--- /dev/null
+'use strict';
+
+const crypto = require('crypto');
+
+const PerMessageDeflate = require('./permessage-deflate');
+const bufferUtil = require('./buffer-util');
+const validation = require('./validation');
+const constants = require('./constants');
+
+/**
+ * HyBi Sender implementation.
+ */
+class Sender {
+ /**
+ * Creates a Sender instance.
+ *
+ * @param {net.Socket} socket The connection socket
+ * @param {Object} extensions An object containing the negotiated extensions
+ */
+ constructor (socket, extensions) {
+ this._extensions = extensions || {};
+ this._socket = socket;
+
+ this._firstFragment = true;
+ this._compress = false;
+
+ this._bufferedBytes = 0;
+ this._deflating = false;
+ this._queue = [];
+ }
+
+ /**
+ * Frames a piece of data according to the HyBi WebSocket protocol.
+ *
+ * @param {Buffer} data The data to frame
+ * @param {Object} options Options object
+ * @param {Number} options.opcode The opcode
+ * @param {Boolean} options.readOnly Specifies whether `data` can be modified
+ * @param {Boolean} options.fin Specifies whether or not to set the FIN bit
+ * @param {Boolean} options.mask Specifies whether or not to mask `data`
+ * @param {Boolean} options.rsv1 Specifies whether or not to set the RSV1 bit
+ * @return {Buffer[]} The framed data as a list of `Buffer` instances
+ * @public
+ */
+ static frame (data, options) {
+ const merge = data.length < 1024 || (options.mask && options.readOnly);
+ var offset = options.mask ? 6 : 2;
+ var payloadLength = data.length;
+
+ if (data.length >= 65536) {
+ offset += 8;
+ payloadLength = 127;
+ } else if (data.length > 125) {
+ offset += 2;
+ payloadLength = 126;
+ }
+
+ const target = Buffer.allocUnsafe(merge ? data.length + offset : offset);
+
+ target[0] = options.fin ? options.opcode | 0x80 : options.opcode;
+ if (options.rsv1) target[0] |= 0x40;
+
+ if (payloadLength === 126) {
+ target.writeUInt16BE(data.length, 2);
+ } else if (payloadLength === 127) {
+ target.writeUInt32BE(0, 2);
+ target.writeUInt32BE(data.length, 6);
+ }
+
+ if (!options.mask) {
+ target[1] = payloadLength;
+ if (merge) {
+ data.copy(target, offset);
+ return [target];
+ }
+
+ return [target, data];
+ }
+
+ const mask = crypto.randomBytes(4);
+
+ target[1] = payloadLength | 0x80;
+ target[offset - 4] = mask[0];
+ target[offset - 3] = mask[1];
+ target[offset - 2] = mask[2];
+ target[offset - 1] = mask[3];
+
+ if (merge) {
+ bufferUtil.mask(data, mask, target, offset, data.length);
+ return [target];
+ }
+
+ bufferUtil.mask(data, mask, data, 0, data.length);
+ return [target, data];
+ }
+
+ /**
+ * Sends a close message to the other peer.
+ *
+ * @param {(Number|undefined)} code The status code component of the body
+ * @param {String} data The message component of the body
+ * @param {Boolean} mask Specifies whether or not to mask the message
+ * @param {Function} cb Callback
+ * @public
+ */
+ close (code, data, mask, cb) {
+ var buf;
+
+ if (code === undefined) {
+ buf = constants.EMPTY_BUFFER;
+ } else if (typeof code !== 'number' || !validation.isValidStatusCode(code)) {
+ throw new TypeError('First argument must be a valid error code number');
+ } else if (data === undefined || data === '') {
+ buf = Buffer.allocUnsafe(2);
+ buf.writeUInt16BE(code, 0);
+ } else {
+ buf = Buffer.allocUnsafe(2 + Buffer.byteLength(data));
+ buf.writeUInt16BE(code, 0);
+ buf.write(data, 2);
+ }
+
+ if (this._deflating) {
+ this.enqueue([this.doClose, buf, mask, cb]);
+ } else {
+ this.doClose(buf, mask, cb);
+ }
+ }
+
+ /**
+ * Frames and sends a close message.
+ *
+ * @param {Buffer} data The message to send
+ * @param {Boolean} mask Specifies whether or not to mask `data`
+ * @param {Function} cb Callback
+ * @private
+ */
+ doClose (data, mask, cb) {
+ this.sendFrame(Sender.frame(data, {
+ fin: true,
+ rsv1: false,
+ opcode: 0x08,
+ mask,
+ readOnly: false
+ }), cb);
+ }
+
+ /**
+ * Sends a ping message to the other peer.
+ *
+ * @param {*} data The message to send
+ * @param {Boolean} mask Specifies whether or not to mask `data`
+ * @param {Function} cb Callback
+ * @public
+ */
+ ping (data, mask, cb) {
+ var readOnly = true;
+
+ if (!Buffer.isBuffer(data)) {
+ if (data instanceof ArrayBuffer) {
+ data = Buffer.from(data);
+ } else if (ArrayBuffer.isView(data)) {
+ data = viewToBuffer(data);
+ } else {
+ data = Buffer.from(data);
+ readOnly = false;
+ }
+ }
+
+ if (this._deflating) {
+ this.enqueue([this.doPing, data, mask, readOnly, cb]);
+ } else {
+ this.doPing(data, mask, readOnly, cb);
+ }
+ }
+
+ /**
+ * Frames and sends a ping message.
+ *
+ * @param {*} data The message to send
+ * @param {Boolean} mask Specifies whether or not to mask `data`
+ * @param {Boolean} readOnly Specifies whether `data` can be modified
+ * @param {Function} cb Callback
+ * @private
+ */
+ doPing (data, mask, readOnly, cb) {
+ this.sendFrame(Sender.frame(data, {
+ fin: true,
+ rsv1: false,
+ opcode: 0x09,
+ mask,
+ readOnly
+ }), cb);
+ }
+
+ /**
+ * Sends a pong message to the other peer.
+ *
+ * @param {*} data The message to send
+ * @param {Boolean} mask Specifies whether or not to mask `data`
+ * @param {Function} cb Callback
+ * @public
+ */
+ pong (data, mask, cb) {
+ var readOnly = true;
+
+ if (!Buffer.isBuffer(data)) {
+ if (data instanceof ArrayBuffer) {
+ data = Buffer.from(data);
+ } else if (ArrayBuffer.isView(data)) {
+ data = viewToBuffer(data);
+ } else {
+ data = Buffer.from(data);
+ readOnly = false;
+ }
+ }
+
+ if (this._deflating) {
+ this.enqueue([this.doPong, data, mask, readOnly, cb]);
+ } else {
+ this.doPong(data, mask, readOnly, cb);
+ }
+ }
+
+ /**
+ * Frames and sends a pong message.
+ *
+ * @param {*} data The message to send
+ * @param {Boolean} mask Specifies whether or not to mask `data`
+ * @param {Boolean} readOnly Specifies whether `data` can be modified
+ * @param {Function} cb Callback
+ * @private
+ */
+ doPong (data, mask, readOnly, cb) {
+ this.sendFrame(Sender.frame(data, {
+ fin: true,
+ rsv1: false,
+ opcode: 0x0a,
+ mask,
+ readOnly
+ }), cb);
+ }
+
+ /**
+ * Sends a data message to the other peer.
+ *
+ * @param {*} data The message to send
+ * @param {Object} options Options object
+ * @param {Boolean} options.compress Specifies whether or not to compress `data`
+ * @param {Boolean} options.binary Specifies whether `data` is binary or text
+ * @param {Boolean} options.fin Specifies whether the fragment is the last one
+ * @param {Boolean} options.mask Specifies whether or not to mask `data`
+ * @param {Function} cb Callback
+ * @public
+ */
+ send (data, options, cb) {
+ var opcode = options.binary ? 2 : 1;
+ var rsv1 = options.compress;
+ var readOnly = true;
+
+ if (!Buffer.isBuffer(data)) {
+ if (data instanceof ArrayBuffer) {
+ data = Buffer.from(data);
+ } else if (ArrayBuffer.isView(data)) {
+ data = viewToBuffer(data);
+ } else {
+ data = Buffer.from(data);
+ readOnly = false;
+ }
+ }
+
+ const perMessageDeflate = this._extensions[PerMessageDeflate.extensionName];
+
+ if (this._firstFragment) {
+ this._firstFragment = false;
+ if (rsv1 && perMessageDeflate) {
+ rsv1 = data.length >= perMessageDeflate._threshold;
+ }
+ this._compress = rsv1;
+ } else {
+ rsv1 = false;
+ opcode = 0;
+ }
+
+ if (options.fin) this._firstFragment = true;
+
+ if (perMessageDeflate) {
+ const opts = {
+ fin: options.fin,
+ rsv1,
+ opcode,
+ mask: options.mask,
+ readOnly
+ };
+
+ if (this._deflating) {
+ this.enqueue([this.dispatch, data, this._compress, opts, cb]);
+ } else {
+ this.dispatch(data, this._compress, opts, cb);
+ }
+ } else {
+ this.sendFrame(Sender.frame(data, {
+ fin: options.fin,
+ rsv1: false,
+ opcode,
+ mask: options.mask,
+ readOnly
+ }), cb);
+ }
+ }
+
+ /**
+ * Dispatches a data message.
+ *
+ * @param {Buffer} data The message to send
+ * @param {Boolean} compress Specifies whether or not to compress `data`
+ * @param {Object} options Options object
+ * @param {Number} options.opcode The opcode
+ * @param {Boolean} options.readOnly Specifies whether `data` can be modified
+ * @param {Boolean} options.fin Specifies whether or not to set the FIN bit
+ * @param {Boolean} options.mask Specifies whether or not to mask `data`
+ * @param {Boolean} options.rsv1 Specifies whether or not to set the RSV1 bit
+ * @param {Function} cb Callback
+ * @private
+ */
+ dispatch (data, compress, options, cb) {
+ if (!compress) {
+ this.sendFrame(Sender.frame(data, options), cb);
+ return;
+ }
+
+ const perMessageDeflate = this._extensions[PerMessageDeflate.extensionName];
+
+ this._deflating = true;
+ perMessageDeflate.compress(data, options.fin, (_, buf) => {
+ options.readOnly = false;
+ this.sendFrame(Sender.frame(buf, options), cb);
+ this._deflating = false;
+ this.dequeue();
+ });
+ }
+
+ /**
+ * Executes queued send operations.
+ *
+ * @private
+ */
+ dequeue () {
+ while (!this._deflating && this._queue.length) {
+ const params = this._queue.shift();
+
+ this._bufferedBytes -= params[1].length;
+ params[0].apply(this, params.slice(1));
+ }
+ }
+
+ /**
+ * Enqueues a send operation.
+ *
+ * @param {Array} params Send operation parameters.
+ * @private
+ */
+ enqueue (params) {
+ this._bufferedBytes += params[1].length;
+ this._queue.push(params);
+ }
+
+ /**
+ * Sends a frame.
+ *
+ * @param {Buffer[]} list The frame to send
+ * @param {Function} cb Callback
+ * @private
+ */
+ sendFrame (list, cb) {
+ if (list.length === 2) {
+ this._socket.write(list[0]);
+ this._socket.write(list[1], cb);
+ } else {
+ this._socket.write(list[0], cb);
+ }
+ }
+}
+
+module.exports = Sender;
+
+/**
+ * Converts an `ArrayBuffer` view into a buffer.
+ *
+ * @param {(DataView|TypedArray)} view The view to convert
+ * @return {Buffer} Converted view
+ * @private
+ */
+function viewToBuffer (view) {
+ const buf = Buffer.from(view.buffer);
+
+ if (view.byteLength !== view.buffer.byteLength) {
+ return buf.slice(view.byteOffset, view.byteOffset + view.byteLength);
+ }
+
+ return buf;
+}