file.hpp

mysql-5.0.22.tar.gz源码包

/* Copyright (C) 2003 MySQL AB

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

   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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */

#ifndef FILE_H
#define FILE_H

#include <ndb_global.h>

/**
 * This class provides a file abstraction . It has operations
 * to create, read, write and delete a file.
 *
 * @version #@ $Id: File.hpp,v 1.5 2002/04/26 13:15:38 ejonore Exp $
 */
class File_class
{
public:
  /**
   * Returns true if the file exist.
   *
   * @param aFileName a filename to check.
   * @return true if the file exists.
   */
  static bool exists(const char* aFileName);      

  /**
   * Returns the size of a file.
   *
   * @param f a pointer to a FILE descriptor.
   * @return the size of the file.
   */
  static long size(FILE* f);

  /**
   * Renames a file.
   *
   * @param currFileName the current name of the file.
   * @param newFileName the new name of the file.
   * @return true if successful.
   */
  static bool rename(const char* currFileName, const char* newFileName);

  /**
   * Removes/deletes a file.
   *
   * @param aFileName the file to remove.
   * @return true if successful.
   */
  static bool remove(const char* aFileName);      
  
  /**
   * Default constructor.
   */
  File_class();

  /**
   * Creates a new File  with the specified filename and file mode. 
   * The real file itself will not be created unless open() is called!
   *
   * To see the available file modes use 'man 3 fopen'.
   *
   * @param aFileName a filename.
   * @param mode the mode which the file should be opened/created with, default "r".
   */
  File_class(const char* aFileName, const char* mode = "r");

  /**
   * Destructor.
   */
  ~File_class();

  /**
   * Opens/creates the file. If open() fails then 'errno' and perror() 
   * should be used to determine the exact failure cause.
   *
   * @return true if successful. Check errno if unsuccessful.
   */
  bool open();

  /**
   * Opens/creates the file with the specified name and mode.
   * If open() fails then 'errno' and perror() should be used to 
   * determine the exact failure cause.
   *
   * @param aFileName the file to open.
   * @param mode the file mode to use.
   * @return true if successful. Check errno if unsuccessful.   
   */
  bool open(const char* aFileName, const char* mode);

  /**
   * Removes the file.
   *
   * @return true if successful.
   */
  bool remove();

  /**
   * Closes the file, i.e., the FILE descriptor is closed.
   */
  bool close();

  /**
   * Read from the file. See fread() for more info.
   *
   * @param buf the buffer to read into.
   * @param itemSize the size of each item. 
   * @param nitems read max n number of items.
   * @return 0 if successful.
   */
  int read(void* buf, size_t itemSize, size_t nitems) const;

  /**
   * Read char from the file. See fread() for more info.
   *
   * @param buf the buffer to read into.
   * @param start the start index of the buf.
   * @param length the length of the buffer.
   * @return 0 if successful.
   */
  int readChar(char* buf, long start, long length) const;  

  /**
   * Read chars from the file. See fread() for more info.
   *
   * @param buf the buffer to read into.
   * @return 0 if successful.
   */
  int readChar(char* buf);  

  /**
   * Write to file. See fwrite() for more info.
   *
   * @param buf the buffer to read from.
   * @param itemSize the size of each item. 
   * @param nitems write max n number of items.
   * @return 0 if successful.
   */
  int write(const void* buf, size_t itemSize, size_t nitems);     

  /**
   * Write chars to file. See fwrite() for more info.
   *
   * @param buf the buffer to read from.
   * @param start the start index of the buf.
   * @param length the length of the buffer.
   * @return 0 if successful.
   */
  int writeChar(const char* buf, long start, long length);   

  /**
   * Write chars to file. See fwrite() for more info.
   *
   * @param buf the buffer to read from.
   * @return 0 if successful.
   */
  int writeChar(const char* buf); 

  /**
   * Returns the file size.
   *
   * @return the file size.
   */
  long size() const;

  /**
   * Returns the filename.
   *
   * @return the filename.
   */
  const char* getName() const;

  /**
   * Flush the buffer.
   *
   * @return 0 if successful.
   */
  int flush() const;

private:
  FILE* m_file;
  char m_fileName[PATH_MAX];
  const char* m_fileMode;
  /* Prohibit */
  File_class (const File_class& aCopy);
  File_class operator = (const File_class&); 
  bool operator == (const File_class&);
};
#endif