Merge #5244

5244: Add a command to compute memory usage statistics r=matklad a=jonas-schievink

This allows inspecting memory usage on a live rust-analyzer instance after it has been used interactively.

This will only work with `--features jemalloc`, so maybe it should print something more useful when that's not available? Right now it will just print 0 Bytes for every query.

Co-authored-by: Jonas Schievink <[email protected]>

4 files changed, 44 insertions, 0 deletions

diff --git a/editors/code/package.json b/editors/code/package.json
index 4b47fc9d3..743a2290c 100644
--- a/editors/code/package.json
+++ b/editors/code/package.json
@@ -61,6 +61,7 @@
     "activationEvents": [
         "onLanguage:rust",
         "onCommand:rust-analyzer.analyzerStatus",
+        "onCommand:rust-analyzer.memoryUsage",
         "onCommand:rust-analyzer.reloadWorkspace",
         "workspaceContains:**/Cargo.toml"
     ],
@@ -143,6 +144,11 @@
                 "category": "Rust Analyzer"
             },
             {
+                "command": "rust-analyzer.memoryUsage",
+                "title": "Memory Usage (Clears Database)",
+                "category": "Rust Analyzer"
+            },
+            {
                 "command": "rust-analyzer.reloadWorkspace",
                 "title": "Reload workspace",
                 "category": "Rust Analyzer"
@@ -844,6 +850,10 @@
                     "when": "inRustProject"
                 },
                 {
+                    "command": "rust-analyzer.memoryUsage",
+                    "when": "inRustProject"
+                },
+                {
                     "command": "rust-analyzer.reloadWorkspace",
                     "when": "inRustProject"
                 },
diff --git a/editors/code/src/commands.ts b/editors/code/src/commands.ts
index 19a9c2a0d..1f3a7cf7e 100644
--- a/editors/code/src/commands.ts
+++ b/editors/code/src/commands.ts
@@ -55,6 +55,38 @@ export function analyzerStatus(ctx: Ctx): Cmd {
     };
 }
 
+export function memoryUsage(ctx: Ctx): Cmd {
+    const tdcp = new class implements vscode.TextDocumentContentProvider {
+        readonly uri = vscode.Uri.parse('rust-analyzer-memory://memory');
+        readonly eventEmitter = new vscode.EventEmitter<vscode.Uri>();
+
+        provideTextDocumentContent(_uri: vscode.Uri): vscode.ProviderResult<string> {
+            if (!vscode.window.activeTextEditor) return '';
+
+            return ctx.client.sendRequest(ra.memoryUsage, null).then((mem) => {
+                return 'Per-query memory usage:\n' + mem + '\n(note: database has been cleared)';
+            });
+        }
+
+        get onDidChange(): vscode.Event<vscode.Uri> {
+            return this.eventEmitter.event;
+        }
+    }();
+
+    ctx.pushCleanup(
+        vscode.workspace.registerTextDocumentContentProvider(
+            'rust-analyzer-memory',
+            tdcp,
+        ),
+    );
+
+    return async () => {
+        tdcp.eventEmitter.fire(tdcp.uri);
+        const document = await vscode.workspace.openTextDocument(tdcp.uri);
+        return vscode.window.showTextDocument(document, vscode.ViewColumn.Two, true);
+    };
+}
+
 export function matchingBrace(ctx: Ctx): Cmd {
     return async () => {
         const editor = ctx.activeRustEditor;
diff --git a/editors/code/src/lsp_ext.ts b/editors/code/src/lsp_ext.ts
index bf4703239..5f32cb40e 100644
--- a/editors/code/src/lsp_ext.ts
+++ b/editors/code/src/lsp_ext.ts
@@ -5,6 +5,7 @@
 import * as lc from "vscode-languageclient";
 
 export const analyzerStatus = new lc.RequestType<null, string, void>("rust-analyzer/analyzerStatus");
+export const memoryUsage = new lc.RequestType<null, string, void>("rust-analyzer/memoryUsage");
 
 export type Status = "loading" | "ready" | "invalid" | "needsReload";
 export const status = new lc.NotificationType<Status>("rust-analyzer/status");
diff --git a/editors/code/src/main.ts b/editors/code/src/main.ts
index 4b990afa1..eda95ae5c 100644
--- a/editors/code/src/main.ts
+++ b/editors/code/src/main.ts
@@ -96,6 +96,7 @@ async function tryActivate(context: vscode.ExtensionContext) {
     });
 
     ctx.registerCommand('analyzerStatus', commands.analyzerStatus);
+    ctx.registerCommand('memoryUsage', commands.memoryUsage);
     ctx.registerCommand('reloadWorkspace', commands.reloadWorkspace);
     ctx.registerCommand('matchingBrace', commands.matchingBrace);
     ctx.registerCommand('joinLines', commands.joinLines);