yetangitu/bitjs
1
0
Fork 0
mirror of https://github.com/codedread/bitjs synced 2025-10-05 18:34:17 +02:00
Code Issues Releases Wiki Activity

For issue #44, make the Zipper use MessageChannel and not have a hard dependency on Worker

Browse source
This commit is contained in:
Jeff Schiller 2023-12-13 12:40:45 -08:00
parent eeb228a52b
commit 48766d0136
5 changed files with 116 additions and 81 deletions
Download patch file Download diff file Expand all files Collapse all files

78
archive/zip.js
View file

@ -11,37 +11,42 @@
* DEFLATE format: http://tools.ietf.org/html/rfc1951
*/
// This file expects to be invoked as a Worker (see onmessage below).
import { ByteBuffer } from '../io/bytebuffer.js';
/**
* The client sends messages to this Worker containing files to archive in order. The client
* indicates to the Worker when the last file has been sent to be compressed.
*
* The Worker emits an event to indicate compression has started: { type: 'start' }
* As the files compress, bytes are sent back in order: { type: 'compress', bytes: Uint8Array }
* After the last file compresses, the Worker indicates finish by: { type 'finish' }
*
* Clients should append the bytes to a single buffer in the order they were received.
*/
/** @type {MessagePort} */
let hostPort;
/**
* @typedef FileInfo An object that is sent to this worker by the client to represent a file.
* The client sends a set of CompressFilesMessage to the MessagePort containing files to archive in
* order. The client sets isLastFile to true to indicate to the implementation when the last file
* has been sent to be compressed.
*
* The impl posts an event to the port indicating compression has started: { type: 'start' }.
* As each file compresses, bytes are sent back in order: { type: 'compress', bytes: Uint8Array }.
* After the last file compresses, we indicate finish by: { type 'finish' }
*
* The client should append the bytes to a single buffer in the order they were received.
*/
// TODO(bitjs): De-dupe this typedef and the one in compress.js.
/**
* @typedef FileInfo An object that is sent by the client to represent a file.
* @property {string} fileName The name of this file. TODO: Includes the path?
* @property {number} lastModTime The number of ms since the Unix epoch (1970-01-01 at midnight).
* @property {Uint8Array} fileData The raw bytes of the file.
*/
// TODO(bitjs): Figure out where this typedef should live.
/**
* @typedef CompressFilesMessage A message the client sends to the implementation.
* @property {FileInfo[]} files A set of files to add to the zip file.
* @property {boolean} isLastFile Indicates this is the last set of files to add to the zip file.
*/
// TODO: Support DEFLATE.
// TODO: Support options that can let client choose levels of compression/performance.
/**
* Ideally these constants should be defined in a common isomorphic ES module. Unfortunately, the
* state of JavaScript is such that modules cannot be shared easily across browsers, worker threads,
* NodeJS environments, etc yet. Thus, these constants, as well as logic that should be extracted to
* common modules and shared with unzip.js are not yet easily possible.
*/
// TODO(bitjs): These constants should be defined in a common isomorphic ES module.
const zLocalFileHeaderSignature = 0x04034b50;
const zCentralFileHeaderSignature = 0x02014b50;
const zEndOfCentralDirSignature = 0x06054b50;
@ -231,39 +236,52 @@ function writeCentralFileDirectory() {
}
/**
* @param {{data: {isLastFile?: boolean, files: FileInfo[]}}} evt The event for the Worker
* to process. It is an error to send any more events to the Worker if a previous event had
* isLastFile is set to true.
* @param {{data: CompressFilesMessage}} evt The event for the implementation to process. It is an
* error to send any more events after a previous event had isLastFile is set to true.
*/
onmessage = function(evt) {
const onmessage = function(evt) {
if (state === CompressorState.FINISHED) {
throw `The zip worker was sent a message after last file received.`;
throw `The zip implementation was sent a message after last file received.`;
}
if (state === CompressorState.NOT_STARTED) {
postMessage({ type: 'start' });
hostPort.postMessage({ type: 'start' });
}
state = CompressorState.COMPRESSING;
/** @type {FileInfo[]} */
const filesToCompress = evt.data.files;
const msg = evt.data;
const filesToCompress = msg.files;
while (filesToCompress.length > 0) {
const fileInfo = filesToCompress.shift();
const fileBuffer = zipOneFile(fileInfo);
filesCompressed.push(fileInfo);
numBytesWritten += fileBuffer.data.byteLength;
this.postMessage({ type: 'compress', bytes: fileBuffer.data }, [ fileBuffer.data.buffer ]);
hostPort.postMessage({ type: 'compress', bytes: fileBuffer.data }, [ fileBuffer.data.buffer ]);
}
if (evt.data.isLastFile) {
const centralBuffer = writeCentralFileDirectory();
numBytesWritten += centralBuffer.data.byteLength;
this.postMessage({ type: 'compress', bytes: centralBuffer.data }, [ centralBuffer.data.buffer ]);
hostPort.postMessage({ type: 'compress', bytes: centralBuffer.data },
[ centralBuffer.data.buffer ]);
state = CompressorState.FINISHED;
this.postMessage({ type: 'finish' });
hostPort.postMessage({ type: 'finish' });
} else {
state = CompressorState.WAITING;
}
};
/**
* Connect the host to the zip implementation with the given MessagePort.
* @param {MessagePort} port
*/
export function connect(port) {
if (hostPort) {
throw `hostPort already connected`;
}
hostPort = port;
port.onmessage = onmessage;
}