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parallel-library/cps/static/js/untar.js

210 lines
6.0 KiB
JavaScript

/**
* untar.js
*
* Licensed under the MIT License
*
* Copyright(c) 2011 Google Inc.
*
* Reference Documentation:
*
* TAR format: http://www.gnu.org/software/automake/manual/tar/Standard.html
*/
// This file expects to be invoked as a Worker (see onmessage below).
importScripts('bytestream.js');
importScripts('archive.js');
const UnarchiveState = {
NOT_STARTED: 0,
UNARCHIVING: 1,
WAITING: 2,
FINISHED: 3,
};
// State - consider putting these into a class.
let unarchiveState = UnarchiveState.NOT_STARTED;
let bytestream = null;
let allLocalFiles = null;
let logToConsole = false;
// Progress variables.
let currentFilename = "";
let currentFileNumber = 0;
let currentBytesUnarchivedInFile = 0;
let currentBytesUnarchived = 0;
let totalUncompressedBytesInArchive = 0;
let totalFilesInArchive = 0;
// Helper functions.
const info = function(str) {
postMessage(new bitjs.archive.UnarchiveInfoEvent(str));
};
const err = function(str) {
postMessage(new bitjs.archive.UnarchiveErrorEvent(str));
};
// Removes all characters from the first zero-byte in the string onwards.
var readCleanString = function(bstr, numBytes) {
var str = bstr.readString(numBytes);
var zIndex = str.indexOf(String.fromCharCode(0));
return zIndex != -1 ? str.substr(0, zIndex) : str;
};
const postProgress = function() {
postMessage(new bitjs.archive.UnarchiveProgressEvent(
currentFilename,
currentFileNumber,
currentBytesUnarchivedInFile,
currentBytesUnarchived,
totalUncompressedBytesInArchive,
totalFilesInArchive,
bytestream.getNumBytesRead(),
));
};
class TarLocalFile {
// takes a ByteStream and parses out the local file information
constructor(bstream) {
this.isValid = false;
let bytesRead = 0;
// Read in the header block
this.name = readCleanString(bstream, 100);
this.mode = readCleanString(bstream, 8);
this.uid = readCleanString(bstream, 8);
this.gid = readCleanString(bstream, 8);
this.size = parseInt(readCleanString(bstream, 12), 8);
this.mtime = readCleanString(bstream, 12);
this.chksum = readCleanString(bstream, 8);
this.typeflag = readCleanString(bstream, 1);
this.linkname = readCleanString(bstream, 100);
this.maybeMagic = readCleanString(bstream, 6);
if (this.maybeMagic == "ustar") {
this.version = readCleanString(bstream, 2);
this.uname = readCleanString(bstream, 32);
this.gname = readCleanString(bstream, 32);
this.devmajor = readCleanString(bstream, 8);
this.devminor = readCleanString(bstream, 8);
this.prefix = readCleanString(bstream, 155);
if (this.prefix.length) {
this.name = this.prefix + this.name;
}
bstream.readBytes(12); // 512 - 500in
} else {
bstream.readBytes(255); // 512 - 257
}
bytesRead += 512;
// Done header, now rest of blocks are the file contents.
this.filename = this.name;
this.fileData = null;
info("Untarring file '" + this.filename + "'");
info(" size = " + this.size);
info(" typeflag = " + this.typeflag);
// A regular file.
if (this.typeflag == 0) {
info(" This is a regular file.");
const sizeInBytes = parseInt(this.size);
this.fileData = new Uint8Array(bstream.readBytes(sizeInBytes));
bytesRead += sizeInBytes;
if (this.name.length > 0 && this.size > 0 && this.fileData && this.fileData.buffer) {
this.isValid = true;
}
// Round up to 512-byte blocks.
const remaining = 512 - bytesRead % 512;
if (remaining > 0 && remaining < 512) {
bstream.readBytes(remaining);
}
} else if (this.typeflag == 5) {
info(" This is a directory.")
}
}
}
const untar = function() {
let bstream = bytestream.tee();
// While we don't encounter an empty block, keep making TarLocalFiles.
while (bstream.peekNumber(4) != 0) {
const oneLocalFile = new TarLocalFile(bstream);
if (oneLocalFile && oneLocalFile.isValid) {
// If we make it to this point and haven't thrown an error, we have successfully
// read in the data for a local file, so we can update the actual bytestream.
bytestream = bstream.tee();
allLocalFiles.push(oneLocalFile);
totalUncompressedBytesInArchive += oneLocalFile.size;
// update progress
currentFilename = oneLocalFile.filename;
currentFileNumber = totalFilesInArchive++;
currentBytesUnarchivedInFile = oneLocalFile.size;
currentBytesUnarchived += oneLocalFile.size;
postMessage(new bitjs.archive.UnarchiveExtractEvent(oneLocalFile));
postProgress();
}
}
totalFilesInArchive = allLocalFiles.length;
postProgress();
bytestream = bstream.tee();
};
// event.data.file has the first ArrayBuffer.
// event.data.bytes has all subsequent ArrayBuffers.
onmessage = function(event) {
const bytes = event.data.file || event.data.bytes;
logToConsole = !!event.data.logToConsole;
// This is the very first time we have been called. Initialize the bytestream.
if (!bytestream) {
bytestream = new bitjs.io.ByteStream(bytes);
} else {
bytestream.push(bytes);
}
if (unarchiveState === UnarchiveState.NOT_STARTED) {
currentFilename = "";
currentFileNumber = 0;
currentBytesUnarchivedInFile = 0;
currentBytesUnarchived = 0;
totalUncompressedBytesInArchive = 0;
totalFilesInArchive = 0;
allLocalFiles = [];
postMessage(new bitjs.archive.UnarchiveStartEvent());
unarchiveState = UnarchiveState.UNARCHIVING;
postProgress();
}
if (unarchiveState === UnarchiveState.UNARCHIVING ||
unarchiveState === UnarchiveState.WAITING) {
try {
untar();
unarchiveState = UnarchiveState.FINISHED;
postMessage(new bitjs.archive.UnarchiveFinishEvent());
} catch (e) {
if (typeof e === 'string' && e.startsWith('Error! Overflowed')) {
// Overrun the buffer.
unarchiveState = UnarchiveState.WAITING;
} else {
console.error('Found an error while untarring');
console.dir(e);
throw e;
}
}
}
};