libi2ncommon: (gerd) initial submission, not in use yet

[libi2ncommon] / src / oftmpstream.cpp

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/stat.h>

#include <oftmpstream.hxx>

using namespace std;

void fdoutbuf::set_fd(int _fd) {
    fd = _fd;
}

int fdoutbuf::overflow (int_type c) {
    if (fd == -1)
        return c;

    if (c != EOF) {
        char z = c;
        if (write (fd, &z, 1) != 1) {
            return EOF;
        }
    }
    return c;
}
// write multiple characters
std::streamsize fdoutbuf::xsputn (const char* s,
                                  std::streamsize num) {
    if (fd == -1)
        return (num);
    
    return write(fd,s,num);
}


oftmpstream::oftmpstream () : ostream(0) {
    fd = -1;
    rdbuf(&buf);
    is_open = false;
}

oftmpstream::oftmpstream (const char *name) : ostream(0) {
    fd = -1;
    rdbuf(&buf);
    is_open = false;

    open(name);
}

oftmpstream::~oftmpstream () {
    close();
}

void oftmpstream::open (const char *name)
{
    if (is_open)
        close();

    realname = name;
    tmpname=string(name)+".XXXXXX";
    
    char* chbuf=new char[tmpname.size()+1];
    tmpname.copy(chbuf,tmpname.size()+1);
    chbuf[tmpname.size()]=0;
    fd=mkstemp(chbuf);
    tmpname=chbuf;
    delete[] chbuf;

    if (fd==-1)
    {
        string err="error creating temporary file "+tmpname;
        err+=": ";
        err+=strerror(errno);
        throw ios_base::failure(err);
    }
    
    buf.set_fd(fd);
    is_open = true;
}

void oftmpstream::close()
{
    if (!is_open)
        return;

    fsync(fd);
    fchmod (fd, 0644);    // fix mkstemp permissions
    ::close (fd);

    if (rename (tmpname.c_str(), realname.c_str()) != 0)
    {
        string err="error renaming temporary file "+tmpname;
        err+=" to "+realname;
        err+=": ";
        err+=strerror(errno);
        throw ios_base::failure(err);
    }

    fd = -1;
    is_open = false;
}