Minor rewrite to support sources that don't use a shared buffer

Implemented `lazy`

Author: james-pre

src/zip/fs.ts

@@ -1,9 +1,9 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
-import { FileSystem, Inode, Sync, type UsageInfo } from '@zenfs/core';
+import { FileSystem, Inode, type UsageInfo } from '@zenfs/core';
 import type { Backend } from '@zenfs/core/backends/backend.js';
 import { Readonly } from '@zenfs/core/mixins/readonly.js';
 import { parse } from '@zenfs/core/path.js';
-import { S_IFDIR } from '@zenfs/core/vfs/constants.js';
+import { S_IFDIR, S_IFREG } from '@zenfs/core/vfs/constants.js';
 import { withErrno } from 'kerium';
 import { err } from 'kerium/log';
 import { _throw } from 'utilium';
@@ -63,7 +63,7 @@ export interface ZipOptions<TBuffer extends ArrayBufferLike = ArrayBuffer> {
  *   - Stream it out to a location.
  *   This isn't that bad, so we might do this at a later date.
  */
-export class ZipFS<TBuffer extends ArrayBufferLike = ArrayBuffer> extends Readonly(Sync(FileSystem)) {
+export class ZipFS<TBuffer extends ArrayBufferLike = ArrayBuffer> extends Readonly(FileSystem) {
 	protected files: Map<string, FileEntry<TBuffer>> = new Map();
 	protected directories: Map<string, Set<string>> = new Map();
 
@@ -91,8 +91,9 @@ export class ZipFS<TBuffer extends ArrayBufferLike = ArrayBuffer> extends Readon
 		const cdEnd = ptr + this.eocd.size;
 
 		while (ptr < cdEnd) {
-			const entryData = await this.data.get(ptr, FileEntry.size);
-			const cd = new FileEntry<TBuffer>(entryData.buffer, entryData.byteOffset);
+			const cd = await FileEntry.from<TBuffer>(this.data, ptr);
+
+			if (!this.lazy) await cd.loadContents();
 			/* 	Paths must be absolute,
 			yet zip file paths are always relative to the zip root.
 			So we prepend '/' and call it a day. */
@@ -132,7 +133,8 @@ export class ZipFS<TBuffer extends ArrayBufferLike = ArrayBuffer> extends Readon
 
 	public constructor(
 		public label: string,
-		protected data: ZipDataSource<TBuffer>
+		protected data: ZipDataSource<TBuffer>,
+		public readonly lazy: boolean = false
 	) {
 		super(0x207a6970, 'zipfs');
 	}
@@ -144,6 +146,10 @@ export class ZipFS<TBuffer extends ArrayBufferLike = ArrayBuffer> extends Readon
 		};
 	}
 
+	public async stat(path: string): Promise<Inode> {
+		return this.statSync(path);
+	}
+
 	public statSync(path: string): Inode {
 		// The EOCD/Header does not track directories, so it does not exist in `entries`
 		if (this.directories.has(path)) {
@@ -161,27 +167,54 @@ export class ZipFS<TBuffer extends ArrayBufferLike = ArrayBuffer> extends Readon
 
 		if (!entry) throw withErrno('ENOENT');
 
-		return entry.inode;
+		return new Inode({
+			mode: 0o555 | (entry.isDirectory ? S_IFDIR : S_IFREG),
+			size: entry.uncompressedSize,
+			mtimeMs: entry.lastModified.getTime(),
+		});
+	}
+
+	public async readdir(path: string): Promise<string[]> {
+		const inode = await this.stat(path);
+		if (!(inode.mode & S_IFDIR)) throw withErrno('ENOTDIR');
+
+		const entries = this.directories.get(path);
+		if (!entries) throw withErrno('ENODATA');
+
+		return Array.from(entries);
 	}
 
 	public readdirSync(path: string): string[] {
 		const inode = this.statSync(path);
-
 		if (!(inode.mode & S_IFDIR)) throw withErrno('ENOTDIR');
 
 		const entries = this.directories.get(path);
-
 		if (!entries) throw withErrno('ENODATA');
 
 		return Array.from(entries);
 	}
 
+	public async read(path: string, buffer: Uint8Array, offset: number, end: number): Promise<void> {
+		if (this.directories.has(path)) throw withErrno('EISDIR');
+
+		const file = this.files.get(path) ?? _throw(withErrno('ENOENT'));
+
+		if (!file.contents) await file.loadContents();
+
+		buffer.set(file.contents.subarray(offset, end));
+	}
+
 	public readSync(path: string, buffer: Uint8Array, offset: number, end: number): void {
 		if (this.directories.has(path)) throw withErrno('EISDIR');
 
-		const { contents: data } = this.files.get(path) ?? _throw(withErrno('ENOENT'));
+		const file = this.files.get(path) ?? _throw(withErrno('ENOENT'));
+
+		if (!file.contents) {
+			void file.loadContents();
+			throw withErrno('EAGAIN');
+		}
 
-		buffer.set(data.subarray(offset, end));
+		buffer.set(file.contents.subarray(offset, end));
 	}
 }
 
@@ -278,8 +311,8 @@ const _Zip = {
 		return true;
 	},
 
-	create<TBuffer extends ArrayBufferLike = ArrayBuffer>({ name, data }: ZipOptions<TBuffer>): ZipFS<TBuffer> {
-		return new ZipFS<TBuffer>(name ?? '', getSource(data));
+	create<TBuffer extends ArrayBufferLike = ArrayBuffer>(opt: ZipOptions<TBuffer>): ZipFS<TBuffer> {
+		return new ZipFS<TBuffer>(opt.name ?? '', getSource(opt.data), opt.lazy);
 	},
 } satisfies Backend<ZipFS, ZipOptions>;
 type _Zip = typeof _Zip;

src/zip/utils.ts

@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
 import { decodeUTF8 } from 'utilium';
+import type { ZipDataSource } from './fs.js';
 
 /**
  * Converts the input `time` and `date` in MS-DOS format into a `Date`.
@@ -163,12 +164,12 @@ export const extendedASCIIChars = [
  * Safely decodes the string from a buffer.
  * @hidden
  */
-export function safeDecode(buffer: Uint8Array, utf8: boolean, start: number, length: number): string {
+export async function safeDecode(source: ZipDataSource<any>, utf8: boolean, start: number, length: number): Promise<string> {
 	if (length === 0) {
 		return '';
 	}
 
-	const uintArray = buffer.subarray(start, start + length);
+	const uintArray = await source.get(start, length);
 	if (utf8) {
 		return decodeUTF8(uintArray);
 	} else {