/* GLIB - Library of useful routines for C programming

 * gmappedfile.c: Simplified wrapper around the mmap() function.

 *

 * Copyright 2005 Matthias Clasen

 * Portions copyright (c) 2006-2009 Nokia Corporation.  All rights reserved.

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2 of the License, or (at your option) any later version.

 *

 * This library is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with this library; if not, write to the

 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,

 * Boston, MA 02111-1307, USA.

 */

#include "config.h"

#include <errno.h>

#include <sys/types.h> 

#include <sys/stat.h> 

#include <fcntl.h>

#ifdef HAVE_UNISTD_H

#include <unistd.h>

#endif

#ifdef HAVE_MMAP

#include <sys/mman.h>

#endif

#include "glibconfig.h"

#ifdef G_OS_WIN32

#include <windows.h>

#include <io.h>

#endif

#include "gconvert.h"

#include "gerror.h"

#include "gfileutils.h"

#include "gmappedfile.h"

#include "gmem.h"

#include "gmessages.h"

#include "gstdio.h"

#include "gstrfuncs.h"

#include "glibintl.h"

#include "galias.h"

#ifndef _O_BINARY

#define _O_BINARY 0

#endif

#ifndef MAP_FAILED

#define MAP_FAILED ((void *) -1)

#endif

struct _GMappedFile 

{

  gsize  length;

  gchar *contents;

#ifdef G_OS_WIN32

  HANDLE mapping;

#endif

};

/**

 * g_mapped_file_new:

 * @filename: The path of the file to load, in the GLib filename encoding

 * @writable: whether the mapping should be writable

 * @error: return location for a #GError, or %NULL

 *

 * Maps a file into memory. On UNIX, this is using the mmap() function.

 *

 * If @writable is %TRUE, the mapped buffer may be modified, otherwise

 * it is an error to modify the mapped buffer. Modifications to the buffer 

 * are not visible to other processes mapping the same file, and are not 

 * written back to the file.

 *

 * Note that modifications of the underlying file might affect the contents

 * of the #GMappedFile. Therefore, mapping should only be used if the file 

 * will not be modified, or if all modifications of the file are done

 * atomically (e.g. using g_file_set_contents()). 

 *

 * Return value: a newly allocated #GMappedFile which must be freed

 *    with g_mapped_file_free(), or %NULL if the mapping failed. 

 *

 * Since: 2.8

 */

EXPORT_C GMappedFile *

g_mapped_file_new (const gchar  *filename,

		   gboolean      writable,

		   GError      **error)

{

  GMappedFile *file;

  int fd;

  struct stat st;

  g_return_val_if_fail (filename != NULL, NULL);

  g_return_val_if_fail (!error || *error == NULL, NULL);

  fd = g_open (filename, (writable ? O_RDWR : O_RDONLY) | _O_BINARY, 0);

  if (fd == -1)

    {

      int save_errno = errno;

      gchar *display_filename = g_filename_display_name (filename);

      g_set_error (error,

                   G_FILE_ERROR,

                   g_file_error_from_errno (save_errno),

                   _("Failed to open file '%s': open() failed: %s"),

                   display_filename, 

		   g_strerror (save_errno));

      g_free (display_filename);

      return NULL;

    }

  file = g_new0 (GMappedFile, 1);

  if (fstat (fd, &st) == -1)

    {

      int save_errno = errno;

      gchar *display_filename = g_filename_display_name (filename);

      g_set_error (error,

                   G_FILE_ERROR,

                   g_file_error_from_errno (save_errno),

                   _("Failed to get attributes of file '%s': fstat() failed: %s"),

                   display_filename, 

		   g_strerror (save_errno));

      g_free (display_filename);

      goto out;

    }

  if (st.st_size == 0)

    {

      file->length = 0;

      file->contents = "";

      close (fd);

      return file;

    }

  file->contents = MAP_FAILED;

#ifdef HAVE_MMAP

  if (st.st_size > G_MAXSIZE)

    {

      errno = EINVAL;

    }

  else

    {      

      file->length = (gsize) st.st_size;

      file->contents = (gchar *) mmap (NULL,  file->length,

				       writable ? PROT_READ|PROT_WRITE : PROT_READ,

				       MAP_PRIVATE, fd, 0);

    }

#endif

#ifdef G_OS_WIN32

  file->length = st.st_size;

  file->mapping = CreateFileMapping ((HANDLE) _get_osfhandle (fd), NULL,

				     writable ? PAGE_WRITECOPY : PAGE_READONLY,

				     0, 0,

				     NULL);

  if (file->mapping != NULL)

    {

      file->contents = MapViewOfFile (file->mapping,

				      writable ? FILE_MAP_COPY : FILE_MAP_READ,

				      0, 0,

				      0);

      if (file->contents == NULL)

	{

	  file->contents = MAP_FAILED;

	  CloseHandle (file->mapping);

	  file->mapping = NULL;

	}

    }

#endif

  if (file->contents == MAP_FAILED)

    {

      int save_errno = errno;

      gchar *display_filename = g_filename_display_name (filename);

      g_set_error (error,

		   G_FILE_ERROR,

		   g_file_error_from_errno (save_errno),

		   _("Failed to map file '%s': mmap() failed: %s"),

		   display_filename,

		   g_strerror (save_errno));

      g_free (display_filename);

      goto out;

    }

  close (fd);

  return file;

 out:

  close (fd);

  g_free (file);

  return NULL;

}

/**

 * g_mapped_file_get_length:

 * @file: a #GMappedFile

 *

 * Returns the length of the contents of a #GMappedFile.

 *

 * Returns: the length of the contents of @file.

 *

 * Since: 2.8

 */

EXPORT_C gsize

g_mapped_file_get_length (GMappedFile *file)

{

  g_return_val_if_fail (file != NULL, 0);

  return file->length;

}

/**

 * g_mapped_file_get_contents:

 * @file: a #GMappedFile

 *

 * Returns the contents of a #GMappedFile. 

 *

 * Note that the contents may not be zero-terminated,

 * even if the #GMappedFile is backed by a text file.

 *

 * Returns: the contents of @file.

 *

 * Since: 2.8

 */

EXPORT_C gchar *

g_mapped_file_get_contents (GMappedFile *file)

{

  g_return_val_if_fail (file != NULL, NULL);

  return file->contents;

}

/**

 * g_mapped_file_free:

 * @file: a #GMappedFile

 *

 * Unmaps the buffer of @file and frees it. 

 *

 * Since: 2.8

 */

EXPORT_C void

g_mapped_file_free (GMappedFile *file)

{

  g_return_if_fail (file != NULL);

  if (file->length)

  {

#ifdef HAVE_MMAP

    munmap (file->contents, file->length);

#endif

#ifdef G_OS_WIN32

    UnmapViewOfFile (file->contents);

    CloseHandle (file->mapping);

#endif

  }

  g_free (file);

}

#define __G_MAPPED_FILE_C__

#include "galiasdef.c"