TcpConnection.cpp

#include "TcpConnection.h"
#include "Logger.h"
#include "Socket.h"
#include "Channel.h"
#include "EventLoop.h"

#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <strings.h>
#include <netinet/tcp.h>

static EventLoop* CheckLoopNotNULL(EventLoop* loop)
{
    if (loop == nullptr)
    {
        LOG_FATAL("%s:%s:%d TcpConnection is null! \n", __FILE__, __FUNCTION__, __LINE__);

    }
    return loop;
}

TcpConnection::TcpConnection(EventLoop* loop,
                                const std::string &nameArg,
                                int sockfd,
                                const InetAddress& localAddr,
                                const InetAddress& peerAddr)
    : loop_(CheckLoopNotNULL(loop))
    , name_(nameArg)
    , state_(kConnecting)
    , reading_(true)
    , socket_(new Socket(sockfd))
    , channel_(new Channel(loop, sockfd))
    , localAddr_(localAddr)
    , peerAddr_(peerAddr)
    , highWaterMark_(64*1024*1024)
{
    channel_->setReadEventCallback(std::bind(&TcpConnection::handleRead, this, std::placeholders::_1));
    channel_->setWriteCallback(std::bind(&TcpConnection::handleWrite, this));
    channel_->setCloseCallback(std::bind(&TcpConnection::handleClose, this));
    channel_->setErrorCallback(std::bind(&TcpConnection::handleError, this));
    LOG_INFO("TcpConnection::ctor[%s] at fd=%d\n", name_.c_str(), sockfd);
    socket_->setKeepAlive(true);
}

TcpConnection::~TcpConnection()
{
    LOG_INFO("TcpConnection::dtor[%s] at fd=%d state=%d\n", name_.c_str(), channel_->fd(), (int)state_);
}

void TcpConnection::handleRead(Timestamp receiveTime)
{
    int savedErrno = 0;
    ssize_t n = inputBuffer_.readFd(channel_->fd(), &savedErrno);
    if (n > 0)
    {
        // 已建立连接的用户，有可读事件发生，调用用户传入的回调操作
        messageCallback_(shared_from_this(), &inputBuffer_, receiveTime);
    }
    else if (n == 0)
    {
        handleClose();
    }
    else
    {
        errno = savedErrno;
        LOG_ERROR("TcpConnection::handleRead\n");
        handleError();
    }
}

void TcpConnection::handleWrite()
{
    if (channel_->isWriting())
    {
        int savedErrno = 0;
        ssize_t n = outputBuffer_.writeFd(channel_->fd(), &savedErrno);
        if (n > 0)
        {
            outputBuffer_.retrieve(n);
            if (outputBuffer_.readableBytes() == 0)
            {
                channel_->disableWriting();
                if (writeCompleteCallback_)
                {
                    loop_->queueInLoop(std::bind(writeCompleteCallback_, shared_from_this()));
                }
                if (state_ == kDisconnecting)
                {
                    shutdownInLoop();
                }
            }
        }
        else
        {
            LOG_ERROR("TcpConnection::handleWrite.\n");
        }

    }
    else
    {
        LOG_ERROR("TcpConnection fd=%d is down, no more writing \n", channel_->fd());
    }
}

void TcpConnection::handleError()
{
    int optval;
    socklen_t optlen = sizeof optval;
    int err = 0;
    if (::getsockopt(channel_->fd(), SOL_SOCKET, SO_ERROR, &optval, &optlen) < 0)
    {
        err = errno;
    }
    else
    {
        err = optval;
    }
    LOG_ERROR("TcpConnection::handleError name:%s -SO_ERROR:%d\n", name_.c_str(), err);
}

// Poller通知Channel调用closeCallback方法，-》调用TcpConnection的handleClose方法
void TcpConnection::handleClose()
{
    LOG_INFO("fd=%d, state=%d\n", channel_->fd(), (int)state_);
    setState(kDisconnected);
    channel_->disableAll();
    TcpConnectionPtr connPtr(shared_from_this());
    connectionCallback_(connPtr); // 执行连接关闭的回调
    closeCallback_(connPtr);  // 关闭连接的回调
}

void TcpConnection::send(const std::string& buf)
{
    if (state_ == kConnected)
    {
        if (loop_->isInLoopThread())
        {
            sendInLoop(buf.c_str(), buf.size());
        }
        else
        {
            loop_->runInLoop(std::bind(&TcpConnection::sendInLoop, this, buf.c_str(), buf.size()));
        }
    }
}

void TcpConnection::sendInLoop(const void* data, size_t len)
{
    ssize_t nwrote = 0;
    ssize_t remaining = len;
    bool faultError = false;
    // 调用过shutdown
    if (state_ == kDisconnected)
    {
        LOG_ERROR("Disconnected, giveup writing.\n");
        return;
    }

    // channel第一次开始写数据，缓冲区没有待发送的数据
    if (!channel_->isWriting() && outputBuffer_.readableBytes() == 0)
    {
        nwrote = ::write(channel_->fd(), data, len);
        if (nwrote >=0 )
        {
            remaining = len - nwrote;
            if (remaining == 0 && writeCompleteCallback_)
            {
                // 既然一次性发送完成，就不用再给channel设置epollout事件
                loop_->queueInLoop(std::bind(writeCompleteCallback_, shared_from_this()));
            }
        }
        else
        {
            nwrote = 0;
            if (errno != EWOULDBLOCK)
            {
                LOG_ERROR("TcpConnection::sendInLoop\n");
                if (errno == EPIPE || errno == ECONNREFUSED)
                {
                    faultError = true;
                }
            }
        }
    }

    // 之前的一次write没有把数据全部发送出去，剩余的数据需要保存到缓冲区中，给channel注册epollout事件
    // poller发现tcp的发送缓冲区有空间，会通知相应的sock-channel，调用handlewrite回调方法
    // 也就是调用TcpConnection::handleWrite方法，把发送缓冲区的数据全部发送完成
    if (!faultError && remaining > 0)
    {
        size_t oldlen = outputBuffer_.readableBytes();
        if (oldlen + remaining >= highWaterMark_ &&
            oldlen < highWaterMark_ &&
            hightWaterMarkCallback_)
        {
            loop_->queueInLoop(std::bind(hightWaterMarkCallback_, shared_from_this(), oldlen + remaining));
        }
        outputBuffer_.append((char*)data + nwrote, remaining);
        if (!channel_->isWriting())
        {
            channel_->enableWriting(); // 一定要注册channel的写事件，否则Poller不会给Channel通知EPOLLOUT
        }
    }
}

void TcpConnection::shutdown()
{
    if (state_ == kConnected)
    {
        setState(kDisconnecting);
        loop_->runInLoop(std::bind(&TcpConnection::shutdownInLoop, this));
    }
}

void TcpConnection::shutdownInLoop()
{
    if (!channel_->isWriting()) // 当前outputbuffer中的数据已经全部发送完成
    {
        socket_->shutdownWrite(); // 关闭写端
    }
}

// 在创建连接时调用
void TcpConnection::connectEstablised()
{
    setState(kConnected);
    channel_->tie(shared_from_this());
    channel_->enableReading();

    connectionCallback_(shared_from_this());
}

// 在连接关闭时调用
void TcpConnection::connectDestroyed()
{
    if (state_ == kConnected)
    {
        setState(kDisconnected);
        channel_->disableAll(); // 把channel所有感兴趣的事件从Poller中del掉

        connectionCallback_(shared_from_this());
    }
    channel_->remove(); // 把channel从Poller中删除掉
}