jsmediatags/build2/MediaTagReader.js

Media Tags Reader (ID3, MP4)

'use strict';

function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }

function _defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } }

function _createClass(Constructor, protoProps, staticProps) { if (protoProps) _defineProperties(Constructor.prototype, protoProps); if (staticProps) _defineProperties(Constructor, staticProps); return Constructor; }

function _defineProperty(obj, key, value) { if (key in obj) { Object.defineProperty(obj, key, { value: value, enumerable: true, configurable: true, writable: true }); } else { obj[key] = value; } return obj; }

var MediaFileReader = require('./MediaFileReader');

var MediaTagReader = /*#__PURE__*/function () {
  function MediaTagReader(mediaFileReader) {
    _classCallCheck(this, MediaTagReader);

    _defineProperty(this, "_mediaFileReader", void 0);

    _defineProperty(this, "_tags", void 0);

    this._mediaFileReader = mediaFileReader;
    this._tags = null;
  }
  /**
   * Returns the byte range that needs to be loaded and fed to
   * _canReadTagFormat in order to identify if the file contains tag
   * information that can be read.
   */


  _createClass(MediaTagReader, [{
    key: "setTagsToRead",
    value: function setTagsToRead(tags) {
      this._tags = tags;
      return this;
    }
  }, {
    key: "read",
    value: function read(callbacks) {
      var self = this;

      this._mediaFileReader.init({
        onSuccess: function onSuccess() {
          self._loadData(self._mediaFileReader, {
            onSuccess: function onSuccess() {
              try {
                var tags = self._parseData(self._mediaFileReader, self._tags);
              } catch (ex) {
                if (callbacks.onError) {
                  callbacks.onError({
                    "type": "parseData",
                    "info": ex.message
                  });
                  return;
                }
              } // TODO: destroy mediaFileReader


              callbacks.onSuccess(tags);
            },
            onError: callbacks.onError
          });
        },
        onError: callbacks.onError
      });
    }
  }, {
    key: "getShortcuts",
    value: function getShortcuts() {
      return {};
    }
    /**
     * Load the necessary bytes from the media file.
     */

  }, {
    key: "_loadData",
    value: function _loadData(mediaFileReader, callbacks) {
      throw new Error("Must implement _loadData function");
    }
    /**
     * Parse the loaded data to read the media tags.
     */

  }, {
    key: "_parseData",
    value: function _parseData(mediaFileReader, tags) {
      throw new Error("Must implement _parseData function");
    }
  }, {
    key: "_expandShortcutTags",
    value: function _expandShortcutTags(tagsWithShortcuts) {
      if (!tagsWithShortcuts) {
        return null;
      }

      var tags = [];
      var shortcuts = this.getShortcuts();

      for (var i = 0, tagOrShortcut; tagOrShortcut = tagsWithShortcuts[i]; i++) {
        tags = tags.concat(shortcuts[tagOrShortcut] || [tagOrShortcut]);
      }

      return tags;
    }
  }], [{
    key: "getTagIdentifierByteRange",
    value: function getTagIdentifierByteRange() {
      throw new Error("Must implement");
    }
    /**
     * Given a tag identifier (read from the file byte positions speficied by
     * getTagIdentifierByteRange) this function checks if it can read the tag
     * format or not.
     */

  }, {
    key: "canReadTagFormat",
    value: function canReadTagFormat(tagIdentifier) {
      throw new Error("Must implement");
    }
  }]);

  return MediaTagReader;
}();

module.exports = MediaTagReader;