modernize index.js
This commit is contained in:
Jimmy Wärting
parent
aa3f1459de
commit
f84070f89a
450
index.js
450
index.js
@ -1,240 +1,240 @@
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var bencode = require('bencode')
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var BitField = require('bitfield')
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var debug = require('debug')('ut_metadata')
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var EventEmitter = require('events').EventEmitter
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var inherits = require('inherits')
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var sha1 = require('simple-sha1')
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const { EventEmitter } = require('events')
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const bencode = require('bencode')
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const BitField = require('bitfield')
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const debug = require('debug')('ut_metadata')
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const sha1 = require('simple-sha1')
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var MAX_METADATA_SIZE = 10000000 // 10MB
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var BITFIELD_GROW = 1000
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var PIECE_LENGTH = 16 * 1024
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const MAX_METADATA_SIZE = 10000000 // 10MB
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const BITFIELD_GROW = 1000
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const PIECE_LENGTH = 16 * 1024
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module.exports = function (metadata) {
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inherits(utMetadata, EventEmitter)
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module.exports = metadata => {
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class utMetadata extends EventEmitter {
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constructor (wire) {
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super()
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function utMetadata (wire) {
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EventEmitter.call(this)
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this._wire = wire
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this._wire = wire
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this._metadataComplete = false
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this._metadataSize = null
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this._remainingRejects = null // how many reject messages to tolerate before quitting
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this._fetching = false
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this._metadataComplete = false
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this._metadataSize = null
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this._remainingRejects = null // how many reject messages to tolerate before quitting
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this._fetching = false
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// The largest .torrent file that I know of is ~1-2MB, which is ~100 pieces.
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// Therefore, cap the bitfield to 10x that (1000 pieces) so a malicious peer can't
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// make it grow to fill all memory.
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this._bitfield = new BitField(0, { grow: BITFIELD_GROW })
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// The largest .torrent file that I know of is ~1-2MB, which is ~100 pieces.
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// Therefore, cap the bitfield to 10x that (1000 pieces) so a malicious peer can't
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// make it grow to fill all memory.
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this._bitfield = new BitField(0, { grow: BITFIELD_GROW })
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if (Buffer.isBuffer(metadata)) {
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this.setMetadata(metadata)
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}
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}
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if (Buffer.isBuffer(metadata)) {
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this.setMetadata(metadata)
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onHandshake (infoHash, peerId, extensions) {
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this._infoHash = infoHash
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}
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onExtendedHandshake (handshake) {
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if (!handshake.m || !handshake.m.ut_metadata) {
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return this.emit('warning', new Error('Peer does not support ut_metadata'))
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}
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if (!handshake.metadata_size) {
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return this.emit('warning', new Error('Peer does not have metadata'))
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}
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if (typeof handshake.metadata_size !== 'number' ||
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MAX_METADATA_SIZE < handshake.metadata_size ||
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handshake.metadata_size <= 0) {
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return this.emit('warning', new Error('Peer gave invalid metadata size'))
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}
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this._metadataSize = handshake.metadata_size
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this._numPieces = Math.ceil(this._metadataSize / PIECE_LENGTH)
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this._remainingRejects = this._numPieces * 2
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if (this._fetching) {
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this._requestPieces()
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}
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}
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onMessage (buf) {
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let dict
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let trailer
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try {
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const str = buf.toString()
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const trailerIndex = str.indexOf('ee') + 2
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dict = bencode.decode(str.substring(0, trailerIndex))
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trailer = buf.slice(trailerIndex)
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} catch (err) {
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// drop invalid messages
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return
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}
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switch (dict.msg_type) {
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case 0:
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// ut_metadata request (from peer)
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// example: { 'msg_type': 0, 'piece': 0 }
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this._onRequest(dict.piece)
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break
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case 1:
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// ut_metadata data (in response to our request)
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// example: { 'msg_type': 1, 'piece': 0, 'total_size': 3425 }
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this._onData(dict.piece, trailer, dict.total_size)
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break
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case 2:
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// ut_metadata reject (peer doesn't have piece we requested)
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// { 'msg_type': 2, 'piece': 0 }
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this._onReject(dict.piece)
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break
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}
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}
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/**
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* Ask the peer to send metadata.
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* @public
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*/
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fetch () {
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if (this._metadataComplete) {
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return
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}
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this._fetching = true
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if (this._metadataSize) {
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this._requestPieces()
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}
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}
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/**
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* Stop asking the peer to send metadata.
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* @public
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*/
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cancel () {
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this._fetching = false
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}
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setMetadata (metadata) {
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if (this._metadataComplete) return true
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debug('set metadata')
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// if full torrent dictionary was passed in, pull out just `info` key
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try {
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const info = bencode.decode(metadata).info
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if (info) {
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metadata = bencode.encode(info)
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}
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} catch (err) {}
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// check hash
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if (this._infoHash && this._infoHash !== sha1.sync(metadata)) {
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return false
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}
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this.cancel()
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this.metadata = metadata
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this._metadataComplete = true
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this._metadataSize = this.metadata.length
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this._wire.extendedHandshake.metadata_size = this._metadataSize
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this.emit('metadata', bencode.encode({ info: bencode.decode(this.metadata) }))
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return true
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}
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_send (dict, trailer) {
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let buf = bencode.encode(dict)
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if (Buffer.isBuffer(trailer)) {
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buf = Buffer.concat([buf, trailer])
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}
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this._wire.extended('ut_metadata', buf)
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}
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_request (piece) {
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this._send({ msg_type: 0, piece })
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}
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_data (piece, buf, totalSize) {
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const msg = { msg_type: 1, piece }
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if (typeof totalSize === 'number') {
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msg.total_size = totalSize
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}
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this._send(msg, buf)
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}
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_reject (piece) {
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this._send({ msg_type: 2, piece })
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}
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_onRequest (piece) {
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if (!this._metadataComplete) {
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this._reject(piece)
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return
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}
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const start = piece * PIECE_LENGTH
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let end = start + PIECE_LENGTH
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if (end > this._metadataSize) {
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end = this._metadataSize
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}
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const buf = this.metadata.slice(start, end)
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this._data(piece, buf, this._metadataSize)
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}
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_onData (piece, buf, totalSize) {
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if (buf.length > PIECE_LENGTH) {
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return
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}
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buf.copy(this.metadata, piece * PIECE_LENGTH)
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this._bitfield.set(piece)
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this._checkDone()
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}
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_onReject (piece) {
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if (this._remainingRejects > 0 && this._fetching) {
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// If we haven't been rejected too much, then try to request the piece again
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this._request(piece)
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this._remainingRejects -= 1
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} else {
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this.emit('warning', new Error('Peer sent "reject" too much'))
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}
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}
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_requestPieces () {
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this.metadata = Buffer.alloc(this._metadataSize)
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for (let piece = 0; piece < this._numPieces; piece++) {
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this._request(piece)
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}
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}
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_checkDone () {
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let done = true
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for (let piece = 0; piece < this._numPieces; piece++) {
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if (!this._bitfield.get(piece)) {
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done = false
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break
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}
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}
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if (!done) return
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// attempt to set metadata -- may fail sha1 check
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const success = this.setMetadata(this.metadata)
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if (!success) {
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this._failedMetadata()
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}
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}
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_failedMetadata () {
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// reset bitfield & try again
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this._bitfield = new BitField(0, { grow: BITFIELD_GROW })
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this._remainingRejects -= this._numPieces
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if (this._remainingRejects > 0) {
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this._requestPieces()
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} else {
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this.emit('warning', new Error('Peer sent invalid metadata'))
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}
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}
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}
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// Name of the bittorrent-protocol extension
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utMetadata.prototype.name = 'ut_metadata'
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utMetadata.prototype.onHandshake = function (infoHash, peerId, extensions) {
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this._infoHash = infoHash
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}
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utMetadata.prototype.onExtendedHandshake = function (handshake) {
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if (!handshake.m || !handshake.m.ut_metadata) {
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return this.emit('warning', new Error('Peer does not support ut_metadata'))
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}
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if (!handshake.metadata_size) {
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return this.emit('warning', new Error('Peer does not have metadata'))
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}
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if (typeof handshake.metadata_size !== 'number' ||
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MAX_METADATA_SIZE < handshake.metadata_size ||
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handshake.metadata_size <= 0) {
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return this.emit('warning', new Error('Peer gave invalid metadata size'))
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}
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this._metadataSize = handshake.metadata_size
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this._numPieces = Math.ceil(this._metadataSize / PIECE_LENGTH)
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this._remainingRejects = this._numPieces * 2
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if (this._fetching) {
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this._requestPieces()
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}
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}
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utMetadata.prototype.onMessage = function (buf) {
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var dict, trailer
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try {
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var str = buf.toString()
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var trailerIndex = str.indexOf('ee') + 2
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dict = bencode.decode(str.substring(0, trailerIndex))
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trailer = buf.slice(trailerIndex)
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} catch (err) {
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// drop invalid messages
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return
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}
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switch (dict.msg_type) {
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case 0:
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// ut_metadata request (from peer)
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// example: { 'msg_type': 0, 'piece': 0 }
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this._onRequest(dict.piece)
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break
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case 1:
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// ut_metadata data (in response to our request)
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// example: { 'msg_type': 1, 'piece': 0, 'total_size': 3425 }
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this._onData(dict.piece, trailer, dict.total_size)
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break
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case 2:
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// ut_metadata reject (peer doesn't have piece we requested)
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// { 'msg_type': 2, 'piece': 0 }
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this._onReject(dict.piece)
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break
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}
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}
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/**
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* Ask the peer to send metadata.
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* @public
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*/
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utMetadata.prototype.fetch = function () {
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if (this._metadataComplete) {
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return
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}
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this._fetching = true
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if (this._metadataSize) {
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this._requestPieces()
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}
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}
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/**
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* Stop asking the peer to send metadata.
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* @public
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*/
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utMetadata.prototype.cancel = function () {
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this._fetching = false
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}
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utMetadata.prototype.setMetadata = function (metadata) {
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if (this._metadataComplete) return true
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debug('set metadata')
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// if full torrent dictionary was passed in, pull out just `info` key
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try {
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var info = bencode.decode(metadata).info
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if (info) {
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metadata = bencode.encode(info)
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}
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} catch (err) {}
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// check hash
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if (this._infoHash && this._infoHash !== sha1.sync(metadata)) {
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return false
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}
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this.cancel()
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this.metadata = metadata
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this._metadataComplete = true
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this._metadataSize = this.metadata.length
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this._wire.extendedHandshake.metadata_size = this._metadataSize
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this.emit('metadata', bencode.encode({ info: bencode.decode(this.metadata) }))
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return true
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}
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utMetadata.prototype._send = function (dict, trailer) {
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var buf = bencode.encode(dict)
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if (Buffer.isBuffer(trailer)) {
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buf = Buffer.concat([buf, trailer])
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}
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this._wire.extended('ut_metadata', buf)
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}
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utMetadata.prototype._request = function (piece) {
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this._send({ msg_type: 0, piece: piece })
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}
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utMetadata.prototype._data = function (piece, buf, totalSize) {
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var msg = { msg_type: 1, piece: piece }
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if (typeof totalSize === 'number') {
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msg.total_size = totalSize
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}
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this._send(msg, buf)
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}
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utMetadata.prototype._reject = function (piece) {
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this._send({ msg_type: 2, piece: piece })
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}
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utMetadata.prototype._onRequest = function (piece) {
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if (!this._metadataComplete) {
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this._reject(piece)
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return
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}
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var start = piece * PIECE_LENGTH
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var end = start + PIECE_LENGTH
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if (end > this._metadataSize) {
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end = this._metadataSize
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}
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var buf = this.metadata.slice(start, end)
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this._data(piece, buf, this._metadataSize)
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}
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utMetadata.prototype._onData = function (piece, buf, totalSize) {
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if (buf.length > PIECE_LENGTH) {
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return
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}
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buf.copy(this.metadata, piece * PIECE_LENGTH)
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this._bitfield.set(piece)
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this._checkDone()
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}
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utMetadata.prototype._onReject = function (piece) {
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if (this._remainingRejects > 0 && this._fetching) {
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// If we haven't been rejected too much, then try to request the piece again
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this._request(piece)
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this._remainingRejects -= 1
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} else {
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this.emit('warning', new Error('Peer sent "reject" too much'))
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}
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}
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utMetadata.prototype._requestPieces = function () {
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this.metadata = Buffer.alloc(this._metadataSize)
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for (var piece = 0; piece < this._numPieces; piece++) {
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this._request(piece)
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}
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}
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utMetadata.prototype._checkDone = function () {
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var done = true
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for (var piece = 0; piece < this._numPieces; piece++) {
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if (!this._bitfield.get(piece)) {
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done = false
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break
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}
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}
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if (!done) return
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// attempt to set metadata -- may fail sha1 check
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var success = this.setMetadata(this.metadata)
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if (!success) {
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this._failedMetadata()
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}
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}
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utMetadata.prototype._failedMetadata = function () {
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// reset bitfield & try again
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this._bitfield = new BitField(0, { grow: BITFIELD_GROW })
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this._remainingRejects -= this._numPieces
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if (this._remainingRejects > 0) {
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this._requestPieces()
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} else {
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this.emit('warning', new Error('Peer sent invalid metadata'))
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}
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}
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return utMetadata
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}
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