Start on issue #29: Add a Zipper that can take multiple files and produce a zip file as an array of bytes (storage only, no compression)

2025-10-04 01:59:15 +02:00 · 2021-12-12 23:39:09 -08:00 · 2021-12-12 23:39:09 -08:00 · c0afe7637e
commit c0afe7637e
parent 7389b71cf9
5 changed files with 447 additions and 2 deletions
--- a/archive/compress.js
+++ b/archive/compress.js
@ -0,0 +1,130 @@
+
+import { ByteBuffer } from '../io/bytebuffer.js';
+
+// NOTE: THIS IS A VERY HACKY WORK-IN-PROGRESS! THE API IS NOT FROZEN! USE AT YOUR OWN RISK!
+
+/**
+ * @typedef FileInfo An object that is sent to the worker to represent a file to zip.
+ * @property {string} fileName The name of the file. TODO: Includes the path?
+ * @property {number} lastModTime The number of ms since the Unix epoch (1970-01-01 at midnight).
+ * @property {ArrayBuffer} fileData The bytes of the file.
+ */
+
+/**
+ * @typedef CompressorOptions
+ * @property {string} pathToBitJS A string indicating where the BitJS files are located.
+ */
+
+/**
+ * @readonly
+ * @enum {string}
+ */
+export const CompressStatus = {
+  NOT_STARTED: 'not_started',
+  READY: 'ready',
+  WORKING: 'working',
+  COMPLETE: 'complete',
+  ERROR: 'error',
+};
+
+/**
+ * A thing that zips files.
+ * NOTE: THIS IS A VERY HACKY WORK-IN-PROGRESS! THE API IS NOT FROZEN! USE AT YOUR OWN RISK!
+ */
+export class Zipper {
+  /**
+   * @param {CompressorOptions} options
+   */
+  constructor(options) {
+    /**
+     * The path to the BitJS files.
+     * @type {string}
+     * @private
+     */
+    this.pathToBitJS = options.pathToBitJS || '/';
+
+    /**
+     * Private web worker initialized during start().
+     * @type {Worker}
+     * @private
+     */
+    this.worker_ = null;
+
+    /**
+     * @type {CompressStatus}
+     * @private
+     */
+    this.compressState = CompressStatus.NOT_STARTED;
+
+    /**
+     * @type {Uint8Array}
+     * @private
+     */
+    this.byteArray = new Uint8Array(0);
+  }
+
+  /**
+   * Must only be called on a Zipper that has been started. See start().
+   * @param {FileInfo[]} files 
+   * @param {boolean} isLastFile 
+   */
+  appendFiles(files, isLastFile) {
+    if (!this.worker_) {
+      throw `Worker not initialized. Did you forget to call start() ?`;
+    }
+    if (![CompressStatus.READY, CompressStatus.WORKING].includes(this.compressState)) {
+      throw `Zipper not in the right state: ${this.compressState}`;
+    }
+
+    this.worker_.postMessage({ files, isLastFile });
+  }
+
+  /**
+   * @param {FileInfo[]} files
+   * @param {boolean} isLastFile
+   * @returns {Promise<Uint8Array>} A Promise that contains the entire zipped archive.
+   */
+  start(files, isLastFile) {
+    return new Promise((resolve, reject) => {
+      this.worker_ = new Worker(this.pathToBitJS + `archive/zip.js`);
+      this.worker_.onerror = (evt) => {
+        console.log('Worker error: message = ' + evt.message);
+        throw evt.message;
+      };
+      this.worker_.onmessage = (evt) => {
+        if (typeof evt.data == 'string') {
+          // Just log any strings the worker pumps our way.
+          console.log(evt.data);
+        } else {
+          switch (evt.data.type) {
+            case 'start':
+              this.compressState = CompressStatus.WORKING;
+              break;
+            case 'finish':
+              this.compressState = CompressStatus.COMPLETE;
+              resolve(this.byteArray);
+              break;
+            case 'compress':
+              this.addBytes_(evt.data.bytes);
+              break;
+          }
+        }
+      };
+
+      this.compressState = CompressStatus.READY;
+      this.appendFiles(files, isLastFile);
+    });
+  }
+
+  /**
+   * Updates the internal byte array with new bytes (by allocating a new array and copying).
+   * @param {Uint8Array} newBytes
+   * @private
+   */
+  addBytes_(newBytes) {
+    const oldArray = this.byteArray;
+    this.byteArray = new Uint8Array(oldArray.byteLength + newBytes.byteLength);
+    this.byteArray.set(oldArray);
+    this.byteArray.set(newBytes, oldArray.byteLength);
+  }
+}