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module.exports = FSStorage
var Storage = require('bittorrent-client').Storage
var inherits = require('inherits')
var extend = require('extend.js')
var os = require('os')
var fs = require('fs')
var path = require('path')
var raf = require('random-access-file')
var mkdirp = require('mkdirp')
var rimraf = require('rimraf')
var thunky = require('thunky')
var TMP = fs.existsSync('/tmp') ? '/tmp' : os.tmpDir()
inherits(FSStorage, Storage)
/**
* fs-backed Storage for a torrent download.
*
* @param {Object} parsedTorrent
* @param {Object} opts
*/
function FSStorage (parsedTorrent, opts) {
var self = this
opts = extend({
nobuffer: true,
tmp: TMP,
name: 'webtorrent'
}, opts || {})
Storage.call(self, parsedTorrent, opts)
if (!opts.path) {
opts.path = path.join(opts.tmp, opts.name, parsedTorrent.infoHash)
}
self.path = opts.path
self.piecesMap = []
self.files.forEach(function (file) {
var fileStart = file.offset
var fileEnd = fileStart + file.length
var firstPiece = file.pieces[0].index
var lastPiece = file.pieces[file.pieces.length - 1].index
var pieceLength = file.pieceLength
var open = thunky(function (cb) {
var filePath = path.join(self.path, file.path)
var fileDir = path.dirname(filePath)
mkdirp(fileDir, function (err) {
if (err) return cb(err)
if (self.closed) return cb(new Error('Storage closed'))
var fd = raf(filePath)
file.fd = fd
cb(null, fd)
})
})
file.pieces.forEach(function (piece) {
var index = piece.index
var pieceStart = index * pieceLength
var pieceEnd = pieceStart + piece.length
var from = (fileStart < pieceStart) ? 0 : fileStart - pieceStart
var to = (fileEnd > pieceEnd) ? pieceLength : fileEnd - pieceStart
var offset = (fileStart > pieceStart) ? 0 : pieceStart - fileStart
if (!self.piecesMap[index]) self.piecesMap[index] = []
self.piecesMap[index].push({
from: from,
to: to,
offset: offset,
open: open
})
})
})
}
FSStorage.prototype.readBlock = function (index, offset, length, cb) {
var self = this
if (!cb) return console.error('FSStorage.readBlock requires a callback')
var piece = self.pieces[index]
if (!piece) return cb(new Error("invalid piece index " + index))
if (piece.verified && piece.buffer) {
// piece is verified and cached in memory, so read directly from its buffer
// instead of reading from the filesystem.
return piece.readBlock(offset, length, cb)
}
var rangeFrom = offset
var rangeTo = rangeFrom + length
var targets = self.piecesMap[index].filter(function (target) {
return (target.to > rangeFrom && target.from < rangeTo)
})
if (!targets.length) return cb(new Error("no file matching the requested range?"))
var buffers = []
var end = targets.length
var i = 0
var readFromNextFile = function(err, buffer) {
if (err) return cb(err)
if (buffer) buffers.push(buffer)
if (i >= end) return cb(null, Buffer.concat(buffers))
var target = targets[i++]
var from = target.from
var to = target.to
var offset = target.offset
if(to > rangeTo) to = rangeTo
if(from < rangeFrom) {
offset += rangeFrom - from
from = rangeFrom
}
target.open(function(err, file) {
if (err) return cb(err)
file.read(offset, to - from, readFromNextFile)
})
}
readFromNextFile()
}
// flush pieces to file once they're done and verified
FSStorage.prototype._onPieceDone = function (piece) {
var self = this
var targets = self.piecesMap[piece.index]
var end = targets.length
var i = 0
var writeToNextFile = function(err) {
if (err) return self.emit('error', err)
if (i >= end) {
return Storage.prototype._onPieceDone.call(self, piece)
}
var target = targets[i++]
target.open(function(err, file) {
if (err) return self.emit('error', err)
file.write(target.offset, piece.buffer.slice(target.from, target.to), writeToNextFile)
})
}
writeToNextFile()
}
/**
* Removes and cleans up any backing store for this storage.
*/
FSStorage.prototype.remove = function (cb) {
var self = this
if (!cb) cb = noop
self.close(function (err) {
if (err) return cb(err)
var root = self.files[0].path.split(path.sep)[0]
rimraf(path.join(self.path, root), cb)
})
}
/**
* Closes the backing store for this storage.
*/
FSStorage.prototype.close = function (cb) {
var self = this
if (!cb) cb = noop
if (self.closed) return cb()
Storage.prototype.close.call(self, function (err) {
if (err) return cb(err)
var i = 0
function loop (err) {
if (i >= self.files.length) return cb()
if (err) return cb(err)
var next = self.files[i++]
if (!next) return process.nextTick(loop)
next.fd.close(loop)
}
process.nextTick(loop)
})
}
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