DataCache - Simple storage wrapper

Allows JSON data to be persisted easily by user scripts

Dieses Skript sollte nicht direkt installiert werden. Es handelt sich hier um eine Bibliothek für andere Skripte, welche über folgenden Befehl in den Metadaten eines Skriptes eingebunden wird // @require https://update.greasyfork.org/scripts/10443/56962/DataCache%20-%20Simple%20storage%20wrapper.js

function DataCache(key) {
  this._key = key;
  this._data = {};
  this.load();
}
 
DataCache.prototype = {
  getValue: function(k) {
    return this._data[k];
  },
  setValue: function(k, v) {
    this._data[k] = v;
    this.save();
  },
  deleteValue: function(k) {
    if (k in this._data) {
      delete this._data[k];
      this.save();
    }
  },
  hasValue: function(k) {
    return k in this._data;
  },
  listValues: function() {
    return Object.keys(this._data).sort();
  },
  clear: function() {
    this._data = {};
    this.save();
  },
  save: function() {
    var s = JSON.stringify(this._data);
    GM_setValue(this._key, s);
    console.info('Cache(' + this._key + ') saved: ' + s);
  },
  load: function(s) {
    try {
      this._data = JSON.parse(s || GM_getValue(this._key));
    }
    catch (ex) {
      this.clear();
    }
  },
  edit: function() {
    var res = window.prompt('Edit cached package URLs', JSON.stringify(this._data, null, 2));
    if (res !== null) {
      try {
        this._data = res ? JSON.parse(res) : {};
        this.save();
      }
      catch (ex) {
        console.warn('Failed to update cache data: %s %o', ex.toString(), ex);
      }
    }
  },
  toString: function() {
    return 'Cache(' + this._key + '): [' + this.listValues.join('\n') + ']';
  },
  dump: function() {
    console.log('Cache(' + this._key + '):\n' + JSON.stringify(this._data, null, 2));
  }
};