refractor torrent to make it easier to add new sources

moved the storage creation into a module ‘torrent-manager’ this will
allow for further source to be added easily.

index.js

@@ -18,7 +18,7 @@ var parseTorrent = require('parse-torrent')
 var speedometer = require('speedometer')
 var Storage = require('./lib/storage')
 var stream = require('stream')
-var Torrent = require('./lib/torrent')
+var Torrent = require('./lib/torrent-manager')
 
 inherits(WebTorrent, EventEmitter)
 

lib/torrent-manager.js

@@ -0,0 +1,114 @@
+module.exports = torrentManager 
+
+var debug = require('debug')('webtorrent:torrentmanager')
+var EventEmitter = require('events').EventEmitter
+var inherits = require('inherits')
+var parseTorrent = require('parse-torrent')
+var Torrent = require('./torrent')
+var Storage = require('./storage')
+var Server = require('./server') // browser exclude
+
+inherits(torrentManager, EventEmitter)
+
+ function torrentManager(torrentId, opts) {
+  var self = this
+ self._storageImpl = opts.storage || Storage
+
+  var parsedTorrent = parseTorrent(torrentId)
+  if (parsedTorrent && parsedTorrent.infoHash) {
+    onTorrentId(parsedTorrent)
+
+  } else if (typeof hh.get === 'function' && /^https?:/.test(torrentId)) {
+    // http or https url to torrent file
+    httpGet(torrentId, function (err, torrent) {
+      if (err)
+        return self.emit('error', new Error('error downloading torrent: ' + err.message))
+      onTorrentId(torrent)
+    })
+
+  } else if (typeof fs.readFile === 'function') {
+    // assume it's a filesystem path
+    fs.readFile(torrentId, function (err, torrent) {
+      if (err) return self.emit('error', new Error('invalid torrent id'))
+      onTorrentId(torrent)
+    })
+
+  } else throw new Error('invalid torrent id')
+
+
+  function onTorrentId (torrentId) {
+    parsedTorrent = parseTorrent(torrentId)
+    self.infoHash = parsedTorrent.infoHash
+    debug(self.infoHash);
+    if (parsedTorrent.name) self.name = parsedTorrent.name // preliminary name
+    self.torrent = new Torrent(self, parsedTorrent, opts);
+    if (parsedTorrent.info) self.onMetadata(parsedTorrent)
+  }
+}
+
+torrentManager.prototype.createServer = function (opts) {
+  var self = this
+  if (typeof Server === 'function' /* browser exclude */) {
+    return new Server(self.torrent, opts)
+  }
+}
+
+/**
+ * Called when the metadata is received.
+ */
+torrentManager.prototype.onMetadata = function (metadata) {
+  var self = this
+  if (self.metadata || self._destroyed) return
+  debug('got metadata')
+
+  if (metadata && metadata.infoHash) {
+    // `metadata` is a parsed torrent (from parse-torrent module)
+    self.metadata = parseTorrent.toBuffer(metadata)
+    self.parsedTorrent = metadata
+  } else {
+    self.metadata = metadata
+    try {
+      self.parsedTorrent = parseTorrent(self.metadata)
+    } catch (err) {
+      return self.emit('error', err)
+    }
+  }
+
+  self.storage = new self._storageImpl(self.parsedTorrent, self.storageOpts)
+  if (self.verify) {
+    process.nextTick(function () {
+      debug('verifying existing torrent data')
+      var numPieces = 0
+      var numVerified = 0
+
+      // TODO: move storage verification to storage.js?
+      parallel(self.storage.pieces.map(function (piece) {
+        return function (cb) {
+          self.storage.read(piece.index, function (err, buffer) {
+            numPieces += 1
+            self.emit('verifying', {
+              percentDone: 100 * numPieces / self.storage.pieces.length,
+              percentVerified: 100 * numVerified / self.storage.pieces.length,
+            })
+
+            if (!err && buffer) {
+              // TODO: this is a bit hacky; figure out a cleaner way of verifying the buffer
+              piece.verify(buffer)
+              numVerified += piece.verified
+              debug('piece ' + (piece.verified ? 'verified' : 'invalid') + ' ' + piece.index)
+            }
+            // continue regardless of whether piece verification failed
+            cb()
+          }, true) // forces override to allow reading from non-verified pieces
+        }
+      }), function() { self.torrent.attachStorage(self.storage) })
+    })
+  } else {
+    process.nextTick(function() { self.torrent.attachStorage(self.storage) })
+  }
+
+  process.nextTick(function () {
+    self.torrent.updateMetadata(self.parsedTorrent)
+    self.emit('metadata')
+  })
+}