LUMIERA.clone/src/backend/file.h
Christian Thaeter 444b142d85 Correct File flag masking
The hash lookup needs to ignore O_EXCL|O_TRUNC|O_CREAT as well as file
reopening must not use this flags.
2008-05-19 16:27:29 +02:00

123 lines
3.7 KiB
C

/*
file.h - interface to files by filename
Copyright (C) Lumiera.org
2008, Christian Thaeter <ct@pipapo.org>
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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#ifndef LUMIERA_FILE_H
#define LUMIERA_FILE_H
#include "lib/mutex.h"
#include "lib/llist.h"
#include "lib/error.h"
NOBUG_DECLARE_FLAG (file);
LUMIERA_ERROR_DECLARE(FILE_CHANGED);
/**
* @file
* File management
* Handling Files is splitted into different classes:
* 1. The 'lumiera_file' class which acts as interface to the outside for managing files.
* 'lumiera_file' is addressed by the name of the file. Since files can have more than one name (hardlinks)
* many 'lumiera_file' can point to a single 'lumiera_filedescriptor'
* 2. The 'lumiera_filedescriptor' class which does the real work managing the file in the back.
* 3. Since OS-filehandles are a limited resource we access the lazily as 'lumiera_filehandle' which are
* managed in a 'lumiera_filehandlecache'
*/
typedef struct lumiera_file_struct lumiera_file;
typedef lumiera_file* LumieraFile;
#include "backend/filehandle.h"
#include "backend/filedescriptor.h"
#define LUMIERA_FILE_READONLY (O_RDONLY | O_LARGEFILE | O_NOATIME)
#define LUMIERA_FILE_READWRITE (O_RDWR | O_LARGEFILE | O_NOATIME)
#define LUMIERA_FILE_CREATE (O_RDWR | O_LARGEFILE | O_NOATIME | O_CREAT | O_EXCL)
#define LUMIERA_FILE_RECREATE (O_RDWR | O_LARGEFILE | O_NOATIME | O_CREAT | O_TRUNC)
/* creat and excl flags will be masked out for descriptor lookup */
#define LUMIERA_FILE_MASK ~(O_CREAT | O_EXCL | O_TRUNC)
struct lumiera_file_struct
{
const char* name;
LumieraFiledescriptor descriptor;
};
/**
* Initialize a file structure.
* @param self pointer to the file structure
* @param name filename
* @param flags open flags
* @return self
*/
LumieraFile
lumiera_file_init (LumieraFile self, const char* name, int flags);
/**
* Destroy a file structure.
* frees all associated resources, releases the filedescriptor etc.
* @param self file structure to be destroyed
* @return self
*/
LumieraFile
lumiera_file_destroy (LumieraFile self);
/**
* Allocate a new file structure.
* @param name filename
* @param flags open flags
* @return new file structure
*/
LumieraFile
lumiera_file_new (const char* name, int flags);
/**
* Frees a file structure.
* @param self file structure to be freed
*/
void
lumiera_file_delete (LumieraFile self);
/**
* Get a POSIX filehandle for a file.
* Filehandles are opened on demand and must be acquired for use.
* Using filehandles is refcounted and might be nested.
* After using them they must be released which puts them back into filehandlecache aging.
* @param self file structure
* @return POSIX filehandle or -1 on error, check lumiera_error() to retrieve the errorcode
* Currently only LUMIERA_ERROR_ERRNO will be raised but this might change in future.
* Opening files can fail for many reasons and at any time!
*/
int
lumiera_file_handle_acquire (LumieraFile self);
/**
* Put filehandle back into cache aging.
* @param self file which handle to be released
*/
void
lumiera_file_handle_release (LumieraFile self);
#endif