/* Copyright (c) 2014-2018 Dovecot authors, see the included COPYING file */

#include "lib.h"

#include "fdpass.h"

#include "istream-file-private.h"

#include "istream-unix.h"

struct unix_istream {

  struct file_istream fstream;

  bool next_read_fd;

  int read_fd;

};

static void

i_stream_unix_close(struct iostream_private *stream, bool close_parent)

{

  struct unix_istream *ustream =

    container_of(stream, struct unix_istream,

           fstream.istream.iostream);

  i_close_fd(&ustream->read_fd);

  i_stream_file_close(stream, close_parent);

}

static ssize_t i_stream_unix_read(struct istream_private *stream)

{

  struct unix_istream *ustream =

    container_of(stream, struct unix_istream, fstream.istream);

  size_t size;

  ssize_t ret;

  if (!ustream->next_read_fd)

    return i_stream_file_read(stream);

  i_assert(ustream->read_fd == -1);

  i_assert(ustream->fstream.skip_left == 0); /* not supported here.. */

  if (!i_stream_try_alloc(stream, 1, &size))

    return -2;

  ret = fd_read(stream->fd, stream->w_buffer + stream->pos, size,

          &ustream->read_fd);

  if (ustream->read_fd != -1)

    ustream->next_read_fd = FALSE;

  if (ret == 0) {

    /* EOF */

    stream->istream.eof = TRUE;

    ustream->fstream.seen_eof = TRUE;

    return -1;

  }

  if (unlikely(ret < 0)) {

    if ((errno == EINTR || errno == EAGAIN) &&

        !stream->istream.blocking) {

      return 0;

    } else {

      i_assert(errno != 0);

      /* if we get EBADF for a valid fd, it means something's

         really wrong and we'd better just crash. */

      i_assert(errno != EBADF);

      stream->istream.stream_errno = errno;

      return -1;

    }

  }

  stream->pos += ret;

  return ret;

}

struct istream *i_stream_create_unix(int fd, size_t max_buffer_size)

{

  struct unix_istream *ustream;

  struct istream *input;

  i_assert(fd != -1);

  ustream = i_new(struct unix_istream, 1);

  ustream->read_fd = -1;

  input = i_stream_create_file_common(&ustream->fstream, fd, NULL,

              max_buffer_size, FALSE);

  input->real_stream->iostream.close = i_stream_unix_close;

  input->real_stream->read = i_stream_unix_read;

  return input;

}

void i_stream_unix_set_read_fd(struct istream *input)

{

  struct unix_istream *ustream =

    container_of(input->real_stream, struct unix_istream,

           fstream.istream);

  ustream->next_read_fd = TRUE;

}

void i_stream_unix_unset_read_fd(struct istream *input)

{

  struct unix_istream *ustream =

    container_of(input->real_stream, struct unix_istream,

           fstream.istream);

  ustream->next_read_fd = FALSE;

}

int i_stream_unix_get_read_fd(struct istream *input)

{

  struct unix_istream *ustream =

    container_of(input->real_stream, struct unix_istream,

           fstream.istream);

  int fd;

  fd = ustream->read_fd;

  ustream->read_fd = -1;

  return fd;

}