local storage data source

lsdatasource.js

// simple setup
// localStorage is an object, where the propertyName will be the baseName + _ + recTypeName
// the content will be an array, where records can be removed from and push onto


SC.LocalStorageDataSource = SC.DataSource.extend({

  baseName: null,

  lsIdFor: function(rectype){
    if(!this.get('baseName')) throw new Error("No basename defined in LocalStorageDataSource");
    return [this.get('baseName'),"_",rectype.toString()].join("");
  },

  writeLS: function(id,data){
    var d;
    d = (SC.typeOf(data) !== SC.T_STRING)? JSON.stringify(data): data;
    localStorage[id] = d;
  },

  readLS: function(id){
    return localStorage[id];
  },

  fetch: function(store,query){
     // find the record type from the query
     var lsId = lsIdFor(query.get('recordType'));
     var ret = this.readLS(lsId);
     // push into the store
     // do something with dataSourceDidCompleteQuery... forgot the exact API
  },

  retrieveRecord: function(store,sk,id){
    var recType = store.recordTypeFor(sk);
    var pk = recType.prototype.primaryKey || 'id';
    var lsId = lsIdFor(recType);
    var allrecs = this.readLS(lsId);
    var ret = allrecs.findProperty(pk,id); 
    // and push in the store, and return yes
  },

  createRecord: function(store,sk,params){ // no clue what params is
    var recType = store.recordTypeFor(sk);
    var pk = recType.prototype.primaryKey || 'id';
    var lsId = lsIdFor(recType);
    var allrecs = this.readLS(lsId) || [];    
    var hash = store.readEditableDataHash(sk); // editable, because we need to assign an id if needed
    if(!hash[pk]) hash[pk] = allrecs.length;
    allrecs.push(hash);
    this.writeLS(lsId,allrecs);
    // now update the store and return yes
  },

  // and so forth...
});