playcanvas/build/playcanvas/src/framework/handlers/untar.js

PlayCanvas WebGL game engine

import { EventHandler } from '../../core/event-handler.js';

class Untar extends EventHandler {
		constructor(fetchPromise, assetsPrefix = ''){
				super(), this.headerSize = 512, this.paddingSize = 512, this.bytesRead = 0, this.bytesReceived = 0, this.headerRead = false, this.reader = null, this.data = new Uint8Array(0), this.decoder = null, this.prefix = '', this.fileName = '', this.fileSize = 0, this.fileType = '', this.ustarFormat = '';
				this.prefix = assetsPrefix || '';
				this.reader = fetchPromise.body.getReader();
				this.reader.read().then((res)=>{
						this.pump(res.done, res.value);
				}).catch((err)=>{
						this.fire('error', err);
				});
		}
		pump(done, value) {
				if (done) {
						this.fire('done');
						return null;
				}
				this.bytesReceived += value.byteLength;
				const data = new Uint8Array(this.data.length + value.length);
				data.set(this.data);
				data.set(value, this.data.length);
				this.data = data;
				while(this.readFile());
				return this.reader.read().then((res)=>{
						this.pump(res.done, res.value);
				}).catch((err)=>{
						this.fire('error', err);
				});
		}
		readFile() {
				if (!this.headerRead && this.bytesReceived > this.bytesRead + this.headerSize) {
						this.headerRead = true;
						const view = new DataView(this.data.buffer, this.bytesRead, this.headerSize);
						this.decoder ??= new TextDecoder('windows-1252');
						const headers = this.decoder.decode(view);
						this.fileName = headers.substring(0, 100).replace(/\0/g, '');
						this.fileSize = parseInt(headers.substring(124, 136), 8);
						this.fileType = headers.substring(156, 157);
						this.ustarFormat = headers.substring(257, 263);
						if (this.ustarFormat.indexOf('ustar') !== -1) {
								const prefix = headers.substring(345, 500).replace(/\0/g, '');
								if (prefix.length > 0) {
										this.fileName = prefix.trim() + this.fileName.trim();
								}
						}
						this.bytesRead += 512;
				}
				if (this.headerRead) {
						if (this.bytesReceived < this.bytesRead + this.fileSize) {
								return false;
						}
						if (this.fileType === '' || this.fileType === '0') {
								const dataView = new DataView(this.data.buffer, this.bytesRead, this.fileSize);
								const file = {
										name: this.prefix + this.fileName,
										size: this.fileSize,
										data: dataView
								};
								this.fire('file', file);
						}
						this.bytesRead += this.fileSize;
						this.headerRead = false;
						const bytesRemained = this.bytesRead % this.paddingSize;
						if (bytesRemained !== 0) {
								this.bytesRead += this.paddingSize - bytesRemained;
						}
						return true;
				}
				return false;
		}
}

export { Untar };