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/*
* A socket.io encoder and decoder written in JavaScript complying with version 4
* of socket.io-protocol. Used by socket.io and socket.io-client.
*
* Copyright (c) 2014 Guillermo Rauch <guillermo@learnboost.com>
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of the library source tree.
*
*/
/* eslint-disable no-unused-vars */
"use strict";
const Emitter = require("resource://devtools/client/netmonitor/src/components/messages/parsers/socket-io/component-emitter.js");
const binary = require("resource://devtools/client/netmonitor/src/components/messages/parsers/socket-io/binary.js");
const isBuf = require("resource://devtools/client/netmonitor/src/components/messages/parsers/socket-io/is-buffer.js");
/**
* Packet types
*/
const TYPES = [
"CONNECT",
"DISCONNECT",
"EVENT",
"ACK",
"ERROR",
"BINARY_EVENT",
"BINARY_ACK",
];
/**
* Packet type `connect`
*/
const CONNECT = 0;
/**
* Packet type `disconnect`
*/
const DISCONNECT = 1;
/**
* Packet type `event`
*/
const EVENT = 2;
/**
* Packet type `ack`
*/
const ACK = 3;
/**
* Packet type `error`
*/
const ERROR = 4;
/**
* Packet type 'binary event'
*/
const BINARY_EVENT = 5;
/**
* Packet type `binary ack`. For acks with binary arguments
*/
const BINARY_ACK = 6;
/**
* A socket.io Decoder instance
*
* @return {Object} decoder
* @api public
*/
function Decoder() {
this.reconstructor = null;
}
/**
* Mix in `Emitter` with Decoder.
*/
Emitter(Decoder.prototype);
/**
* A manager of a binary event's 'buffer sequence'. Should
* be constructed whenever a packet of type BINARY_EVENT is
* decoded.
*
* @param {Object} packet
* @return {BinaryReconstructor} initialized reconstructor
* @api private
*/
function BinaryReconstructor(packet) {
this.reconPack = packet;
this.buffers = [];
}
/**
* Method to be called when binary data received from connection
* after a BINARY_EVENT packet.
*
* @param {Buffer | ArrayBuffer} binData - the raw binary data received
* @return {null | Object} returns null if more binary data is expected or
* a reconstructed packet object if all buffers have been received.
* @api private
*/
BinaryReconstructor.prototype.takeBinaryData = function (binData) {
this.buffers.push(binData);
if (this.buffers.length === this.reconPack.attachments) {
// done with buffer list
const packet = binary.reconstructPacket(this.reconPack, this.buffers);
this.finishedReconstruction();
return packet;
}
return null;
};
/**
* Cleans up binary packet reconstruction variables.
*
* @api private
*/
BinaryReconstructor.prototype.finishedReconstruction = function () {
this.reconPack = null;
this.buffers = [];
};
/**
* Decodes an encoded packet string into packet JSON.
*
* @param {String} obj - encoded packet
* @return {Object} packet
* @api public
*/
Decoder.prototype.add = function (obj) {
let packet;
if (typeof obj === "string") {
packet = decodeString(obj);
if (BINARY_EVENT === packet.type || BINARY_ACK === packet.type) {
// binary packet's json
this.reconstructor = new BinaryReconstructor(packet);
// no attachments, labeled binary but no binary data to follow
if (this.reconstructor.reconPack.attachments === 0) {
this.emit("decoded", packet);
}
} else {
// non-binary full packet
this.emit("decoded", packet);
}
} else if (isBuf(obj) || obj.base64) {
// raw binary data
if (!this.reconstructor) {
throw new Error("got binary data when not reconstructing a packet");
} else {
packet = this.reconstructor.takeBinaryData(obj);
if (packet) {
// received final buffer
this.reconstructor = null;
this.emit("decoded", packet);
}
}
} else {
throw new Error("Unknown type: " + obj);
}
};
/**
* Decode a packet String (JSON data)
*
* @param {String} str
* @return {Object} packet
* @api private
*/
// eslint-disable-next-line complexity
function decodeString(str) {
let i = 0;
// look up type
const p = {
type: Number(str.charAt(0)),
};
if (TYPES[p.type] == null) {
return error("unknown packet type " + p.type);
}
// look up attachments if type binary
if (BINARY_EVENT === p.type || BINARY_ACK === p.type) {
let buf = "";
while (str.charAt(++i) !== "-") {
buf += str.charAt(i);
if (i === str.length) {
break;
}
}
if (buf != Number(buf) || str.charAt(i) !== "-") {
throw new Error("Illegal attachments");
}
p.attachments = Number(buf);
}
// look up namespace (if any)
if (str.charAt(i + 1) === "/") {
p.nsp = "";
while (++i) {
const c = str.charAt(i);
if (c === ",") {
break;
}
p.nsp += c;
if (i === str.length) {
break;
}
}
} else {
p.nsp = "/";
}
// look up id
const next = str.charAt(i + 1);
if (next !== "" && Number(next) == next) {
p.id = "";
while (++i) {
const c = str.charAt(i);
if (c == null || Number(c) != c) {
--i;
break;
}
p.id += str.charAt(i);
if (i === str.length) {
break;
}
}
p.id = Number(p.id);
}
// look up json data
if (str.charAt(++i)) {
const payload = tryParse(str.substr(i));
const isPayloadValid =
payload !== false && (p.type === ERROR || Array.isArray(payload));
if (isPayloadValid) {
p.data = payload;
} else {
return error("invalid payload");
}
}
return p;
}
function tryParse(str) {
try {
return JSON.parse(str);
} catch (e) {
return false;
}
}
/**
* Deallocates a parser's resources
*
* @api public
*/
Decoder.prototype.destroy = function () {
if (this.reconstructor) {
this.reconstructor.finishedReconstruction();
}
};
function error(msg) {
return {
type: ERROR,
data: "parser error: " + msg,
};
}
module.exports = Decoder;