read-xml/lib/DecoderXMLStream.js

Read a xml file respecting its encoding information

'use strict';

Object.defineProperty(exports, "__esModule", {
  value: true
});

var _debug = require('debug');

var _debug2 = _interopRequireDefault(_debug);

var _stream = require('stream');

var _stream2 = _interopRequireDefault(_stream);

var _iconvLite = require('iconv-lite');

var _iconvLite2 = _interopRequireDefault(_iconvLite);

var _findEncoding = require('./findEncoding');

var _findEncoding2 = _interopRequireDefault(_findEncoding);

var _defaultEncoding = require('./defaultEncoding');

var _defaultEncoding2 = _interopRequireDefault(_defaultEncoding);

var _package = require('../package.json');

var _package2 = _interopRequireDefault(_package);

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

var Transform = _stream2.default.Transform;

var debugMe = (0, _debug2.default)(_package2.default.name + ':stream');

function concatBuffers(chunks) {
  var totalLength = chunks.reduce(function (previousValue, chunk) {
    return previousValue + chunk.length;
  }, 0);

  return Buffer.concat(chunks, totalLength);
}

function DecoderXMLStream(streamOpts) {
  var options = streamOpts || {};

  // eslint-disable-next-line no-multi-assign
  options.encoding = this.encoding = _defaultEncoding2.default; // we output strings

  this.chunks = [];
  this.bufContent = null;
  this.encodingDetected = null;
  Transform.call(this, options);
}

DecoderXMLStream.prototype = Object.create(Transform.prototype, {
  constructor: {
    value: DecoderXMLStream
  }
});

// eslint-disable-next-line no-underscore-dangle
DecoderXMLStream.prototype._transform = function (chunk, encoding, done) {
  var _this = this;

  if (!Buffer.isBuffer(chunk)) {
    return done(new Error('read-xml#createStream needs buffers as its input'));
  }

  debugMe('receiving chunk..');

  try {
    if (this.encodingDetected) {
      debugMe('encoding was detected before, decoding chunk to ' + this.encodingDetected + '..');
      this.push(_iconvLite2.default.decode(chunk, this.encodingDetected), this.encoding);
      return done();
    }

    this.chunks.push(chunk);
    this.bufContent = concatBuffers(this.chunks);

    debugMe('trying to find encoding..');

    (0, _findEncoding2.default)(this.bufContent, _defaultEncoding2.default, function (err, detectedEncoding) {
      if (err) {
        return done(err);
      }

      if (detectedEncoding == null) {
        debugMe('could not find encoding in chunk, decoding to default ' + _this.encoding + '..');
        _this.push(_iconvLite2.default.decode(chunk, _this.encoding), _this.encoding);
        return done();
      }

      if (!_iconvLite2.default.encodingExists(detectedEncoding)) {
        return done(new Error(detectedEncoding + ' is not supported'));
      }

      debugMe('encoding detected, decoding chunk to ' + detectedEncoding + '..');

      _this.emit('encodingDetected', detectedEncoding);

      _this.encodingDetected = detectedEncoding;
      _this.push(_iconvLite2.default.decode(chunk, detectedEncoding), _this.encoding);
      done();
    });
  } catch (err) {
    done(err);
  }
};

exports.default = DecoderXMLStream;
module.exports = exports['default'];