GH-13: Forbid parallel LS-start command execution.

arduino-ide-extension/package.json

@@ -46,6 +46,7 @@
     "@types/temp": "^0.8.34",
     "@types/which": "^1.3.1",
     "ajv": "^6.5.3",
+    "async-mutex": "^0.3.0",
     "css-element-queries": "^1.2.0",
     "dateformat": "^3.0.3",
     "deepmerge": "^4.2.2",

arduino-ide-extension/src/browser/arduino-frontend-contribution.tsx

@@ -1,4 +1,4 @@
-const debounce = require('lodash.debounce');
+import { Mutex } from 'async-mutex';
 import { MAIN_MENU_BAR, MenuContribution, MenuModelRegistry, SelectionService, ILogger } from '@theia/core';
 import {
     ContextMenuRenderer,
@@ -201,7 +201,6 @@ export class ArduinoFrontendContribution implements FrontendApplicationContribut
             if (selectedBoard) {
                 const { name, fqbn } = selectedBoard;
                 if (fqbn) {
-                    await this.hostedPluginSupport.didStart;
                     this.startLanguageServer(fqbn, name);
                 }
             }
@@ -225,33 +224,44 @@ export class ArduinoFrontendContribution implements FrontendApplicationContribut
         });
     }
 
-    protected startLanguageServer = debounce((fqbn: string, name: string | undefined) => this.doStartLanguageServer(fqbn, name));
-    protected async doStartLanguageServer(fqbn: string, name: string | undefined): Promise<void> {
-        this.logger.info(`Starting language server: ${fqbn}`);
-        const log = this.arduinoPreferences.get('arduino.language.log');
-        let currentSketchPath: string | undefined = undefined;
-        if (log) {
-            const currentSketch = await this.sketchServiceClient.currentSketch();
-            if (currentSketch) {
-                currentSketchPath = await this.fileSystem.fsPath(new URI(currentSketch.uri));
+    protected languageServerFqbn?: string;
+    protected languageServerStartMutex = new Mutex();
+    protected async startLanguageServer(fqbn: string, name: string | undefined): Promise<void> {
+        const release = await this.languageServerStartMutex.acquire();
+        try {
+            if (fqbn === this.languageServerFqbn) {
+                // NOOP
+                return;
             }
-        }
-        const { clangdUri, cliUri, lsUri } = await this.executableService.list();
-        const [clangdPath, cliPath, lsPath] = await Promise.all([
-            this.fileSystem.fsPath(new URI(clangdUri)),
-            this.fileSystem.fsPath(new URI(cliUri)),
-            this.fileSystem.fsPath(new URI(lsUri)),
-        ]);
-        this.commandRegistry.executeCommand('arduino.languageserver.start', {
-            lsPath,
-            cliPath,
-            clangdPath,
-            log: currentSketchPath ? currentSketchPath : log,
-            board: {
-                fqbn,
-                name: name ? `"${name}"` : undefined
+            await this.hostedPluginSupport.didStart;
+            this.logger.info(`Starting language server: ${fqbn}`);
+            const log = this.arduinoPreferences.get('arduino.language.log');
+            let currentSketchPath: string | undefined = undefined;
+            if (log) {
+                const currentSketch = await this.sketchServiceClient.currentSketch();
+                if (currentSketch) {
+                    currentSketchPath = await this.fileSystem.fsPath(new URI(currentSketch.uri));
+                }
             }
-        });
+            const { clangdUri, cliUri, lsUri } = await this.executableService.list();
+            const [clangdPath, cliPath, lsPath] = await Promise.all([
+                this.fileSystem.fsPath(new URI(clangdUri)),
+                this.fileSystem.fsPath(new URI(cliUri)),
+                this.fileSystem.fsPath(new URI(lsUri)),
+            ]);
+            this.languageServerFqbn = await this.commandRegistry.executeCommand('arduino.languageserver.start', {
+                lsPath,
+                cliPath,
+                clangdPath,
+                log: currentSketchPath ? currentSketchPath : log,
+                board: {
+                    fqbn,
+                    name: name ? `"${name}"` : undefined
+                }
+            });
+        } finally {
+            release();
+        }
     }
 
     registerToolbarItems(registry: TabBarToolbarRegistry): void {

yarn.lock

@@ -3804,6 +3804,13 @@ async-limiter@~1.0.0:
   resolved "https://registry.yarnpkg.com/async-limiter/-/async-limiter-1.0.1.tgz#dd379e94f0db8310b08291f9d64c3209766617fd"
   integrity sha512-csOlWGAcRFJaI6m+F2WKdnMKr4HhdhFVBk0H/QbJFMCr+uO2kwohwXQPxw/9OCxp05r5ghVBFSyioixx3gfkNQ==
 
+async-mutex@^0.3.0:
+  version "0.3.0"
+  resolved "https://registry.yarnpkg.com/async-mutex/-/async-mutex-0.3.0.tgz#5bc765c271dfc05c48040c12032a92f1dbef2dc3"
+  integrity sha512-6VIpUM7s37EMXvnO3TvujgaS6gx4yJby13BhxovMYSap7nrbS0gJ1UzGcjD+HElNSdTz/+IlAIqj7H48N0ZlyQ==
+  dependencies:
+    tslib "^2.1.0"
+
 [email protected]:
   version "0.9.2"
   resolved "https://registry.yarnpkg.com/async/-/async-0.9.2.tgz#aea74d5e61c1f899613bf64bda66d4c78f2fd17d"
@@ -14580,6 +14587,11 @@ tslib@^1.10.0, tslib@^1.8.0, tslib@^1.8.1, tslib@^1.9.0:
   resolved "https://registry.yarnpkg.com/tslib/-/tslib-1.14.1.tgz#cf2d38bdc34a134bcaf1091c41f6619e2f672d00"
   integrity sha512-Xni35NKzjgMrwevysHTCArtLDpPvye8zV/0E4EyYn43P7/7qvQwPh9BGkHewbMulVntbigmcT7rdX3BNo9wRJg==
 
+tslib@^2.1.0:
+  version "2.1.0"
+  resolved "https://registry.yarnpkg.com/tslib/-/tslib-2.1.0.tgz#da60860f1c2ecaa5703ab7d39bc05b6bf988b97a"
+  integrity sha512-hcVC3wYEziELGGmEEXue7D75zbwIIVUMWAVbHItGPx0ziyXxrOMQx4rQEVEV45Ut/1IotuEvwqPopzIOkDMf0A==
+
 tslint@^5.5.0:
   version "5.20.1"
   resolved "https://registry.yarnpkg.com/tslint/-/tslint-5.20.1.tgz#e401e8aeda0152bc44dd07e614034f3f80c67b7d"