//
//  NSFileManager-AliasExtensions.m
//
//  Created by Drew Hamlin on 8/26/06.
//  Copyright 2006 Drew Hamlin. All rights reserved.
//

#import "NSFileManager-AliasExtensions.h"

@implementation NSFileManager (AliasExtensions)

- (NSData *)aliasDataForPath:(NSString *)path;
{
    if (!path)
        return nil;
    
    // Convert the path to a file reference
    FSRef fileReference;
    if (FSPathMakeRef((const UInt8 *)[[path stringByStandardizingPath] fileSystemRepresentation], &fileReference, false) != noErr)
        return nil;
    
    // Create an alias
    Handle aliasHandle;
    if (FSNewAlias(NULL, &fileReference, (AliasHandle *)&aliasHandle) != noErr)
        return nil;
    
    // Convert the handle to data
    if (!aliasHandle)
        return nil;
    HLock(aliasHandle);
    CFDataRef aliasData = CFDataCreate(kCFAllocatorDefault, (const UInt8 *)*aliasHandle, GetHandleSize(aliasHandle));
    HSetState(aliasHandle, HGetState(aliasHandle));
    
    return [(NSData *)aliasData autorelease];
}

- (NSString *)pathForAliasData:(NSData *)aliasData;
{
    if (!aliasData)
        return nil;
    
    // Convert the data to a handle
    CFIndex dataLength = CFDataGetLength((CFDataRef)aliasData);
    Handle aliasHandle = NewHandle(dataLength);
    if (!(aliasHandle && dataLength))
        return nil;
    HLock(aliasHandle);
    BlockMoveData(CFDataGetBytePtr((CFDataRef)aliasData), *aliasHandle, dataLength);
    HUnlock(aliasHandle);
    
    // Resolve the alias
    FSRef fileReference;
    Boolean wasChanged;
    if (FSResolveAlias(NULL, (AliasHandle)aliasHandle, &fileReference, &wasChanged) != noErr)
        return nil;
    
    // Convert the file reference to a path
    CFURLRef temporaryURL = CFURLCreateFromFSRef(kCFAllocatorDefault, &fileReference);
    if (!temporaryURL)
        return nil;
    CFStringRef path = CFURLCopyFileSystemPath(temporaryURL, kCFURLPOSIXPathStyle);
    CFRelease(temporaryURL);
    
    return [(NSString *)path autorelease];
}

@end