chat: store disk sessions using an 'append log'

src/vs/base/common/buffer.ts

@@ -213,7 +213,7 @@ export function binaryIndexOf(haystack: Uint8Array, needle: Uint8Array, offset =
 	}
 
 	if (needleLen === 1) {
-		return haystack.indexOf(needle[0]);
+		return haystack.indexOf(needle[0], offset);
 	}
 
 	if (needleLen > haystackLen - offset) {

src/vs/base/test/common/buffer.test.ts

@@ -437,10 +437,12 @@ suite('Buffer', () => {
 
 		assert.strictEqual(haystack.indexOf(VSBuffer.fromString('a')), 0);
 		assert.strictEqual(haystack.indexOf(VSBuffer.fromString('c')), 2);
+		assert.strictEqual(haystack.indexOf(VSBuffer.fromString('c'), 4), 7);
 
 		assert.strictEqual(haystack.indexOf(VSBuffer.fromString('abcaa')), 0);
 		assert.strictEqual(haystack.indexOf(VSBuffer.fromString('caaab')), 8);
 		assert.strictEqual(haystack.indexOf(VSBuffer.fromString('ccc')), 15);
+		assert.strictEqual(haystack.indexOf(VSBuffer.fromString('cc'), 9), 15);
 
 		assert.strictEqual(haystack.indexOf(VSBuffer.fromString('cccb')), -1);
 	});

src/vs/platform/files/browser/indexedDBFileSystemProvider.ts

@@ -156,6 +156,7 @@ export class IndexedDBFileSystemProvider extends Disposable implements IFileSyst
 
 	readonly capabilities: FileSystemProviderCapabilities =
 		FileSystemProviderCapabilities.FileReadWrite
+		| FileSystemProviderCapabilities.FileAppend
 		| FileSystemProviderCapabilities.PathCaseSensitive;
 	readonly onDidChangeCapabilities: Event<void> = Event.None;
 
@@ -260,7 +261,18 @@ export class IndexedDBFileSystemProvider extends Disposable implements IFileSyst
 		if (existing?.type === FileType.Directory) {
 			throw ERR_FILE_IS_DIR;
 		}
-		await this.bulkWrite([[resource, content]]);
+
+		let finalContent = content;
+		if (opts.append && existing) {
+			// Read existing content and append new content to it
+			const existingContent = await this.readFile(resource);
+			const combined = new Uint8Array(existingContent.byteLength + content.byteLength);
+			combined.set(existingContent, 0);
+			combined.set(content, existingContent.byteLength);
+			finalContent = combined;
+		}
+
+		await this.bulkWrite([[resource, finalContent]]);
 	}
 
 	async rename(from: URI, to: URI, opts: IFileOverwriteOptions): Promise<void> {

src/vs/platform/files/common/diskFileSystemProviderClient.ts

@@ -13,7 +13,7 @@ import { newWriteableStream, ReadableStreamEventPayload, ReadableStreamEvents }
 import { URI } from '../../../base/common/uri.js';
 import { generateUuid } from '../../../base/common/uuid.js';
 import { IChannel } from '../../../base/parts/ipc/common/ipc.js';
-import { createFileSystemProviderError, IFileAtomicReadOptions, IFileDeleteOptions, IFileOpenOptions, IFileOverwriteOptions, IFileReadStreamOptions, FileSystemProviderCapabilities, FileSystemProviderErrorCode, FileType, IFileWriteOptions, IFileChange, IFileSystemProviderWithFileAtomicReadCapability, IFileSystemProviderWithFileCloneCapability, IFileSystemProviderWithFileFolderCopyCapability, IFileSystemProviderWithFileReadStreamCapability, IFileSystemProviderWithFileReadWriteCapability, IFileSystemProviderWithOpenReadWriteCloseCapability, IStat, IWatchOptions, IFileSystemProviderError } from './files.js';
+import { createFileSystemProviderError, FileSystemProviderCapabilities, FileSystemProviderErrorCode, FileType, IFileAtomicReadOptions, IFileChange, IFileDeleteOptions, IFileOpenOptions, IFileOverwriteOptions, IFileReadStreamOptions, IFileSystemProviderError, IFileSystemProviderWithFileAtomicReadCapability, IFileSystemProviderWithFileCloneCapability, IFileSystemProviderWithFileFolderCopyCapability, IFileSystemProviderWithFileReadStreamCapability, IFileSystemProviderWithFileReadWriteCapability, IFileSystemProviderWithOpenReadWriteCloseCapability, IFileWriteOptions, IStat, IWatchOptions } from './files.js';
 import { reviveFileChanges } from './watcher.js';
 
 export const LOCAL_FILE_SYSTEM_CHANNEL_NAME = 'localFilesystem';
@@ -56,6 +56,7 @@ export class DiskFileSystemProviderClient extends Disposable implements
 				FileSystemProviderCapabilities.FileAtomicRead |
 				FileSystemProviderCapabilities.FileAtomicWrite |
 				FileSystemProviderCapabilities.FileAtomicDelete |
+				FileSystemProviderCapabilities.FileAppend |
 				FileSystemProviderCapabilities.FileClone |
 				FileSystemProviderCapabilities.FileRealpath;
 

src/vs/platform/files/common/fileService.ts

@@ -18,7 +18,7 @@ import { extUri, extUriIgnorePathCase, IExtUri, isAbsolutePath } from '../../../
 import { consumeStream, isReadableBufferedStream, isReadableStream, listenStream, newWriteableStream, peekReadable, peekStream, transform } from '../../../base/common/stream.js';
 import { URI } from '../../../base/common/uri.js';
 import { localize } from '../../../nls.js';
-import { ensureFileSystemProviderError, etag, ETAG_DISABLED, FileChangesEvent, IFileDeleteOptions, FileOperation, FileOperationError, FileOperationEvent, FileOperationResult, FilePermission, FileSystemProviderCapabilities, FileSystemProviderErrorCode, FileType, hasFileAtomicReadCapability, hasFileFolderCopyCapability, hasFileReadStreamCapability, hasOpenReadWriteCloseCapability, hasReadWriteCapability, ICreateFileOptions, IFileContent, IFileService, IFileStat, IFileStatWithMetadata, IFileStreamContent, IFileSystemProvider, IFileSystemProviderActivationEvent, IFileSystemProviderCapabilitiesChangeEvent, IFileSystemProviderRegistrationEvent, IFileSystemProviderWithFileAtomicReadCapability, IFileSystemProviderWithFileReadStreamCapability, IFileSystemProviderWithFileReadWriteCapability, IFileSystemProviderWithOpenReadWriteCloseCapability, IReadFileOptions, IReadFileStreamOptions, IResolveFileOptions, IFileStatResult, IFileStatResultWithMetadata, IResolveMetadataFileOptions, IStat, IFileStatWithPartialMetadata, IWatchOptions, IWriteFileOptions, NotModifiedSinceFileOperationError, toFileOperationResult, toFileSystemProviderErrorCode, hasFileCloneCapability, TooLargeFileOperationError, hasFileAtomicDeleteCapability, hasFileAtomicWriteCapability, IWatchOptionsWithCorrelation, IFileSystemWatcher, IWatchOptionsWithoutCorrelation, hasFileRealpathCapability } from './files.js';
+import { ensureFileSystemProviderError, etag, ETAG_DISABLED, FileChangesEvent, IFileDeleteOptions, FileOperation, FileOperationError, FileOperationEvent, FileOperationResult, FilePermission, FileSystemProviderCapabilities, FileSystemProviderErrorCode, FileType, hasFileAppendCapability, hasFileAtomicReadCapability, hasFileFolderCopyCapability, hasFileReadStreamCapability, hasOpenReadWriteCloseCapability, hasReadWriteCapability, ICreateFileOptions, IFileContent, IFileService, IFileStat, IFileStatWithMetadata, IFileStreamContent, IFileSystemProvider, IFileSystemProviderActivationEvent, IFileSystemProviderCapabilitiesChangeEvent, IFileSystemProviderRegistrationEvent, IFileSystemProviderWithFileAtomicReadCapability, IFileSystemProviderWithFileReadStreamCapability, IFileSystemProviderWithFileReadWriteCapability, IFileSystemProviderWithOpenReadWriteCloseCapability, IReadFileOptions, IReadFileStreamOptions, IResolveFileOptions, IFileStatResult, IFileStatResultWithMetadata, IResolveMetadataFileOptions, IStat, IFileStatWithPartialMetadata, IWatchOptions, IWriteFileOptions, NotModifiedSinceFileOperationError, toFileOperationResult, toFileSystemProviderErrorCode, hasFileCloneCapability, TooLargeFileOperationError, hasFileAtomicDeleteCapability, hasFileAtomicWriteCapability, IWatchOptionsWithCorrelation, IFileSystemWatcher, IWatchOptionsWithoutCorrelation, hasFileRealpathCapability } from './files.js';
 import { readFileIntoStream } from './io.js';
 import { ILogService } from '../../log/common/log.js';
 import { ErrorNoTelemetry } from '../../../base/common/errors.js';
@@ -460,6 +460,11 @@ export class FileService extends Disposable implements IFileService {
 			throw new Error(localize('writeFailedUnlockUnsupported', "Unable to unlock file '{0}' because provider does not support it.", this.resourceForError(resource)));
 		}
 
+		// Validate append support
+		if (options?.append && !hasFileAppendCapability(provider)) {
+			throw new FileOperationError(localize('err.noAppend', "Filesystem provider for scheme '{0}' does not does not support append", this.resourceForError(resource)), FileOperationResult.FILE_PERMISSION_DENIED);
+		}
+
 		// Validate atomic support
 		const atomic = !!options?.atomic;
 		if (atomic) {
@@ -1263,7 +1268,7 @@ export class FileService extends Disposable implements IFileService {
 		return this.writeQueue.queueFor(resource, async () => {
 
 			// open handle
-			const handle = await provider.open(resource, { create: true, unlock: options?.unlock ?? false });
+			const handle = await provider.open(resource, { create: true, unlock: options?.unlock ?? false, append: options?.append ?? false });
 
 			// write into handle until all bytes from buffer have been written
 			try {
@@ -1374,7 +1379,7 @@ export class FileService extends Disposable implements IFileService {
 		}
 
 		// Write through the provider
-		await provider.writeFile(resource, buffer.buffer, { create: true, overwrite: true, unlock: options?.unlock ?? false, atomic: options?.atomic ?? false });
+		await provider.writeFile(resource, buffer.buffer, { create: true, overwrite: true, unlock: options?.unlock ?? false, atomic: options?.atomic ?? false, append: options?.append ?? false });
 	}
 
 	private async doPipeBuffered(sourceProvider: IFileSystemProviderWithOpenReadWriteCloseCapability, source: URI, targetProvider: IFileSystemProviderWithOpenReadWriteCloseCapability, target: URI): Promise<void> {

src/vs/platform/files/common/files.ts

@@ -158,6 +158,7 @@ export interface IFileService {
 
 	/**
 	 * Updates the content replacing its previous value.
+	 * If `options.append` is true, appends content to the end of the file instead.
 	 *
 	 * Emits a `FileOperation.WRITE` file operation event when successful.
 	 */
@@ -381,6 +382,12 @@ export interface IFileWriteOptions extends IFileOverwriteOptions, IFileUnlockOpt
 	 * throw an error otherwise if the file does not exist.
 	 */
 	readonly create: boolean;
+
+	/**
+	 * Set to `true` to append content to the end of the file. Implies `create: true`,
+	 * and set only when the corresponding `FileAppend` capability is defined.
+	 */
+	readonly append?: boolean;
 }
 
 export type IFileOpenOptions = IFileOpenForReadOptions | IFileOpenForWriteOptions;
@@ -403,6 +410,12 @@ export interface IFileOpenForWriteOptions extends IFileUnlockOptions {
 	 * A hint that the file should be opened for reading and writing.
 	 */
 	readonly create: true;
+
+	/**
+	 * Open the file in append mode. This will write data to the
+	 * end of the file.
+	 */
+	readonly append?: boolean;
 }
 
 export interface IFileDeleteOptions {
@@ -654,7 +667,12 @@ export const enum FileSystemProviderCapabilities {
 	/**
 	 * Provider support to resolve real paths.
 	 */
-	FileRealpath = 1 << 18
+	FileRealpath = 1 << 18,
+
+	/**
+	 * Provider support to append to files.
+	 */
+	FileAppend = 1 << 19
 }
 
 export interface IFileSystemProvider {
@@ -696,6 +714,10 @@ export function hasReadWriteCapability(provider: IFileSystemProvider): provider
 	return !!(provider.capabilities & FileSystemProviderCapabilities.FileReadWrite);
 }
 
+export function hasFileAppendCapability(provider: IFileSystemProvider): boolean {
+	return !!(provider.capabilities & FileSystemProviderCapabilities.FileAppend);
+}
+
 export interface IFileSystemProviderWithFileFolderCopyCapability extends IFileSystemProvider {
 	copy(from: URI, to: URI, opts: IFileOverwriteOptions): Promise<void>;
 }
@@ -1387,6 +1409,12 @@ export interface IWriteFileOptions {
 	 * and then renaming it over the target.
 	 */
 	readonly atomic?: IFileAtomicOptions | false;
+
+	/**
+	 * If set to true, will append to the end of the file instead of
+	 * replacing its contents. Will create the file if it doesn't exist.
+	 */
+	readonly append?: boolean;
 }
 
 export interface IResolveFileOptions {

src/vs/platform/files/common/inMemoryFilesystemProvider.ts

@@ -9,7 +9,7 @@ import { Disposable, IDisposable } from '../../../base/common/lifecycle.js';
 import * as resources from '../../../base/common/resources.js';
 import { ReadableStreamEvents, newWriteableStream } from '../../../base/common/stream.js';
 import { URI } from '../../../base/common/uri.js';
-import { FileChangeType, IFileDeleteOptions, IFileOverwriteOptions, FileSystemProviderCapabilities, FileSystemProviderErrorCode, FileType, IFileWriteOptions, IFileChange, IFileSystemProviderWithFileReadWriteCapability, IStat, IWatchOptions, createFileSystemProviderError, IFileSystemProviderWithOpenReadWriteCloseCapability, IFileOpenOptions, IFileSystemProviderWithFileAtomicDeleteCapability, IFileSystemProviderWithFileAtomicReadCapability, IFileSystemProviderWithFileAtomicWriteCapability, IFileSystemProviderWithFileReadStreamCapability } from './files.js';
+import { FileChangeType, IFileDeleteOptions, IFileOverwriteOptions, FileSystemProviderCapabilities, FileSystemProviderErrorCode, FileType, IFileWriteOptions, IFileChange, IFileSystemProviderWithFileReadWriteCapability, IStat, IWatchOptions, createFileSystemProviderError, IFileSystemProviderWithOpenReadWriteCloseCapability, IFileOpenOptions, IFileSystemProviderWithFileAtomicDeleteCapability, IFileSystemProviderWithFileAtomicReadCapability, IFileSystemProviderWithFileAtomicWriteCapability, IFileSystemProviderWithFileReadStreamCapability, isFileOpenForWriteOptions } from './files.js';
 
 class File implements IStat {
 
@@ -61,18 +61,17 @@ export class InMemoryFileSystemProvider extends Disposable implements
 	IFileSystemProviderWithFileAtomicDeleteCapability {
 
 	private memoryFdCounter = 0;
-	private readonly fdMemory = new Map<number, Uint8Array>();
+	private readonly fdMemory = new Map<number, { file: File; resource: URI; append: boolean; write: boolean }>();
 	private _onDidChangeCapabilities = this._register(new Emitter<void>());
 	readonly onDidChangeCapabilities = this._onDidChangeCapabilities.event;
 
-	private _capabilities = FileSystemProviderCapabilities.FileReadWrite | FileSystemProviderCapabilities.PathCaseSensitive;
+	private _capabilities = FileSystemProviderCapabilities.FileReadWrite | FileSystemProviderCapabilities.FileOpenReadWriteClose | FileSystemProviderCapabilities.FileAppend | FileSystemProviderCapabilities.PathCaseSensitive;
 	get capabilities(): FileSystemProviderCapabilities { return this._capabilities; }
 
 	setReadOnly(readonly: boolean) {
 		const isReadonly = !!(this._capabilities & FileSystemProviderCapabilities.Readonly);
 		if (readonly !== isReadonly) {
-			this._capabilities = readonly ? FileSystemProviderCapabilities.Readonly | FileSystemProviderCapabilities.PathCaseSensitive | FileSystemProviderCapabilities.FileReadWrite
-				: FileSystemProviderCapabilities.FileReadWrite | FileSystemProviderCapabilities.PathCaseSensitive;
+			this._capabilities = FileSystemProviderCapabilities.FileReadWrite | FileSystemProviderCapabilities.FileAppend | FileSystemProviderCapabilities.PathCaseSensitive | (readonly ? FileSystemProviderCapabilities.Readonly : 0);
 			this._onDidChangeCapabilities.fire();
 		}
 	}
@@ -130,47 +129,100 @@ export class InMemoryFileSystemProvider extends Disposable implements
 			this._fireSoon({ type: FileChangeType.ADDED, resource });
 		}
 		entry.mtime = Date.now();
-		entry.size = content.byteLength;
-		entry.data = content;
+
+		if (opts.append) {
+			entry.size += content.byteLength;
+			const oldData = entry.data ?? new Uint8Array(0);
+			const newData = new Uint8Array(oldData.byteLength + content.byteLength);
+			newData.set(oldData, 0);
+			newData.set(content, oldData.byteLength);
+			entry.data = newData;
+		} else {
+			entry.size = content.byteLength;
+			entry.data = content;
+		}
 
 		this._fireSoon({ type: FileChangeType.UPDATED, resource });
 	}
 
 	// file open/read/write/close
 	open(resource: URI, opts: IFileOpenOptions): Promise<number> {
-		const data = this._lookupAsFile(resource, false).data;
-		if (data) {
-			const fd = this.memoryFdCounter++;
-			this.fdMemory.set(fd, data);
-			return Promise.resolve(fd);
+		let file = this._lookup(resource, true);
+		const write = isFileOpenForWriteOptions(opts);
+		const append = write && !!opts.append;
+
+		if (!file) {
+			if (!write) {
+				throw createFileSystemProviderError('file not found', FileSystemProviderErrorCode.FileNotFound);
+			}
+			// Create the file if opening for write
+			const basename = resources.basename(resource);
+			const parent = this._lookupParentDirectory(resource);
+			file = new File(basename);
+			file.data = new Uint8Array(0);
+			parent.entries.set(basename, file);
+			this._fireSoon({ type: FileChangeType.ADDED, resource });
+		} else if (file instanceof Directory) {
+			throw createFileSystemProviderError('file is directory', FileSystemProviderErrorCode.FileIsADirectory);
 		}
-		throw createFileSystemProviderError('file not found', FileSystemProviderErrorCode.FileNotFound);
+
+		if (!file.data) {
+			file.data = new Uint8Array(0);
+		}
+
+		const fd = this.memoryFdCounter++;
+		this.fdMemory.set(fd, { file, resource, write, append });
+		return Promise.resolve(fd);
 	}
 
 	close(fd: number): Promise<void> {
+		const fdData = this.fdMemory.get(fd);
+		if (fdData?.write) {
+			// Update file metadata on close
+			fdData.file.mtime = Date.now();
+			fdData.file.size = fdData.file.data?.byteLength ?? 0;
+			this._fireSoon({ type: FileChangeType.UPDATED, resource: fdData.resource });
+		}
 		this.fdMemory.delete(fd);
 		return Promise.resolve();
 	}
 
 	read(fd: number, pos: number, data: Uint8Array, offset: number, length: number): Promise<number> {
-		const memory = this.fdMemory.get(fd);
-		if (!memory) {
+		const fdData = this.fdMemory.get(fd);
+		if (!fdData) {
 			throw createFileSystemProviderError(`No file with that descriptor open`, FileSystemProviderErrorCode.Unavailable);
 		}
 
-		const toWrite = VSBuffer.wrap(memory).slice(pos, pos + length);
+		if (!fdData.file.data) {
+			return Promise.resolve(0);
+		}
+
+		const toWrite = VSBuffer.wrap(fdData.file.data).slice(pos, pos + length);
 		data.set(toWrite.buffer, offset);
 		return Promise.resolve(toWrite.byteLength);
 	}
 
 	write(fd: number, pos: number, data: Uint8Array, offset: number, length: number): Promise<number> {
-		const memory = this.fdMemory.get(fd);
-		if (!memory) {
+		const fdData = this.fdMemory.get(fd);
+		if (!fdData) {
 			throw createFileSystemProviderError(`No file with that descriptor open`, FileSystemProviderErrorCode.Unavailable);
 		}
 
 		const toWrite = VSBuffer.wrap(data).slice(offset, offset + length);
-		memory.set(toWrite.buffer, pos);
+		fdData.file.data ??= new Uint8Array(0);
+
+		// In append mode, always write at the end
+		const writePos = fdData.append ? fdData.file.data.byteLength : pos;
+
+		// Grow the buffer if needed
+		const endPos = writePos + toWrite.byteLength;
+		if (endPos > fdData.file.data.byteLength) {
+			const newData = new Uint8Array(endPos);
+			newData.set(fdData.file.data, 0);
+			fdData.file.data = newData;
+		}
+
+		fdData.file.data.set(toWrite.buffer, writePos);
 		return Promise.resolve(toWrite.byteLength);
 	}