ClickHouse/libs/libcommon/include/common/Pipe.h

#pragma once

#include <sys/types.h>
#include <sys/wait.h>
#include <fcntl.h>
#include <dlfcn.h>
#include <Common/Exception.h>
#include <port/unistd.h>
#include <stdexcept>

struct LazyPipe
{
    int fds_rw[2] = {-1, -1};

    LazyPipe() = default;

    virtual void open()
    {
        for (int &fd : fds_rw)
        {
            if (fd >= 0)
            {
                throw std::logic_error("Pipe is already opened");
            }
        }

#ifndef __APPLE__
        if (0 != pipe2(fds_rw, O_CLOEXEC))
            throw std::runtime_error("Cannot create pipe");
#else
        if (0 != pipe(fds_rw))
            throw std::runtime_error("Cannot create pipe");
        if (0 != fcntl(fds_rw[0], F_SETFD, FD_CLOEXEC))
            throw std::runtime_error("Cannot setup auto-close on exec for read end of pipe");
        if (0 != fcntl(fds_rw[1], F_SETFD, FD_CLOEXEC))
            throw std::runtime_error("Cannot setup auto-close on exec for write end of pipe");
#endif
    }

    virtual void close() {
        for (int fd : fds_rw)
        {
            if (fd >= 0)
            {
                ::close(fd);
            }
        }
    }

    virtual ~LazyPipe() = default;
};

struct Pipe : public LazyPipe {
    Pipe()
    {
        open();
    }

    ~Pipe()
    {
        close();
    }
};