2019-09-21 16:11:55 +02:00

125 lines
3.7 KiB
JavaScript

var Promise = require('bluebird');
var Decrypt = require('../Decrypt');
var PullStream = require('../PullStream');
var Stream = require('stream');
var binary = require('binary');
var zlib = require('zlib');
var parseExtraField = require('../parseExtraField');
var Buffer = require('../Buffer');
var parseDateTime = require('../parseDateTime');
// Backwards compatibility for node versions < 8
if (!Stream.Writable || !Stream.Writable.prototype.destroy)
Stream = require('readable-stream');
module.exports = function unzip(source,offset,_password, directoryVars) {
var file = PullStream(),
entry = Stream.PassThrough();
var req = source.stream(offset);
req.pipe(file).on('error', function(e) {
entry.emit('error', e);
});
entry.vars = file.pull(30)
.then(function(data) {
var vars = binary.parse(data)
.word32lu('signature')
.word16lu('versionsNeededToExtract')
.word16lu('flags')
.word16lu('compressionMethod')
.word16lu('lastModifiedTime')
.word16lu('lastModifiedDate')
.word32lu('crc32')
.word32lu('compressedSize')
.word32lu('uncompressedSize')
.word16lu('fileNameLength')
.word16lu('extraFieldLength')
.vars;
vars.lastModifiedDateTime = parseDateTime(vars.lastModifiedDate, vars.lastModifiedTime);
return file.pull(vars.fileNameLength)
.then(function(fileName) {
vars.fileName = fileName.toString('utf8');
return file.pull(vars.extraFieldLength);
})
.then(function(extraField) {
var checkEncryption;
vars.extra = parseExtraField(extraField, vars);
// Ignore logal file header vars if the directory vars are available
if (directoryVars && directoryVars.compressedSize) vars = directoryVars;
if (vars.flags & 0x01) checkEncryption = file.pull(12)
.then(function(header) {
if (!_password)
throw new Error('MISSING_PASSWORD');
var decrypt = Decrypt();
String(_password).split('').forEach(function(d) {
decrypt.update(d);
});
for (var i=0; i < header.length; i++)
header[i] = decrypt.decryptByte(header[i]);
vars.decrypt = decrypt;
vars.compressedSize -= 12;
var check = (vars.flags & 0x8) ? (vars.lastModifiedTime >> 8) & 0xff : (vars.crc32 >> 24) & 0xff;
if (header[11] !== check)
throw new Error('BAD_PASSWORD');
return vars;
});
return Promise.resolve(checkEncryption)
.then(function() {
entry.emit('vars',vars);
return vars;
});
});
});
entry.vars.then(function(vars) {
var fileSizeKnown = !(vars.flags & 0x08) || vars.compressedSize > 0,
eof;
var inflater = vars.compressionMethod ? zlib.createInflateRaw() : Stream.PassThrough();
if (fileSizeKnown) {
entry.size = vars.uncompressedSize;
eof = vars.compressedSize;
} else {
eof = Buffer.alloc(4);
eof.writeUInt32LE(0x08074b50, 0);
}
var stream = file.stream(eof);
if (vars.decrypt)
stream = stream.pipe(vars.decrypt.stream());
stream
.pipe(inflater)
.on('error',function(err) { entry.emit('error',err);})
.pipe(entry)
.on('finish', function() {
if (req.abort)
req.abort();
else if (req.close)
req.close();
else if (req.push)
req.push();
else
console.log('warning - unable to close stream');
});
})
.catch(function(e) {
entry.emit('error',e);
});
return entry;
};