/*
	EXVFSProtocol.h

	Protocol which is implemented by the classes which permits to interact with 
	a VFS.

	Copyright (C) 2004 Quentin Mathe <qmathe@club-internet.fr>

	Author:   Quentin Mathe <qmathe@club-internet.fr>
	Date:  July 2004

	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 2.1 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
*/

typedef enum _EXLinkStyle
{
    EXLinkStyleSoft,
    EXLinkStyleHard,
    EXLinkStyleUniversal // Should be used most of the time
} EXLinkStyle;

typedef enum _EXReadWritePosition
{
    EXReadWritePositionStart,
    EXReadWritePositionCurrent,
    EXReadWritePositionEnd
} EXReadWritePosition;

typedef enum _EXVFSContentMode
{
    EXVFSContentModeRead,
    EXVFSContentModeWrite,
    EXVFSContentModeReadWrite
} EXVFSContentMode;

@class NSError;
@class EXContext;
@class EXVFSHandle;

@protocol EXVFSProtocol

/*
 * Protocols related methods
 */

- (NSArray *) supportedProtocols;

/*
 * Destroy and create contexts
 */

- (BOOL) createEntityContextAtURL: (NSURL *)url error: (NSError **)error;
- (BOOL) createElementContextAtURL: (NSURL *)url error: (NSError **)error;
- (BOOL) removeContextAtURL: (NSURL *)url handler: (id)handler;
- (BOOL) removeContextsAtURLs: (NSArray *)urls handler: (id)handler;

/*
 * Manipulate contexts
 */

- (BOOL) copyContextWithURL: (NSURL *)source 
                      toURL: (NSURL *)destination 
                    handler: (id)handler;
- (BOOL) copyContextsWithURLs: (NSArray *)sources 
                        toURL: (NSURL *)destination 
                      handler: (id)handler;
- (BOOL) linkContextWithURL: (NSURL *)source 
                      toURL: (NSURL *)destination 
                    handler: (id)handler
                  linkStyle: (EXLinkStyle) style;
- (BOOL) moveContextWithURL: (NSURL *)source 
                      toURL: (NSURL *)destination 
                    handler: (id)handler;
- (BOOL) moveContextsWithURLs: (NSArray *)sources 
                        toURL: (NSURL *)destination 
                      handler: (id)handler;

/*
 * Visit contexts
 */
 
- (NSArray *) subcontextsURLsAtURL: (NSURL *)url deep: (BOOL)flag;
 
/*
 * Open, close contexts
 */
 
- (EXVFSHandle *) openContextWithURL: (NSURL *)url mode: (EXVFSContentMode)mode;
- (void) closeContextWithVFSHandle: (EXVFSHandle *)handle;

/*
 * Read, write contexts
 */
  
- (NSData *) readContextWithVFSHandle: (EXVFSHandle *)handle 
                               lenght: (unsigned long long)lenght 
                                error: (NSError **)error;
- (void) writeContextWithVFSHandle: (EXVFSHandle *)handle  
                              data: (NSData *)data 
                            lenght: (unsigned long long)lenght 
                             error: (NSError **)error;
- (void) setPositionIntoContextWithVFSHandle: (EXVFSHandle *)handle 
                                       start: (EXReadWritePosition)start 
                                      offset: (long long)offset 
                                       error: (NSError **)error;
- (long long) positionIntoContextWithVFSHandle: (EXVFSHandle *)handle 
                                         error: (NSError **)error;
                                     
@end