libs-base/Source/NSUserDefaults.m

/* Implementation for NSUserDefaults for GNUstep
   Copyright (C) 1995, 1996 Free Software Foundation, Inc.

   Written by:  Georg Tuparev, EMBL & Academia Naturalis, 
                Heidelberg, Germany
                Tuparev@EMBL-Heidelberg.de
  
   This file is part of the GNUstep Base Library.

   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public
   License as published by the Free Software Foundation; either
   version 2 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
   Library General Public License for more details.
   
   You should have received a copy of the GNU Library General Public
   License along with this library; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111 USA.
*/ 

#include <config.h>
#include <base/preface.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <errno.h>

#include <Foundation/NSUserDefaults.h>
#include <Foundation/NSFileManager.h>
#include <Foundation/NSPathUtilities.h>
#include <Foundation/NSDictionary.h>
#include <Foundation/NSArray.h>
#include <Foundation/NSDate.h>
#include <Foundation/NSUtilities.h>
#include <Foundation/NSArchiver.h>
#include <Foundation/NSException.h>
#include <Foundation/NSNotification.h>
#include <Foundation/NSTimer.h>
#include <Foundation/NSProcessInfo.h>
#include <Foundation/NSDistributedLock.h>
#include <Foundation/NSRunLoop.h>
#include <Foundation/NSBundle.h>
#include <base/GSLocale.h>

/* Wait for access */
#define _MAX_COUNT 5          /* Max 10 sec. */

static SEL	nextObjectSel;
static SEL	objectForKeySel;
static SEL	addSel;

/* User's Defaults database */
static NSString	*GNU_UserDefaultsPrefix = @"GNUstep";
static NSString	*GNU_UserDefaultsDatabase = @".GNUstepDefaults";
static NSString	*GNU_UserDefaultsDatabaseLock = @".GNUstepUDLock";

static Class	NSArrayClass;
static Class	NSDataClass;
static Class	NSDictionaryClass;
static Class	NSMutableDictionaryClass;
static Class	NSStringClass;

/*************************************************************************
 *** Local method definitions
 *************************************************************************/
@interface NSUserDefaults (__local_NSUserDefaults)
- (void) __createStandardSearchList;
- (NSDictionary*) __createArgumentDictionary;
- (void) __changePersistentDomain: (NSString*)domainName;
- (void) __timerTicked: (NSTimer*)tim;
@end

@implementation NSUserDefaults: NSObject
/*************************************************************************
 *** Class variables
 *************************************************************************/
static NSUserDefaults    *sharedDefaults = nil;
static NSMutableString   *processName = nil;
static NSMutableArray    *userLanguages = nil;

/*************************************************************************
 *** Getting the Shared Instance
 *************************************************************************/
static BOOL setSharedDefaults = NO;	/* Flag to prevent infinite recursion */

+ (void) initialize
{
  if (self == [NSUserDefaults class])
    {
      nextObjectSel = @selector(nextObject);
      objectForKeySel = @selector(objectForKey:);
      addSel = @selector(addEntriesFromDictionary:);
      /*
       * Cache class info for more rapid testing of the types of defaults.
       */
      NSArrayClass = [NSArray class];
      NSDataClass = [NSData class];
      NSDictionaryClass = [NSDictionary class];
      NSMutableDictionaryClass = [NSMutableDictionary class];
      NSStringClass = [NSString class];
    }
}

+ (void) resetUserDefaults
{
  if (sharedDefaults != nil)
    {
      NSDictionary	*regDefs;

      regDefs = RETAIN([sharedDefaults->_tempDomains
	objectForKey: NSRegistrationDomain]);
      setSharedDefaults = NO;
      DESTROY(sharedDefaults);
      if (regDefs != nil)
	{
	  [self standardUserDefaults];
	  if (sharedDefaults != nil)
	    {
	      [sharedDefaults->_tempDomains setObject: regDefs
					       forKey: NSRegistrationDomain];
	    }
	  RELEASE(regDefs);
	}
    }
}

/* Create a locale dictionary when we have absolutely no information
   about the locale. This method should go away, since it will never
   be called in a properly installed system. */
+ (NSDictionary *) _unlocalizedDefaults
{
  NSDictionary   *registrationDefaults;
  NSArray	 *ampm;
  NSArray	 *long_day;
  NSArray	 *long_month;
  NSArray	 *short_day;
  NSArray	 *short_month;
  NSArray	 *earlyt;
  NSArray	 *latert;
  NSArray	 *hour_names;
  NSArray	 *ymw_names;
  
  ampm = [NSArray arrayWithObjects: @"AM", @"PM", nil];

  short_month = [NSArray arrayWithObjects: 
    @"Jan",
    @"Feb",
    @"Mar",
    @"Apr",
    @"May",
    @"Jun",
    @"Jul",
    @"Aug",
    @"Sep",
    @"Oct",
    @"Nov",
    @"Dec",
    nil];

  long_month = [NSArray arrayWithObjects: 
    @"January",
    @"February",
    @"March",
    @"April",
    @"May",
    @"June",
    @"July",
    @"August",
    @"September",
    @"October",
    @"November",
    @"December",
    nil];

  short_day = [NSArray arrayWithObjects: 
    @"Sun",
    @"Mon",
    @"Tue",
    @"Wed",
    @"Thu",
    @"Fri",
    @"Sat",
    nil];

  long_day = [NSArray arrayWithObjects: 
    @"Sunday",
    @"Monday",
    @"Tuesday",
    @"Wednesday",
    @"Thursday",
    @"Friday",
    @"Saturday",
    nil];

  earlyt = [NSArray arrayWithObjects: 
    @"prior",
    @"last",
    @"past",
    @"ago",
    nil];

  latert = [NSArray arrayWithObjects: @"next", nil];

  ymw_names = [NSArray arrayWithObjects: @"year", @"month", @"week", nil];

  hour_names = [NSArray arrayWithObjects: 
    [NSArray arrayWithObjects: @"0", @"midnight", nil],
    [NSArray arrayWithObjects: @"12", @"noon", @"lunch", nil],
    [NSArray arrayWithObjects: @"10", @"morning", nil],
    [NSArray arrayWithObjects: @"14", @"afternoon", nil],
    [NSArray arrayWithObjects: @"19", @"dinner", nil],
    nil];

  registrationDefaults = [NSDictionary dictionaryWithObjectsAndKeys: 
    ampm, NSAMPMDesignation,
    long_month, NSMonthNameArray,
    long_day, NSWeekDayNameArray,
    short_month, NSShortMonthNameArray,
    short_day, NSShortWeekDayNameArray,
    @"DMYH", NSDateTimeOrdering,
    [NSArray arrayWithObject: @"tomorrow"], NSNextDayDesignations,
    [NSArray arrayWithObject: @"nextday"], NSNextNextDayDesignations,
    [NSArray arrayWithObject: @"yesterday"], NSPriorDayDesignations,
    [NSArray arrayWithObject: @"today"], NSThisDayDesignations,
    earlyt, NSEarlierTimeDesignations,
    latert, NSLaterTimeDesignations,
    hour_names, NSHourNameDesignations,
    ymw_names, NSYearMonthWeekDesignations,
    nil];
  return registrationDefaults;
}

+ (NSUserDefaults*) standardUserDefaults
  /*
    Returns the shared defaults object. If it doesn't exist yet, it's
    created. The defaults are initialized for the current user.
    The search list is guaranteed to be standard only the first time 
    this method is invoked. The shared instance is provided as a 
    convenience; other instances may also be created.
    */
{
  BOOL added_locale, added_lang;
  id lang;
  NSArray *uL;
  NSEnumerator *enumerator;

  if (setSharedDefaults)
    {
      return sharedDefaults;
    }
  setSharedDefaults = YES;
  /*
   * Get the user languages *before* setting up sharedDefaults, to avoid
   * the userLanguages method trying to look up languages in a partially
   * constructed user defaults object.
   */
  uL = [[self class] userLanguages];
  // Create new sharedDefaults (NOTE: Not added to the autorelease pool!)
  sharedDefaults = [[self alloc] init];
  if (sharedDefaults == nil)
    {
      NSLog(@"WARNING - unable to create shared user defaults!\n");
      return nil;
    }
	
  [sharedDefaults __createStandardSearchList];

  /* Set up language constants */
  added_locale = NO;
  added_lang = NO;
  enumerator = [uL objectEnumerator];
  while ((lang = [enumerator nextObject]))
    {
      NSString *path;
      NSDictionary *dict;
      path = [NSBundle pathForGNUstepResource: lang
		                       ofType: nil
		                  inDirectory: @"Resources/Languages"];
      dict = nil;
      if (path)
	dict = [NSDictionary dictionaryWithContentsOfFile: path];
      if (dict)
	{
	  [sharedDefaults setVolatileDomain: dict forName: lang];
	  added_lang = YES;
	}
      else if (added_locale == NO)
	{
	  NSString *locale = GSSetLocale(nil);
	  if (locale == nil)
	    break;
	  /* See if we can get the dictionary from i18n functions.
	     Note that we get the dict from the current locale regardless
	     of what 'lang' is, since it should match anyway. */
	  /* Also, I don't think that the i18n routines can handle more than
	     one locale, but tell me if I'm wrong... */
	  if (GSLanguageFromLocale(locale))
	    lang = GSLanguageFromLocale(locale);
	  dict = GSDomainFromDefaultLocale();
	  if (dict)
	    [sharedDefaults setVolatileDomain: dict forName: lang];
	  added_locale = YES;
	}
    }
  if (added_lang == NO)
    {
      /* Ack! We should never get here */
      NSLog(@"Improper installation: No language locale found");
      [sharedDefaults registerDefaults: [self _unlocalizedDefaults]];
    }
  return sharedDefaults;
}


+ (NSArray*) userLanguages
{
  NSArray	*currLang = nil;
  NSString	*locale;

  if (userLanguages != nil)
    {
      return userLanguages;
    }
  userLanguages = RETAIN([NSMutableArray arrayWithCapacity: 5]);
  locale = GSSetLocale(@"");
  if (sharedDefaults == nil)
    {
      /* Create our own defaults to get "NSLanguages" since sharedDefaults
	 depends on us */
      NSUserDefaults	*tempDefaults;

      tempDefaults = [[self alloc] init];
      if (tempDefaults != nil)
	{	
	  NSMutableArray	*sList;

	  /*
	   * Can't use the standard method to set up a search list,
	   * it would cause mutual recursion as it includes languages.
	   */
	  sList = [[NSMutableArray alloc] initWithCapacity: 4];
	  [sList addObject: NSArgumentDomain];
	  [sList addObject: processName];
	  [sList addObject: NSGlobalDomain];
	  [sList addObject: NSRegistrationDomain];
	  [tempDefaults setSearchList: sList];
	  RELEASE(sList);
	  currLang = [tempDefaults stringArrayForKey: @"NSLanguages"];
	  AUTORELEASE(tempDefaults);
	}
    }
  else
    {
      currLang
	= [[self standardUserDefaults] stringArrayForKey: @"NSLanguages"];
    }
  if (currLang == nil && locale != 0 && GSLanguageFromLocale(locale))
    {
      currLang = [NSArray arrayWithObject: GSLanguageFromLocale(locale)];
    }
#ifdef __MINGW__
  if (currLang == nil && locale != 0)
    {
      /* Check for language as the first part of the locale string */
      NSRange under = [locale rangeOfString: @"_"];
      if (under.location)
        currLang = [NSArray arrayWithObject: 
	             [locale substringToIndex: under.location]];
    }
#endif
  if (currLang == nil)
    { 
      const char	*env_list;
      NSString		*env;

      env_list = getenv("LANGUAGES");
      if (env_list != 0)
	{
	  env = [NSStringClass stringWithCString: env_list];
	  currLang = [env componentsSeparatedByString: @";"];
	}
    }

  if (currLang != nil)
    {
      if ([currLang containsObject: @""] == YES)
	{
	  NSMutableArray	*a = [currLang mutableCopy];

	  [a removeObject: @""];
	  currLang = (NSArray*)AUTORELEASE(a);
	}
      [userLanguages addObjectsFromArray: currLang];
    }

  /* Check if "English" is included. We do this to make sure all the
     required language constants are set somewhere if they aren't set
     in the default language */
  if ([userLanguages containsObject: @"English"] == NO)
    {
      [userLanguages addObject: @"English"];
    }

  return userLanguages;
}

+ (void) setUserLanguages: (NSArray*)languages
{
  NSMutableDictionary	*globDict = [[self standardUserDefaults] 
			    persistentDomainForName: NSGlobalDomain];
	
  if (languages == nil)          // Remove the entry
    [globDict removeObjectForKey: @"NSLanguages"];
  else
    [globDict setObject: languages forKey: @"NSLanguages"];
  [[self standardUserDefaults] 
    setPersistentDomain: globDict forName: NSGlobalDomain];
  return;
}

/*************************************************************************
 *** Initializing the User Defaults
 *************************************************************************/
- (id) init
  /* Initializes defaults for current user calling initWithUser: . */
{
  return [self initWithUser: NSUserName()];
}

static NSString	*pathForUser(NSString *user) 
{
  NSFileManager	*mgr = [NSFileManager defaultManager];
  NSString	*home;
  NSString	*path;
  BOOL		isDir;
	
  home = NSHomeDirectoryForUser(user);
  if (home == nil)
    {  
      /* Probably on MINGW. Where to put it? */
      NSLog(@"Could not get home dir. Using GNUSTEP_ROOT");
      home = NSOpenStepRootDirectory();
      path = home;
    }
  else
    path = [home stringByAppendingPathComponent: GNU_UserDefaultsPrefix];
  if ([mgr fileExistsAtPath: path isDirectory: &isDir] == NO)
    {
      NSLog(@"Directory '%@' does not exist - creating it", path);
      if ([mgr createDirectoryAtPath: path attributes: nil] == NO)
	{
	  NSLog(@"Unable to create user GNUstep directory '%@'", path);
	  return nil;
	}
    }
  if (isDir == NO)
    {
      NSLog(@"ERROR - '%@' is not a directory!", path);
      return nil;
    }
  path = [path stringByAppendingPathComponent: GNU_UserDefaultsDatabase];
  return path;
}

/* Initializes defaults for the specified user calling initWithFile: . */
- (id) initWithUser: (NSString*)userName
{
  NSString	*path = pathForUser(userName);
	
  if (path == nil)
    {  
      RELEASE(self);
      return nil;
    }
  return [self initWithContentsOfFile: path];
}

- (id) initWithContentsOfFile: (NSString*)path
  /* Initializes defaults for the specified path. Returns an object with 
     an empty search list. */
{
  [super init];
	
  // Find the user's home folder and build the paths (executed only once)
  if (_defaultsDatabase == nil)
    {
      if (path != nil && [path isEqual: @""] == NO)
	{
	  _defaultsDatabase = [path copy];
	}
      else
	{
	  _defaultsDatabase = [pathForUser(NSUserName()) copy];
	}

      if ([[_defaultsDatabase lastPathComponent] isEqual: 
	GNU_UserDefaultsDatabase] == YES)
	{
	  path = [_defaultsDatabase stringByDeletingLastPathComponent];
	}
      else
	{
	  path = [pathForUser(NSUserName()) stringByDeletingLastPathComponent];
	}
      path = [path stringByAppendingPathComponent:
	GNU_UserDefaultsDatabaseLock];
      _defaultsDatabaseLockName = [path copy];
      _defaultsDatabaseLock =
	RETAIN([NSDistributedLock lockWithPath: _defaultsDatabaseLockName]);
    }
  if (processName == nil)
    processName = RETAIN([[NSProcessInfo processInfo] processName]);

  // Create an empty search list
  _searchList = [[NSMutableArray alloc] initWithCapacity: 10];
	
  // Initialize _persDomains from the archived user defaults (persistent)
  _persDomains = [[NSMutableDictionaryClass alloc] initWithCapacity: 10];
  if ([self synchronize] == NO)
    {
      NSRunLoop	*runLoop = [NSRunLoop currentRunLoop];
      BOOL	done = NO;
      int	attempts;

      // Retry for a couple of seconds in case we are locked out.
      for (attempts = 0; done == NO && attempts < 10; attempts++)
	{
	  [runLoop runMode: [runLoop currentMode]
		beforeDate: [NSDate dateWithTimeIntervalSinceNow: 0.2]];
	  if ([self synchronize] == YES)
	    done = YES;
        }
      if (done == NO)
	{
          RELEASE(self);
          return self = nil;
        }
    }
	
  // Check and if not existent add the Application and the Global domains
  if (![_persDomains objectForKey: processName])
    {
      [_persDomains
	setObject: [NSMutableDictionaryClass dictionaryWithCapacity: 10]
	forKey: processName];
      [self __changePersistentDomain: processName];
    }
  if (![_persDomains objectForKey: NSGlobalDomain])
    {
      [_persDomains
	setObject: [NSMutableDictionaryClass dictionaryWithCapacity: 10]
	forKey: NSGlobalDomain];
      [self __changePersistentDomain: NSGlobalDomain];
    }
	
  // Create volatile defaults and add the Argument and the Registration domains
  _tempDomains = [[NSMutableDictionaryClass alloc] initWithCapacity: 10];
  [_tempDomains setObject: [self __createArgumentDictionary] 
		   forKey: NSArgumentDomain];
  [_tempDomains
    setObject: [NSMutableDictionaryClass dictionaryWithCapacity: 10]
    forKey: NSRegistrationDomain];
	
  return self;
}

- (void) dealloc
{
  if (_tickingTimer)
    [_tickingTimer invalidate];
  RELEASE(_lastSync);
  RELEASE(_searchList);
  RELEASE(_persDomains);
  RELEASE(_tempDomains);
  RELEASE(_changedDomains);
  RELEASE(_dictionaryRep);
  [super dealloc];
}

- (NSString*) description
{
  NSMutableString *desc;

  desc = [NSMutableString stringWithFormat: @"%@", [super description]];
  [desc appendFormat: @" SearchList: %@", _searchList];
  [desc appendFormat: @" Persistant: %@", _persDomains];
  [desc appendFormat: @" Temporary: %@", _tempDomains];
  return desc;
}

/*************************************************************************
 *** Getting and Setting a Default
 *************************************************************************/
- (NSArray*) arrayForKey: (NSString*)defaultName
{
  id	obj = [self objectForKey: defaultName];
	
  if (obj != nil && [obj isKindOfClass: NSArrayClass])
    return obj;
  return nil;
}

- (BOOL) boolForKey: (NSString*)defaultName
{
  id	obj = [self stringForKey: defaultName];
	
  if (obj != nil)
    return [obj boolValue];
  return NO;
}

- (NSData*) dataForKey: (NSString*)defaultName
{
  id	obj = [self objectForKey: defaultName];
	
  if (obj != nil && [obj isKindOfClass: NSDataClass])
    return obj;
  return nil;
}

- (NSDictionary*) dictionaryForKey: (NSString*)defaultName
{
  id	obj = [self objectForKey: defaultName];
	
  if (obj != nil && [obj isKindOfClass: NSDictionaryClass])
    return obj;
  return nil;
}

- (float) floatForKey: (NSString*)defaultName
{
  id	obj = [self stringForKey: defaultName];
	
  if (obj != nil)
    return [obj floatValue];
  return 0.0;
}

- (int) integerForKey: (NSString*)defaultName
{
  id	obj = [self stringForKey: defaultName];
	
  if (obj != nil)
    return [obj intValue];
  return 0;
}

- (id) objectForKey: (NSString*)defaultName
{
  NSEnumerator	*enumerator = [_searchList objectEnumerator];
  IMP		nImp = [enumerator methodForSelector: nextObjectSel];
  id		object = nil;
  id		dN;
  IMP		pImp = [_persDomains methodForSelector: objectForKeySel];
  IMP		tImp = [_tempDomains methodForSelector: objectForKeySel];
	
  while ((dN = (*nImp)(enumerator, nextObjectSel)) != nil)
    {
      id	dict;
      
      dict = (*pImp)(_persDomains, objectForKeySel, dN);
      if (dict != nil && (object = [dict objectForKey: defaultName]))
	break;
      dict = (*tImp)(_tempDomains, objectForKeySel, dN);
      if (dict != nil && (object = [dict objectForKey: defaultName]))
	break;
    }
	
  return object;
}

- (void) removeObjectForKey: (NSString*)defaultName
{
  id	obj;
	
  obj = [[_persDomains objectForKey: processName] objectForKey: defaultName];
  if (obj != nil)
    {
      NSMutableDictionary	*dict;
      id			obj = [_persDomains objectForKey: processName];

      if ([obj isKindOfClass: NSMutableDictionaryClass] == YES)
	{
	  dict = obj;
	}
      else
	{
	  dict = [obj mutableCopy];
	  [_persDomains setObject: dict forKey: processName];
	}
      [dict removeObjectForKey: defaultName];
      [self __changePersistentDomain: processName];
    }
  return;
}

- (void) setBool: (BOOL)value forKey: (NSString*)defaultName
{
  id	obj = (value)?@"YES": @"NO";
	
  [self setObject: obj forKey: defaultName];
  return;
}

- (void) setFloat: (float)value forKey: (NSString*)defaultName
{	
  char	buf[32];

  sprintf(buf,"%g",value);
  [self setObject: [NSStringClass stringWithCString: buf] forKey: defaultName];
  return;
}

- (void) setInteger: (int)value forKey: (NSString*)defaultName
{
  char	buf[32];

  sprintf(buf,"%d",value);
  [self setObject: [NSStringClass stringWithCString: buf] forKey: defaultName];
  return;
}

- (void) setObject: (id)value forKey: (NSString*)defaultName
{
  if (value && defaultName && ([defaultName length] > 0))
    {
      NSMutableDictionary	*dict;
      id			obj = [_persDomains objectForKey: processName];

      if ([obj isKindOfClass: NSMutableDictionaryClass] == YES)
	{
	  dict = obj;
	}
      else
	{
	  dict = [obj mutableCopy];
	  [_persDomains setObject: dict forKey: processName];
	  RELEASE(dict);
	}
      [dict setObject: value forKey: defaultName];
      [self __changePersistentDomain: processName];
    }
  return;
}

- (NSArray*) stringArrayForKey: (NSString*)defaultName
{
  id	arr = [self arrayForKey: defaultName];
	
  if (arr != nil)
    {
      NSEnumerator	*enumerator = [arr objectEnumerator];
      id		obj;
		
      while ((obj = [enumerator nextObject]))
	{
	  if ([obj isKindOfClass: NSStringClass] == NO)
	    {
	      return nil;
	    }
	}
      return arr;
    }
  return nil;
}

- (NSString*) stringForKey: (NSString*)defaultName
{
  id	obj = [self objectForKey: defaultName];
	
  if (obj != nil && [obj isKindOfClass: NSStringClass])
    return obj;
  return nil;
}

/*************************************************************************
 *** Returning the Search List
 *************************************************************************/
- (NSArray*) searchList
{
  return AUTORELEASE([_searchList copy]);
}

- (void) setSearchList: (NSArray*)newList
{
  DESTROY(_dictionaryRep);
  RELEASE(_searchList);
  _searchList = [newList mutableCopy];
}

/*************************************************************************
 *** Maintaining Persistent Domains
 *************************************************************************/
- (NSDictionary*) persistentDomainForName: (NSString*)domainName
{
  return AUTORELEASE([[_persDomains objectForKey: domainName] copy]);
}

- (NSArray*) persistentDomainNames
{
  return [_persDomains allKeys];
}

- (void) removePersistentDomainForName: (NSString*)domainName
{
  if ([_persDomains objectForKey: domainName])
    {
      [_persDomains removeObjectForKey: domainName];
      [self __changePersistentDomain: domainName];
    }
  return;
}

- (void) setPersistentDomain: (NSDictionary*)domain 
		     forName: (NSString*)domainName
{
  id	dict = [_tempDomains objectForKey: domainName];
	
  if (dict)
    {
      [NSException raise: NSInvalidArgumentException 
		   format: @"Persistant domain %@ already exists", domainName];
      return;
    }
  domain = [domain mutableCopy];
  [_persDomains setObject: domain forKey: domainName];
  RELEASE(domain);
  [self __changePersistentDomain: domainName];
  return;
}

- (BOOL) synchronize
{
  NSFileManager		*mgr = [NSFileManager defaultManager];
  NSMutableDictionary	*newDict;
  NSDictionary		*attr;
  NSDate		*mod;

  if (_tickingTimer == nil)
    {
      _tickingTimer = [NSTimer scheduledTimerWithTimeInterval: 30
	       target: self
	       selector: @selector(__timerTicked:)
	       userInfo: nil
	       repeats: NO];
    }

  /*
   *	If we haven't changed anything, we only need to synchronise if
   *	the on-disk database has been changed by someone else.
   */
  if (_changedDomains == NO)
    {
      BOOL		wantRead = NO;

      if (_lastSync == nil)
	wantRead = YES;
      else
	{
	  attr = [mgr fileAttributesAtPath: _defaultsDatabase
			      traverseLink: YES];
	  if (attr == nil)
	    wantRead = YES;
	  else
	    {
	      mod = [attr objectForKey: NSFileModificationDate];
	      if ([_lastSync earlierDate: mod] != _lastSync)
		wantRead = YES;
	    }
	}
      if (wantRead == NO)
	return YES;
    }

  /*
   * Get file lock - break any lock that is more than five minute old.
   */
  if ([_defaultsDatabaseLock tryLock] == NO)
    {
      if ([[_defaultsDatabaseLock lockDate] timeIntervalSinceNow] < -300.0)
	{
	  [_defaultsDatabaseLock breakLock];
	  if ([_defaultsDatabaseLock tryLock] == NO)
	    {
	      return NO;
	    }
	}
      else
	{
	  return NO;
	}
    }
	
  DESTROY(_dictionaryRep);

  // Read the persistent data from the stored database
  if ([mgr fileExistsAtPath: _defaultsDatabase])
    {
      newDict = [[NSMutableDictionaryClass allocWithZone: [self zone]]
        initWithContentsOfFile: _defaultsDatabase];
      if (newDict == nil)
	{
	  [_defaultsDatabaseLock unlock];	// release file lock
	  NSLog(@"Unable to load defaults from '%@'", _defaultsDatabase);
	  return NO;
	}
    }
  else
    {
      attr = [NSDictionary dictionaryWithObjectsAndKeys: 
	NSUserName(), NSFileOwnerAccountName, nil];
      NSLog(@"Creating defaults database file %@", _defaultsDatabase);
      [mgr createFileAtPath: _defaultsDatabase
		   contents: nil
		 attributes: attr];
      newDict = [[NSMutableDictionaryClass allocWithZone: [self zone]]
		  initWithCapacity: 1];
      [newDict writeToFile: _defaultsDatabase atomically: YES];
    }

  if (_changedDomains)
    {           // Synchronize both dictionaries
      NSEnumerator	*enumerator = [_changedDomains objectEnumerator];
      IMP		nextImp;
      IMP		pImp;
      id		obj, dict;
		
      nextImp = [enumerator methodForSelector: nextObjectSel];
      pImp = [_persDomains methodForSelector: objectForKeySel];
      while ((obj = (*nextImp)(enumerator, nextObjectSel)) != nil)
	{
	  dict = (*pImp)(_persDomains, objectForKeySel, obj);
	  if (dict)       // Domain was added or changed
	    {
	      [newDict setObject: dict forKey: obj];
	    }
	  else            // Domain was removed
	    {
	      [newDict removeObjectForKey: obj];
	    }
	}
      RELEASE(_persDomains);
      _persDomains = newDict;
      // Save the changes
      if (![_persDomains writeToFile: _defaultsDatabase atomically: YES])
	{
	  [_defaultsDatabaseLock unlock];
	  return NO;
	}
      attr = [mgr fileAttributesAtPath: _defaultsDatabase
			  traverseLink: YES];
      mod = [attr objectForKey: NSFileModificationDate];
      ASSIGN(_lastSync, mod);
      [_defaultsDatabaseLock unlock];	// release file lock
    }
  else
    {
      attr = [mgr fileAttributesAtPath: _defaultsDatabase
			  traverseLink: YES];
      mod = [attr objectForKey: NSFileModificationDate];
      ASSIGN(_lastSync, mod);
      [_defaultsDatabaseLock unlock];	// release file lock
      if ([_persDomains isEqual: newDict] == NO)
	{
	  RELEASE(_persDomains);
	  _persDomains = newDict;
	  [[NSNotificationCenter defaultCenter] 
	    postNotificationName: NSUserDefaultsDidChangeNotification
			  object: nil];
	}
      else
	{
	  RELEASE(newDict);
	}
    }

  return YES;
}


/*************************************************************************
 *** Maintaining Volatile Domains
 *************************************************************************/
- (void) removeVolatileDomainForName: (NSString*)domainName
{
  DESTROY(_dictionaryRep);
  [_tempDomains removeObjectForKey: domainName];
}

- (void) setVolatileDomain: (NSDictionary*)domain 
		   forName: (NSString*)domainName
{
  id	dict = [_persDomains objectForKey: domainName];
	
  if (dict)
    {
      [NSException raise: NSInvalidArgumentException 
		  format: @"Volatile domain %@ already exists", domainName];
      return;
    }
  DESTROY(_dictionaryRep);
  domain = [domain mutableCopy];
  [_tempDomains setObject: domain forKey: domainName];
  RELEASE(domain);
  return;
}

- (NSDictionary*) volatileDomainForName: (NSString*)domainName
{
  return AUTORELEASE([[_tempDomains objectForKey: domainName] copy]);
}

- (NSArray*) volatileDomainNames
{
  return [_tempDomains allKeys];
}

/*************************************************************************
 *** Making Advanced Use of Defaults
 *************************************************************************/
- (NSDictionary*) dictionaryRepresentation
{
  if (_dictionaryRep == nil)
    {
      NSEnumerator		*enumerator;
      NSMutableDictionary	*dictRep;
      id			obj;
      id			dict;
      IMP			nImp;
      IMP			pImp;
      IMP			tImp;
      IMP			addImp;
	
      pImp = [_persDomains methodForSelector: objectForKeySel];
      tImp = [_tempDomains methodForSelector: objectForKeySel];

      enumerator = [_searchList reverseObjectEnumerator];
      nImp = [enumerator methodForSelector: nextObjectSel];

      dictRep = [NSMutableDictionaryClass allocWithZone: NSDefaultMallocZone()];
      dictRep = [dictRep initWithCapacity: 512];
      addImp = [dictRep methodForSelector: addSel];

      while ((obj = (*nImp)(enumerator, nextObjectSel)) != nil)
	{
	  if ( (dict = (*pImp)(_persDomains, objectForKeySel, obj)) != nil
	    || (dict = (*tImp)(_tempDomains, objectForKeySel, obj)) != nil)
	    (*addImp)(dictRep, addSel, dict);
	}
      _dictionaryRep = [dictRep copy];
      RELEASE(dictRep);
    }
  return _dictionaryRep;
}

- (void) registerDefaults: (NSDictionary*)newVals
{
  NSMutableDictionary	*regDefs;

  regDefs = [_tempDomains objectForKey: NSRegistrationDomain];
  if (regDefs == nil)
    {
      regDefs = [NSMutableDictionaryClass
	dictionaryWithCapacity: [newVals count]];
      [_tempDomains setObject: regDefs forKey: NSRegistrationDomain];
    }
  DESTROY(_dictionaryRep);
  [regDefs addEntriesFromDictionary: newVals];
}

/*************************************************************************
 *** Accessing the User Defaults database
 *************************************************************************/
- (void) __createStandardSearchList
{
  NSArray	*uL;
  NSEnumerator	*enumerator;
  id		object;
	
  // Note: The search list should exist!
	
  // 1. NSArgumentDomain
  [_searchList addObject: NSArgumentDomain];
	
  // 2. Application
  [_searchList addObject: processName];

  // 3. NSGlobalDomain
  [_searchList addObject: NSGlobalDomain];
	
  // 4. User's preferred languages
  uL = [[self class] userLanguages];
  enumerator = [uL objectEnumerator];
  while ((object = [enumerator nextObject]))
    {
      [_searchList addObject: object];
    }
	
  // 5. NSRegistrationDomain
  [_searchList addObject: NSRegistrationDomain];
	
  return;
}

- (NSDictionary*) __createArgumentDictionary
{
  NSArray	*args = [[NSProcessInfo processInfo] arguments];
  //$$$	NSArray *args = _searchList;  // $$$
  NSEnumerator	*enumerator = [args objectEnumerator];
  NSMutableDictionary *argDict =
    [NSMutableDictionaryClass dictionaryWithCapacity: 2];
  BOOL		done;
  id		key, val;
	
  [enumerator nextObject];	// Skip process name.
  done = ((key = [enumerator nextObject]) == nil);
	
  while (!done)
    {
      if ([key hasPrefix: @"-"])
	{
	  NSString	*old = nil;

	  /* anything beginning with a '-' is a defaults key and we must strip
	      the '-' from it.  As a special case, we leave the '- in place
	      for '-GS...' and '--GS...' for backward compatibility. */
	  if ([key hasPrefix: @"-GS"] == YES || [key hasPrefix: @"--GS"] == YES)
	    {
	      old = key;
	    }
	  key = [key substringFromIndex: 1];
	  val = [enumerator nextObject];
	  if (val == nil)
	    {            // No more args
	      [argDict setObject: @"" forKey: key];		// arg is empty.
	      if (old != nil)
		{
		  [argDict setObject: @"" forKey: old];
		}
	      done = YES;
	      continue;
	    }
	  else if ([val hasPrefix: @"-"] == YES)
	    {  // Yet another argument
	      [argDict setObject: @"" forKey: key];		// arg is empty.
	      if (old != nil)
		{
		  [argDict setObject: @"" forKey: old];
		}
	      key = val;
	      continue;
	    }
	  else
	    {                            // Real parameter
	      /* Parsing the argument as a property list is very
		 delicate.  We *MUST NOT* crash here just because a
		 strange parameter (such as `(load "test.scm")`) is
		 passed, otherwise the whole library is useless in a
		 foreign environment. */
	      NSObject *plist_val;
	      
	      NS_DURING
		{
		  plist_val = [val propertyList];
		}
	      NS_HANDLER
		{
		  plist_val = val;
		}
	      NS_ENDHANDLER
		
	      /* Make sure we don't crash being caught adding nil to
                 a dictionary. */
	      if (plist_val == nil)
		{
		  plist_val = val;
		}

	      [argDict setObject: plist_val  forKey: key];
	      if (old != nil)
		{
		  [argDict setObject: plist_val  forKey: old];
		}
	    }
	}
      done = ((key = [enumerator nextObject]) == nil);
    }
  
  return argDict;
}

- (void) __changePersistentDomain: (NSString*)domainName
{
  NSEnumerator	*enumerator = nil;
  IMP		nImp;
  id		obj;

  DESTROY(_dictionaryRep);
  if (!_changedDomains)
    {
      _changedDomains = [[NSMutableArray alloc] initWithCapacity: 5];
      [[NSNotificationCenter defaultCenter] 
	postNotificationName: NSUserDefaultsDidChangeNotification object: nil];
    }
	
  enumerator = [_changedDomains objectEnumerator];
  nImp = [enumerator methodForSelector: nextObjectSel];
  while ((obj = (*nImp)(enumerator, nextObjectSel)) != nil)
    {
      if ([obj isEqualToString: domainName])
	return;
    }
  [_changedDomains addObject: domainName];
  return;
}

- (void) __timerTicked: (NSTimer*)tim
{
  if (tim == _tickingTimer)
    _tickingTimer = nil;

  [self synchronize];
}
@end