'use strict';

var utils = require('../utils');
var GenericWorker = require('./GenericWorker');

/**
 * A worker which calculate the total length of the data flowing through.
 * @constructor
 * @param {String} propName the name used to expose the length
 */
function DataLengthProbe(propName) {
    GenericWorker.call(this, "DataLengthProbe for " + propName);
    this.propName = propName;
    this.withStreamInfo(propName, 0);
}
utils.inherits(DataLengthProbe, GenericWorker);

/**
 * @see GenericWorker.processChunk
 */
DataLengthProbe.prototype.processChunk = function (chunk) {
    if(chunk) {
        var length = this.streamInfo[this.propName] || 0;
        this.streamInfo[this.propName] = length + chunk.data.length;
    }
    GenericWorker.prototype.processChunk.call(this, chunk);
};
module.exports = DataLengthProbe;