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| // Basically just a wrapper around an fs.ReadStream
module.exports = FileReader
var fs = require('graceful-fs')
var inherits = require('inherits')
var Reader = require('./reader.js')
var EOF = {EOF: true}
var CLOSE = {CLOSE: true}
inherits(FileReader, Reader)
function FileReader (props) {
// console.error(" FR create", props.path, props.size, new Error().stack)
var self = this
Iif (!(self instanceof FileReader)) {
throw new Error('FileReader must be called as constructor.')
}
// should already be established as a File type
// XXX Todo: preserve hardlinks by tracking dev+inode+nlink,
// with a HardLinkReader class.
Iif (!((props.type === 'Link' && props.Link) ||
(props.type === 'File' && props.File))) {
throw new Error('Non-file type ' + props.type)
}
self._buffer = []
self._bytesEmitted = 0
Reader.call(self, props)
}
FileReader.prototype._getStream = function () {
var self = this
var stream = self._stream = fs.createReadStream(self._path, self.props)
Eif (self.props.blksize) {
stream.bufferSize = self.props.blksize
}
stream.on('open', self.emit.bind(self, 'open'))
stream.on('data', function (c) {
// console.error('\t\t%d %s', c.length, self.basename)
self._bytesEmitted += c.length
// no point saving empty chunks
Iif (!c.length) {
return
} else Iif (self._paused || self._buffer.length) {
self._buffer.push(c)
self._read()
} else self.emit('data', c)
})
stream.on('end', function () {
Iif (self._paused || self._buffer.length) {
// console.error('FR Buffering End', self._path)
self._buffer.push(EOF)
self._read()
} else {
self.emit('end')
}
Iif (self._bytesEmitted !== self.props.size) {
self.error("Didn't get expected byte count\n" +
'expect: ' + self.props.size + '\n' +
'actual: ' + self._bytesEmitted)
}
})
stream.on('close', function () {
Iif (self._paused || self._buffer.length) {
// console.error('FR Buffering Close', self._path)
self._buffer.push(CLOSE)
self._read()
} else {
// console.error('FR close 1', self._path)
self.emit('close')
}
})
stream.on('error', function (e) {
self.emit('error', e)
})
self._read()
}
FileReader.prototype._read = function () {
var self = this
// console.error('FR _read', self._path)
Iif (self._paused) {
// console.error('FR _read paused', self._path)
return
}
if (!self._stream) {
// console.error('FR _getStream calling', self._path)
return self._getStream()
}
// clear out the buffer, if there is one.
Iif (self._buffer.length) {
// console.error('FR _read has buffer', self._buffer.length, self._path)
var buf = self._buffer
for (var i = 0, l = buf.length; i < l; i++) {
var c = buf[i]
if (c === EOF) {
// console.error('FR Read emitting buffered end', self._path)
self.emit('end')
} else if (c === CLOSE) {
// console.error('FR Read emitting buffered close', self._path)
self.emit('close')
} else {
// console.error('FR Read emitting buffered data', self._path)
self.emit('data', c)
}
if (self._paused) {
// console.error('FR Read Re-pausing at '+i, self._path)
self._buffer = buf.slice(i)
return
}
}
self._buffer.length = 0
}
// console.error("FR _read done")
// that's about all there is to it.
}
FileReader.prototype.pause = function (who) {
var self = this
// console.error('FR Pause', self._path)
if (self._paused) return
who = who || self
self._paused = true
if (self._stream) self._stream.pause()
self.emit('pause', who)
}
FileReader.prototype.resume = function (who) {
var self = this
// console.error('FR Resume', self._path)
if (!self._paused) return
who = who || self
self.emit('resume', who)
self._paused = false
if (self._stream) self._stream.resume()
self._read()
}
|