# all files / lib/ file-reader.js

50.6% Statements 42/83
42% Branches 21/50
66.67% Functions 6/9
53.16% Lines 42/79

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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()
    }