haiku-beta6/headers/private/disk_scanner/fs.h

//----------------------------------------------------------------------
//  This software is part of the OpenBeOS distribution and is covered 
//  by the OpenBeOS license.
//---------------------------------------------------------------------
/*!
	\file filesystem.h
	hook function declarations for disk_scanner filesystem modules
*/

#ifndef _PARTSCAN_FS_H
#define _PARTSCAN_FS_H

#include <module.h>

struct extended_partition_info;

struct fs_buffer_cache;
typedef status_t (*fs_get_buffer)(struct fs_buffer_cache *cache,
	off_t offset, size_t size, void **buffer, size_t *actualSize);

typedef bool (*fs_identify_hook)(int deviceFD,
	struct extended_partition_info *partitionInfo, float *priority,
	fs_get_buffer get_buffer, struct fs_buffer_cache *cache);

typedef struct fs_module_info {
	module_info			module;

	fs_identify_hook	identify;
} fs_module_info;

/*
	identify():
	----------

	Expects partitionInfo to be partially initialized and, if
	the module is able to recognize the FS on the partition, fills in
	the fields:
	* file_system_short_name
	* file_system_long_name
	* volume_name

	The minimally required fields are:
	* offset
	* size
	* logical_block_size

	params:
	deviceFD: a device FD
	partitionInfo: the partition info
	priority: Pointer to a float in which the priority of the FS shall be
			  stored. Used in case several FS add-ons recognize the FS;
			  then the module returning the highest priority is used.
			  -1 <= *priority <= 1
	get_buffer: Function that should be used to read data from the device.
	cache: To be passed to get_buffer.

	Returns true, if successful (i.e. the FS was recognized), false otherwise.


	fs_get_buffer():
	---------------

	Supplied with offset and size the function reads data from the device
	into a buffer it allocates, and returns the buffer.

	params:
	cache: the cache for the device
	offset: offset from which to read, relative to the beginning of the
			*partition*
	size: number of bytes to be read
	buffer: pointer to a pre-allocated void* to be set to the read buffer
	actualSize: pointer to a pre-allocated size_t to be set to the actual
				number of bytes read from the device

	Returns B_OK, if everything went fine, an error code otherwise.
*/

#endif	// _PARTSCAN_FS_H