/* mpsioan.c: RAVENBROOK MEMORY POOL SYSTEM I/O IMPLEMENTATION (ANSI)
 *
 * $Id$
 * Copyright (c) 2001-2020 Ravenbrook Limited.  See end of file for license.
 *
 * .readership: For MPS client application developers and MPS developers.
 * .sources: <design/io>
 */

#include "mpsio.h"
#include "mpstd.h"

/* We don't want to use the ANSI assert() to check that the interface
 * is being used correctly, because it's not controlled by the MPS
 * variety mechanism: we might end up with assertions being turned on
 * in the HOT variety or turned off in the COOL variety (depending on
 * whether or not the client program compiles the MPS with NDEBUG
 * defined). So we include "check.h" and use AVER() instead. See
 * job003504. If you are developing your own plinth, you should
 * consider whether to use your own preferred assertion mechanism
 * instead.
 */
#include "check.h"
#include "config.h"  /* to get platform configurations */

#include <stdio.h>
#include <stdlib.h>


static FILE *ioFile = NULL;

#ifdef MPS_BUILD_MV
/* MSVC warning 4996 = stdio / C runtime 'unsafe' */
/* Objects to: fopen.  See job001934. */
#pragma warning( disable : 4996 )
#endif

mps_res_t mps_io_create(mps_io_t *mps_io_r)
{
  FILE *f;
  const char *filename;

  if(ioFile != NULL) /* See <code/event.c#trans.log> */
    return MPS_RES_LIMIT; /* Cannot currently open more than one log */

  filename = getenv("MPS_TELEMETRY_FILENAME");
  if(filename == NULL)
    filename = "mpsio.log";

  f = fopen(filename, "wb");
  if(f == NULL)
    return MPS_RES_IO;

  *mps_io_r = (mps_io_t)f;
  ioFile = f;
  return MPS_RES_OK;
}


void mps_io_destroy(mps_io_t mps_io)
{
  FILE *f = (FILE *)mps_io;
  AVER(f == ioFile);
  AVER(f != NULL);

  ioFile = NULL;
  (void)fclose(f);
}


mps_res_t mps_io_write(mps_io_t mps_io, void *buf, size_t size)
{
  FILE *f = (FILE *)mps_io;
  size_t n;
  AVER(f == ioFile);
  AVER(f != NULL);

  n = fwrite(buf, size, 1, f);
  if(n != 1)
    return MPS_RES_IO;

  return MPS_RES_OK;
}


mps_res_t mps_io_flush(mps_io_t mps_io)
{
  FILE *f = (FILE *)mps_io;
  int e;
  AVER(f == ioFile);
  AVER(f != NULL);

  e = fflush(f);
  if(e == EOF)
    return MPS_RES_IO;

  return MPS_RES_OK;
}


/* C. COPYRIGHT AND LICENSE
 *
 * Copyright (C) 2001-2020 Ravenbrook Limited <https://www.ravenbrook.com/>.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the
 *    distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
 * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */