//
//  ExtendedAttributes.m, based on UKXattrMetadataStore.m
//
//	License: MIT <http://opensource.org/licenses/mit-license.php>
//
//  Modified by Chris Lee <clee@mg8.org>
//  Originally created by Uli Kusterer on 12.03.06.
//  Copyright 2006 Uli Kusterer. All rights reserved.
//

#if MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_4
// -----------------------------------------------------------------------------
//	Headers:
// -----------------------------------------------------------------------------

#import "ExtendedAttributes.h"
#import <sys/xattr.h>


@implementation ExtendedAttributes

// -----------------------------------------------------------------------------
//	allKeysAtPath:
//		Return an NSArray of NSStrings containing all xattr names currently set
//		for the file at the specified path.
// -----------------------------------------------------------------------------

+ (NSArray *)allKeysAtPath: (NSString *)path
{
	NSMutableArray*	allKeys = [NSMutableArray array];
	size_t dataSize = listxattr([path fileSystemRepresentation], NULL, ULONG_MAX, 0);
	if (dataSize == ULONG_MAX)
		return allKeys;	// Empty list.

	NSMutableData* listBuffer = [NSMutableData dataWithLength: dataSize];
	dataSize = listxattr([path fileSystemRepresentation], [listBuffer mutableBytes], [listBuffer length], 0);
	char* nameStart = [listBuffer mutableBytes];
	int x;
	for (x = 0; x < dataSize; x++) {
		if (((char*)[listBuffer mutableBytes])[x] == 0) {
			NSString* str = [NSString stringWithUTF8String: nameStart];
			nameStart = [listBuffer mutableBytes] + x + 1;
			[allKeys addObject: str];
		}
	}
	
	return allKeys;
}


// -----------------------------------------------------------------------------
//	setData:forKey:atPath:
//		Set the xattr with name key to a block of raw binary data.
//		path is the file whose xattr you want to set.
// -----------------------------------------------------------------------------

+ (void)setData: (NSData *)data forKey: (NSString *)key atPath: (NSString *)path
{
	setxattr([path fileSystemRepresentation], [key UTF8String], [data bytes], [data length], 0, 0);
}


// -----------------------------------------------------------------------------
//	setObject:forKey:atPath:
//		Set the xattr with name key to an XML property list representation of
//		the specified object (or object graph).
//		path is the file whose xattr you want to set.
// -----------------------------------------------------------------------------

+ (void)setObject: (id)obj forKey: (NSString *)key atPath: (NSString *)path
{
	// Serialize our objects into a property list XML string:
	NSString* errMsg = nil;
	NSData* plistData = [NSPropertyListSerialization dataFromPropertyList: obj
								format: NSPropertyListXMLFormat_v1_0
								errorDescription: &errMsg];
	if (errMsg) {
		[errMsg autorelease];
		[NSException raise: @"UKXattrMetastoreCantSerialize" format: @"%@", errMsg];
	}
	else
		[[self class] setData: plistData forKey: key atPath: path];
}


// -----------------------------------------------------------------------------
//	setString:forKey:atPath:
//		Set the xattr with name key to an XML property list representation of
//		the specified object (or object graph).
//		path is the file whose xattr you want to set.
// -----------------------------------------------------------------------------

+ (void)setString: (NSString *)str forKey: (NSString *)key atPath: (NSString *)path
{
	NSData *data = [str dataUsingEncoding: NSUTF8StringEncoding];

	if (!data)
		[NSException raise: NSCharacterConversionException format: @"Couldn't convert string to UTF8 for xattr storage."];

	[[self class] setData: data forKey: key atPath: path];
}


// -----------------------------------------------------------------------------
//	dataForKey:atPath:
//		Retrieve the xattr with name key as a raw block of data.
//		path is the file whose xattr you want to set.
// -----------------------------------------------------------------------------

+ (NSMutableData *)dataForKey: (NSString *)key atPath: (NSString *)path
{
	size_t dataSize = getxattr([path fileSystemRepresentation], [key UTF8String], NULL, ULONG_MAX, 0, 0);
	if (dataSize == ULONG_MAX)
		return nil;
	NSMutableData *data = [NSMutableData dataWithLength: dataSize];
	getxattr([path fileSystemRepresentation], [key UTF8String], [data mutableBytes], [data length], 0, 0);
	return data;
}


// -----------------------------------------------------------------------------
//	objectForKey:atPath:
//		Retrieve the xattr with name key, which is an XML property list
//		and unserialize it back into an object or object graph.
//		path is the file whose xattr you want to set.
// -----------------------------------------------------------------------------

+ (id)objectForKey: (NSString *)key atPath: (NSString *)path
{
	NSString *errMsg = nil;
	NSMutableData *data = [[self class] dataForKey: key atPath: path];
	NSPropertyListFormat outFormat = NSPropertyListXMLFormat_v1_0;
	id obj = [NSPropertyListSerialization propertyListFromData: data mutabilityOption: NSPropertyListImmutable format: &outFormat errorDescription: &errMsg];
	if (errMsg) {
		[errMsg autorelease];
		[NSException raise: @"UKXattrMetastoreCantUnserialize" format: @"%@", errMsg];
	}

	return obj;
}


// -----------------------------------------------------------------------------
//	stringForKey:atPath:
//		Retrieve the xattr with name key, which is an XML property list
//		and unserialize it back into an object or object graph.
//		path is the file whose xattr you want to set.
// -----------------------------------------------------------------------------

+ (id)stringForKey: (NSString *)key atPath: (NSString *)path
{
	NSMutableData *data = [[self class] dataForKey: key atPath: path];	
	return [[[NSString alloc] initWithData: data encoding: NSUTF8StringEncoding] autorelease];
}


@end

#endif /*MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_4*/