//

 //  KVUtils.m

 //  MYUtilities

 //

 //  Created by Jens Alfke on 2/25/08.

 //  Copyright 2008 Jens Alfke. All rights reserved.

 //

 #import "KVUtils.h"

 @implementation Observance

 - (id) initWithTarget: (id)target 

                action: (SEL)action

              observed: (id)observed

               keyPath: (NSString*)keyPath 

               options: (NSKeyValueObservingOptions)options

 {

     self = [super init];

     if (self != nil) {

         _target = target;

         _action = action;

         _observed = observed;

         _keyPath = [keyPath copy];

         _options = options;

         options &= ~(MYKeyValueObservingOptionOnce | MYKeyValueObservingOptionDelayed);

         [_observed addObserver: self forKeyPath: _keyPath options: options context: _action];

     }

     return self;

 }

 - (void) dealloc

 {

     [_observed removeObserver: self forKeyPath: _keyPath];

     [_keyPath release];

     [super dealloc];

 }

 @synthesize observed=_observed, keyPath=_keyPath;

 - (void) stopObserving

 {

     [_observed removeObserver: self forKeyPath: _keyPath];

     _observed = nil;

     _target = nil;

     _action = NULL;

 }

 - (void) _callTargetWithChange: (NSDictionary*)change

 {

     @try{

         [_target performSelector: _action withObject: _observed withObject: change];

     }@catch( NSException *x ) {

         Warn(@"Uncaught exception in -[%@<%p> %s] while observing change of key-path %@ in %@<%p>: %@",

              _target,_target, _action, _keyPath, _observed,_observed, x);

         [NSApp reportException: x];

     }

 }

 - (void)observeValueForKeyPath:(NSString *)keyPath 

                       ofObject:(id)object 

                         change:(NSDictionary *)change 

                        context:(void *)context

 {

     if( object == _observed ) {

         if( _options & MYKeyValueObservingOptionDelayed )

             [self performSelector: @selector(_callTargetWithChange:) withObject: change

                        afterDelay: 0.0];

         else

             [self _callTargetWithChange: change];

         if( _options & MYKeyValueObservingOptionOnce )

             [self stopObserving];

     }

 }

 @end

 @implementation Observer

 - (id) init

 {

     return [self initWithTarget: self];

 }

 - (id) initWithTarget: (id)target

 {

     Assert(target);

     self = [super init];

     if (self != nil) {

         _target = target;

         _observances = [[NSMutableArray alloc] init];

     }

     return self;

 }

 - (void) dealloc

 {

     [self stopObserving];

     [_observances release];

     [super dealloc];

 }

 @synthesize target=_target;

 - (void) observe: (id)observed 

          keyPath: (NSString*)keyPath 

          options: (NSKeyValueObservingOptions)options

           action: (SEL)action

 {

     Observance *o = [[Observance alloc] initWithTarget: _target

                                                 action: action

                                               observed: observed

                                                keyPath: keyPath

                                                options: options];

     [_observances addObject: o];

     [o release];

 }

 - (void) observe: (id)observed 

          keyPath: (NSString*)keyPath 

           action: (SEL)action

 {

     [self observe: observed keyPath: keyPath options: 0 action: action];

 }

 - (void) stopObserving

 {

     [_observances makeObjectsPerformSelector: @selector(stopObserving)];

     [_observances removeAllObjects];

 }

 - (void) stopObserving: (id)observed

 {

     [self stopObserving: observed keyPath: nil];

 }

 - (void) stopObserving: (id)observed keyPath: (NSString*)keyPath

 {

     // observed or keyPath may be nil

     for( int i=_observances.count-1; i>=0; i-- ) {

         Observance *o = [_observances objectAtIndex: i];

         if( (observed==nil || observed==o.observed) && (keyPath==nil || [keyPath isEqual: o.keyPath]) ) {

             [o stopObserving];

             [_observances removeObjectAtIndex: i];

         }

     }

 }

 @end

 /*

  Copyright (c) 2008, Jens Alfke <jens@mooseyard.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.

  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 CONTRI-

  BUTORS 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.

  */