Fix resetting

frontend/sync-client/src/file-operations/file-operations.ts

@@ -254,4 +254,8 @@ export class FileOperations {
 
 		return newName;
 	}
+
+	public reset(): void {
+		this.fs.reset();
+	}
 }

frontend/sync-client/src/file-operations/safe-filesystem-operations.ts

@@ -138,4 +138,8 @@ export class SafeFileSystemOperations implements FileSystemOperations {
 			}
 		}
 	}
+
+	public reset(): void {
+		this.locks.reset();
+	}
 }

frontend/sync-client/src/persistence/database.ts

@@ -133,7 +133,7 @@ export class Database {
 
 		toUpdate.metadata = metadata;
 
-		this.save();
+		this.saveInTheBackground();
 	}
 
 	public removeDocumentPromise(promise: Promise<unknown>): void {
@@ -153,7 +153,7 @@ export class Database {
 
 	public removeDocument(find: DocumentRecord): void {
 		this.documents = this.documents.filter((document) => document !== find);
-		this.save();
+		this.saveInTheBackground();
 	}
 
 	public getLatestDocumentByRelativePath(
@@ -210,7 +210,7 @@ export class Database {
 		};
 
 		this.documents.push(entry);
-		this.save();
+		this.saveInTheBackground();
 
 		return entry;
 	}
@@ -234,7 +234,7 @@ export class Database {
 		};
 
 		this.documents.push(entry);
-		this.save();
+		this.saveInTheBackground();
 
 		return entry;
 	}
@@ -271,7 +271,7 @@ export class Database {
 		oldDocument.parallelVersion =
 			newDocument !== undefined ? newDocument.parallelVersion + 1 : 0;
 
-		this.save();
+		this.saveInTheBackground();
 	}
 
 	public delete(relativePath: RelativePath): void {
@@ -290,7 +290,7 @@ export class Database {
 
 	public setHasInitialSyncCompleted(value: boolean): void {
 		this.hasInitialSyncCompleted = value;
-		this.save();
+		this.saveInTheBackground();
 	}
 
 	public getLastSeenUpdateId(): VaultUpdateId {
@@ -301,13 +301,13 @@ export class Database {
 		const previousMin = this.lastSeenUpdateIds.min;
 		this.lastSeenUpdateIds.add(value);
 		if (previousMin !== this.lastSeenUpdateIds.min) {
-			this.save();
+			this.saveInTheBackground();
 		}
 	}
 
 	public setLastSeenUpdateId(value: number): void {
 		this.lastSeenUpdateIds.min = value;
-		this.save();
+		this.saveInTheBackground();
 	}
 
 	public reset(): void {
@@ -316,12 +316,18 @@ export class Database {
 			0 // the first updateId will be 1 which is the first integer after -1
 		);
 		this.hasInitialSyncCompleted = false;
-		this.save();
+		this.saveInTheBackground();
 	}
 
-	private save(): void {
+	private saveInTheBackground(): void {
 		this.ensureConsistency();
-		void this.saveData({
+		void this.save().catch((error: unknown) => {
+			this.logger.error(`Error saving data: ${error}`);
+		});
+	}
+
+	public save(): Promise<void> {
+		return this.saveData({
 			documents: this.resolvedDocuments.map(
 				({ relativePath, documentId, metadata }) => ({
 					documentId,
@@ -332,8 +338,6 @@ export class Database {
 			),
 			lastSeenUpdateId: this.lastSeenUpdateIds.min,
 			hasInitialSyncCompleted: this.hasInitialSyncCompleted
-		}).catch((error: unknown) => {
-			this.logger.error(`Error saving data: ${error}`);
 		});
 	}
 

frontend/sync-client/src/services/fetch-controller.ts

@@ -77,7 +77,7 @@ export class FetchController {
 	 */
 	public finishReset(): void {
 		if (!this.isResetting) {
-			throw new Error("Cannot finish reset when not resetting");
+			return;
 		}
 
 		this.isResetting = false;

frontend/sync-client/src/services/websocket-manager.ts

@@ -21,13 +21,13 @@ export class WebSocketManager {
 		cursors: ClientCursors[]
 	) => Promise<void>)[] = [];
 
-	private webSocket: WebSocket | undefined;
-
 	private isStopped = true;
 	private resolveDisconnectingPromise: null | (() => unknown) = null;
 	private reconnectTimeoutId: ReturnType<typeof setTimeout> | undefined;
 
 	private readonly outstandingPromises: Promise<unknown>[] = [];
+
+	private webSocket: WebSocket | undefined;
 	private readonly webSocketFactoryImplementation: typeof globalThis.WebSocket;
 
 	public constructor(

frontend/sync-client/src/sync-client.ts

@@ -29,6 +29,8 @@ import { DIFF_CACHE_SIZE_MB } from "./consts";
 export class SyncClient {
 	private hasStartedOfflineSync = false;
 	private hasFinishedOfflineSync = false;
+	private hasStarted = false;
+	private hasBeenDestroyed = false;
 	private unloadTelemetry?: () => void;
 
 	private constructor(
@@ -43,6 +45,7 @@ export class SyncClient {
 		private readonly cursorTracker: CursorTracker,
 		private readonly fileChangeNotifier: FileChangeNotifier,
 		private readonly contentCache: FixedSizeDocumentCache,
+		private readonly fileOperations: FileOperations,
 		private readonly persistence: PersistenceProvider<
 			Partial<{
 				settings: Partial<SyncSettings>;
@@ -52,7 +55,17 @@ export class SyncClient {
 	) {}
 
 	public async start(): Promise<void> {
-		if (this.settings.getSettings().enableTelemetry) {
+		this.checkIfDestroyed();
+
+		if (this.hasStarted) {
+			throw new Error("SyncClient has already been started");
+		}
+		this.hasStarted = true;
+
+		if (
+			!this.unloadTelemetry &&
+			this.settings.getSettings().enableTelemetry
+		) {
 			this.unloadTelemetry = setUpTelemetry();
 		}
 
@@ -73,10 +86,14 @@ export class SyncClient {
 		}
 	}
 
-	// Reload settings from disk overriding current in-memory settings.
-	// Missing values will be filled in from DEFAULT_SETTINGS rather than
-	// retaining current in-memory settings.
+	/**
+	 * Reload settings from disk overriding current in-memory settings.
+	 * Missing values will be filled in from DEFAULT_SETTINGS rather than
+	 * retaining current in-memory settings.
+	 */
 	public async reloadSettings(): Promise<void> {
+		this.checkIfDestroyed();
+
 		const state = (await this.persistence.load()) ?? {
 			settings: undefined
 		};
@@ -93,15 +110,20 @@ export class SyncClient {
 		newSettings: SyncSettings,
 		oldSettings: SyncSettings
 	): Promise<void> {
-		if (newSettings.vaultName !== oldSettings.vaultName) {
-			await this.reset();
+		this.checkIfDestroyed();
+
+		if (
+			newSettings.vaultName !== oldSettings.vaultName ||
+			newSettings.remoteUri !== oldSettings.remoteUri
+		) {
+			await this.applyChangedConnectionSettings();
 		}
 
 		if (newSettings.isSyncEnabled !== oldSettings.isSyncEnabled) {
 			if (newSettings.isSyncEnabled) {
 				await this.startSyncing();
 			} else {
-				this.stop();
+				await this.pause();
 			}
 		}
 
@@ -119,10 +141,14 @@ export class SyncClient {
 	}
 
 	public get documentCount(): number {
+		this.checkIfDestroyed();
+
 		return this.database.length;
 	}
 
 	public get isWebSocketConnected(): boolean {
+		this.checkIfDestroyed();
+
 		return this.webSocketManager.isWebSocketConnected;
 	}
 
@@ -203,7 +229,6 @@ export class SyncClient {
 		const fileOperations = new FileOperations(
 			logger,
 			database,
-			settings,
 			fs,
 			nativeLineEndings
 		);
@@ -258,6 +283,7 @@ export class SyncClient {
 			cursorTracker,
 			fileChangeNotifier,
 			contentCache,
+			fileOperations,
 			persistence
 		);
 
@@ -267,6 +293,8 @@ export class SyncClient {
 	}
 
 	public async checkConnection(): Promise<NetworkConnectionStatus> {
+		this.checkIfDestroyed();
+
 		const server = await this.syncService.checkConnection();
 		return {
 			isSuccessful: server.isSuccessful,
@@ -276,59 +304,94 @@ export class SyncClient {
 	}
 
 	public getHistoryEntries(): readonly HistoryEntry[] {
+		this.checkIfDestroyed();
+
 		return this.history.entries;
 	}
 
 	public addSyncHistoryUpdateListener(
 		listener: (stats: HistoryStats) => unknown
 	): void {
+		this.checkIfDestroyed();
+
 		this.history.addSyncHistoryUpdateListener(listener);
 	}
 
 	private async startSyncing(): Promise<void> {
+		this.checkIfDestroyed();
+
 		if (!this.hasStartedOfflineSync) {
 			this.hasStartedOfflineSync = true;
 			await this.syncer.scheduleSyncForOfflineChanges();
 		}
 
 		this.hasFinishedOfflineSync = true;
-		this.webSocketManager.start();
-	}
-
-	private stop(): void {
-		this.hasFinishedOfflineSync = false;
-		this.webSocketManager.stop();
-
-		this.unloadTelemetry?.();
-	}
-
-	public async waitUntilStopped(): Promise<void> {
-		await this.syncer.waitUntilFinished();
-	}
-
-	public async applyChangedConnectionSettings(): Promise<void> {
-		this.fetchController.startReset();
-		this.webSocketManager.stop();
-
-		this.webSocketManager.start();
 		this.fetchController.finishReset();
+		this.webSocketManager.start();
 	}
 
-	/// Wait for the in-flight operations to finish, reset all tracking,
-	/// and the local database but retain the settings.
-	/// The SyncClient can be used again after calling this method.
-	private async reset(): Promise<void> {
-		this.stop();
-		this.fetchController.startReset();
-		this.contentCache.clear();
-		await this.syncer.reset();
-		this.history.reset();
+	/**
+	 * Wait for the in-flight operations to finish, reset all tracking,
+	 * and the local database but retain the settings.
+	 * The SyncClient can be used again after calling this method.
+	 */
+	public async applyChangedConnectionSettings(): Promise<void> {
+		this.checkIfDestroyed();
+
+		this.logger.info(
+			"Stopping SyncClient to apply changed connection settings"
+		);
+		await this.pause();
+
+		// clear all local state
+		this.logger.info("Resetting SyncClient's local state");
 		this.database.reset();
-		this.logger.reset();
+		await this.database.save(); // ensure the new database reads as empty
+		this.resetInMemoryState();
+		this.hasStartedOfflineSync = false;
+		this.hasFinishedOfflineSync = false;
+
+		// restart syncing
 		this.fetchController.finishReset();
 		await this.startSyncing();
 	}
 
+	/**
+	 * Completely destroy the SyncClient, cancelling all in-progress operations.
+	 * After calling this method, the SyncClient cannot be used again.
+	 */
+	public async destroy(): Promise<void> {
+		this.checkIfDestroyed();
+
+		// cancel everything that's in progress
+		this.fetchController.startReset();
+		await this.pause();
+
+		// clean-up memory early
+		this.resetInMemoryState();
+
+		this.logger.info("SyncClient has been successfully disposed");
+
+		this.unloadTelemetry?.();
+	}
+
+	private async pause(): Promise<void> {
+		this.checkIfDestroyed();
+
+		this.fetchController.startReset();
+		await this.webSocketManager.stop();
+		await this.syncer.waitUntilFinished();
+		await this.database.save(); // flush all changes to disk
+	}
+
+	private resetInMemoryState(): void {
+		this.history.reset();
+		this.contentCache.reset();
+		this.logger.reset();
+		this.cursorTracker.reset();
+		this.syncer.reset();
+		this.fileOperations.reset();
+	}
 	public getSettings(): SyncSettings {
 		return this.settings.getSettings();
 	}
@@ -420,4 +483,12 @@ export class SyncClient {
 	): void {
 		this.cursorTracker.addRemoteCursorsUpdateListener(listener);
 	}
+
+	private checkIfDestroyed(): void {
+		if (this.hasBeenDestroyed) {
+			throw new Error(
+				"SyncClient has been destroyed and can no longer be used."
+			);
+		}
+	}
 }

frontend/sync-client/src/sync-operations/cursor-tracker.ts

@@ -250,4 +250,11 @@ export class CursorTracker {
 			? DocumentUpToDateness.UpToDate
 			: DocumentUpToDateness.Prior;
 	}
+
+	public reset(): void {
+		this.knownRemoteCursors = [];
+		this.lastLocalCursorState = [];
+		this.lastLocalCursorStateWithoutDirtyDocuments = [];
+		this.updateLock.reset();
+	}
 }

frontend/sync-client/src/sync-operations/syncer.ts

@@ -32,7 +32,6 @@ export class Syncer {
 	private readonly syncQueue: PQueue;
 
 	private _isFirstSyncComplete = false;
-
 	private runningScheduleSyncForOfflineChanges: Promise<void> | undefined;
 
 	public constructor(
@@ -514,4 +513,11 @@ export class Syncer {
 
 		this.database.setHasInitialSyncCompleted(true);
 	}
+
+	public reset(): void {
+		this._isFirstSyncComplete = false;
+		this.syncQueue.clear();
+		this.remoteDocumentsLock.reset();
+		this.runningScheduleSyncForOfflineChanges = undefined;
+	}
 }

frontend/sync-client/src/utils/data-structures/fix-sized-cache.test.ts

@@ -89,7 +89,7 @@ describe("fixedSizeDocumentCache", () => {
 		assert.equal(cache.get(1), doc1);
 		assert.equal(cache.get(2), doc2);
 
-		cache.clear();
+		cache.reset();
 		assert.equal(cache.get(1), undefined);
 		assert.equal(cache.get(2), undefined);
 

frontend/sync-client/src/utils/data-structures/fix-sized-cache.ts

@@ -57,7 +57,7 @@ export class FixedSizeDocumentCache {
 		this.fitBelowMaxSize();
 	}
 
-	public clear(): void {
+	public reset(): void {
 		this.cache.clear();
 		this.head = null;
 		this.tail = null;

frontend/sync-client/src/utils/data-structures/locks.ts

@@ -131,6 +131,11 @@ export class Locks<T> {
 			this.locked.delete(key);
 		}
 	}
+
+	public reset(): void {
+		this.locked.clear();
+		this.waiters.clear();
+	}
 }
 
 export class Lock {
@@ -143,4 +148,8 @@ export class Lock {
 	public async withLock<R>(fn: () => R | Promise<R>): Promise<R> {
 		return this.locks.withLock(true, fn);
 	}
+
+	public reset(): void {
+		this.locks.reset();
+	}
 }