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DataCache - Simple storage wrapper

Allows JSON data to be persisted easily by user scripts

This script should not be not be installed directly. It is a library for other scripts to include with the meta directive // @require https://update.greatest.deepsurf.us/scripts/10443/56962/DataCache%20-%20Simple%20storage%20wrapper.js 

  1. function DataCache(key) {
  2.   this._key = key;
  3.   this._data = {};
  4.   this.load();
  5. }
  6.  
  7. DataCache.prototype = {
  8.   getValue: function(k) {
  9.     return this._data[k];
  10.   },
  11.   setValue: function(k, v) {
  12.     this._data[k] = v;
  13.     this.save();
  14.   },
  15.   deleteValue: function(k) {
  16.     if (k in this._data) {
  17.       delete this._data[k];
  18.       this.save();
  19.     }
  20.   },
  21.   hasValue: function(k) {
  22.     return k in this._data;
  23.   },
  24.   listValues: function() {
  25.     return Object.keys(this._data).sort();
  26.   },
  27.   clear: function() {
  28.     this._data = {};
  29.     this.save();
  30.   },
  31.   save: function() {
  32.     var s = JSON.stringify(this._data);
  33.     GM_setValue(this._key, s);
  34.     console.info('Cache(' + this._key + ') saved: ' + s);
  35.   },
  36.   load: function(s) {
  37.     try {
  38.       this._data = JSON.parse(s || GM_getValue(this._key));
  39.     }
  40.     catch (ex) {
  41.       this.clear();
  42.     }
  43.   },
  44.   edit: function() {
  45.     var res = window.prompt('Edit cached package URLs', JSON.stringify(this._data, null, 2));
  46.     if (res !== null) {
  47.       try {
  48.         this._data = res ? JSON.parse(res) : {};
  49.         this.save();
  50.       }
  51.       catch (ex) {
  52.         console.warn('Failed to update cache data: %s %o', ex.toString(), ex);
  53.       }
  54.     }
  55.   },
  56.   toString: function() {
  57.     return 'Cache(' + this._key + '): [' + this.listValues.join('\n') + ']';
  58.   },
  59.   dump: function() {
  60.     console.log('Cache(' + this._key + '):\n' + JSON.stringify(this._data, null, 2));
  61.   }
  62. };