Method getFunctions

lib/metadata/schema-parser.js:291–336

* @param {String} keyspaceName * @param {String} name * @param {Boolean} aggregate * @param {Object} cache * @returns {Promise }

(keyspaceName, name, aggregate, cache)

   * @returns {Promise<Map>}
   */
  async getFunctions(keyspaceName, name, aggregate, cache) {
    /** @type {String} */
    let query = this.selectFunctions;
    let parser = row => this._parseFunction(row);
    if (aggregate) {
      query = this.selectAggregates;
      parser = row => this._parseAggregate(row);
    }
    // if it's not already loaded, get all functions with that name
    // cache it by name and, within name, by signature
    let functionsInfo = cache && cache[name];
    if (!functionsInfo) {
      functionsInfo = new events.EventEmitter();
      if (cache) {
        cache[name] = functionsInfo;
      }
      functionsInfo.setMaxListeners(0);
    }
    if (functionsInfo.values) {
      return functionsInfo.values;
    }
    if (functionsInfo.loading) {
      return promiseUtils.fromEvent(functionsInfo, 'load');
    }
    functionsInfo.loading = true;
    try {
      const rows = await this._getRows(format(query, keyspaceName, name));
      const funcs = await Promise.all(rows.map(parser));
      const result = new Map();
      if (rows.length > 0) {
        // Cache positive hits
        functionsInfo.values = result;
      }

      funcs.forEach(f => functionsInfo.values.set(f.signature.join(','), f));
      functionsInfo.emit('load', null, result);
      return result;
    }
    catch (err) {
      functionsInfo.emit('load', err);
      throw err;
    }
    finally {
      functionsInfo.loading = false;
    }
  }

  /**
   * @abstract