[Muduo socket] InetAddress encapsulates the socket address type

When parsing the source code ： First understand the core code , You don't need to know about branches first , Reading line by line is easy to get confused  

First of all, the log is finished , Let's see TcpServer, TcpServer Namely muduo A class of program entry of Network Library . Then combine this class , Let's look at its constructor ：

1. EventLoop *loop : Event The event loop , The larger , Just leave it alone
2. const InetAddress& listenAddr  ：IP Address and port number encapsulate classes , As TcpServer The parameters of the constructor of the object are passed in . This class is relatively small . You can deal with it first
3. const string& nameArg  ：    
4. Option option = kNoReusePort ：

encapsulation SOCKET Address type ：ipv4,Ipv6

We only package ipv4

Member functions ：

1. explicit InetAddress(uint16_t port, std::string ip = "127.0.0.1") ： Constructor passes in the port number and IP Address , Then encapsulate the address port

2. explicit InetAddress(const sockaddr_in &addr): addr_(addr) { } ： Direct in sockaddr Of sock Address

3. std::string toIp() const;    obtain IP Information

4. std::string toIpPort() const;  obtain IP、PORT Information

5. uint64_t toPort() const;  Get the port number

6. const sockaddr_in* getSockaddr() const :  Get member variables

Member variables ：

1. sockaddr_in addr_;    sock Address

//InetAddress.h

#pragma once

#include <arpa/inet.h>
#include <netinet/in.h>
#include <string>

class InetAddress
{
    public:
        explicit InetAddress(uint16_t port, std::string ip = "127.0.0.1");
        explicit InetAddress(const sockaddr_in &addr): addr_(addr) { }

        std::string toIp() const;
        std::string toIpPort() const;

        uint64_t toPort() const;

        const sockaddr_in* getSockaddr() const { return &addr_; }
    private:
        sockaddr_in addr_;
};

//InetAddress.cc

#include "InetAddress.h"

#include <strings.h>
#include <string.h>

InetAddress::InetAddress(uint16_t port, std::string ip)
{
    bzero(&addr_, sizeof addr_); // Zero clearing 
    addr_.sin_family = AF_INET;
    addr_.sin_port = htons(port); 
    // Convert a string into an integer ip Address , Then turn to network byte order 
    addr_.sin_addr.s_addr = inet_addr(ip.c_str()); 
}
        
std::string InetAddress::toIp() const
{
    // Because we have converted the network byte order , Need to reverse local byte order 
    char buf[64] = {0};
    ::inet_ntop(AF_INET, &addr_.sin_addr, buf, sizeof(buf));
    return buf;
}

std::string InetAddress::toIpPort() const
{
    char buf[64] = {0};
    ::inet_ntop(AF_INET, &addr_.sin_addr, buf, sizeof(buf));

    size_t end = strlen(buf);
    uint16_t port = ntohs(addr_.sin_port);
    sprintf(buf+ end, ":%u", port);
    return buf;
}

uint64_t InetAddress::toPort() const
{
    return ntohs(addr_.sin_port);
}

// #include <iostream>
// int main()
// {
//     InetAddress addr(8080);
//     std::cout << addr.toIpPort() << std::endl;
//     return 0;
// }