feat(vscode): implemented requestIdentifierGenerator for Dart Frog daemon (#929)

Author: alestiago

extensions/vscode/src/daemon/dart-frog-daemon.ts

@@ -10,6 +10,10 @@ import {
   isReadyDaemonEvent,
 } from "./protocol";
 import { EventEmitter } from "events";
+import {
+  AscendingNumericalIdentifierGenerator,
+  IdentifierGenerator,
+} from "../utils";
 
 /**
  * The types of events that are emitted by the {@link DartFrogDaemon}.
@@ -46,6 +50,15 @@ export class DartFrogDaemon {
     return this._instance || (this._instance = new this());
   }
 
+  /**
+   * Generates unique and valid identifiers for requests.
+   *
+   * Should not be used as a request counter, since it is not guaranteed to
+   * be called the same number of times as the number of requests sent.
+   */
+  public readonly requestIdentifierGenerator: IdentifierGenerator =
+    new AscendingNumericalIdentifierGenerator();
+
   private daemonMessagesEventEmitter = new EventEmitter();
 
   /**

extensions/vscode/src/test/suite/utils/identifier-generator.test.ts

@@ -0,0 +1,42 @@
+import { AscendingNumericalIdentifierGenerator } from "../../../utils";
+import * as assert from "assert";
+
+suite("AscendingNumericalIdentifierGenerator", () => {
+  suite("generate", () => {
+    test("generates identifiers in ascending order", () => {
+      const generator = new AscendingNumericalIdentifierGenerator();
+
+      const identifiers = [];
+      for (let i = 0; i < 100; i++) {
+        identifiers.push(generator.generate());
+      }
+
+      assert.deepStrictEqual(identifiers, identifiers.sort());
+    });
+
+    test("generates unique identifiers", () => {
+      const generator = new AscendingNumericalIdentifierGenerator();
+
+      const identifiers = [];
+      for (let i = 0; i < 100; i++) {
+        identifiers.push(generator.generate());
+      }
+
+      assert.deepStrictEqual(identifiers.length, new Set(identifiers).size);
+    });
+
+    test("generates numerical identifiers", () => {
+      const generator = new AscendingNumericalIdentifierGenerator();
+
+      const identifiers = [];
+      for (let i = 0; i < 100; i++) {
+        identifiers.push(generator.generate());
+      }
+
+      assert.equal(
+        identifiers.every((id) => /^\d+$/.test(id)),
+        true
+      );
+    });
+  });
+});

extensions/vscode/src/utils/identifier-generator.ts

@@ -0,0 +1,27 @@
+export abstract class IdentifierGenerator {
+  /**
+   * Generates a new unique identifier.
+   *
+   * @returns A new unique identifier, consecutive calls to this method should
+   * always return different identifiers.
+   */
+  abstract generate(): string;
+}
+
+/**
+ * Generates incremental identifiers.
+ *
+ * @example
+ * const generator = new AscendingNumericalIdentifierGenerator();
+ * generator.generate(); // "0"
+ * generator.generate(); // "1"
+ */
+export class AscendingNumericalIdentifierGenerator
+  implements IdentifierGenerator
+{
+  private counter: bigint = 0n;
+
+  public generate(): string {
+    return `${this.counter++}`;
+  }
+}

extensions/vscode/src/utils/index.ts

@@ -1,3 +1,4 @@
 export * from "./cli-version";
 export * from "./dart-frog-structure";
 export * from "./suggest-installing-dart-frog-cli";
+export * from "./identifier-generator";