13 files changed, 63 insertions, 15 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 579daecf1..2c1c7099e 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1058,7 +1058,7 @@ dependencies = [
  "ra_syntax 0.1.0",
  "relative-path 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-hash 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "salsa 0.12.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "salsa 0.12.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "test_utils 0.1.0",
 ]
 
@@ -1478,11 +1478,12 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "salsa"
-version = "0.12.2"
+version = "0.12.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "derive-new 0.5.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "indexmap 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "linked-hash-map 0.5.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "lock_api 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2125,7 +2126,7 @@ dependencies = [
 "checksum rustc-hash 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "7540fc8b0c49f096ee9c961cda096467dce8084bec6bdca2fc83895fd9b28cb8"
 "checksum rustc_version 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "138e3e0acb6c9fb258b19b67cb8abd63c00679d2851805ea151465464fe9030a"
 "checksum ryu 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)" = "b96a9549dc8d48f2c283938303c4b5a77aa29bfbc5b54b084fb1630408899a8f"
-"checksum salsa 0.12.2 (registry+https://github.com/rust-lang/crates.io-index)" = "f2208fabe493ad352dc4f544c482b39e9b9a2c1719d9aa4a0f5e828a61210956"
+"checksum salsa 0.12.3 (registry+https://github.com/rust-lang/crates.io-index)" = "2891cd628406e8a0ca714b827511de1bff76f796e3382cc72a3de732ccad5aea"
 "checksum salsa-macros 0.12.1 (registry+https://github.com/rust-lang/crates.io-index)" = "b7f1e25ca2b995bdf032946174929d62156ffd57abd7ff88dc6f9bdeb5ac0c59"
 "checksum same-file 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)" = "8f20c4be53a8a1ff4c1f1b2bd14570d2f634628709752f0702ecdd2b3f9a5267"
 "checksum scopeguard 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "94258f53601af11e6a49f722422f6e3425c52b06245a5cf9bc09908b174f5e27"
diff --git a/crates/ra_batch/src/lib.rs b/crates/ra_batch/src/lib.rs
index a445dcb4d..c59821f44 100644
--- a/crates/ra_batch/src/lib.rs
+++ b/crates/ra_batch/src/lib.rs
@@ -7,7 +7,7 @@ use std::collections::HashSet;
 use rustc_hash::FxHashMap;
 
 use ra_db::{
-    CrateGraph, FileId, SourceRoot, SourceRootId, SourceDatabase, salsa,
+    CrateGraph, FileId, SourceRoot, SourceRootId, SourceDatabase, salsa::{self, Database},
 };
 use ra_hir::db;
 use ra_project_model::ProjectWorkspace;
@@ -43,6 +43,12 @@ fn vfs_root_to_id(r: ra_vfs::VfsRoot) -> SourceRootId {
 impl BatchDatabase {
     pub fn load(crate_graph: CrateGraph, vfs: &mut Vfs) -> BatchDatabase {
         let mut db = BatchDatabase { runtime: salsa::Runtime::default() };
+        let lru_cap = std::env::var("RA_LRU_CAP")
+            .ok()
+            .and_then(|it| it.parse::<usize>().ok())
+            .unwrap_or(ra_db::DEFAULT_LRU_CAP);
+        db.query_mut(ra_db::ParseQuery).set_lru_capacity(lru_cap);
+        db.query_mut(ra_hir::db::ParseMacroQuery).set_lru_capacity(lru_cap);
         db.set_crate_graph(Arc::new(crate_graph));
 
         // wait until Vfs has loaded all roots
diff --git a/crates/ra_db/Cargo.toml b/crates/ra_db/Cargo.toml
index 827855b2f..f73dd739a 100644
--- a/crates/ra_db/Cargo.toml
+++ b/crates/ra_db/Cargo.toml
@@ -5,7 +5,7 @@ version = "0.1.0"
 authors = ["rust-analyzer developers"]
 
 [dependencies]
-salsa = "0.12.1"
+salsa = "0.12.3"
 relative-path = "0.4.0"
 rustc-hash = "1.0"
 
diff --git a/crates/ra_db/src/lib.rs b/crates/ra_db/src/lib.rs
index 7c49c585b..f08616100 100644
--- a/crates/ra_db/src/lib.rs
+++ b/crates/ra_db/src/lib.rs
@@ -65,6 +65,8 @@ pub struct FileRange {
     pub range: TextRange,
 }
 
+pub const DEFAULT_LRU_CAP: usize = 128;
+
 /// Database which stores all significant input facts: source code and project
 /// model. Everything else in rust-analyzer is derived from these queries.
 #[salsa::query_group(SourceDatabaseStorage)]
diff --git a/crates/ra_ide_api/src/change.rs b/crates/ra_ide_api/src/change.rs
index 247dc0fee..ce03a0f95 100644
--- a/crates/ra_ide_api/src/change.rs
+++ b/crates/ra_ide_api/src/change.rs
@@ -225,7 +225,6 @@ impl RootDatabase {
         let sweep = SweepStrategy::default().discard_values().sweep_all_revisions();
 
         self.query(ra_db::ParseQuery).sweep(sweep);
-
         self.query(hir::db::ParseMacroQuery).sweep(sweep);
         self.query(hir::db::MacroDefQuery).sweep(sweep);
         self.query(hir::db::MacroArgQuery).sweep(sweep);
diff --git a/crates/ra_ide_api/src/db.rs b/crates/ra_ide_api/src/db.rs
index d1a452ecb..b3f395502 100644
--- a/crates/ra_ide_api/src/db.rs
+++ b/crates/ra_ide_api/src/db.rs
@@ -5,7 +5,7 @@ use std::{
 
 use ra_db::{
     CheckCanceled, FileId, Canceled, SourceDatabase,
-    salsa,
+    salsa::{self, Database},
 };
 
 use crate::{LineIndex, symbol_index::{self, SymbolsDatabase}};
@@ -41,6 +41,12 @@ impl salsa::Database for RootDatabase {
 
 impl Default for RootDatabase {
     fn default() -> RootDatabase {
+        RootDatabase::new(None)
+    }
+}
+
+impl RootDatabase {
+    pub fn new(lru_capacity: Option<usize>) -> RootDatabase {
         let mut db = RootDatabase {
             runtime: salsa::Runtime::default(),
             last_gc: time::Instant::now(),
@@ -49,6 +55,9 @@ impl Default for RootDatabase {
         db.set_crate_graph(Default::default());
         db.set_local_roots(Default::default());
         db.set_library_roots(Default::default());
+        let lru_capacity = lru_capacity.unwrap_or(ra_db::DEFAULT_LRU_CAP);
+        db.query_mut(ra_db::ParseQuery).set_lru_capacity(lru_capacity);
+        db.query_mut(hir::db::ParseMacroQuery).set_lru_capacity(lru_capacity);
         db
     }
 }
diff --git a/crates/ra_ide_api/src/lib.rs b/crates/ra_ide_api/src/lib.rs
index dbebf50a6..8741e736f 100644
--- a/crates/ra_ide_api/src/lib.rs
+++ b/crates/ra_ide_api/src/lib.rs
@@ -242,12 +242,21 @@ pub struct CallInfo {
 }
 
 /// `AnalysisHost` stores the current state of the world.
-#[derive(Debug, Default)]
+#[derive(Debug)]
 pub struct AnalysisHost {
     db: db::RootDatabase,
 }
 
+impl Default for AnalysisHost {
+    fn default() -> AnalysisHost {
+        AnalysisHost::new(None)
+    }
+}
+
 impl AnalysisHost {
+    pub fn new(lru_capcity: Option<usize>) -> AnalysisHost {
+        AnalysisHost { db: db::RootDatabase::new(lru_capcity) }
+    }
     /// Returns a snapshot of the current state, which you can query for
     /// semantic information.
     pub fn analysis(&self) -> Analysis {
diff --git a/crates/ra_lsp_server/src/init.rs b/crates/ra_lsp_server/src/init.rs
index 1b77e0312..b894b449d 100644
--- a/crates/ra_lsp_server/src/init.rs
+++ b/crates/ra_lsp_server/src/init.rs
@@ -17,11 +17,17 @@ pub struct InitializationOptions {
     /// Defaults to `true`
     #[serde(deserialize_with = "nullable_bool_true")]
     pub show_workspace_loaded: bool,
+
+    pub lru_capacity: Option<usize>,
 }
 
 impl Default for InitializationOptions {
     fn default() -> InitializationOptions {
-        InitializationOptions { publish_decorations: false, show_workspace_loaded: true }
+        InitializationOptions {
+            publish_decorations: false,
+            show_workspace_loaded: true,
+            lru_capacity: None,
+        }
     }
 }
 
@@ -54,8 +60,10 @@ mod test {
         assert_eq!(default, serde_json::from_str(r#"{}"#).unwrap());
         assert_eq!(
             default,
-            serde_json::from_str(r#"{"publishDecorations":null, "showWorkspaceLoaded":null}"#)
-                .unwrap()
+            serde_json::from_str(
+                r#"{"publishDecorations":null, "showWorkspaceLoaded":null, "lruCapacity":null}"#
+            )
+            .unwrap()
         );
     }
 }
diff --git a/crates/ra_lsp_server/src/main_loop.rs b/crates/ra_lsp_server/src/main_loop.rs
index 090fb9b1b..0790ea472 100644
--- a/crates/ra_lsp_server/src/main_loop.rs
+++ b/crates/ra_lsp_server/src/main_loop.rs
@@ -73,7 +73,7 @@ pub fn main_loop(
         loaded_workspaces
     };
 
-    let mut state = WorldState::new(ws_roots, workspaces);
+    let mut state = WorldState::new(ws_roots, workspaces, options.lru_capacity);
 
     let pool = ThreadPool::new(THREADPOOL_SIZE);
     let (task_sender, task_receiver) = unbounded::<Task>();
diff --git a/crates/ra_lsp_server/src/world.rs b/crates/ra_lsp_server/src/world.rs
index cd8df4fdb..f9ce570ca 100644
--- a/crates/ra_lsp_server/src/world.rs
+++ b/crates/ra_lsp_server/src/world.rs
@@ -46,7 +46,11 @@ pub struct WorldSnapshot {
 }
 
 impl WorldState {
-    pub fn new(folder_roots: Vec<PathBuf>, workspaces: Vec<ProjectWorkspace>) -> WorldState {
+    pub fn new(
+        folder_roots: Vec<PathBuf>,
+        workspaces: Vec<ProjectWorkspace>,
+        lru_capacity: Option<usize>,
+    ) -> WorldState {
         let mut change = AnalysisChange::new();
 
         let mut roots = Vec::new();
@@ -74,7 +78,7 @@ impl WorldState {
         }
         change.set_crate_graph(crate_graph);
 
-        let mut analysis_host = AnalysisHost::default();
+        let mut analysis_host = AnalysisHost::new(lru_capacity);
         analysis_host.apply_change(change);
         WorldState {
             roots_to_scan,
diff --git a/editors/code/package.json b/editors/code/package.json
index 05c808394..c2ed8d126 100644
--- a/editors/code/package.json
+++ b/editors/code/package.json
@@ -232,6 +232,11 @@
                     ],
                     "default": "off",
                     "description": "Trace output of cargo-watch"
+                },
+                "rust-analyzer.lruCapacity": {
+                    "type": "number",
+                    "default": null,
+                    "description": "Number of syntax trees rust-analyzer keeps in memory"
                 }
             }
         },
diff --git a/editors/code/src/config.ts b/editors/code/src/config.ts
index 8d73a6b34..3024546d2 100644
--- a/editors/code/src/config.ts
+++ b/editors/code/src/config.ts
@@ -19,6 +19,7 @@ export class Config {
     public enableEnhancedTyping = true;
     public raLspServerPath = RA_LSP_DEBUG || 'ra_lsp_server';
     public showWorkspaceLoadedNotification = true;
+    public lruCapacity: null | number = null;
     public cargoWatchOptions: CargoWatchOptions = {
         enableOnStartup: 'ask',
         trace: 'off',
@@ -109,5 +110,8 @@ export class Config {
                 ''
             );
         }
+        if (config.has('lruCapacity')) {
+            this.lruCapacity = config.get('lruCapacity') as number;
+        }
     }
 }
diff --git a/editors/code/src/server.ts b/editors/code/src/server.ts
index 81c2b3fff..7029142fd 100644
--- a/editors/code/src/server.ts
+++ b/editors/code/src/server.ts
@@ -35,7 +35,8 @@ export class Server {
             initializationOptions: {
                 publishDecorations: true,
                 showWorkspaceLoaded:
-                    Server.config.showWorkspaceLoadedNotification
+                    Server.config.showWorkspaceLoadedNotification,
+                lruCapacity: Server.config.lruCapacity
             },
             traceOutputChannel
         };