mysql5/mysql-5.7.27/mysys/my_fstream.c

/* Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; version 2 of the License.

   This program 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 General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */

#include "mysys_priv.h"
#include "my_sys.h"
#include "mysys_err.h"
#include <errno.h>
#include <stdio.h>
#include "my_thread_local.h"


#ifdef HAVE_FSEEKO
#undef ftell
#undef fseek
#define ftell(A) ftello(A)
#define fseek(A,B,C) fseeko((A),(B),(C))
#endif

/*
  Read a chunk of bytes from a FILE

  SYNOPSIS
   my_fread()
   stream	File descriptor
   Buffer	Buffer to read to
   Count	Number of bytes to read
   MyFlags	Flags on what to do on error

  RETURN
    (size_t) -1 Error
    #		Number of bytes read
 */

size_t my_fread(FILE *stream, uchar *Buffer, size_t Count, myf MyFlags)
{
  size_t readbytes;
  DBUG_ENTER("my_fread");
  DBUG_PRINT("my",("stream: 0x%lx  Buffer: 0x%lx  Count: %u  MyFlags: %d",
		   (long) stream, (long) Buffer, (uint) Count, MyFlags));

  if ((readbytes= fread(Buffer, sizeof(char), Count, stream)) != Count)
  {
    DBUG_PRINT("error",("Read only %d bytes", (int) readbytes));
    if (MyFlags & (MY_WME | MY_FAE | MY_FNABP))
    {
      if (ferror(stream))
      {
        char errbuf[MYSYS_STRERROR_SIZE];
        my_error(EE_READ, MYF(0),
                 my_filename(my_fileno(stream)),
                 errno, my_strerror(errbuf, sizeof(errbuf), errno));
      }
      else
      if (MyFlags & (MY_NABP | MY_FNABP))
      {
        char errbuf[MYSYS_STRERROR_SIZE];
        my_error(EE_EOFERR, MYF(0),
                 my_filename(my_fileno(stream)), errno,
                 my_strerror(errbuf, sizeof(errbuf), errno));
      }
    }
    set_my_errno(errno ? errno : -1);
    if (ferror(stream) || MyFlags & (MY_NABP | MY_FNABP))
      DBUG_RETURN((size_t) -1);			/* Return with error */
  }
  if (MyFlags & (MY_NABP | MY_FNABP))
    DBUG_RETURN(0);				/* Read ok */
  DBUG_RETURN(readbytes);
} /* my_fread */


/*
  Write a chunk of bytes to a stream

   my_fwrite()
   stream	File descriptor
   Buffer	Buffer to write from
   Count	Number of bytes to write
   MyFlags	Flags on what to do on error

  RETURN
    (size_t) -1 Error
    #		Number of bytes written
*/

size_t my_fwrite(FILE *stream, const uchar *Buffer, size_t Count, myf MyFlags)
{
  size_t writtenbytes =0;
  my_off_t seekptr;

  DBUG_ENTER("my_fwrite");
  DBUG_PRINT("my",("stream: 0x%lx  Buffer: 0x%lx  Count: %u  MyFlags: %d",
		   (long) stream, (long) Buffer, (uint) Count, MyFlags));
  DBUG_EXECUTE_IF("simulate_fwrite_error",  DBUG_RETURN(-1););

  seekptr= ftell(stream);
  for (;;)
  {
    size_t written;
    if ((written = (size_t) fwrite((char*) Buffer,sizeof(char),
                                   Count, stream)) != Count)
    {
      DBUG_PRINT("error",("Write only %d bytes", (int) writtenbytes));
      set_my_errno(errno);
      if (written != (size_t) -1)
      {
	seekptr+=written;
	Buffer+=written;
	writtenbytes+=written;
	Count-=written;
      }
      if (errno == EINTR)
      {
	(void) my_fseek(stream,seekptr,MY_SEEK_SET,MYF(0));
	continue;
      }
      if (ferror(stream) || (MyFlags & (MY_NABP | MY_FNABP)))
      {
        if (MyFlags & (MY_WME | MY_FAE | MY_FNABP))
        {
          char errbuf[MYSYS_STRERROR_SIZE];
          my_error(EE_WRITE, MYF(0),
                   my_filename(my_fileno(stream)),
                   errno, my_strerror(errbuf, sizeof(errbuf), errno));
        }
        writtenbytes= (size_t) -1;        /* Return that we got error */
        break;
      }
    }
    if (MyFlags & (MY_NABP | MY_FNABP))
      writtenbytes= 0;				/* Everything OK */
    else
      writtenbytes+= written;
    break;
  }
  DBUG_RETURN(writtenbytes);
} /* my_fwrite */


/* Seek to position in file */

my_off_t my_fseek(FILE *stream, my_off_t pos, int whence,
		  myf MyFlags MY_ATTRIBUTE((unused)))
{
  DBUG_ENTER("my_fseek");
  DBUG_PRINT("my",("stream: 0x%lx  pos: %lu  whence: %d  MyFlags: %d",
                   (long) stream, (long) pos, whence, MyFlags));
  DBUG_RETURN(fseek(stream, (off_t) pos, whence) ?
	      MY_FILEPOS_ERROR : (my_off_t) ftell(stream));
} /* my_seek */


/* Tell current position of file */

my_off_t my_ftell(FILE *stream, myf MyFlags MY_ATTRIBUTE((unused)))
{
  off_t pos;
  DBUG_ENTER("my_ftell");
  DBUG_PRINT("my",("stream: 0x%lx  MyFlags: %d", (long) stream, MyFlags));
  pos=ftell(stream);
  DBUG_PRINT("exit",("ftell: %lu",(ulong) pos));
  DBUG_RETURN((my_off_t) pos);
} /* my_ftell */


/* Get a File corresponding to the stream*/
int my_fileno(FILE *f)
{
#ifdef _WIN32
  return my_win_fileno(f);
#else
 return fileno(f);
#endif
}