FUSEObjectFileSystem.m

/*
  Copyright (c) 2007-2011, Marcus Müller <znek@mulle-kybernetik.com>.
  All rights reserved.


  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions are met:

  - Redistributions of source code must retain the above copyright notice, this
    list of conditions and the following disclaimer.

  - Redistributions in binary form must reproduce the above copyright notice,
    this list of conditions and the following disclaimer in the documentation
    and/or other materials provided with the distribution.

  - Neither the name of Mulle kybernetiK nor the names of its contributors
    may be used to endorse or promote products derived from this software
    without specific prior written permission.

  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  POSSIBILITY OF SUCH DAMAGE.
*/

#import "FUSEObjectFileSystem.h"
#import "NSObject+FUSEOFS.h"
#import "FUSEOFSLookupContext.h"
#import "FUSESupport.h"
#include <fcntl.h>

@interface FUSEObjectFileSystem (Private)
- (id)lookupPath:(NSString *)_path;
- (BOOL)createFileAtPath:(NSString *)_path
  attributes:(NSDictionary *)_attrs
  userData:(id *)_ud
  error:(NSError **)_err;
@end

@interface NSObject (FUSEObjectFileSystem_HackHackHack)
- (NSString *)iconFileForPath:(NSString *)_path;
@end

@implementation NSObject (FUSEObjectFileSystem_HackHackHack)
- (NSString *)iconFileForPath:(NSString *)_path {
  return nil;
}
@end

@implementation FUSEObjectFileSystem

static BOOL         debugLookup = NO;
static BOOL         debugAccess = NO;
static NSDictionary *fileDict   = nil;
static NSDictionary *dirDict    = nil;
static NSDictionary *emptyDict  = nil;
static NSArray      *emptyArray = nil;

+ (void)initialize {
  static BOOL    didInit = NO;
  NSUserDefaults *ud;
  
  if (didInit) return;
  didInit     = YES;
  ud          = [NSUserDefaults standardUserDefaults];
  debugLookup = [ud boolForKey:@"FUSEObjectFileSystemDebugPathLookup"];
  debugAccess = [ud boolForKey:@"FUSEObjectFileSystemAccessDebugEnabled"];
  fileDict    = [[NSDictionary alloc] initWithObjectsAndKeys:NSFileTypeRegular, NSFileType, nil];
  dirDict     = [[NSDictionary alloc] initWithObjectsAndKeys:NSFileTypeDirectory, NSFileType, nil];
  emptyDict   = [[NSDictionary alloc] init];
  emptyArray  = [[NSArray alloc] init];
}

- (id)init {
  
  self = [super init];
  if (self) {
    self->fs = [[GMUserFileSystem alloc] initWithDelegate:self
                                         isThreadSafe:NO];
  }
  return self;
}

- (void)dealloc {
  // NOTE: these SHOULD already be gone (via -willUnmount)
  [self->mountPoint release];
  [self->fs         release];
  [super dealloc];
}

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

- (void)mountAtPath:(NSString *)_path {
  self->mountPoint = [_path copy];
  [self->fs mountAtPath:self->mountPoint
            withOptions:[self fuseOptions]];
}

- (void)unmount {
  [self->fs unmount];
}

- (void)willUnmount {
  [self->mountPoint release];
  self->mountPoint = nil;
  [self->fs setDelegate:nil];
  [self->fs release];
  self->fs = nil;
}

- (NSString *)mountPoint {
  return self->mountPoint;
}

- (NSArray *)pathFromFSPath:(NSString *)_path {
  return [_path pathComponents];
}

- (id)rootObject {
  return self;
}

- (id)lookupPath:(NSString *)_path {
  NSArray *path = [self pathFromFSPath:_path];
  NSUInteger i, count = [path count];
  if (!count) return nil;

  id obj = [self rootObject];
  if (debugLookup)
    NSLog(@"lookup [#0, %@] -> %@", [path objectAtIndex:0], obj);

  id ctx = [[FUSEOFSLookupContext alloc] init];
  [ctx setClientObject:self];

  for (i = 1; i < count; i++) {
    id co = obj;
    obj = [obj lookupPathComponent:[path objectAtIndex:i] inContext:ctx];
    if (i < (count - 1))
      [ctx setClientObject:co];
    if (debugLookup)
      NSLog(@"lookup [#%lu, %@] -> %@",
            (unsigned long)i, [path objectAtIndex:i], obj);
  }
  [ctx release];
  return obj;
}

/* required FUSE read methods */

- (NSArray *)contentsOfDirectoryAtPath:(NSString *)_path
  error:(NSError **)_err
{
  return [[self lookupPath:_path] containerContents];
}

- (NSDictionary *)attributesOfItemAtPath:(NSString *)_path
  userData:(id)_ud
  error:(NSError **)_err
{
  NSObject *obj = [self lookupPath:_path];
  if (!obj) return nil;
  NSDictionary *attr = [obj fileAttributes];
  if (!attr) {
    if ([obj isContainer])
      return dirDict;
    else
      return fileDict;
  }
  if (debugAccess)
    NSLog(@"%@ path:%@ attrs:%@", NSStringFromSelector(_cmd), _path, attr);
  return attr;
}

- (NSData *)contentsAtPath:(NSString *)_path {
  return [[self lookupPath:_path] fileContents];
}

- (NSString *)destinationOfSymbolicLinkAtPath:(NSString *)_path
  error:(NSError **)_err
{
  return [[self lookupPath:_path] symbolicLinkTarget];
}

/* optional FUSE read methods */

#ifndef NO_OSX_ADDITIONS

- (NSDictionary *)finderAttributesAtPath:(NSString *)_path 
  error:(NSError **)_err
{
	return [[self lookupPath:_path] finderAttributes];
}

- (NSDictionary *)resourceAttributesAtPath:(NSString *)_path
  error:(NSError **)_err
{
  return [[self lookupPath:_path] resourceAttributes];
}

#endif

- (NSDictionary *)attributesOfFileSystemForPath:(NSString *)_path
  error:(NSError **)_err
{
  NSDictionary *attr = [[self lookupPath:_path] fileSystemAttributes];
  if (!attr)
    attr = emptyDict;
  return attr;
}

/* required FUSE write methods */

- (BOOL)createDirectoryAtPath:(NSString *)_path
  attributes:(NSDictionary *)_attrs
  error:(NSError **)_err
{
  id obj = [self lookupPath:[_path stringByDeletingLastPathComponent]];
  if (!obj || ![obj isMutable]) {
    if (_err)
      *_err = [FUSEObjectFileSystem errorWithCode:EACCES];
    if (debugAccess)
      NSLog(@"%@ path:%@ attrs:%@ -> [NO] (EACCESS / ![obj isMutable])",
            NSStringFromSelector(_cmd), _path, _attrs);
    return NO;
  }
  BOOL success = [obj createContainerNamed:[_path lastPathComponent]
                      withAttributes:_attrs];
  if (debugAccess)
    NSLog(@"%@ path:%@ attrs:%@ -> [%s]",
          NSStringFromSelector(_cmd), _path, _attrs, success ? "YES" : "NO");
  return success;
}

// macFUSE 3.x future compat
- (BOOL)createFileAtPath:(NSString *)_path
  attributes:(NSDictionary *)_attrs
  flags:(int)_flags
  userData:(id *)_ud
  error:(NSError **)_err
{
  return [self createFileAtPath:_path attributes:_attrs userData:_ud error:_err];
}

- (BOOL)createFileAtPath:(NSString *)_path
  attributes:(NSDictionary *)_attrs
  userData:(id *)_ud
  error:(NSError **)_err
{
  id obj = [self lookupPath:[_path stringByDeletingLastPathComponent]];
  if (!obj || ![obj isMutable]) {
    if (_err)
      *_err = [FUSEObjectFileSystem errorWithCode:EACCES];
    if (debugAccess)
      NSLog(@"%@ path:%@ attrs:%@ -> [NO] (EACCESS / ![obj isMutable])",
            NSStringFromSelector(_cmd), _path, _attrs);
    return NO;
  }
  BOOL success = [obj createFileNamed:[_path lastPathComponent]
                      withAttributes:_attrs];
  if (debugAccess)
    NSLog(@"%@ path:%@ attrs:%@ -> [%s]",
          NSStringFromSelector(_cmd), _path, _attrs, success ? "YES" : "NO");
  return success;
}

- (BOOL)openFileAtPath:(NSString *)_path 
  mode:(int)_mode
  userData:(id *)_ud
  error:(NSError **)_err
{
  if (_mode == O_RDONLY) {
    BOOL success = ([self lookupPath:_path] != nil);
    if (debugAccess)
      NSLog(@"%@ path:%@ -> [%s]",
            NSStringFromSelector(_cmd), _path, success ? "YES" : "NO");
    return success;
  }

  id   obj     = [self lookupPath:[_path stringByDeletingLastPathComponent]];
  BOOL success = [obj isMutable];
  if (debugAccess)
    NSLog(@"%@ path:%@ -> [%s]",
          NSStringFromSelector(_cmd), _path, success ? "YES" : "NO");
  return success;
}

- (void)releaseFileAtPath:(NSString *)_path
  userData:(id)_ud
{
}

- (int)writeFileAtPath:(NSString *)_path 
  userData:(id)_ud 
  buffer:(const char *)_buffer
  size:(size_t)_size 
  offset:(off_t)_offset
  error:(NSError **)_err
{
  id obj = [self lookupPath:[_path stringByDeletingLastPathComponent]];
  if (!obj || ![obj isMutable]) {
    if (_err)
      *_err = [FUSEObjectFileSystem errorWithCode:EACCES];
    if (debugAccess)
      NSLog(@"%@ path:%@ -> [NO] (EACCES / ![obj isMutable])",
			NSStringFromSelector(_cmd), _path);
    return -1;
  }

  NSData *data = [NSData dataWithBytes:(void *)_buffer length:_size];
  if([obj writeFileNamed:[_path lastPathComponent]
          withData:data])
  {
    if (debugAccess)
      NSLog(@"%@ path:%@ -> [OK]", NSStringFromSelector(_cmd), _path);
    return (int)_size;
  }
  else {
    if (debugAccess)
      NSLog(@"%@ path:%@ -> [NO] (writeFileNamed:withData: failed)",
            NSStringFromSelector(_cmd), _path);
    return -1;
  }
}

- (BOOL)moveItemAtPath:(NSString *)_src 
  toPath:(NSString *)_dst
  error:(NSError **)_err
{
  // TODO: Fix this method to allow moving directories!
  id src = [self lookupPath:_src];
  if (!src) {
    if (debugAccess)
      NSLog(@"%@ path:%@ toPath:%@ -> [NO] (![self lookupPath:_src])",
            NSStringFromSelector(_cmd), _src, _dst);
    return NO;
  }
  id dst = [self lookupPath:[_dst stringByDeletingLastPathComponent]];
  if (!dst) {
    if (debugAccess)
      NSLog(@"%@ path:%@ toPath:%@ -> [NO] (!dst)",
            NSStringFromSelector(_cmd), _src, _dst);
    return NO;
  }

  NSString *dstName = [_dst lastPathComponent];

  // NOTE: this doesn't matter if it fails!
  [dst createFileNamed:dstName withAttributes:[src fileAttributes]];
  if (![dst writeFileNamed:dstName withData:[src fileContents]])
  {
    if (debugAccess)
      NSLog(@"%@ path:%@ toPath:%@ -> [NO] (![dst writeFileNamed:withData:])",
            NSStringFromSelector(_cmd), _src, _dst);
    return NO;
  }

  id srcFolder = [self lookupPath:[_src stringByDeletingLastPathComponent]];
  if (![srcFolder removeItemNamed:[_src lastPathComponent]]) {
    [dst removeItemNamed:[_dst lastPathComponent]];
    if (debugAccess)
      NSLog(@"%@ path:%@ toPath:%@ -> [NO] (![srcFolder removeItemNamed:])",
            NSStringFromSelector(_cmd), _src, _dst);
    return NO;
  }

  if (debugAccess)
    NSLog(@"%@ path:%@ toPath:%@ -> [YES]",
		  NSStringFromSelector(_cmd), _src, _dst);
  return YES;
}

- (BOOL)removeItemAtPath:(NSString *)_path error:(NSError **)_err {
  NSString *path = [_path stringByDeletingLastPathComponent];

  id obj = [self lookupPath:path];
  if (![obj isMutable]) {
    if (_err)
      *_err = [FUSEObjectFileSystem errorWithCode:EACCES];
    if (debugAccess)
      NSLog(@"%@ path:%@ -> [NO] (EACCES ![obj isMutable])",
			NSStringFromSelector(_cmd), _path);
    return NO;
  }
  BOOL success = [obj removeItemNamed:[_path lastPathComponent]];
  if (debugAccess)
    NSLog(@"%@ path:%@ -> [%s]",
		  NSStringFromSelector(_cmd), _path, success ? "YES" : "NO");
  return success;
}

/* optional write methods */

// hardlink
- (BOOL)linkItemAtPath:(NSString *)_src
  toPath:(NSString *)_dst
  error:(NSError **)_err
{
  if (debugAccess)
    NSLog(@"%@ path:%@ toPath:%@ -> [NO]",
		  NSStringFromSelector(_cmd), _src, _dst);

  // TODO: Implement!
  if (_err)
    *_err = [FUSEObjectFileSystem errorWithCode:ENOTSUP];
  return NO;
}

- (BOOL)createSymbolicLinkAtPath:(NSString *)_src
  withDestinationPath:(NSString *)_dst
  error:(NSError **)_err
{
  if (debugAccess)
    NSLog(@"%@ path:%@ toPath:%@ -> [NO]",
		  NSStringFromSelector(_cmd), _src, _dst);

  // TODO: Implement!
  if (_err)
    *_err = [FUSEObjectFileSystem errorWithCode:ENOTSUP];
  return NO;
}

- (BOOL)setAttributes:(NSDictionary *)_attrs 
  ofItemAtPath:(NSString *)_path
  userData:(id)_ud
  error:(NSError **)_err
{
  BOOL success = [(NSObject *)[self lookupPath:_path] setFileAttributes:_attrs];
  if (debugAccess)
    NSLog(@"%@ path:%@ attrs:%@ -> [%s]",
          NSStringFromSelector(_cmd), _path, _attrs, success ? "YES" : "NO");

  return success;
}

/* extended attributes */

- (NSArray *)extendedAttributesOfItemAtPath:_path error:(NSError **)_err {
  NSDictionary *extAttrs = [[self lookupPath:_path] extendedFileAttributes];
  NSArray      *names    = extAttrs ? [extAttrs allKeys] : emptyArray;
  if (debugAccess)
    NSLog(@"%@ path:%@ -> %@", NSStringFromSelector(_cmd), _path, names);
  return names;
}

- (NSData *)valueOfExtendedAttribute:(NSString *)_name
  ofItemAtPath:(NSString *)_path
  position:(off_t)_pos
  error:(NSError **)_err
{
  NSDictionary *extAttrs = [[self lookupPath:_path] extendedFileAttributes];
  NSData       *value    = [extAttrs objectForKey:_name];
  if (_pos)
    value = [value subdataWithRange:NSMakeRange((NSUInteger)_pos, (NSUInteger)([value length] - _pos))];
  if (debugAccess && 0)
    NSLog(@"%@ path:%@ name:%@ -> %@", NSStringFromSelector(_cmd), _path, _name, value);
  return value;
}

- (BOOL)setExtendedAttribute:(NSString *)_name 
  ofItemAtPath:(NSString *)_path 
  value:(NSData *)_value
  position:(off_t)_pos
  options:(int)_options
  error:(NSError **)_err
{
  BOOL success;
  id obj = [self lookupPath:_path];
  if (obj) {
    success = [obj setExtendedAttribute:_name value:_value];
  }
  else {
    success = NO;
  }
  if (debugAccess)
    NSLog(@"%@ path:%@ name:%@ -> [%s]",
          NSStringFromSelector(_cmd), _path, _name, success ? "YES" : "NO");
  return success;
}

#ifndef NO_OSX_ADDITIONS

// NOTE: workaround for a bug in MacFUSE...
// GMUserFileSystem.m:1589 tests this selector instead of
// removeExtendedAttribute:ofItemAtPath:error:
- (BOOL)setExtendedAttribute:(NSString *)_name 
  ofItemAtPath:(NSString *)_path 
  value:(NSData *)_value
  flags:(int)_options
  error:(NSError **)_err
{
  return [self setExtendedAttribute:_name
               ofItemAtPath:_path
               value:_value
               position:0
               options:_options
               error:_err];
}

#endif

- (BOOL)removeExtendedAttribute:(NSString *)_name
  ofItemAtPath:(NSString *)_path
  error:(NSError **)_err
{
  BOOL success;
  id obj = [self lookupPath:_path];
  if (obj) {
    success = [obj removeExtendedAttribute:_name];
  }
  else {
    success = NO;
  }
  if (debugAccess)
    NSLog(@"%@ path:%@ name:%@ -> [%s]",
          NSStringFromSelector(_cmd), _path, _name, success ? "YES" : "NO");
  return success;
}

/* FUSE helpers */

- (NSArray *)fuseOptions {
  NSMutableArray *os = [NSMutableArray array];

#if 0
  // TODO: pretty lame, couldn't we set this using reflection on FS mutability?
  [os addObject:@"rdonly"];
#endif

  // don't let FUSE cache anything for us
  [os addObject:@"direct_io"];

#ifndef NO_OSX_ADDITIONS
  NSString *volIconPath = [[self rootObject] iconFileForPath:@"/"];
  if (volIconPath) {
    // this is necessary, unfortunately
    [os addObject:[@"volicon=" stringByAppendingString:volIconPath]];
  }
#endif

  return os;
}

@end /* FUSEObjectFileSystem */