3 files changed, 107 insertions, 9 deletions

diff --git a/crates/ra_ide_api/src/status.rs b/crates/ra_ide_api/src/status.rs
index d499dd878..c184ca892 100644
--- a/crates/ra_ide_api/src/status.rs
+++ b/crates/ra_ide_api/src/status.rs
@@ -1,3 +1,6 @@
+use std::fmt;
+
+use ra_syntax::AstNode;
 use ra_db::{
     SourceFileQuery,
     salsa::{Database, debug::DebugQueryTable},
@@ -6,10 +9,53 @@ use ra_db::{
 use crate::db::RootDatabase;
 
 pub(crate) fn status(db: &RootDatabase) -> String {
-    let n_parsed_files = db.query(SourceFileQuery).entries::<Vec<_>>().len();
+    let file_stats = {
+        let mut stats = FilesStats::default();
+        for entry in db.query(SourceFileQuery).entries::<Vec<_>>() {
+            stats.total += 1;
+            if let Some(value) = entry.value {
+                stats.retained += 1;
+                stats.retained_size = stats
+                    .retained_size
+                    .checked_add(value.syntax().memory_size_of_subtree())
+                    .unwrap();
+            }
+        }
+        stats
+    };
     let n_defs = {
         let interner: &hir::HirInterner = db.as_ref();
         interner.len()
     };
-    format!("#n_parsed_files {}\n#n_defs {}\n", n_parsed_files, n_defs)
+    format!("{}\nn_defs {}\n", file_stats, n_defs)
+}
+
+#[derive(Default)]
+struct FilesStats {
+    total: usize,
+    retained: usize,
+    retained_size: usize,
+}
+
+impl fmt::Display for FilesStats {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        let (size, suff) = human_bytes(self.retained_size);
+        write!(
+            fmt,
+            "{} parsed_files, {} ({}{}) retained",
+            self.total, self.retained, size, suff
+        )
+    }
+}
+
+fn human_bytes(bytes: usize) -> (usize, &'static str) {
+    if bytes < 4096 {
+        return (bytes, " bytes");
+    }
+    let kb = bytes / 1024;
+    if kb < 4096 {
+        return (kb, "kb");
+    }
+    let mb = kb / 1024;
+    (mb, "mb")
 }
diff --git a/editors/code/src/commands/analyzer_status.ts b/editors/code/src/commands/analyzer_status.ts
index 5c56b9c4c..bb46a1990 100644
--- a/editors/code/src/commands/analyzer_status.ts
+++ b/editors/code/src/commands/analyzer_status.ts
@@ -1,12 +1,61 @@
 import * as vscode from 'vscode';
 import { Server } from '../server';
 
+const statusUri = vscode.Uri.parse('ra-lsp-status://status');
+
+export class TextDocumentContentProvider
+    implements vscode.TextDocumentContentProvider {
+    public eventEmitter = new vscode.EventEmitter<vscode.Uri>();
+    public syntaxTree: string = 'Not available';
+
+    public provideTextDocumentContent(
+        uri: vscode.Uri
+    ): vscode.ProviderResult<string> {
+        const editor = vscode.window.activeTextEditor;
+        if (editor == null) {
+            return '';
+        }
+        return Server.client.sendRequest<string>('ra/analyzerStatus', null);
+    }
+
+    get onDidChange(): vscode.Event<vscode.Uri> {
+        return this.eventEmitter.event;
+    }
+}
+
+let poller: NodeJS.Timer | null = null;
+
 // Shows status of rust-analyzer (for debugging)
-export async function handle() {
-    const status = await Server.client.sendRequest<string>(
-        'ra/analyzerStatus',
-        null
+
+export function makeCommand(context: vscode.ExtensionContext) {
+    const textDocumentContentProvider = new TextDocumentContentProvider();
+    context.subscriptions.push(
+        vscode.workspace.registerTextDocumentContentProvider(
+            'ra-lsp-status',
+            textDocumentContentProvider
+        )
     );
-    const doc = await vscode.workspace.openTextDocument({ content: status });
-    await vscode.window.showTextDocument(doc, vscode.ViewColumn.Two);
+
+    context.subscriptions.push({
+        dispose() {
+            if (poller != null) {
+                clearInterval(poller);
+            }
+        }
+    });
+
+    return async function handle() {
+        if (poller == null) {
+            poller = setInterval(
+                () => textDocumentContentProvider.eventEmitter.fire(statusUri),
+                1000
+            );
+        }
+        const document = await vscode.workspace.openTextDocument(statusUri);
+        return vscode.window.showTextDocument(
+            document,
+            vscode.ViewColumn.Two,
+            true
+        );
+    };
 }
diff --git a/editors/code/src/extension.ts b/editors/code/src/extension.ts
index 288a852aa..3af95c599 100644
--- a/editors/code/src/extension.ts
+++ b/editors/code/src/extension.ts
@@ -45,7 +45,10 @@ export function activate(context: vscode.ExtensionContext) {
     }
 
     // Commands are requests from vscode to the language server
-    registerCommand('ra-lsp.analyzerStatus', commands.analyzerStatus.handle);
+    registerCommand(
+        'ra-lsp.analyzerStatus',
+        commands.analyzerStatus.makeCommand(context)
+    );
     registerCommand('ra-lsp.syntaxTree', commands.syntaxTree.handle);
     registerCommand('ra-lsp.extendSelection', commands.extendSelection.handle);
     registerCommand('ra-lsp.matchingBrace', commands.matchingBrace.handle);