socket编程04: 错误处理和读写控制

原生的API中没有进行错误处理以及读写控制，在此我们将其封装：

#pragma once
#include <stdlib.h>
#include <errno.h>
#include <sys/socket.h>
#include <cstdio>
#include <error.h>
#include <zconf.h>

namespace wrap
{
void wrap_perr_exit(const char* str)
{
    perror(str);
    exit(1);
}

int wrap_accept(int fd, struct sockaddr *sockaddr_, socklen_t *socklen_)
{
    while (true)
    {
        int n = accept(fd, sockaddr_, socklen_);
        if(n < 0)
        {
            if( (errno == ECONNABORTED) || (errno == EINTR))
                continue;
            else
                perror("accept error");
        }
        else
            return n;
    }
}

void wrap_bind(int fd, const struct sockaddr *sockaddr_, socklen_t socklen_)
{
    if(bind(fd, sockaddr_, socklen_) < 0)
        perror("bind error");
}

void wrap_connect(int fd, const struct sockaddr *sockaddr_, socklen_t socklen_)
{
    if(connect(fd, sockaddr_, socklen_) < 0)
        perror("connect error");
}

void wrap_listen(int fd, int backlog)
{
    if(listen(fd, backlog) < 0)
        perror("listen error");
}

int wrap_socket(int family, int type, int protocol)
{
    int n = socket(family, type, protocol);
    if(n < 0)
        perror("socket error");
    return n;
}

ssize_t wrap_read(int fd, void *ptr, size_t n_bytes)
{
    while (true)
    {
        ssize_t n = read(fd, ptr, n_bytes);
        if(n == -1)
        {
            if(errno == EINTR)
                continue;
            else
                return -1;
        }
        else
            return n;
    }
}

ssize_t wrap_write(int fd, const void *ptr, size_t n_bytes)
{
    while(true)
    {
        ssize_t n = write(fd, ptr, n_bytes);
        if(n == -1)
        {
            if(errno == EINTR)
                continue;
            else
                return -1;
        }
        else
            return n;
    }
}

void wrap_close(int fd)
{
    int n = close(fd);
    if(n == -1)
        perror("close error");
}

ssize_t wrap_read_n(int fd, void *vptr, size_t n)
{
    size_t nleft = n;
    ssize_t nread;
    auto ptr = (char*) vptr;

    while(nleft > 0)
    {
        nread = read(fd, ptr, nleft);
        if(nread < 0)
        {
            if(errno == EINTR)
               nread = 0;
            else
                return -1;
        }
        else if(nread == 0)
            break;

        nleft -= nread;
        ptr += nread;
    }

    return n - nleft;
}

ssize_t wrap_write_n(int fd, const void *vptr, size_t n)
{
    size_t nleft = n;
    ssize_t nwritten;
    const char *ptr = (const char*) vptr;

    while(nleft > 0)
    {
        nwritten = write(fd, ptr, nleft);
        if(nwritten <= 0)
        {
            if(nwritten < 0 && errno == EINTR)
                nwritten = 0;
            else
                return -1;
        }
        nleft -= nwritten;
        ptr += nwritten;
    }
    return n;
}

}