NSObject+MMBindings.m

//
//  NSObject+MMBindings.m
//  SteamEngine
//
//  Created by Rob Keniger on 31/07/09.
//  Copyright 2009 Big Bang Software Pty Ltd. All rights reserved.
//

#import "NSObject+MMBindings.h"

@implementation NSObject (MMBindings)
- (void)propagateValue:(id)value forBinding:(NSString*)binding;
{
	NSParameterAssert(binding != nil);

	//WARNING: bindingInfo contains NSNull, so it must be accounted for
	NSDictionary* bindingInfo = [self infoForBinding:binding];

	if(!bindingInfo)
		return; //there is no binding

	//apply the value transformer, if one has been set
	NSDictionary* bindingOptions = [bindingInfo objectForKey:NSOptionsKey];

	if(bindingOptions)
	{
		NSValueTransformer* transformer = [bindingOptions valueForKey:NSValueTransformerBindingOption];

		if(!transformer || (id)transformer == [NSNull null])
		{
			NSString* transformerName = [bindingOptions valueForKey:NSValueTransformerNameBindingOption];

			if(transformerName && (id)transformerName != [NSNull null])
			{
				transformer = [NSValueTransformer valueTransformerForName:transformerName];
			}
		}

		if(transformer && (id)transformer != [NSNull null])
		{
			if([[transformer class] allowsReverseTransformation])
			{
				value = [transformer reverseTransformedValue:value];
			}
			else
			{
				NSLog(@"WARNING: binding \"%@\" has value transformer, but it doesn't allow reverse transformations in %s", binding, __PRETTY_FUNCTION__);
			}
		}
	}

	id boundObject = [bindingInfo objectForKey:NSObservedObjectKey];

	if(!boundObject || boundObject == [NSNull null])
	{
		NSLog(@"ERROR: NSObservedObjectKey was nil for binding \"%@\" in %s", binding, __PRETTY_FUNCTION__);
		return;
	}

	NSString* boundKeyPath = [bindingInfo objectForKey:NSObservedKeyPathKey];

	if(!boundKeyPath || (id)boundKeyPath == [NSNull null])
	{
		NSLog(@"ERROR: NSObservedKeyPathKey was nil for binding \"%@\" in %s", binding, __PRETTY_FUNCTION__);
		return;
	}

	[boundObject setValue:value forKeyPath:boundKeyPath];
}
@end