lib/display/metadata.js

/**
 * @licstart The following is the entire license notice for the
 * Javascript code in this page
 *
 * Copyright 2020 Mozilla Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * @licend The above is the entire license notice for the
 * Javascript code in this page
 */
"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.Metadata = void 0;

var _util = require("../shared/util.js");

var _xml_parser = require("./xml_parser.js");

class Metadata {
  constructor(data) {
    (0, _util.assert)(typeof data === "string", "Metadata: input is not a string");
    data = this._repair(data);
    const parser = new _xml_parser.SimpleXMLParser();
    const xmlDocument = parser.parseFromString(data);
    this._metadataMap = new Map();

    if (xmlDocument) {
      this._parse(xmlDocument);
    }
  }

  _repair(data) {
    return data.replace(/^[^<]+/, "").replace(/>\\376\\377([^<]+)/g, function (all, codes) {
      const bytes = codes.replace(/\\([0-3])([0-7])([0-7])/g, function (code, d1, d2, d3) {
        return String.fromCharCode(d1 * 64 + d2 * 8 + d3 * 1);
      }).replace(/&(amp|apos|gt|lt|quot);/g, function (str, name) {
        switch (name) {
          case "amp":
            return "&";

          case "apos":
            return "'";

          case "gt":
            return ">";

          case "lt":
            return "<";

          case "quot":
            return '"';
        }

        throw new Error(`_repair: ${name} isn't defined.`);
      });
      let chars = "";

      for (let i = 0, ii = bytes.length; i < ii; i += 2) {
        const code = bytes.charCodeAt(i) * 256 + bytes.charCodeAt(i + 1);

        if (code >= 32 && code < 127 && code !== 60 && code !== 62 && code !== 38) {
          chars += String.fromCharCode(code);
        } else {
          chars += "&#x" + (0x10000 + code).toString(16).substring(1) + ";";
        }
      }

      return ">" + chars;
    });
  }

  _parse(xmlDocument) {
    let rdf = xmlDocument.documentElement;

    if (rdf.nodeName.toLowerCase() !== "rdf:rdf") {
      rdf = rdf.firstChild;

      while (rdf && rdf.nodeName.toLowerCase() !== "rdf:rdf") {
        rdf = rdf.nextSibling;
      }
    }

    const nodeName = rdf ? rdf.nodeName.toLowerCase() : null;

    if (!rdf || nodeName !== "rdf:rdf" || !rdf.hasChildNodes()) {
      return;
    }

    const children = rdf.childNodes;

    for (let i = 0, ii = children.length; i < ii; i++) {
      const desc = children[i];

      if (desc.nodeName.toLowerCase() !== "rdf:description") {
        continue;
      }

      for (let j = 0, jj = desc.childNodes.length; j < jj; j++) {
        if (desc.childNodes[j].nodeName.toLowerCase() !== "#text") {
          const entry = desc.childNodes[j];
          const name = entry.nodeName.toLowerCase();

          this._metadataMap.set(name, entry.textContent.trim());
        }
      }
    }
  }

  get(name) {
    return this._metadataMap.has(name) ? this._metadataMap.get(name) : null;
  }

  getAll() {
    return Object.fromEntries(this._metadataMap);
  }

  has(name) {
    return this._metadataMap.has(name);
  }

}

exports.Metadata = Metadata;