-        let files = &db.file_set(()).files;
-        files.contains(&file_id)
+        self.db.file_set(())
+            .files
+            .contains(&file_id)
     }
     fn lines(&self, file_id: FileId) -> Arc<LineIndex> {
-        self.db.read().file_lines(file_id)
+        self.db.file_lines(file_id)
     }
     fn syntax(&self, file_id: FileId) -> File {
-        self.db.read().file_syntax(file_id)
+        self.db.file_syntax(file_id)
     }
     fn symbols<'a>(&'a self, acc: &mut Vec<Arc<SymbolIndex>>) {
-        let db = self.db.read();
+        let db = &self.db;
         let symbols =  db.file_set(());
         let symbols = symbols
             .files