file-writer.js
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module.exports = FileWriter
var fs = require('graceful-fs')
var Writer = require('./writer.js')
var inherits = require('inherits')
var EOF = {}
inherits(FileWriter, Writer)
function FileWriter (props) {
var self = this
if (!(self instanceof FileWriter)) {
throw new Error('FileWriter must be called as constructor.')
}
// should already be established as a File type
if (props.type !== 'File' || !props.File) {
throw new Error('Non-file type ' + props.type)
}
self._buffer = []
self._bytesWritten = 0
Writer.call(this, props)
}
FileWriter.prototype._create = function () {
var self = this
if (self._stream) return
var so = {}
if (self.props.flags) so.flags = self.props.flags
so.mode = Writer.filemode
if (self._old && self._old.blksize) so.bufferSize = self._old.blksize
self._stream = fs.createWriteStream(self._path, so)
self._stream.on('open', function () {
// console.error("FW open", self._buffer, self._path)
self.ready = true
self._buffer.forEach(function (c) {
if (c === EOF) self._stream.end()
else self._stream.write(c)
})
self.emit('ready')
// give this a kick just in case it needs it.
self.emit('drain')
})
self._stream.on('error', function (er) { self.emit('error', er) })
self._stream.on('drain', function () { self.emit('drain') })
self._stream.on('close', function () {
// console.error('\n\nFW Stream Close', self._path, self.size)
self._finish()
})
}
FileWriter.prototype.write = function (c) {
var self = this
self._bytesWritten += c.length
if (!self.ready) {
if (!Buffer.isBuffer(c) && typeof c !== 'string') {
throw new Error('invalid write data')
}
self._buffer.push(c)
return false
}
var ret = self._stream.write(c)
// console.error('\t-- fw wrote, _stream says', ret, self._stream._queue.length)
// allow 2 buffered writes, because otherwise there's just too
// much stop and go bs.
if (ret === false && self._stream._queue) {
return self._stream._queue.length <= 2
} else {
return ret
}
}
FileWriter.prototype.end = function (c) {
var self = this
if (c) self.write(c)
if (!self.ready) {
self._buffer.push(EOF)
return false
}
return self._stream.end()
}
FileWriter.prototype._finish = function () {
var self = this
if (typeof self.size === 'number' && self._bytesWritten !== self.size) {
self.error(
'Did not get expected byte count.\n' +
'expect: ' + self.size + '\n' +
'actual: ' + self._bytesWritten)
}
Writer.prototype._finish.call(self)
}