IXWebSocket/ixwebsocket/IXWebSocketTransport.h

/*
 *  IXWebSocketTransport.h
 *  Author: Benjamin Sergeant
 *  Copyright (c) 2017-2018 Machine Zone, Inc. All rights reserved.
 */

#pragma once

//
// Adapted from https://github.com/dhbaird/easywsclient
//

#include <string>
#include <vector>
#include <functional>
#include <memory>
#include <mutex>
#include <atomic>

#include "IXWebSocketSendInfo.h"
#include "IXWebSocketPerMessageDeflate.h"
#include "IXWebSocketPerMessageDeflateOptions.h"
#include "IXWebSocketHttpHeaders.h"
#include "IXCancellationRequest.h"
#include "IXWebSocketHandshake.h"

namespace ix 
{
    class Socket;

    class WebSocketTransport
    {
    public:
        enum ReadyStateValues
        {
            CLOSING,
            CLOSED,
            CONNECTING,
            OPEN
        };

        enum MessageKind
        {
            MSG,
            PING,
            PONG
        };

        using OnMessageCallback = std::function<void(const std::string&,
                                                     size_t,
                                                     bool,
                                                     MessageKind)>;
        using OnCloseCallback = std::function<void(uint16_t,
                                                   const std::string&,
                                                   size_t)>;

        WebSocketTransport();
        ~WebSocketTransport();

        void configure(const WebSocketPerMessageDeflateOptions& perMessageDeflateOptions,
                       int hearBeatPeriod);

        WebSocketInitResult connectToUrl(const std::string& url, // Client
                                         int timeoutSecs);
        WebSocketInitResult connectToSocket(int fd,              // Server
                                            int timeoutSecs);

        void poll();
        WebSocketSendInfo sendBinary(const std::string& message);
        WebSocketSendInfo sendPing(const std::string& message);
        void close();
        ReadyStateValues getReadyState() const;
        void setReadyState(ReadyStateValues readyStateValue);
        void setOnCloseCallback(const OnCloseCallback& onCloseCallback);
        void dispatch(const OnMessageCallback& onMessageCallback);

    private:
        std::string _url;
        std::string _origin;

        struct wsheader_type {
            unsigned header_size;
            bool fin;
            bool rsv1;
            bool mask;
            enum opcode_type {
                CONTINUATION = 0x0,
                TEXT_FRAME = 0x1,
                BINARY_FRAME = 0x2,
                CLOSE = 8,
                PING = 9,
                PONG = 0xa,
            } opcode;
            int N0;
            uint64_t N;
            uint8_t masking_key[4];
        };

        std::vector<uint8_t> _rxbuf;
        std::vector<uint8_t> _txbuf;
        mutable std::mutex _txbufMutex;
        std::vector<uint8_t> _receivedData;

        std::shared_ptr<Socket> _socket;

        std::atomic<ReadyStateValues> _readyState;

        OnCloseCallback _onCloseCallback;
        uint16_t _closeCode;
        std::string _closeReason;
        size_t _closeWireSize;
        mutable std::mutex _closeDataMutex;

        WebSocketPerMessageDeflate _perMessageDeflate;
        WebSocketPerMessageDeflateOptions _perMessageDeflateOptions;
        std::atomic<bool> _enablePerMessageDeflate;

        // Used to cancel dns lookup + socket connect + http upgrade
        std::atomic<bool> _requestInitCancellation;
        
        // Optional Heartbeat
        int _heartBeatPeriod;
        static const int kDefaultHeartBeatPeriod;
        const static std::string kHeartBeatPingMessage;
        mutable std::mutex _lastSendTimePointMutex;
        std::chrono::time_point<std::chrono::steady_clock> _lastSendTimePoint;

        // No data was send through the socket for longer that the hearbeat period
        bool heartBeatPeriodExceeded();

        void sendOnSocket();
        WebSocketSendInfo sendData(wsheader_type::opcode_type type, 
                                   const std::string& message,
                                   bool compress);

        void emitMessage(MessageKind messageKind, 
                         const std::string& message,
                         const wsheader_type& ws,
                         const OnMessageCallback& onMessageCallback);

        bool isSendBufferEmpty() const;
        void appendToSendBuffer(const std::vector<uint8_t>& header,
                                std::string::const_iterator begin,
                                std::string::const_iterator end,
                                uint64_t message_size,
                                uint8_t masking_key[4]);
        void appendToSendBuffer(const std::vector<uint8_t>& buffer);

        unsigned getRandomUnsigned();
        void unmaskReceiveBuffer(const wsheader_type& ws);
    };
}