5 files changed, 107 insertions, 42 deletions

diff --git a/crates/ra_project_model/src/cargo_workspace.rs b/crates/ra_project_model/src/cargo_workspace.rs
index 6d1154056..4182ca156 100644
--- a/crates/ra_project_model/src/cargo_workspace.rs
+++ b/crates/ra_project_model/src/cargo_workspace.rs
@@ -155,7 +155,7 @@ impl CargoWorkspace {
         if let Some(target) = cargo_features.target.as_ref() {
             meta.other_options(vec![String::from("--filter-platform"), target.clone()]);
         }
-        let meta = meta.exec().with_context(|| {
+        let mut meta = meta.exec().with_context(|| {
             format!("Failed to run `cargo metadata --manifest-path {}`", cargo_toml.display())
         })?;
 
@@ -175,6 +175,7 @@ impl CargoWorkspace {
 
         let ws_members = &meta.workspace_members;
 
+        meta.packages.sort_by(|a, b| a.id.cmp(&b.id));
         for meta_pkg in meta.packages {
             let cargo_metadata::Package { id, edition, name, manifest_path, version, .. } =
                 meta_pkg;
@@ -210,7 +211,7 @@ impl CargoWorkspace {
             }
         }
         let resolve = meta.resolve.expect("metadata executed with deps");
-        for node in resolve.nodes {
+        for mut node in resolve.nodes {
             let source = match pkg_by_id.get(&node.id) {
                 Some(&src) => src,
                 // FIXME: replace this and a similar branch below with `.unwrap`, once
@@ -221,6 +222,7 @@ impl CargoWorkspace {
                     continue;
                 }
             };
+            node.deps.sort_by(|a, b| a.pkg.cmp(&b.pkg));
             for dep_node in node.deps {
                 let pkg = match pkg_by_id.get(&dep_node.pkg) {
                     Some(&pkg) => pkg,
diff --git a/crates/rust-analyzer/src/global_state.rs b/crates/rust-analyzer/src/global_state.rs
index c8d34e15a..9a9a6547a 100644
--- a/crates/rust-analyzer/src/global_state.rs
+++ b/crates/rust-analyzer/src/global_state.rs
@@ -26,6 +26,7 @@ use crate::{
     to_proto::url_from_abs_path,
     Result,
 };
+use ra_prof::profile;
 
 #[derive(Eq, PartialEq, Copy, Clone)]
 pub(crate) enum Status {
@@ -122,6 +123,10 @@ impl GlobalState {
     }
 
     pub(crate) fn process_changes(&mut self) -> bool {
+        let _p = profile("GlobalState::process_changes");
+        let mut fs_changes = Vec::new();
+        let mut has_fs_changes = false;
+
         let change = {
             let mut change = AnalysisChange::new();
             let (vfs, line_endings_map) = &mut *self.vfs.write();
@@ -130,13 +135,14 @@ impl GlobalState {
                 return false;
             }
 
-            let fs_op = changed_files.iter().any(|it| it.is_created_or_deleted());
-            if fs_op {
-                let roots = self.source_root_config.partition(&vfs);
-                change.set_roots(roots)
-            }
-
             for file in changed_files {
+                if file.is_created_or_deleted() {
+                    if let Some(path) = vfs.file_path(file.file_id).as_path() {
+                        fs_changes.push((path.to_path_buf(), file.change_kind));
+                        has_fs_changes = true;
+                    }
+                }
+
                 let text = if file.exists() {
                     let bytes = vfs.file_contents(file.file_id).to_vec();
                     match String::from_utf8(bytes).ok() {
@@ -152,10 +158,15 @@ impl GlobalState {
                 };
                 change.change_file(file.file_id, text);
             }
+            if has_fs_changes {
+                let roots = self.source_root_config.partition(&vfs);
+                change.set_roots(roots);
+            }
             change
         };
 
         self.analysis_host.apply_change(change);
+        self.maybe_refresh(&fs_changes);
         true
     }
 
diff --git a/crates/rust-analyzer/src/main_loop.rs b/crates/rust-analyzer/src/main_loop.rs
index 96e2399ce..702f25a19 100644
--- a/crates/rust-analyzer/src/main_loop.rs
+++ b/crates/rust-analyzer/src/main_loop.rs
@@ -22,6 +22,7 @@ use crate::{
     Result,
 };
 use ra_project_model::ProjectWorkspace;
+use vfs::ChangeKind;
 
 pub fn main_loop(config: Config, connection: Connection) -> Result<()> {
     log::info!("initial config: {:#?}", config);
@@ -197,39 +198,49 @@ impl GlobalState {
                 }
                 self.analysis_host.maybe_collect_garbage();
             }
-            Event::Vfs(task) => match task {
-                vfs::loader::Message::Loaded { files } => {
-                    let vfs = &mut self.vfs.write().0;
-                    for (path, contents) in files {
-                        let path = VfsPath::from(path);
-                        if !self.mem_docs.contains(&path) {
-                            vfs.set_file_contents(path, contents)
+            Event::Vfs(mut task) => {
+                let _p = profile("GlobalState::handle_event/vfs");
+                loop {
+                    match task {
+                        vfs::loader::Message::Loaded { files } => {
+                            let vfs = &mut self.vfs.write().0;
+                            for (path, contents) in files {
+                                let path = VfsPath::from(path);
+                                if !self.mem_docs.contains(&path) {
+                                    vfs.set_file_contents(path, contents)
+                                }
+                            }
+                        }
+                        vfs::loader::Message::Progress { n_total, n_done } => {
+                            if n_total == 0 {
+                                self.transition(Status::Invalid);
+                            } else {
+                                let state = if n_done == 0 {
+                                    self.transition(Status::Loading);
+                                    Progress::Begin
+                                } else if n_done < n_total {
+                                    Progress::Report
+                                } else {
+                                    assert_eq!(n_done, n_total);
+                                    self.transition(Status::Ready);
+                                    Progress::End
+                                };
+                                self.report_progress(
+                                    "roots scanned",
+                                    state,
+                                    Some(format!("{}/{}", n_done, n_total)),
+                                    Some(Progress::percentage(n_done, n_total)),
+                                )
+                            }
                         }
                     }
-                }
-                vfs::loader::Message::Progress { n_total, n_done } => {
-                    if n_total == 0 {
-                        self.transition(Status::Invalid);
-                    } else {
-                        let state = if n_done == 0 {
-                            self.transition(Status::Loading);
-                            Progress::Begin
-                        } else if n_done < n_total {
-                            Progress::Report
-                        } else {
-                            assert_eq!(n_done, n_total);
-                            self.transition(Status::Ready);
-                            Progress::End
-                        };
-                        self.report_progress(
-                            "roots scanned",
-                            state,
-                            Some(format!("{}/{}", n_done, n_total)),
-                            Some(Progress::percentage(n_done, n_total)),
-                        )
+                    // Coalesce many VFS event into a single loop turn
+                    task = match self.loader.receiver.try_recv() {
+                        Ok(task) => task,
+                        Err(_) => break,
                     }
                 }
-            },
+            }
             Event::Flycheck(task) => match task {
                 flycheck::Message::AddDiagnostic { workspace_root, diagnostic } => {
                     let diagnostics = crate::diagnostics::to_proto::map_rust_diagnostic_to_lsp(
@@ -428,7 +439,9 @@ impl GlobalState {
                 if let Some(flycheck) = &this.flycheck {
                     flycheck.handle.update();
                 }
-                this.maybe_refresh(params.text_document.uri.as_str());
+                if let Ok(abs_path) = from_proto::abs_path(&params.text_document.uri) {
+                    this.maybe_refresh(&[(abs_path, ChangeKind::Modify)]);
+                }
                 Ok(())
             })?
             .on::<lsp_types::notification::DidChangeConfiguration>(|this, _params| {
diff --git a/crates/rust-analyzer/src/reload.rs b/crates/rust-analyzer/src/reload.rs
index 0a201fceb..ffe234a5b 100644
--- a/crates/rust-analyzer/src/reload.rs
+++ b/crates/rust-analyzer/src/reload.rs
@@ -6,7 +6,7 @@ use flycheck::FlycheckHandle;
 use ra_db::{CrateGraph, SourceRoot, VfsPath};
 use ra_ide::AnalysisChange;
 use ra_project_model::{PackageRoot, ProcMacroClient, ProjectWorkspace};
-use vfs::{file_set::FileSetConfig, AbsPath};
+use vfs::{file_set::FileSetConfig, AbsPath, AbsPathBuf, ChangeKind};
 
 use crate::{
     config::{Config, FilesWatcher, LinkedProject},
@@ -14,9 +14,11 @@ use crate::{
     lsp_ext,
     main_loop::Task,
 };
+use ra_prof::profile;
 
 impl GlobalState {
     pub(crate) fn update_configuration(&mut self, config: Config) {
+        let _p = profile("GlobalState::update_configuration");
         let old_config = mem::replace(&mut self.config, config);
         if self.config.lru_capacity != old_config.lru_capacity {
             self.analysis_host.update_lru_capacity(old_config.lru_capacity);
@@ -27,8 +29,8 @@ impl GlobalState {
             self.reload_flycheck();
         }
     }
-    pub(crate) fn maybe_refresh(&mut self, saved_doc_url: &str) {
-        if !(saved_doc_url.ends_with("Cargo.toml") || saved_doc_url.ends_with("Cargo.lock")) {
+    pub(crate) fn maybe_refresh(&mut self, changes: &[(AbsPathBuf, ChangeKind)]) {
+        if !changes.iter().any(|(path, kind)| is_interesting(path, *kind)) {
             return;
         }
         match self.status {
@@ -40,6 +42,41 @@ impl GlobalState {
         } else {
             self.transition(Status::NeedsReload);
         }
+
+        fn is_interesting(path: &AbsPath, change_kind: ChangeKind) -> bool {
+            const IMPLICIT_TARGET_FILES: &[&str] = &["build.rs", "src/main.rs", "src/lib.rs"];
+            const IMPLICIT_TARGET_DIRS: &[&str] = &["src/bin", "examples", "tests", "benches"];
+
+            if path.ends_with("Cargo.toml") || path.ends_with("Cargo.lock") {
+                return true;
+            }
+            if change_kind == ChangeKind::Modify {
+                return false;
+            }
+            if path.extension().map(|it| it.to_str()) != Some("rs".into()) {
+                return false;
+            }
+            if IMPLICIT_TARGET_FILES.iter().any(|it| path.ends_with(it)) {
+                return true;
+            }
+            let parent = match path.parent() {
+                Some(it) => it,
+                None => return false,
+            };
+            if IMPLICIT_TARGET_DIRS.iter().any(|it| parent.ends_with(it)) {
+                return true;
+            }
+            if path.ends_with("main.rs") {
+                let grand_parent = match parent.parent() {
+                    Some(it) => it,
+                    None => return false,
+                };
+                if IMPLICIT_TARGET_DIRS.iter().any(|it| grand_parent.ends_with(it)) {
+                    return true;
+                }
+            }
+            false
+        }
     }
     pub(crate) fn transition(&mut self, new_status: Status) {
         self.status = new_status;
@@ -79,6 +116,7 @@ impl GlobalState {
         });
     }
     pub(crate) fn switch_workspaces(&mut self, workspaces: Vec<anyhow::Result<ProjectWorkspace>>) {
+        let _p = profile("GlobalState::switch_workspaces");
         log::info!("reloading projects: {:?}", self.config.linked_projects);
 
         let mut has_errors = false;
@@ -267,6 +305,7 @@ pub(crate) struct SourceRootConfig {
 
 impl SourceRootConfig {
     pub(crate) fn partition(&self, vfs: &vfs::Vfs) -> Vec<SourceRoot> {
+        let _p = profile("SourceRootConfig::partition");
         self.fsc
             .partition(vfs)
             .into_iter()
diff --git a/crates/vfs/src/lib.rs b/crates/vfs/src/lib.rs
index 024e58018..3bfecd08f 100644
--- a/crates/vfs/src/lib.rs
+++ b/crates/vfs/src/lib.rs
@@ -70,7 +70,7 @@ impl ChangedFile {
     }
 }
 
-#[derive(Eq, PartialEq)]
+#[derive(Eq, PartialEq, Copy, Clone, Debug)]
 pub enum ChangeKind {
     Create,
     Modify,