Make Datastore optional

Author: schmidt-sebastian

packages/firestore/exp/src/api/components.ts

@@ -0,0 +1,124 @@
+/**
+ * @license
+ * Copyright 2020 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { Firestore } from './database';
+import { DatabaseInfo } from '../../../src/core/database_info';
+import {
+  FirestoreClient,
+  PersistenceSettings
+} from '../../../src/core/firestore_client';
+import { Code, FirestoreError } from '../../../src/util/error';
+import {
+  ComponentProvider,
+  MemoryComponentProvider
+} from '../../../src/core/component_provider';
+import { DEFAULT_HOST, DEFAULT_SSL } from '../../../lite/src/api/components';
+
+// The components module manages the lifetime of dependencies of the Firestore
+// client. Dependencies can be lazily constructed and only one exists per
+// Firestore instance.
+
+/**
+ * An instance map that ensures only one FirestoreClient exists per Firestore
+ * instance.
+ */
+const firestoreClientInstances = new Map<Firestore, Promise<FirestoreClient>>();
+
+/**
+ * Returns the initialized and started FirestoreClient for the given Firestore
+ * instance. If none exists, creates a new FirestoreClient with memory
+ * persistence. Callers must invoke removeFirestoreClient() when the Firestore
+ * instance is terminated.
+ */
+export function getFirestoreClient(
+  firestore: Firestore
+): Promise<FirestoreClient> {
+  if (firestore._terminated) {
+    throw new FirestoreError(
+      Code.FAILED_PRECONDITION,
+      'The client has already been terminated.'
+    );
+  }
+  if (!firestoreClientInstances.has(firestore)) {
+    // eslint-disable-next-line @typescript-eslint/no-floating-promises
+    initializeFirestoreClient(firestore, new MemoryComponentProvider(), {
+      durable: false
+    });
+  }
+  return firestoreClientInstances.get(firestore)!;
+}
+
+/**
+ * Creates a new FirestoreClient for the given Firestore instance. Throws if the
+ * instance exists.
+ *
+ * @param firestore The Firestore instance for which to create the
+ * FirestoreClient.
+ * @param componentProvider The component provider to use.
+ * @param persistenceSettings Settings for the component provider.
+ */
+export function initializeFirestoreClient(
+  firestore: Firestore,
+  componentProvider: ComponentProvider,
+  persistenceSettings: PersistenceSettings
+): Promise<void> {
+  if (firestore._initialized) {
+    throw new FirestoreError(
+      Code.FAILED_PRECONDITION,
+      'Firestore has already been started and persistence can no longer ' +
+        'be enabled. You can only enable persistence before calling ' +
+        'any other methods on a Firestore object.'
+    );
+  }
+
+  const settings = firestore._getSettings();
+  const databaseInfo = new DatabaseInfo(
+    firestore._databaseId,
+    firestore._persistenceKey,
+    settings.host ?? DEFAULT_HOST,
+    settings.ssl ?? DEFAULT_SSL,
+    /** forceLongPolling= */ false
+  );
+  const firestoreClient = new FirestoreClient(
+    firestore._credentials,
+    firestore._queue
+  );
+  const initializationPromise = firestoreClient.start(
+    databaseInfo,
+    componentProvider,
+    persistenceSettings
+  );
+  firestoreClientInstances.set(
+    firestore,
+    initializationPromise.then(() => firestoreClient)
+  );
+  return initializationPromise;
+}
+
+/**
+ * Removes and terminates the FirestoreClient for the given instance if it has
+ * been started.
+ */
+export async function removeFirestoreClient(
+  firestore: Firestore
+): Promise<void> {
+  const firestoreClient = await firestoreClientInstances.get(firestore);
+  if (firestoreClient) {
+    firestoreClientInstances.delete(firestore);
+    return firestoreClient.terminate();
+  }
+}