function spliceOne(list, index) { for (var i = index, k = i + 1, n = list.length; k < n; i += 1, k += 1) list[i] = list[k]; list.pop(); } function Manager(interval, streamInterval, kaCountMax) { var streams = this._streams = []; this._timer = undefined; this._timerInterval = interval; this._timerfn = function() { var now = Date.now(); for (var i = 0, len = streams.length, s, last; i < len; ++i) { s = streams[i]; last = s._kalast; if (last && (now - last) >= streamInterval) { if (++s._kacnt > kaCountMax) { var err = new Error('Keepalive timeout'); err.level = 'client-timeout'; s.emit('error', err); s.disconnect(); spliceOne(streams, i); --i; len = streams.length; } else { s._kalast = now; // XXX: if the server ever starts sending real global requests to the // client, we will need to add a dummy callback here to keep the // correct reply order s.ping(); } } } }; } Manager.prototype.start = function() { if (this._timer) this.stop(); this._timer = setInterval(this._timerfn, this._timerInterval); }; Manager.prototype.stop = function() { if (this._timer) { clearInterval(this._timer); this._timer = undefined; } }; Manager.prototype.add = function(stream) { var streams = this._streams, self = this; stream.once('end', function() { self.remove(stream); }).on('packet', resetKA); streams[streams.length] = stream; resetKA(); if (!this._timer) this.start(); function resetKA() { stream._kalast = Date.now(); stream._kacnt = 0; } }; Manager.prototype.remove = function(stream) { var streams = this._streams, index = streams.indexOf(stream); if (index > -1) spliceOne(streams, index); if (!streams.length) this.stop(); }; module.exports = Manager;