/* Copyright (c) 2015-2018 Dovecot authors, see the included COPYING file */

#include "lib.h"

#include "fdpass.h"

#include "ostream-file-private.h"

#include "ostream-unix.h"

struct unix_ostream {

  struct file_ostream fstream;

  int write_fd;

};

static void

o_stream_unix_close(struct iostream_private *stream, bool close_parent)

{

  o_stream_file_close(stream, close_parent);

}

static ssize_t o_stream_unix_writev(struct file_ostream *fstream,

            const struct const_iovec *iov,

            unsigned int iov_count,

            const char **error_r)

{

  struct unix_ostream *ustream =

    container_of(fstream, struct unix_ostream, fstream);

  size_t sent;

  ssize_t ret;

  if (ustream->write_fd == -1) {

    /* no fd */

    return o_stream_file_writev(fstream, iov, iov_count, error_r);

  }

  /* send first iovec along with fd */

  if (iov_count == 0)

    return 0;

  i_assert(iov[0].iov_len > 0);

  ret = fd_send(fstream->fd, ustream->write_fd,

    iov[0].iov_base, iov[0].iov_len);

  if (ret < 0) {

    *error_r = t_strdup_printf("fd_send() failed: %m");

    return ret;

  }

  /* update stream */

  sent = ret;

  fstream->real_offset += sent;

  ustream->write_fd = -1;

  if (sent < iov[0].iov_len || iov_count == 1) {

    /* caller will call us again to write the rest */

    return sent;

  }

  /* send remaining iovecs */

  ret = o_stream_file_writev(fstream, &iov[1], iov_count-1, error_r);

  if (ret < 0)

    return  (errno == EAGAIN || errno == EINTR ? (ssize_t)sent : ret);

  sent += ret;

  return sent;

}

struct ostream *o_stream_create_unix(int fd, size_t max_buffer_size)

{

  struct unix_ostream *ustream;

  struct ostream *output;

  i_assert(fd != -1);

  ustream = i_new(struct unix_ostream, 1);

  ustream->write_fd = -1;

  output = o_stream_create_file_common(&ustream->fstream, fd,

              max_buffer_size, FALSE);

  output->real_stream->iostream.close = o_stream_unix_close;

  ustream->fstream.writev = o_stream_unix_writev;

  return output;

}

bool o_stream_unix_write_fd(struct ostream *output, int fd)

{

  struct unix_ostream *ustream =

    container_of(output->real_stream, struct unix_ostream,

           fstream.ostream);

  i_assert(fd >= 0);

  if (ustream->write_fd >= 0)

    return FALSE;

  ustream->write_fd = fd;

  return TRUE;

}