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//
//  GMUserFileSystem.m
//
//  Created by ted on 12/29/07.
//  Based on FUSEFileSystem originally by alcor.
//
#import "GMUserFileSystem.h"

#define FUSE_USE_VERSION 26
#include <fuse.h>
#include <fuse/fuse_darwin.h>

#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/param.h>
#include <sys/mount.h>
#include <sys/ioctl.h>
#include <sys/sysctl.h>
#include <sys/utsname.h>

#import <Foundation/Foundation.h>
#import "GMAppleDouble.h"
#import "GMFinderInfo.h"
#import "GMResourceFork.h"
#import "GMDataBackedFileDelegate.h"

#import "GMDTrace.h"

#define GM_EXPORT __attribute__((visibility("default")))

// Creates a dtrace-ready string with any newlines removed.
#define DTRACE_STRING(s)  \
((char *)[[s stringByReplacingOccurrencesOfString:@"\n" withString:@" "] UTF8String])

// Notifications
GM_EXPORT NSString* const kGMUserFileSystemErrorDomain = @"GMUserFileSystemErrorDomain";
GM_EXPORT NSString* const kGMUserFileSystemMountPathKey = @"mountPath";
GM_EXPORT NSString* const kGMUserFileSystemErrorKey = @"error";
GM_EXPORT NSString* const kGMUserFileSystemMountFailed = @"kGMUserFileSystemMountFailed";
GM_EXPORT NSString* const kGMUserFileSystemDidMount = @"kGMUserFileSystemDidMount";
GM_EXPORT NSString* const kGMUserFileSystemDidUnmount = @"kGMUserFileSystemDidUnmount";

// Attribute keys
GM_EXPORT NSString* const kGMUserFileSystemFileFlagsKey = @"kGMUserFileSystemFileFlagsKey";
GM_EXPORT NSString* const kGMUserFileSystemFileAccessDateKey = @"kGMUserFileSystemFileAccessDateKey";
GM_EXPORT NSString* const kGMUserFileSystemFileChangeDateKey = @"kGMUserFileSystemFileChangeDateKey";
GM_EXPORT NSString* const kGMUserFileSystemFileBackupDateKey = @"kGMUserFileSystemFileBackupDateKey";
GM_EXPORT NSString* const kGMUserFileSystemVolumeSupportsExtendedDatesKey = @"kGMUserFileSystemVolumeSupportsExtendedDatesKey";

// TODO: Remove comment on EXPORT if/when setvolname is supported.
/* GM_EXPORT */ NSString* const kGMUserFileSystemVolumeSupportsSetVolumeNameKey = @"kGMUserFileSystemVolumeSupportsSetVolumeNameKey";
/* GM_EXPORT */ NSString* const kGMUserFileSystemVolumeNameKey = @"kGMUserFileSystemVolumeNameKey";

// FinderInfo and ResourceFork keys
GM_EXPORT NSString* const kGMUserFileSystemFinderFlagsKey = @"kGMUserFileSystemFinderFlagsKey";
GM_EXPORT NSString* const kGMUserFileSystemFinderExtendedFlagsKey = @"kGMUserFileSystemFinderExtendedFlagsKey";
GM_EXPORT NSString* const kGMUserFileSystemCustomIconDataKey = @"kGMUserFileSystemCustomIconDataKey";
GM_EXPORT NSString* const kGMUserFileSystemWeblocURLKey = @"kGMUserFileSystemWeblocURLKey";

// Used for time conversions to/from tv_nsec.
static const double kNanoSecondsPerSecond = 1000000000.0;

typedef enum {
  // Unable to unmount a dead FUSE files system located at mount point.
  GMUserFileSystem_ERROR_UNMOUNT_DEADFS = 1000,
  
  // Gave up waiting for system removal of existing dir in /Volumes/x after 
  // unmounting a dead FUSE file system.
  GMUserFileSystem_ERROR_UNMOUNT_DEADFS_RMDIR = 1001,
  
  // The mount point did not exist, and we were unable to mkdir it.
  GMUserFileSystem_ERROR_MOUNT_MKDIR = 1002,
  
  // fuse_main returned while trying to mount and don't know why.
  GMUserFileSystem_ERROR_MOUNT_FUSE_MAIN_INTERNAL = 1003,
} GMUserFileSystemErrorCode;

typedef enum {
  GMUserFileSystem_NOT_MOUNTED,   // Not mounted.
  GMUserFileSystem_MOUNTING,      // In the process of mounting.
  GMUserFileSystem_INITIALIZING,  // Almost done mounting.
  GMUserFileSystem_MOUNTED,       // Confirmed to be mounted.
  GMUserFileSystem_UNMOUNTING,    // In the process of unmounting.
  GMUserFileSystem_FAILURE,       // Failed state; probably a mount failure.
} GMUserFileSystemStatus;

@interface GMUserFileSystemInternal : NSObject {
  NSString* mountPath_;
  GMUserFileSystemStatus status_;
  BOOL isTiger_;                  // Are we running on Tiger?
  BOOL shouldCheckForResource_;   // Try to handle FinderInfo/Resource Forks?
  BOOL isThreadSafe_;  // Is the delegate thread-safe?
  BOOL supportsExtendedTimes_;  // Delegate supports create and backup times?
  BOOL supportsSetVolumeName_;  // Delegate supports setvolname?
  BOOL isReadOnly_;  // Is this mounted read-only?
  id delegate_;
}
- (id)initWithDelegate:(id)delegate isThreadSafe:(BOOL)isThreadSafe;
- (void)setDelegate:(id)delegate;
@end

@implementation GMUserFileSystemInternal

- (id)init {
  return [self initWithDelegate:nil isThreadSafe:NO];
}

- (id)initWithDelegate:(id)delegate isThreadSafe:(BOOL)isThreadSafe {
  if ((self = [super init])) {
    status_ = GMUserFileSystem_NOT_MOUNTED;
    isThreadSafe_ = isThreadSafe;
    supportsExtendedTimes_ = NO;
    supportsSetVolumeName_ = NO;
    isReadOnly_ = NO;
    [self setDelegate:delegate];

    // Version 10.4 requires ._ to appear in directory listings.
    long version = fuse_os_version_major_np();
    isTiger_ = (version < 9);
  }
  return self;
}
- (void)dealloc {
  [mountPath_ release];
  [super dealloc];
}

- (NSString *)mountPath { return mountPath_; }
- (void)setMountPath:(NSString *)mountPath {
  [mountPath_ autorelease];
  mountPath_ = [mountPath copy];
}
- (GMUserFileSystemStatus)status { return status_; }
- (void)setStatus:(GMUserFileSystemStatus)status { status_ = status; }
- (BOOL)isThreadSafe { return isThreadSafe_; }
- (BOOL)supportsExtendedTimes { return supportsExtendedTimes_; }
- (void)setSupportsExtendedTimes:(BOOL)val { supportsExtendedTimes_ = val; }
- (BOOL)supportsSetVolumeName { return supportsSetVolumeName_; }
- (void)setSupportsSetVolumeName:(BOOL)val { supportsSetVolumeName_ = val; }
- (BOOL)isTiger { return isTiger_; }
- (BOOL)shouldCheckForResource { return shouldCheckForResource_; }
- (BOOL)isReadOnly { return isReadOnly_; }
- (void)setIsReadOnly:(BOOL)val { isReadOnly_ = val; }
- (id)delegate { return delegate_; }
- (void)setDelegate:(id)delegate { 
  delegate_ = delegate;
  shouldCheckForResource_ =
    [delegate_ respondsToSelector:@selector(finderAttributesAtPath:error:)] ||
    [delegate_ respondsToSelector:@selector(resourceAttributesAtPath:error:)] ||
    [delegate_ respondsToSelector:@selector(finderFlagsAtPath:)] ||
    [delegate_ respondsToSelector:@selector(iconDataAtPath:)]    ||
    [delegate_ respondsToSelector:@selector(URLOfWeblocAtPath:)];
  
  // Check for deprecated methods.
  SEL deprecatedMethods[] = {
    @selector(valueOfExtendedAttribute:ofItemAtPath:error:),
    @selector(setExtendedAttribute:ofItemAtPath:value:flags:error:),
    @selector(finderFlagsAtPath:),
    @selector(iconDataAtPath:),
    @selector(URLOfWeblocAtPath:),
    @selector(truncateFileAtPath:offset:error:),
    @selector(attributesOfItemAtPath:error:),
    @selector(setAttributes:ofItemAtPath:error:),
    @selector(openFileAtPath:mode:fileDelegate:error:),
    @selector(createFileAtPath:attributes:fileDelegate:error:),
    @selector(releaseFileAtPath:fileDelegate:),
    @selector(readFileAtPath:fileDelegate:buffer:size:offset:error:),
    @selector(writeFileAtPath:fileDelegate:buffer:size:offset:error:),
  };
  int i;
  for (i = 0; i < sizeof(deprecatedMethods)/sizeof(deprecatedMethods[0]); ++i) {
    SEL sel = deprecatedMethods[i];
    if ([delegate_ respondsToSelector:sel]) {
      NSLog(@"*** WARNING: GMUserFileSystem delegate implements deprecated "
            @"selector: %@", NSStringFromSelector(sel));
    }
  }
}

@end

// Deprecated delegate methods that we still support for backward compatibility
// with previously compiled file systems. This will be actively trimmed as 
// new releases occur.
@interface NSObject (GMUserFileSystemDeprecated)
- (NSData *)valueOfExtendedAttribute:(NSString *)name
                        ofItemAtPath:(NSString *)path
                               error:(NSError **)error;
- (BOOL)setExtendedAttribute:(NSString *)name
                ofItemAtPath:(NSString *)path
                       value:(NSData *)value
                       flags:(int)flags
                       error:(NSError **)error;
- (UInt16)finderFlagsAtPath:(NSString *)path;
- (NSData *)iconDataAtPath:(NSString *)path;
- (NSURL *)URLOfWeblocAtPath:(NSString *)path;
- (BOOL)truncateFileAtPath:(NSString *)path 
                    offset:(off_t)offset 
                     error:(NSError **)error;
- (NSDictionary *)attributesOfItemAtPath:(NSString *)path
                                   error:(NSError **)error;
- (BOOL)setAttributes:(NSDictionary *)attributes 
         ofItemAtPath:(NSString *)path
                error:(NSError **)error;
- (BOOL)openFileAtPath:(NSString *)path 
                  mode:(int)mode
          fileDelegate:(id *)fileDelegate
                 error:(NSError **)error;
- (BOOL)createFileAtPath:(NSString *)path 
              attributes:(NSDictionary *)attributes
            fileDelegate:(id *)fileDelegate
                   error:(NSError **)error;
- (void)releaseFileAtPath:(NSString *)path fileDelegate:(id)fileDelegate;
- (int)readFileAtPath:(NSString *)path 
         fileDelegate:(id)fileDelegate
               buffer:(char *)buffer 
                 size:(size_t)size 
               offset:(off_t)offset
                error:(NSError **)error;
- (int)writeFileAtPath:(NSString *)path 
          fileDelegate:(id)fileDelegate 
                buffer:(const char *)buffer
                  size:(size_t)size 
                offset:(off_t)offset
                 error:(NSError **)error;
@end

@interface GMUserFileSystem (GMUserFileSystemPrivate)

// The filesystem for the current thread. Valid only during a fuse callback.
+ (GMUserFileSystem *)currentFS;

// Convenience method to creates an autoreleased NSError in the 
// NSPOSIXErrorDomain. Filesystem errors returned by the delegate must be
// standard posix errno values.
+ (NSError *)errorWithCode:(int)code;

- (void)mount:(NSDictionary *)args;
- (void)waitUntilMounted;

- (NSDictionary *)finderAttributesAtPath:(NSString *)path;
- (NSDictionary *)resourceAttributesAtPath:(NSString *)path;

- (BOOL)hasCustomIconAtPath:(NSString *)path;
- (BOOL)isDirectoryIconAtPath:(NSString *)path dirPath:(NSString **)dirPath;
- (BOOL)isAppleDoubleAtPath:(NSString *)path realPath:(NSString **)realPath;
- (NSData *)finderDataForAttributes:(NSDictionary *)attributes;
- (NSData *)resourceDataForAttributes:(NSDictionary *)attributes;
- (NSData *)appleDoubleContentsAtPath:(NSString *)path;

- (NSDictionary *)defaultAttributesOfItemAtPath:(NSString *)path 
                                       userData:userData
                                          error:(NSError **)error;  
- (BOOL)fillStatBuffer:(struct stat *)stbuf 
               forPath:(NSString *)path
          fileDelegate:(id)fileDelegate
                 error:(NSError **)error;
- (BOOL)fillStatvfsBuffer:(struct statvfs *)stbuf 
                  forPath:(NSString *)path
                    error:(NSError **)error;

- (void)fuseInit;
- (void)fuseDestroy;

@end

@implementation GMUserFileSystem

- (id)init {
  return [self initWithDelegate:nil isThreadSafe:NO];
}

- (id)initWithDelegate:(id)delegate isThreadSafe:(BOOL)isThreadSafe {
  if ((self = [super init])) {
    internal_ = [[GMUserFileSystemInternal alloc] initWithDelegate:delegate
                                                      isThreadSafe:isThreadSafe];
  }
  return self;
}

- (void)dealloc {
  [internal_ release];
  [super dealloc];
}

- (void)setDelegate:(id)delegate {
  [internal_ setDelegate:delegate];
}
- (id)delegate {
  return [internal_ delegate];
}

- (BOOL)enableExtendedTimes {
  return [internal_ supportsExtendedTimes];
}
- (BOOL)enableSetVolumeName {
  return [internal_ supportsSetVolumeName];
}

- (void)mountAtPath:(NSString *)mountPath 
        withOptions:(NSArray *)options {
  [self mountAtPath:mountPath
        withOptions:options
   shouldForeground:YES
    detachNewThread:YES];
}

- (void)mountAtPath:(NSString *)mountPath 
        withOptions:(NSArray *)options
   shouldForeground:(BOOL)shouldForeground
    detachNewThread:(BOOL)detachNewThread {
  [internal_ setMountPath:mountPath];
  NSMutableArray* optionsCopy = [NSMutableArray array];
  for (int i = 0; i < [options count]; ++i) {
    NSString* option = [options objectAtIndex:i];
    if ([option caseInsensitiveCompare:@"rdonly"] == NSOrderedSame ||
        [option caseInsensitiveCompare:@"ro"] == NSOrderedSame) {
      [internal_ setIsReadOnly:YES];
    }
    [optionsCopy addObject:[[option copy] autorelease]];
  }
  NSDictionary* args = 
  [[NSDictionary alloc] initWithObjectsAndKeys:
   optionsCopy, @"options",
   [NSNumber numberWithBool:shouldForeground], @"shouldForeground", 
   nil, nil];
  if (detachNewThread) {
    [NSThread detachNewThreadSelector:@selector(mount:) 
                             toTarget:self 
                           withObject:args];
  } else {
    [self mount:args];
  }
}

- (void)unmount {
  if ([internal_ status] == GMUserFileSystem_MOUNTED) {
    NSArray* args = [NSArray arrayWithObjects:@"-v", [internal_ mountPath], nil];
    NSTask* unmountTask = [NSTask launchedTaskWithLaunchPath:@"/sbin/umount" 
                                                   arguments:args];
    [unmountTask waitUntilExit];
  }
}

+ (NSError *)errorWithCode:(int)code {
  return [NSError errorWithDomain:NSPOSIXErrorDomain code:code userInfo:nil];
}

+ (GMUserFileSystem *)currentFS {
  struct fuse_context* context = fuse_get_context();
  assert(context);
  return (GMUserFileSystem *)context->private_data;
}

#define FUSEDEVIOCGETHANDSHAKECOMPLETE _IOR('F', 2, u_int32_t)
static const int kMaxWaitForMountTries = 50;
static const int kWaitForMountUSleepInterval = 100000;  // 100 ms
- (void)waitUntilMounted {
  NSAutoreleasePool* pool = [[NSAutoreleasePool alloc] init];
  
  for (int i = 0; i < kMaxWaitForMountTries; ++i) {
    UInt32 handShakeComplete = 0;
    int ret = ioctl(fuse_device_fd_np([[internal_ mountPath] UTF8String]), 
                    FUSEDEVIOCGETHANDSHAKECOMPLETE, 
                    &handShakeComplete);
    if (ret == 0 && handShakeComplete) {
      [internal_ setStatus:GMUserFileSystem_MOUNTED];
      
      // Successfully mounted, so post notification.
      NSDictionary* userInfo = 
        [NSDictionary dictionaryWithObjectsAndKeys:
         [internal_ mountPath], kGMUserFileSystemMountPathKey,
         nil, nil];
      NSNotificationCenter* center = [NSNotificationCenter defaultCenter];
      [center postNotificationName:kGMUserFileSystemDidMount object:self
                          userInfo:userInfo];
      [pool release];
      return;
    }
    usleep(kWaitForMountUSleepInterval);
  }
  
  // Tried for a long time and no luck :-(
  // Unmount and report failure?
  [pool release];
}

- (void)fuseInit {
  [internal_ setStatus:GMUserFileSystem_INITIALIZING];

  NSError* error = nil;
  NSDictionary* attribs = [self attributesOfFileSystemForPath:@"/" error:&error];
  if (attribs) {
    NSNumber* supports;
    supports = [attribs objectForKey:kGMUserFileSystemVolumeSupportsExtendedDatesKey];
    if (supports && [supports boolValue]) {
      [internal_ setSupportsExtendedTimes:YES];
    }
    supports = [attribs objectForKey:kGMUserFileSystemVolumeSupportsSetVolumeNameKey];
    if (supports && [supports boolValue]) {
      [internal_ setSupportsSetVolumeName:YES];
    }    
  }
  
  // The mount point won't actually show up until this winds its way
  // back through the kernel after this routine returns. In order to post
  // the kGMUserFileSystemDidMount notification we start a new thread that will
  // poll until it is mounted.
  [NSThread detachNewThreadSelector:@selector(waitUntilMounted) 
                           toTarget:self 
                         withObject:nil];
}

- (void)fuseDestroy {
  if ([[internal_ delegate] respondsToSelector:@selector(willUnmount)]) {
    [[internal_ delegate] willUnmount];
  }
  [internal_ setStatus:GMUserFileSystem_UNMOUNTING];

  NSDictionary* userInfo = 
    [NSDictionary dictionaryWithObjectsAndKeys:
     [internal_ mountPath], kGMUserFileSystemMountPathKey,
     nil, nil];
  NSNotificationCenter* center = [NSNotificationCenter defaultCenter];
  [center postNotificationName:kGMUserFileSystemDidUnmount object:self
                      userInfo:userInfo];
  [internal_ setStatus:GMUserFileSystem_NOT_MOUNTED];
}

#pragma mark Finder Info, Resource Forks and HFS headers

- (NSDictionary *)finderAttributesAtPath:(NSString *)path {
  if (MACFUSE_OBJC_DELEGATE_ENTRY_ENABLED()) {
    MACFUSE_OBJC_DELEGATE_ENTRY(DTRACE_STRING(path));
  }

  UInt16 flags = 0;

  // If a directory icon, we'll make invisible and update the path to parent.
  if ([self isDirectoryIconAtPath:path dirPath:&path]) {
    flags |= kIsInvisible;
  }

  id delegate = [internal_ delegate];
  if ([delegate respondsToSelector:@selector(finderAttributesAtPath:error:)]) {
    NSError* error = nil;
    NSDictionary* dict = [delegate finderAttributesAtPath:path error:&error];
    if (dict != nil) {
      if ([dict objectForKey:kGMUserFileSystemCustomIconDataKey]) {
        // They have custom icon data, so make sure the FinderFlags bit is set.
        flags |= kHasCustomIcon;
      }
      if (flags != 0) {
        // May need to update kGMUserFileSystemFinderFlagsKey if different.
        NSNumber* finderFlags = [dict objectForKey:kGMUserFileSystemFinderFlagsKey];
        if (finderFlags != nil) {
          UInt16 tmp = (UInt16)[finderFlags longValue];
          if (flags == tmp) {
            return dict;  // They already have our desired flags.
          }          
          flags |= tmp;
        }
        // Doh! We need to create a new dict with the updated flags key.
        NSMutableDictionary* newDict = 
          [NSMutableDictionary dictionaryWithDictionary:dict];
        [newDict setObject:[NSNumber numberWithLong:flags] 
                    forKey:kGMUserFileSystemFinderFlagsKey];
        return newDict;
      }
      return dict;
    }
    // Fall through and create dictionary based on flags if necessary.
  } else if ([delegate respondsToSelector:@selector(finderFlagsAtPath:)]) {
    flags |= [delegate finderFlagsAtPath:path];
  } else if ([delegate respondsToSelector:@selector(iconDataAtPath:)] &&
             [delegate iconDataAtPath:path] != nil) {
    flags |= kHasCustomIcon;
  }
  if (flags != 0) {
    return [NSDictionary dictionaryWithObject:[NSNumber numberWithLong:flags]
                                       forKey:kGMUserFileSystemFinderFlagsKey];
  }
  return nil;
}

- (NSDictionary *)resourceAttributesAtPath:(NSString *)path {
  if (MACFUSE_OBJC_DELEGATE_ENTRY_ENABLED()) {
    MACFUSE_OBJC_DELEGATE_ENTRY(DTRACE_STRING(path));
  }
  
  id delegate = [internal_ delegate];
  if ([delegate respondsToSelector:@selector(resourceAttributesAtPath:error:)]) {
    NSError* error = nil;
    return [delegate resourceAttributesAtPath:path error:&error];
  }

  // Support for deprecated selectors.
  NSURL* url = nil;
  if ([path hasSuffix:@".webloc"] &&
      [delegate respondsToSelector:@selector(URLOfWeblocAtPath:)]) {
    url = [delegate URLOfWeblocAtPath:path];
  }
  NSData* imageData = nil;
  if ([delegate respondsToSelector:@selector(iconDataAtPath:)]) {
    imageData = [delegate iconDataAtPath:path];
  }
  if (imageData || url) {
    NSMutableDictionary* dict = [NSMutableDictionary dictionary];
    if (imageData) {
      [dict setObject:imageData forKey:kGMUserFileSystemCustomIconDataKey];
    }
    if (url) {
      [dict setObject:url forKey:kGMUserFileSystemWeblocURLKey];
    }
    return dict;
  }
  return nil;
}

- (BOOL)hasCustomIconAtPath:(NSString *)path {
  if ([path isEqualToString:@"/"]) {
    return NO;  // For a volume icon they should use the volicon= option.
  }
  NSDictionary* finderAttribs = [self finderAttributesAtPath:path];
  if (finderAttribs) {
    NSNumber* finderFlags = 
      [finderAttribs objectForKey:kGMUserFileSystemFinderFlagsKey];
    if (finderFlags) {
      UInt16 flags = (UInt16)[finderFlags longValue];
      return (flags & kHasCustomIcon) == kHasCustomIcon;
    }
  }
  return NO;
  }

- (BOOL)isDirectoryIconAtPath:(NSString *)path dirPath:(NSString **)dirPath {
  NSString* name = [path lastPathComponent];
  if ([name isEqualToString:@"Icon\r"]) {
    if (dirPath) {
      *dirPath = [path stringByDeletingLastPathComponent];
    }
    return YES;
  }
  return NO;
}

- (BOOL)isAppleDoubleAtPath:(NSString *)path realPath:(NSString **)realPath {
  NSString* name = [path lastPathComponent];
  if ([name hasPrefix:@"._"]) {
    if (realPath) {
      name = [name substringFromIndex:2];
      *realPath = [path stringByDeletingLastPathComponent];
      *realPath = [*realPath stringByAppendingPathComponent:name];
    }
    return YES;
  }
  return NO;
}

// If the given attribs dictionary contains any FinderInfo attributes then 
// returns NSData for FinderInfo; otherwise returns nil.
- (NSData *)finderDataForAttributes:(NSDictionary *)attribs {
  if (!attribs) { 
    return nil;
  }

  GMFinderInfo* info = [GMFinderInfo finderInfo];
  BOOL attributeFound = NO;  // Have we found at least one relevant attribute?

  NSNumber* flags = [attribs objectForKey:kGMUserFileSystemFinderFlagsKey];
  if (flags) {
    attributeFound = YES;
    [info setFlags:(UInt16)[flags longValue]];
  }
  
  NSNumber* extendedFlags = 
    [attribs objectForKey:kGMUserFileSystemFinderExtendedFlagsKey];
  if (extendedFlags) {
    attributeFound = YES;
    [info setExtendedFlags:(UInt16)[extendedFlags longValue]];
  }
  
  NSNumber* typeCode = [attribs objectForKey:NSFileHFSTypeCode];
  if (typeCode) {
    attributeFound = YES;
    [info setTypeCode:(OSType)[typeCode longValue]];
  }

  NSNumber* creatorCode = [attribs objectForKey:NSFileHFSCreatorCode];
  if (creatorCode) {
    attributeFound = YES;
    [info setCreatorCode:(OSType)[creatorCode longValue]];
  }

  return attributeFound ? [info data] : nil;
}

// If the given attribs dictionary contains any ResourceFork attributes then 
// returns NSData for the ResourceFork; otherwise returns nil.
- (NSData *)resourceDataForAttributes:(NSDictionary *)attribs {
  if (!attribs) {
    return nil;
  }

  GMResourceFork* fork = [GMResourceFork resourceFork];
  BOOL attributeFound = NO;  // Have we found at least one relevant attribute?
  
  NSData* imageData = [attribs objectForKey:kGMUserFileSystemCustomIconDataKey];
  if (imageData) {
    attributeFound = YES;
    [fork addResourceWithType:'icns'
                        resID:kCustomIconResource // -16455
                         name:nil
                         data:imageData];    
  }
  NSURL* url = [attribs objectForKey:kGMUserFileSystemWeblocURLKey];
  if (url) {
    attributeFound = YES;
    NSString* urlString = [url absoluteString];
    NSData* data = [urlString dataUsingEncoding:NSUTF8StringEncoding];
    [fork addResourceWithType:'url '
                        resID:256
                         name:nil
                         data:data];
  }
  return attributeFound ? [fork data] : nil;
}

// Returns the AppleDouble file contents, if any, for the given path. You should
// call this with the realPath out-param from a call to isAppleDoubleAtPath:.
//
// On 10.5 and (hopefully) above, the Finder will end up using the extended
// attributes and so we won't need to serve ._ files. 
- (NSData *)appleDoubleContentsAtPath:(NSString *)path {
  NSDictionary* finderAttributes = [self finderAttributesAtPath:path];
  NSData* finderData = [self finderDataForAttributes:finderAttributes];
 
  // We treat the ._ for a directory and it's ._Icon\r file the same. This means
  // that we'll put extra resource-fork information in directory's ._ file even 
  // though it isn't needed. It's worth it given that it only affects 10.4.
  [self isDirectoryIconAtPath:path dirPath:&path];

  NSDictionary* resourceAttributes = [self resourceAttributesAtPath:path];
  NSData* resourceData = [self resourceDataForAttributes:resourceAttributes];
  if (finderData != nil || resourceData != nil) {
    GMAppleDouble* doubleFile = [GMAppleDouble appleDouble];
    if (finderData) {
      [doubleFile addEntryWithID:DoubleEntryFinderInfo data:finderData];
    }
    if (resourceData) {
      [doubleFile addEntryWithID:DoubleEntryResourceFork 
                            data:resourceData];
    }
    return [doubleFile data];
  }
  return nil;
}

#pragma mark Internal Stat Operations

- (BOOL)fillStatvfsBuffer:(struct statvfs *)stbuf 
                  forPath:(NSString *)path 
                    error:(NSError **)error {
  NSDictionary* attributes = [self attributesOfFileSystemForPath:path error:error];
  if (!attributes) {
    return NO;
  }
  
  // Maximum length of filenames
  // TODO: Create our own key so that a fileSystem can override this.
  stbuf->f_namemax = 255;
  
  // Block size
  // TODO: Create our own key so that a fileSystem can override this.
  stbuf->f_bsize = stbuf->f_frsize = 4096;
  
  // Size in blocks
  NSNumber* size = [attributes objectForKey:NSFileSystemSize];
  assert(size);
  stbuf->f_blocks = (fsblkcnt_t)([size longLongValue] / stbuf->f_frsize);
  
  // Number of free / available blocks
  NSNumber* freeSize = [attributes objectForKey:NSFileSystemFreeSize];
  assert(freeSize);
  stbuf->f_bfree = stbuf->f_bavail = 
    (fsblkcnt_t)([freeSize longLongValue] / stbuf->f_frsize);
  
  // Number of nodes
  NSNumber* numNodes = [attributes objectForKey:NSFileSystemNodes];
  assert(numNodes);
  stbuf->f_files = (fsfilcnt_t)[numNodes longLongValue];
  
  // Number of free / available nodes
  NSNumber* freeNodes = [attributes objectForKey:NSFileSystemFreeNodes];
  assert(freeNodes);
  stbuf->f_ffree = stbuf->f_favail = (fsfilcnt_t)[freeNodes longLongValue];
  
  return YES;
}

- (BOOL)fillStatBuffer:(struct stat *)stbuf 
               forPath:(NSString *)path 
              userData:(id)userData
                 error:(NSError **)error {
  NSDictionary* attributes = [self defaultAttributesOfItemAtPath:path 
                                                        userData:userData
                                                           error:error];
  if (!attributes) {
    return NO;
  }

  // Inode
  NSNumber* inode = [attributes objectForKey:NSFileSystemFileNumber];
  if (inode) {
    stbuf->st_ino = [inode longLongValue];
  }
  
  // Permissions (mode)
  NSNumber* perm = [attributes objectForKey:NSFilePosixPermissions];
  stbuf->st_mode = [perm longValue];
  NSString* fileType = [attributes objectForKey:NSFileType];
  if ([fileType isEqualToString:NSFileTypeDirectory ]) {
    stbuf->st_mode |= S_IFDIR;
  } else if ([fileType isEqualToString:NSFileTypeRegular]) {
    stbuf->st_mode |= S_IFREG;
  } else if ([fileType isEqualToString:NSFileTypeSymbolicLink]) {
    stbuf->st_mode |= S_IFLNK;
  } else {
    *error = [GMUserFileSystem errorWithCode:EFTYPE];
    return NO;
  }
  
  // Owner and Group
  // Note that if the owner or group IDs are not specified, the effective
  // user and group IDs for the current process are used as defaults.
  NSNumber* uid = [attributes objectForKey:NSFileOwnerAccountID];
  NSNumber* gid = [attributes objectForKey:NSFileGroupOwnerAccountID];
  stbuf->st_uid = uid ? [uid longValue] : geteuid();
  stbuf->st_gid = gid ? [gid longValue] : getegid();

  // nlink
  NSNumber* nlink = [attributes objectForKey:NSFileReferenceCount];
  stbuf->st_nlink = [nlink longValue];

  // flags
  NSNumber* flags = [attributes objectForKey:kGMUserFileSystemFileFlagsKey];
  if (flags) {
    stbuf->st_flags = [flags longValue];
  } else {
    // Just in case they tried to use NSFileImmutable or NSFileAppendOnly
    NSNumber* immutableFlag = [attributes objectForKey:NSFileImmutable];
    if (immutableFlag && [immutableFlag boolValue]) {
      stbuf->st_flags |= UF_IMMUTABLE;
    }
    NSNumber* appendFlag = [attributes objectForKey:NSFileAppendOnly];
    if (appendFlag && [appendFlag boolValue]) {
      stbuf->st_flags |= UF_APPEND;
    }
  }

  // NOTE: We default atime,ctime to mtime if it is provided.
  NSDate* mdate = [attributes objectForKey:NSFileModificationDate];
  if (mdate) {
    const double seconds_dp = [mdate timeIntervalSince1970];
    const time_t t_sec = (time_t) seconds_dp;
    const double nanoseconds_dp = ((seconds_dp - t_sec) * kNanoSecondsPerSecond); 
    const long t_nsec = (nanoseconds_dp > 0 ) ? nanoseconds_dp : 0;

    stbuf->st_mtimespec.tv_sec = t_sec;
    stbuf->st_mtimespec.tv_nsec = t_nsec;
    stbuf->st_atimespec = stbuf->st_mtimespec;  // Default to mtime
    stbuf->st_ctimespec = stbuf->st_mtimespec;  // Default to mtime
  }
  NSDate* adate = [attributes objectForKey:kGMUserFileSystemFileAccessDateKey];
  if (adate) {
    const double seconds_dp = [adate timeIntervalSince1970];
    const time_t t_sec = (time_t) seconds_dp;
    const double nanoseconds_dp = ((seconds_dp - t_sec) * kNanoSecondsPerSecond); 
    const long t_nsec = (nanoseconds_dp > 0 ) ? nanoseconds_dp : 0;
    stbuf->st_atimespec.tv_sec = t_sec;
    stbuf->st_atimespec.tv_nsec = t_nsec;
  }    
  NSDate* cdate = [attributes objectForKey:kGMUserFileSystemFileChangeDateKey];
  if (cdate) {
    const double seconds_dp = [cdate timeIntervalSince1970];
    const time_t t_sec = (time_t) seconds_dp;
    const double nanoseconds_dp = ((seconds_dp - t_sec) * kNanoSecondsPerSecond); 
    const long t_nsec = (nanoseconds_dp > 0 ) ? nanoseconds_dp : 0;
    stbuf->st_ctimespec.tv_sec = t_sec;
    stbuf->st_ctimespec.tv_nsec = t_nsec;
  }

#if __DARWIN_64_BIT_INO_T
  NSDate* bdate = [attributes objectForKey:NSFileCreationDate];
  if (bdate) {
    const double seconds_dp = [bdate timeIntervalSince1970];
    const time_t t_sec = (time_t) seconds_dp;
    const double nanoseconds_dp = ((seconds_dp - t_sec) * kNanoSecondsPerSecond); 
    const long t_nsec = (nanoseconds_dp > 0 ) ? nanoseconds_dp : 0;
    stbuf->st_birthtimespec.tv_sec = t_sec;
    stbuf->st_birthtimespec.tv_nsec = t_nsec;
  }
#endif

  // Size for regular files.
  // TODO: Revisit size for directories.
  if (![fileType isEqualToString:NSFileTypeDirectory]) {
    NSNumber* size = [attributes objectForKey:NSFileSize];
    if (size) {
      stbuf->st_size = [size longLongValue];
    }
  }

  // Set the number of blocks used so that Finder will display size on disk 
  // properly. The man page says that this is in terms of 512 byte blocks.
  if (stbuf->st_size > 0) {
    stbuf->st_blocks = stbuf->st_size / 512;
    if (stbuf->st_size % 512) {
      ++(stbuf->st_blocks);
    }
  }

  return YES;  
}

#pragma mark Moving an Item

- (BOOL)moveItemAtPath:(NSString *)source 
                toPath:(NSString *)destination
                 error:(NSError **)error {
  if (MACFUSE_OBJC_DELEGATE_ENTRY_ENABLED()) {
    NSString* traceinfo = 
      [NSString stringWithFormat:@"%@ -> %@", source, destination];
    MACFUSE_OBJC_DELEGATE_ENTRY(DTRACE_STRING(traceinfo));
  }

  if ([[internal_ delegate] respondsToSelector:@selector(moveItemAtPath:toPath:error:)]) {
    return [[internal_ delegate] moveItemAtPath:source toPath:destination error:error];
  }  
  
  *error = [GMUserFileSystem errorWithCode:EACCES];
  return NO;
}

#pragma mark Removing an Item

- (BOOL)removeDirectoryAtPath:(NSString *)path error:(NSError **)error {
  if (MACFUSE_OBJC_DELEGATE_ENTRY_ENABLED()) {
    MACFUSE_OBJC_DELEGATE_ENTRY(DTRACE_STRING(path));
  }  

  if ([[internal_ delegate] respondsToSelector:@selector(removeDirectoryAtPath:error:)]) {
    return [[internal_ delegate] removeDirectoryAtPath:path error:error];
  }
  return [self removeItemAtPath:path error:error];
}

- (BOOL)removeItemAtPath:(NSString *)path error:(NSError **)error {
  if (MACFUSE_OBJC_DELEGATE_ENTRY_ENABLED()) {
    MACFUSE_OBJC_DELEGATE_ENTRY(DTRACE_STRING(path));
  }  

  if ([[internal_ delegate] respondsToSelector:@selector(removeItemAtPath:error:)]) {
    return [[internal_ delegate] removeItemAtPath:path error:error];
  }

  *error = [GMUserFileSystem errorWithCode:EACCES];
  return NO;
}

#pragma mark Creating an Item

- (BOOL)createDirectoryAtPath:(NSString *)path 
                   attributes:(NSDictionary *)attributes
                        error:(NSError **)error {
  if (MACFUSE_OBJC_DELEGATE_ENTRY_ENABLED()) {
    NSMutableString* traceinfo = 
     [NSMutableString stringWithFormat:@"%@ [%@]", path, attributes]; 
    MACFUSE_OBJC_DELEGATE_ENTRY(DTRACE_STRING(traceinfo));
  }
  
  if ([[internal_ delegate] respondsToSelector:@selector(createDirectoryAtPath:attributes:error:)]) {
    return [[internal_ delegate] createDirectoryAtPath:path attributes:attributes error:error];
  }

  *error = [GMUserFileSystem errorWithCode:EACCES];
  return NO;
}

- (BOOL)createFileAtPath:(NSString *)path 
              attributes:(NSDictionary *)attributes
                userData:(id *)userData
                   error:(NSError **)error {
  if (MACFUSE_OBJC_DELEGATE_ENTRY_ENABLED()) {
    NSString* traceinfo = [NSString stringWithFormat:@"%@ [%@]", path, attributes]; 
    MACFUSE_OBJC_DELEGATE_ENTRY(DTRACE_STRING(traceinfo));
  }

  if ([[internal_ delegate] respondsToSelector:@selector(createFileAtPath:attributes:userData:error:)]) {
    return [[internal_ delegate] createFileAtPath:path attributes:attributes 
                                         userData:userData error:error];
  } else if ([[internal_ delegate] respondsToSelector:@selector(createFileAtPath:attributes:fileDelegate:error:)]) {
    // NOTE: For backward compatibility with version 1.7 and prior.
    return [[internal_ delegate] createFileAtPath:path attributes:attributes 
                                     fileDelegate:userData error:error];
  }

  *error = [GMUserFileSystem errorWithCode:EACCES];
  return NO;
}


#pragma mark Linking an Item

- (BOOL)linkItemAtPath:(NSString *)path
                toPath:(NSString *)otherPath
                 error:(NSError **)error {
  if (MACFUSE_OBJC_DELEGATE_ENTRY_ENABLED()) {
    NSString* traceinfo = [NSString stringWithFormat:@"%@ -> %@", path, otherPath];
    MACFUSE_OBJC_DELEGATE_ENTRY(DTRACE_STRING(traceinfo));
  }

  if ([[internal_ delegate] respondsToSelector:@selector(linkItemAtPath:toPath:error:)]) {
    return [[internal_ delegate] linkItemAtPath:path toPath:otherPath error:error];
  }  

  *error = [GMUserFileSystem errorWithCode:ENOTSUP];  // Note: error not in man page.
  return NO;
}

#pragma mark Symbolic Links

- (BOOL)createSymbolicLinkAtPath:(NSString *)path 
             withDestinationPath:(NSString *)otherPath
                           error:(NSError **)error {
  if (MACFUSE_OBJC_DELEGATE_ENTRY_ENABLED()) {
    NSString* traceinfo = [NSString stringWithFormat:@"%@ -> %@", path, otherPath];
    MACFUSE_OBJC_DELEGATE_ENTRY(DTRACE_STRING(traceinfo));
  }  
  
  if ([[internal_ delegate] respondsToSelector:@selector(createSymbolicLinkAtPath:withDestinationPath:error:)]) {
    return [[internal_ delegate] createSymbolicLinkAtPath:path
                                      withDestinationPath:otherPath
                                                    error:error];
  }

  *error = [GMUserFileSystem errorWithCode:ENOTSUP];  // Note: error not in man page.
  return NO; 
}

- (NSString *)destinationOfSymbolicLinkAtPath:(NSString *)path
                                        error:(NSError **)error {
  if (MACFUSE_OBJC_DELEGATE_ENTRY_ENABLED()) {
    MACFUSE_OBJC_DELEGATE_ENTRY(DTRACE_STRING(path));
  }
  
  if ([[internal_ delegate] respondsToSelector:@selector(destinationOfSymbolicLinkAtPath:error:)]) {
    return [[internal_ delegate] destinationOfSymbolicLinkAtPath:path error:error];
  }

  *error = [GMUserFileSystem errorWithCode:ENOENT];
  return nil;
}

#pragma mark File Contents

// NOTE: Only call this if the delegate does indeed support this method.
- (NSData *)contentsAtPath:(NSString *)path {
  if (MACFUSE_OBJC_DELEGATE_ENTRY_ENABLED()) {
    MACFUSE_OBJC_DELEGATE_ENTRY(DTRACE_STRING(path));
  }

  id delegate = [internal_ delegate];
  return [delegate contentsAtPath:path];
}

- (BOOL)openFileAtPath:(NSString *)path 
                  mode:(int)mode
              userData:(id *)userData 
                 error:(NSError **)error {
  if (MACFUSE_OBJC_DELEGATE_ENTRY_ENABLED()) {
    NSString* traceinfo = [NSString stringWithFormat:@"%@, mode=0x%x", path, mode];
    MACFUSE_OBJC_DELEGATE_ENTRY(DTRACE_STRING(traceinfo));
  }

  id delegate = [internal_ delegate];
  if ([delegate respondsToSelector:@selector(contentsAtPath:)]) {
    NSData* data = [self contentsAtPath:path];
    if (data != nil) {
      *userData = [GMDataBackedFileDelegate fileDelegateWithData:data];
      return YES;
    }
  } else if ([delegate respondsToSelector:@selector(openFileAtPath:mode:userData:error:)]) {
    if ([delegate openFileAtPath:path 
                            mode:mode 
                        userData:userData 
                           error:error]) {
      return YES;  // They handled it.
    }
  } else if ([delegate respondsToSelector:@selector(openFileAtPath:mode:fileDelegate:error:)]) {
    if ([delegate openFileAtPath:path 
                            mode:mode 
                    fileDelegate:userData
                           error:error]) {
      // NOTE: For backward compatibility with version 1.7 and prior.
      return YES;  // They handled it.
    }
  }

  // Still unable to open the file; maybe it is an Icon\r or AppleDouble?
  if ([internal_ shouldCheckForResource]) {
    NSData* data = nil;  // Synthesized data that we provide a file delegate for.

    // Is it an Icon\r file that we handle?
    if ([self isDirectoryIconAtPath:path dirPath:nil]) {
      data = [NSData data];  // The Icon\r file is empty.
    }

    // (Tiger Only): Maybe it is an AppleDouble file that we handle?
    if ([internal_ isTiger]) {
      NSString* realPath;
      if ([self isAppleDoubleAtPath:path realPath:&realPath]) {
        data = [self appleDoubleContentsAtPath:realPath];
      }
    }
    if (data != nil) {
      if ((mode & O_ACCMODE) == O_RDONLY) {
        *userData = [GMDataBackedFileDelegate fileDelegateWithData:data];
      } else {
        NSMutableData* mutableData = [NSMutableData dataWithData:data];
        *userData = 
          [GMMutableDataBackedFileDelegate fileDelegateWithData:mutableData];
      }
      return YES;  // Handled by a synthesized file delegate.
    }
  }
  
  if (*error == nil) {
    *error = [GMUserFileSystem errorWithCode:ENOENT];
  }
  return NO;
}

- (void)releaseFileAtPath:(NSString *)path userData:(id)userData {
  if (MACFUSE_OBJC_DELEGATE_ENTRY_ENABLED()) {
    NSString* traceinfo =
      [NSString stringWithFormat:@"%@, userData=%p", path, userData];
    MACFUSE_OBJC_DELEGATE_ENTRY(DTRACE_STRING(traceinfo));
  }
  
  if (userData != nil && 
      [userData isKindOfClass:[GMDataBackedFileDelegate class]]) {
    return;  // Don't report releaseFileAtPath for internal file.
  }
  if ([[internal_ delegate] respondsToSelector:@selector(releaseFileAtPath:userData:)]) {
    [[internal_ delegate] releaseFileAtPath:path userData:userData];
  } else if ([[internal_ delegate] respondsToSelector:@selector(releaseFileAtPath:fileDelegate:)]) {
    // NOTE: For backward compatibility with version 1.7 and prior.
    [[internal_ delegate] releaseFileAtPath:path fileDelegate:userData];
  }
}

- (int)readFileAtPath:(NSString *)path 
             userData:(id)userData
               buffer:(char *)buffer 
                 size:(size_t)size 
               offset:(off_t)offset
                error:(NSError **)error {
  if (MACFUSE_OBJC_DELEGATE_ENTRY_ENABLED()) {
    NSString* traceinfo =
      [NSString stringWithFormat:@"%@, userData=%p, offset=%lld, size=%d", 
       path, userData, offset, size];
    MACFUSE_OBJC_DELEGATE_ENTRY(DTRACE_STRING(traceinfo));
  }

  if (userData != nil &&
      [userData respondsToSelector:@selector(readToBuffer:size:offset:error:)]) {
    return [userData readToBuffer:buffer size:size offset:offset error:error];
  } else if ([[internal_ delegate] respondsToSelector:@selector(readFileAtPath:userData:buffer:size:offset:error:)]) {
    return [[internal_ delegate] readFileAtPath:path
                                       userData:userData
                                         buffer:buffer
                                           size:size
                                         offset:offset
                                          error:error];
  } else if ([[internal_ delegate] respondsToSelector:@selector(readFileAtPath:fileDelegate:buffer:size:offset:error:)]) {
    // NOTE: For backward compatibility with version 1.7 and prior.
    return [[internal_ delegate] readFileAtPath:path
                                   fileDelegate:userData
                                         buffer:buffer
                                           size:size
                                         offset:offset
                                          error:error];
  }
  *error = [GMUserFileSystem errorWithCode:EACCES];
  return -1;
}

- (int)writeFileAtPath:(NSString *)path 
              userData:(id)userData
                buffer:(const char *)buffer
                  size:(size_t)size 
                offset:(off_t)offset
                 error:(NSError **)error {
  if (MACFUSE_OBJC_DELEGATE_ENTRY_ENABLED()) {
    NSString* traceinfo = 
      [NSString stringWithFormat:@"%@, userData=%p, offset=%lld, size=%d", 
       path, userData, offset, size];
    MACFUSE_OBJC_DELEGATE_ENTRY(DTRACE_STRING(traceinfo));
  }

  if (userData != nil &&
      [userData respondsToSelector:@selector(writeFromBuffer:size:offset:error:)]) {
    return [userData writeFromBuffer:buffer size:size offset:offset error:error];
  } else if ([[internal_ delegate] respondsToSelector:@selector(writeFileAtPath:userData:buffer:size:offset:error:)]) {
    return [[internal_ delegate] writeFileAtPath:path
                                        userData:userData
                                          buffer:buffer
                                            size:size
                                          offset:offset
                                           error:error];
  } else if ([[internal_ delegate] respondsToSelector:@selector(writeFileAtPath:fileDelegate:buffer:size:offset:error:)]) {
    // NOTE: For backward compatibility with version 1.7 and prior.
    return [[internal_ delegate] writeFileAtPath:path
                                    fileDelegate:userData
                                          buffer:buffer
                                            size:size
                                          offset:offset
                                           error:error];
  }
  *error = [GMUserFileSystem errorWithCode:EACCES];
  return -1; 
}

// NOTE: For backward compatibility with version 1.7 and prior.
- (BOOL)truncateFileAtPath:(NSString *)path
              fileDelegate:(id)fileDelegate
                    offset:(off_t)offset 
                     error:(NSError **)error
                   handled:(BOOL*)handled {
  if (fileDelegate != nil &&
      [fileDelegate respondsToSelector:@selector(truncateToOffset:error:)]) {
    *handled = YES;
    return [fileDelegate truncateToOffset:offset error:error];
  } else if ([[internal_ delegate] respondsToSelector:@selector(truncateFileAtPath:offset:error:)]) {
    *handled = YES;
    return [[internal_ delegate] truncateFileAtPath:path 
                                             offset:offset 
                                              error:error];
  }
  *handled = NO;
  return NO;
}

- (BOOL)exchangeDataOfItemAtPath:(NSString *)path1
                  withItemAtPath:(NSString *)path2
                           error:(NSError **)error {
  if (MACFUSE_OBJC_DELEGATE_ENTRY_ENABLED()) {
    NSString* traceinfo = [NSString stringWithFormat:@"%@ <-> %@", path1, path2];
    MACFUSE_OBJC_DELEGATE_ENTRY(DTRACE_STRING(traceinfo));
  }

  if ([[internal_ delegate] respondsToSelector:@selector(exchangeDataOfItemAtPath:withItemAtPath:error:)]) {
    return [[internal_ delegate] exchangeDataOfItemAtPath:path1
                                           withItemAtPath:path2
                                                    error:error];
  }  
  *error = [GMUserFileSystem errorWithCode:ENOSYS];
  return NO;
}

#pragma mark Directory Contents

- (NSArray *)contentsOfDirectoryAtPath:(NSString *)path error:(NSError **)error {
  if (MACFUSE_OBJC_DELEGATE_ENTRY_ENABLED()) {
    MACFUSE_OBJC_DELEGATE_ENTRY(DTRACE_STRING(path));
  }

  NSArray* contents = nil;
  if ([[internal_ delegate] respondsToSelector:@selector(contentsOfDirectoryAtPath:error:)]) {
    contents = [[internal_ delegate] contentsOfDirectoryAtPath:path error:error];
  } else if ([path isEqualToString:@"/"]) {
    contents = [NSArray array];  // Give them an empty root directory for free.
  }
  if (contents != nil && 
      [internal_ isTiger] &&
      [internal_ shouldCheckForResource]) {
    // Note: Tiger (10.4) requires that the ._ file are explicitly listed in 
    // the directory contents if you want a custom icon to show up. If they
    // don't provide their own ._ file and they have a custom icon, then we'll
    // add the ._ file to the directory contents.
    NSMutableSet* fullContents = [NSMutableSet setWithArray:contents];
    for (int i = 0; i < [contents count]; ++i) {
      NSString* name = [contents objectAtIndex:i];
      if ([name hasPrefix:@"._"]) {
        continue;  // Skip over any AppleDouble that they provide.
      }
      NSString* doubleName = [NSString stringWithFormat:@"._%@", name];
      if ([fullContents containsObject:doubleName]) {
        continue;  // They provided their own AppleDouble for 'name'.
      }
      NSString* pathPlusName = [path stringByAppendingPathComponent:name];
      if ([self hasCustomIconAtPath:pathPlusName]) {
        [fullContents addObject:doubleName];
      }
    }
    if ([self hasCustomIconAtPath:path]) {
      [fullContents addObject:@"Icon\r"];
      [fullContents addObject:@"._Icon\r"];
    }
    contents = [fullContents allObjects];
  }
  return contents;
}

#pragma mark Getting and Setting Attributes

- (BOOL)supportsAttributesOfItemAtPath {
  id delegate = [internal_ delegate];
  return [delegate respondsToSelector:@selector(attributesOfItemAtPath:userData:error:)] ||
         [delegate respondsToSelector:@selector(attributesOfItemAtPath:error:)];
}

- (NSDictionary *)attributesOfItemAtPath:(NSString *)path
                                userData:userData
                                   error:(NSError **)error {
  if (MACFUSE_OBJC_DELEGATE_ENTRY_ENABLED()) {
    NSString* traceinfo =
      [NSString stringWithFormat:@"%@, userData=%p", path, userData];
    MACFUSE_OBJC_DELEGATE_ENTRY(DTRACE_STRING(traceinfo));
  }

  id delegate = [internal_ delegate];
  if ([delegate respondsToSelector:@selector(attributesOfItemAtPath:userData:error:)]) {
    return [delegate attributesOfItemAtPath:path userData:userData error:error];
  } else if ([delegate respondsToSelector:@selector(attributesOfItemAtPath:error:)]) {
    return [delegate attributesOfItemAtPath:path error:error];
  }
  return nil;
}

// Get attributesOfItemAtPath from the delegate with default values.
- (NSDictionary *)defaultAttributesOfItemAtPath:(NSString *)path 
                                       userData:userData
                                          error:(NSError **)error {
  // Set up default item attributes.
  NSMutableDictionary* attributes = [NSMutableDictionary dictionary];
  BOOL isReadOnly = [internal_ isReadOnly];
  [attributes setObject:[NSNumber numberWithLong:(isReadOnly ? 0555 : 0775)]
                 forKey:NSFilePosixPermissions];
  [attributes setObject:[NSNumber numberWithLong:1]
                 forKey:NSFileReferenceCount];    // 1 means "don't know"
  if ([path isEqualToString:@"/"]) {
    [attributes setObject:NSFileTypeDirectory forKey:NSFileType];
  } else {
    [attributes setObject:NSFileTypeRegular forKey:NSFileType];
  }
  
  id delegate = [internal_ delegate];
  BOOL isAppleDouble = NO;   // May only be set to YES on Tiger.
  BOOL isDirectoryIcon = NO;

  // The delegate can override any of the above defaults by implementing the
  // attributesOfItemAtPath: selector and returning a custom dictionary.
  NSDictionary* customAttribs = nil;
  BOOL supportsAttributesSelector = [self supportsAttributesOfItemAtPath];
  if (supportsAttribute…