121 lines
3.5 KiB
JavaScript
121 lines
3.5 KiB
JavaScript
const Decrypt = require('../Decrypt');
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const PullStream = require('../PullStream');
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const Stream = require('stream');
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const zlib = require('zlib');
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const parseExtraField = require('../parseExtraField');
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const parseDateTime = require('../parseDateTime');
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const parseBuffer = require('../parseBuffer');
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module.exports = function unzip(source, offset, _password, directoryVars, length) {
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const file = PullStream(),
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entry = Stream.PassThrough();
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const req = source.stream(offset, length);
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req.pipe(file).on('error', function(e) {
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entry.emit('error', e);
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});
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entry.vars = file.pull(30)
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.then(function(data) {
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let vars = parseBuffer.parse(data, [
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['signature', 4],
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['versionsNeededToExtract', 2],
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['flags', 2],
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['compressionMethod', 2],
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['lastModifiedTime', 2],
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['lastModifiedDate', 2],
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['crc32', 4],
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['compressedSize', 4],
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['uncompressedSize', 4],
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['fileNameLength', 2],
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['extraFieldLength', 2],
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]);
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vars.lastModifiedDateTime = parseDateTime(vars.lastModifiedDate, vars.lastModifiedTime);
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return file.pull(vars.fileNameLength)
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.then(function(fileName) {
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vars.fileName = fileName.toString('utf8');
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return file.pull(vars.extraFieldLength);
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})
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.then(function(extraField) {
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let checkEncryption;
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vars.extra = parseExtraField(extraField, vars);
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// Ignore logal file header vars if the directory vars are available
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if (directoryVars && directoryVars.compressedSize) vars = directoryVars;
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if (vars.flags & 0x01) checkEncryption = file.pull(12)
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.then(function(header) {
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if (!_password)
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throw new Error('MISSING_PASSWORD');
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const decrypt = Decrypt();
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String(_password).split('').forEach(function(d) {
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decrypt.update(d);
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});
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for (let i=0; i < header.length; i++)
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header[i] = decrypt.decryptByte(header[i]);
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vars.decrypt = decrypt;
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vars.compressedSize -= 12;
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const check = (vars.flags & 0x8) ? (vars.lastModifiedTime >> 8) & 0xff : (vars.crc32 >> 24) & 0xff;
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if (header[11] !== check)
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throw new Error('BAD_PASSWORD');
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return vars;
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});
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return Promise.resolve(checkEncryption)
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.then(function() {
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entry.emit('vars', vars);
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return vars;
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});
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});
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});
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entry.vars.then(function(vars) {
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const fileSizeKnown = !(vars.flags & 0x08) || vars.compressedSize > 0;
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let eof;
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const inflater = vars.compressionMethod ? zlib.createInflateRaw() : Stream.PassThrough();
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if (fileSizeKnown) {
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entry.size = vars.uncompressedSize;
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eof = vars.compressedSize;
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} else {
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eof = Buffer.alloc(4);
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eof.writeUInt32LE(0x08074b50, 0);
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}
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let stream = file.stream(eof);
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if (vars.decrypt)
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stream = stream.pipe(vars.decrypt.stream());
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stream
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.pipe(inflater)
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.on('error', function(err) { entry.emit('error', err);})
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.pipe(entry)
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.on('finish', function() {
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if(req.destroy)
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req.destroy();
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else if (req.abort)
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req.abort();
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else if (req.close)
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req.close();
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else if (req.push)
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req.push();
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else
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console.log('warning - unable to close stream');
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});
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})
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.catch(function(e) {
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entry.emit('error', e);
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});
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return entry;
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};
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