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For issue #40, support DEFLATE compression in Zipper where the runtime supports it via CompressionStream.

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This commit is contained in:
Jeff Schiller 2024-01-25 01:17:35 -08:00
parent c07aa83e12
commit 6c19e3a908
4 changed files with 88 additions and 18 deletions
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47
archive/zip.js
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@ -13,7 +13,7 @@
import { ByteBuffer } from '../io/bytebuffer.js';
import { CENTRAL_FILE_HEADER_SIG, CRC32_MAGIC_NUMBER, END_OF_CENTRAL_DIR_SIG,
LOCAL_FILE_HEADER_SIG } from './common.js';
LOCAL_FILE_HEADER_SIG, ZipCompressionMethod } from './common.js';
/** @typedef {import('./common.js').FileInfo} FileInfo */
@ -37,9 +37,10 @@ let hostPort;
* @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.
* @property {ZipCompressionMethod=} compressionMethod The compression method to use. Ignored except
* for the first message sent.
*/
// TODO: Support DEFLATE.
// TODO: Support options that can let client choose levels of compression/performance.
/**
@ -54,6 +55,9 @@ let hostPort;
* @property {number} byteOffset (4 bytes)
*/
/** @type {ZipCompressionMethod} */
let compressionMethod = ZipCompressionMethod.STORE;
/** @type {FileInfo[]} */
let filesCompressed = [];
@ -138,30 +142,39 @@ function dateToDosTime(jsDate) {
/**
* @param {FileInfo} file
* @returns {ByteBuffer}
* @returns {Promise<ByteBuffer>}
*/
function zipOneFile(file) {
async function zipOneFile(file) {
/** @type {Uint8Array} */
let compressedBytes;
if (compressionMethod === ZipCompressionMethod.STORE) {
compressedBytes = file.fileData;
} else if (compressionMethod === ZipCompressionMethod.DEFLATE) {
const blob = new Blob([file.fileData.buffer]);
const compressedStream = blob.stream().pipeThrough(new CompressionStream('deflate-raw'));
compressedBytes = new Uint8Array(await new Response(compressedStream).arrayBuffer());
}
// Zip Local File Header has 30 bytes and then the filename and extrafields.
const fileHeaderSize = 30 + file.fileName.length;
/** @type {ByteBuffer} */
const buffer = new ByteBuffer(fileHeaderSize + file.fileData.byteLength);
const buffer = new ByteBuffer(fileHeaderSize + compressedBytes.byteLength);
buffer.writeNumber(LOCAL_FILE_HEADER_SIG, 4); // Magic number.
buffer.writeNumber(0x0A, 2); // Version.
buffer.writeNumber(0, 2); // General Purpose Flags.
buffer.writeNumber(0, 2); // Compression Method. 0 = Store only.
buffer.writeNumber(compressionMethod, 2); // Compression Method.
const jsDate = new Date(file.lastModTime);
/** @type {CentralDirectoryFileHeaderInfo} */
const centralDirectoryInfo = {
compressionMethod: 0,
compressionMethod,
lastModFileTime: dateToDosTime(jsDate),
lastModFileDate: dateToDosDate(jsDate),
crc32: calculateCRC32(0, file.fileData),
// TODO: For now, this is easy. Later when we do DEFLATE, we will have to calculate.
compressedSize: file.fileData.byteLength,
compressedSize: compressedBytes.byteLength,
uncompressedSize: file.fileData.byteLength,
fileName: file.fileName,
byteOffset: numBytesWritten,
@ -176,7 +189,7 @@ function zipOneFile(file) {
buffer.writeNumber(centralDirectoryInfo.fileName.length, 2); // Filename length.
buffer.writeNumber(0, 2); // Extra field length.
buffer.writeASCIIString(centralDirectoryInfo.fileName); // Filename. Assumes ASCII.
buffer.insertBytes(file.fileData); // File data.
buffer.insertBytes(compressedBytes);
return buffer;
}
@ -195,7 +208,7 @@ function writeCentralFileDirectory() {
buffer.writeNumber(0, 2); // Version made by. // 0x31e
buffer.writeNumber(0, 2); // Version needed to extract (minimum). // 0x14
buffer.writeNumber(0, 2); // General purpose bit flag
buffer.writeNumber(0, 2); // Compression method.
buffer.writeNumber(compressionMethod, 2); // Compression method.
buffer.writeNumber(cdInfo.lastModFileTime, 2); // Last Mod File Time.
buffer.writeNumber(cdInfo.lastModFileDate, 2); // Last Mod Date.
buffer.writeNumber(cdInfo.crc32, 4); // crc32.
@ -228,7 +241,7 @@ function writeCentralFileDirectory() {
* @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.
*/
const onmessage = function(evt) {
const onmessage = async function(evt) {
if (state === CompressorState.FINISHED) {
throw `The zip implementation was sent a message after last file received.`;
}
@ -239,11 +252,19 @@ const onmessage = function(evt) {
state = CompressorState.COMPRESSING;
if (filesCompressed.length === 0 && evt.data.compressionMethod !== undefined) {
if (!Object.values(ZipCompressionMethod).includes(evt.data.compressionMethod)) {
throw `Do not support compression method ${evt.data.compressionMethod}`;
}
compressionMethod = evt.data.compressionMethod;
}
const msg = evt.data;
const filesToCompress = msg.files;
while (filesToCompress.length > 0) {
const fileInfo = filesToCompress.shift();
const fileBuffer = zipOneFile(fileInfo);
const fileBuffer = await zipOneFile(fileInfo);
filesCompressed.push(fileInfo);
numBytesWritten += fileBuffer.data.byteLength;
hostPort.postMessage({ type: 'compress', bytes: fileBuffer.data }, [ fileBuffer.data.buffer ]);