sysutil.hxx

#ifndef __sysutil_hxx__
#define __sysutil_hxx__



#include <stdexcept>
#include <errno.h>


template <class T, std::size_t N>
constexpr std::size_t array_size(const T (&array)[N]) noexcept
{
    return N;
}


class SystemException : public std::runtime_error {
public:
    SystemException(const char* msg, int errnum)
        : std::runtime_error(msg),
          errno_(errnum)
    {}

    ~SystemException() noexcept
    {}

    virtual const char* what() const noexcept
    {
        return (
            std::string(std::runtime_error::what()) + ": " +
            std::string(strerror(errno_))
        ).c_str();
    }

private:
    std::string msg_;
    const int errno_;
};


std::string get_current_dir()
{
    char name[4096] = {};
    if ( getcwd(name, sizeof(name)) == NULL )
        throw SystemException("getcwd failed", errno);

    return std::string(name);
}


void change_dir(const std::string &path)
{
    if ( chdir(path.c_str()) != 0 )
        throw SystemException("chdir failed", errno);
}


void ensure_mount_point(const char* mount_point)
{
    if ( mkdir(mount_point, 0777) == -1 )
        if ( errno != EEXIST )
            throw SystemException("Invalid mount point", errno);
}



#endif // include guard