1/*global Blob,File*/
  2
  3/**
  4 * Module requirements
  5 */
  6
  7var isArray = require('isarray');
  8var isBuf = require('./is-buffer');
  9
 10/**
 11 * Replaces every Buffer | ArrayBuffer in packet with a numbered placeholder.
 12 * Anything with blobs or files should be fed through removeBlobs before coming
 13 * here.
 14 *
 15 * @param {Object} packet - socket.io event packet
 16 * @return {Object} with deconstructed packet and list of buffers
 17 * @api public
 18 */
 19
 20exports.deconstructPacket = function(packet){
 21  var buffers = [];
 22  var packetData = packet.data;
 23
 24  function _deconstructPacket(data) {
 25    if (!data) return data;
 26
 27    if (isBuf(data)) {
 28      var placeholder = { _placeholder: true, num: buffers.length };
 29      buffers.push(data);
 30      return placeholder;
 31    } else if (isArray(data)) {
 32      var newData = new Array(data.length);
 33      for (var i = 0; i < data.length; i++) {
 34        newData[i] = _deconstructPacket(data[i]);
 35      }
 36      return newData;
 37    } else if ('object' == typeof data && !(data instanceof Date)) {
 38      var newData = {};
 39      for (var key in data) {
 40        newData[key] = _deconstructPacket(data[key]);
 41      }
 42      return newData;
 43    }
 44    return data;
 45  }
 46
 47  var pack = packet;
 48  pack.data = _deconstructPacket(packetData);
 49  pack.attachments = buffers.length; // number of binary 'attachments'
 50  return {packet: pack, buffers: buffers};
 51};
 52
 53/**
 54 * Reconstructs a binary packet from its placeholder packet and buffers
 55 *
 56 * @param {Object} packet - event packet with placeholders
 57 * @param {Array} buffers - binary buffers to put in placeholder positions
 58 * @return {Object} reconstructed packet
 59 * @api public
 60 */
 61
 62exports.reconstructPacket = function(packet, buffers) {
 63  var curPlaceHolder = 0;
 64
 65  function _reconstructPacket(data) {
 66    if (data && data._placeholder) {
 67      var buf = buffers[data.num]; // appropriate buffer (should be natural order anyway)
 68      return buf;
 69    } else if (isArray(data)) {
 70      for (var i = 0; i < data.length; i++) {
 71        data[i] = _reconstructPacket(data[i]);
 72      }
 73      return data;
 74    } else if (data && 'object' == typeof data) {
 75      for (var key in data) {
 76        data[key] = _reconstructPacket(data[key]);
 77      }
 78      return data;
 79    }
 80    return data;
 81  }
 82
 83  packet.data = _reconstructPacket(packet.data);
 84  packet.attachments = undefined; // no longer useful
 85  return packet;
 86};
 87
 88/**
 89 * Asynchronously removes Blobs or Files from data via
 90 * FileReader's readAsArrayBuffer method. Used before encoding
 91 * data as msgpack. Calls callback with the blobless data.
 92 *
 93 * @param {Object} data
 94 * @param {Function} callback
 95 * @api private
 96 */
 97
 98exports.removeBlobs = function(data, callback) {
 99  function _removeBlobs(obj, curKey, containingObject) {
100    if (!obj) return obj;
101
102    // convert any blob
103    if ((global.Blob && obj instanceof Blob) ||
104        (global.File && obj instanceof File)) {
105      pendingBlobs++;
106
107      // async filereader
108      var fileReader = new FileReader();
109      fileReader.onload = function() { // this.result == arraybuffer
110        if (containingObject) {
111          containingObject[curKey] = this.result;
112        }
113        else {
114          bloblessData = this.result;
115        }
116
117        // if nothing pending its callback time
118        if(! --pendingBlobs) {
119          callback(bloblessData);
120        }
121      };
122
123      fileReader.readAsArrayBuffer(obj); // blob -> arraybuffer
124    } else if (isArray(obj)) { // handle array
125      for (var i = 0; i < obj.length; i++) {
126        _removeBlobs(obj[i], i, obj);
127      }
128    } else if (obj && 'object' == typeof obj && !isBuf(obj)) { // and object
129      for (var key in obj) {
130        _removeBlobs(obj[key], key, obj);
131      }
132    }
133  }
134
135  var pendingBlobs = 0;
136  var bloblessData = data;
137  _removeBlobs(bloblessData);
138  if (!pendingBlobs) {
139    callback(bloblessData);
140  }
141};