Deprecate bittorrent-swarm, inline into webtorrent

bittorrent-swarm and the Torrent object in webtorrent are very coupled.
It doesn't make much sense to publish them separately, as
bittorrent-swarm can't be used independently.

lib/peer.js

@@ -0,0 +1,253 @@
+var debug = require('debug')('webtorrent:peer')
+var Wire = require('bittorrent-protocol')
+
+var WebConn = require('./webconn')
+
+var CONNECT_TIMEOUT = 25000
+var HANDSHAKE_TIMEOUT = 25000
+
+/**
+ * WebRTC peer connections start out connected, because WebRTC peers require an
+ * "introduction" (i.e. WebRTC signaling), and there's no equivalent to an IP address
+ * that lets you refer to a WebRTC endpoint.
+ */
+exports.createWebRTCPeer = function (conn, swarm) {
+  var peer = new Peer(conn.id, 'webrtc')
+  peer.conn = conn
+  peer.swarm = swarm
+
+  if (peer.conn.connected) {
+    peer.onConnect()
+  } else {
+    peer.conn.once('connect', function () { peer.onConnect() })
+    peer.conn.once('error', function (err) { peer.destroy(err) })
+    peer.setConnectTimeout()
+  }
+
+  return peer
+}
+
+/**
+ * Incoming TCP peers start out connected, because the remote peer connected to the
+ * listening port of the TCP server. Until the remote peer sends a handshake, we don't
+ * know what swarm the connection is intended for.
+ */
+exports.createTCPIncomingPeer = function (conn) {
+  var addr = conn.remoteAddress + ':' + conn.remotePort
+  var peer = new Peer(addr, 'tcpIncoming')
+  peer.conn = conn
+  peer.addr = addr
+
+  peer.onConnect()
+
+  return peer
+}
+
+/**
+ * Outgoing TCP peers start out with just an IP address. At some point (when there is an
+ * available connection), the client can attempt to connect to the address.
+ */
+exports.createTCPOutgoingPeer = function (addr, swarm) {
+  var peer = new Peer(addr, 'tcpOutgoing')
+  peer.addr = addr
+  peer.swarm = swarm
+
+  return peer
+}
+
+/**
+ * Peer that represents a Web Seed (BEP17 / BEP19).
+ */
+exports.createWebSeedPeer = function (url, parsedTorrent, swarm) {
+  var peer = new Peer(url, 'webSeed')
+  peer.swarm = swarm
+  peer.conn = new WebConn(url, parsedTorrent)
+
+  peer.onConnect()
+
+  return peer
+}
+
+/**
+ * Peer. Represents a peer in the Swarm.
+ *
+ * @param {string} id "ip:port" string, peer id (for WebRTC peers), or url (for Web Seeds)
+ * @param {string} type the type of the peer
+ */
+function Peer (id, type) {
+  var self = this
+  self.id = id
+  self.type = type
+
+  debug('new Peer %s', id)
+
+  self.addr = null
+  self.conn = null
+  self.swarm = null
+  self.wire = null
+
+  self.connected = false
+  self.destroyed = false
+  self.timeout = null // handshake timeout
+  self.retries = 0 // outgoing TCP connection retry count
+
+  self.sentHandshake = false
+}
+
+/**
+ * Called once the peer is connected (i.e. fired 'connect' event)
+ * @param {Socket} conn
+ */
+Peer.prototype.onConnect = function () {
+  var self = this
+  if (self.destroyed) return
+  self.connected = true
+
+  debug('Peer %s connected', self.id)
+
+  clearTimeout(self.connectTimeout)
+
+  var conn = self.conn
+  conn.once('end', function () {
+    self.destroy()
+  })
+  conn.once('close', function () {
+    self.destroy()
+  })
+  conn.once('finish', function () {
+    self.destroy()
+  })
+  conn.once('error', function (err) {
+    self.destroy(err)
+  })
+
+  var wire = self.wire = new Wire()
+  wire.type = self.type
+  wire.once('end', function () {
+    self.destroy()
+  })
+  wire.once('close', function () {
+    self.destroy()
+  })
+  wire.once('finish', function () {
+    self.destroy()
+  })
+  wire.once('error', function (err) {
+    self.destroy(err)
+  })
+
+  wire.once('handshake', function (infoHash, peerId) {
+    self.onHandshake(infoHash, peerId)
+  })
+  self.setHandshakeTimeout()
+
+  conn.pipe(wire).pipe(conn)
+  if (self.swarm && !self.sentHandshake) self.handshake()
+}
+
+/**
+ * Called when handshake is received from remote peer.
+ * @param {string} infoHash
+ * @param {string} peerId
+ */
+Peer.prototype.onHandshake = function (infoHash, peerId) {
+  var self = this
+  if (!self.swarm) return // `self.swarm` not set yet, so do nothing
+
+  if (self.swarm.destroyed) return self.destroy(new Error('swarm already destroyed'))
+  if (infoHash !== self.swarm.infoHash) {
+    return self.destroy(new Error('unexpected handshake info hash for this swarm'))
+  }
+  if (peerId === self.swarm.peerId) {
+    return self.destroy(new Error('refusing to handshake with self'))
+  }
+
+  debug('Peer %s got handshake %s', self.id, infoHash)
+
+  clearTimeout(self.handshakeTimeout)
+
+  self.retries = 0
+
+  self.wire.on('download', function (downloaded) {
+    if (self.destroyed) return
+    self.swarm.downloaded += downloaded
+    self.swarm.downloadSpeed(downloaded)
+    self.swarm.emit('download', downloaded)
+  })
+
+  self.wire.on('upload', function (uploaded) {
+    if (self.destroyed) return
+    self.swarm.uploaded += uploaded
+    self.swarm.uploadSpeed(uploaded)
+    self.swarm.emit('upload', uploaded)
+  })
+
+  self.swarm.wires.push(self.wire)
+
+  var addr = self.addr
+  if (!addr && self.conn.remoteAddress) {
+    addr = self.conn.remoteAddress + ':' + self.conn.remotePort
+  }
+  self.swarm.emit('wire', self.wire, addr)
+  // swarm could be destroyed in user's 'wire' event handler
+  if (!self.swarm || self.swarm.destroyed) return
+
+  if (!self.sentHandshake) self.handshake()
+}
+
+Peer.prototype.handshake = function () {
+  var self = this
+  self.wire.handshake(self.swarm.infoHash, self.swarm.peerId, self.swarm.handshakeOpts)
+  self.sentHandshake = true
+}
+
+Peer.prototype.setConnectTimeout = function () {
+  var self = this
+  clearTimeout(self.connectTimeout)
+  self.connectTimeout = setTimeout(function () {
+    self.destroy(new Error('connect timeout'))
+  }, CONNECT_TIMEOUT)
+  if (self.connectTimeout.unref) self.connectTimeout.unref()
+}
+
+Peer.prototype.setHandshakeTimeout = function () {
+  var self = this
+  clearTimeout(self.handshakeTimeout)
+  self.handshakeTimeout = setTimeout(function () {
+    self.destroy(new Error('handshake timeout'))
+  }, HANDSHAKE_TIMEOUT)
+  if (self.handshakeTimeout.unref) self.handshakeTimeout.unref()
+}
+
+Peer.prototype.destroy = function (err) {
+  var self = this
+  if (self.destroyed) return
+  self.destroyed = true
+  self.connected = false
+
+  debug('destroy %s (error: %s)', self.id, err && (err.message || err))
+
+  clearTimeout(self.connectTimeout)
+  clearTimeout(self.handshakeTimeout)
+
+  var swarm = self.swarm
+  var conn = self.conn
+  var wire = self.wire
+
+  self.conn = null
+  self.swarm = null
+  self.wire = null
+
+  if (swarm && wire) {
+    var index = swarm.wires.indexOf(wire)
+    if (index >= 0) swarm.wires.splice(index, 1)
+  }
+  if (conn) {
+    conn.on('error', noop)
+    conn.destroy()
+  }
+  if (wire) wire.destroy()
+  if (swarm) swarm.removePeer(self.id)
+}
+
+function noop () {}