PropertyContainer

PropertyContainer.h

//
//  PropertyContainer.h
//
//  Created by Niels Gabel on 12/14/11.
//  Copyright (c) 2011 DoubleDutch Inc. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface PropertyContainer : NSObject
@property ( nonatomic, retain, readonly ) NSMutableDictionary * properties ;

-(id)defaultValueForKey:(NSString*)key ;	// default returns nil

@end

PropertyContainer.m

//
//  PropertyContainer.m
//
//  Created by Niels Gabel on 12/14/11.
//  Copyright (c) 2011 DoubleDutch Inc. All rights reserved.
//

#import "PropertyContainer.h"
#import <objc/runtime.h>

@interface PropertyContainer ()
@property ( nonatomic, retain ) NSMutableDictionary * properties ;
@end

@implementation PropertyContainer
@synthesize properties = _properties ;

+ (BOOL)resolveInstanceMethod:(SEL)sel
{
	if ( ![ super resolveInstanceMethod:sel ] )
	{
		NSString * selectorName = NSStringFromSelector( sel ) ;
		BOOL isSetter = [ selectorName hasPrefix:@"set" ] && [ selectorName hasSuffix:@":" ] && ( selectorName.length > 4 ) ;
		
		NSString * propertyName = nil ;
		if ( isSetter )
		{
			propertyName = [[[ selectorName substringWithRange:(NSRange){ 3, 1 } ] lowercaseString ] stringByAppendingString:[ selectorName substringWithRange:(NSRange){ 4, selectorName.length - 5 } ] ];
		}
		else
		{
			if ( [selectorName hasPrefix:@"get" ] )
			{
				selectorName = [ selectorName substringFromIndex:3 ] ;
			}
			
			propertyName = selectorName ;
		}
		char * propType = propertyName ? property_copyAttributeValue( class_getProperty( self, [ propertyName UTF8String ] ), "T" ) : NULL ;
				
		if ( propType )
		{
			NSString * propTypeString = [ NSString stringWithUTF8String:propType ] ;
			
			id (^block)() = NULL ;
			
			if ( isSetter )
			{
				if ( propType[0] == @encode( id )[0] )
				{
					block = (id(^)())^( PropertyContainer * self, id argument) {
						if ( argument )
						{
							[ self.properties setObject:argument  forKey:propertyName ] ;
						}
						else 
						{
							[ self.properties removeObjectForKey:propertyName ] ;
						}
					} ;				
				}
				else if ( propType[0] == @encode( struct {} )[0] 
						 || propType[0] == @encode( void* )[0] )
				{
					// handle struct types up to 32 bytes:
					
					typedef struct { uint8_t storage[32] ; } someStruct ;
					NSUInteger size = 0 ;						
					NSGetSizeAndAlignment( propType, & size, NULL ) ;
					
					DebugAssert( size <= sizeof( someStruct ) ) ;
					
					block = (id(^)())^(PropertyContainer * self, someStruct arg ) {
						[ self.properties setObject:[ NSValue valueWithBytes:& arg objCType:[ propTypeString UTF8String ] ] 
										forKey:propertyName ] ;
					} ;
				}
				else if ( strcmp( propType, @encode( BOOL ) ) == 0 )
				{
					block = (id(^)())^(PropertyContainer * self, BOOL b ) {
						[ self.properties setObject:[ NSNumber numberWithBool:b ] forKey:propertyName ] ;
					} ;
				}
				else if ( strcmp( propType, @encode( NSUInteger ) ) == 0 )
				{
					block = (id(^)())^(PropertyContainer * self, NSUInteger i ) {
						[ self.properties setObject:[ NSNumber numberWithUnsignedInteger:i ] forKey:propertyName ] ;
					} ;					
				}
				else if ( strcmp( propType, @encode( NSInteger ) ) == 0 )
				{
					block = (id(^)())^(PropertyContainer * self, NSInteger i ) {
						[ self.properties setObject:[ NSNumber numberWithInteger:i ] forKey:propertyName ] ;
					} ;					
				}
			}
			else
			{
				if ( propType[0] == @encode( id )[0] )
				{
					block = (id(^)())^(PropertyContainer * self) {
						return [ self/*.properties*/ valueForKey:propertyName ] ;
					} ;
				}
				else if ( strcmp( propType, @encode( float ) ) == 0 )
				{
					block = (id(^)())^(PropertyContainer * self ) {
						return [ [ self/*.properties*/ valueForKey:propertyName ] floatValue ] ;
					} ;
				}
				else if ( strcmp( propType, @encode( CGRect ) ) == 0 )
				{
					block = (id(^)())^(PropertyContainer * self ) {
						return [ [ self/*.properties*/ valueForKey:propertyName ] CGRectValue ] ;
					} ;
				}
				else if ( strcmp( propType, @encode( CGPoint ) ) == 0 )
				{
					block = (id(^)())^(PropertyContainer * self ) {
						return [ [ self/*.properties*/ valueForKey:propertyName ] CGPointValue ] ;
					} ;
				}
				else if ( strcmp( propType, @encode( BOOL ) ) == 0 )
				{
					block = (id(^)())^(PropertyContainer * self ) {
						return (BOOL)[ [ self/*.properties*/ valueForKey:propertyName ] boolValue ] ;
					} ;
				}
				else if ( strcmp( propType, @encode( NSUInteger ) ) == 0 )
				{
					block = (id(^)())^(PropertyContainer * self ) {
						return (NSUInteger)[ [ self/*.properties*/ valueForKey:propertyName ] unsignedIntegerValue ] ;
					} ;					
				}
				else if ( strcmp( propType, @encode( NSInteger ) ) == 0 )
				{
					block = (id(^)())^(PropertyContainer * self ) {
						return (NSInteger)[ [ self/*.properties*/ valueForKey:propertyName ] integerValue ] ;
					} ;					
				}
				else if ( strcmp( propType, @encode( int ) ) == 0 )
				{
					block = (id(^)())^(PropertyContainer * self ) {
						return (int)[ [ self/*.properties*/ valueForKey:propertyName ] intValue ] ;
					} ;
				}
			}
			
			if ( block )
			{
				const char * types = [ [ NSString stringWithFormat:isSetter ? @"v@:%c" : @"%c@:", propType[0] ] UTF8String ] ;
				IMP imp = imp_implementationWithBlock( (__bridge void *)[ block copy ] ) ;
				
				class_addMethod( self, sel, imp, types ) ;
				return YES ;
			}
			else
			{
				DebugLog(@"PropertyContainer can't make %s! propertyName=%@ type=%s\n", 
						 isSetter ? "setter" : "getter", 
						 propertyName, 
						 propType ) ;				
			}
			free((void*)propType);
		}
	}
	
	return NO ;
}

-(void)setValue:(id)value forUndefinedKey:(NSString *)key
{
}

-(id)init
{
	if (( self = [ super init ] ))
	{
		_properties = [ NSMutableDictionary dictionary ] ;
	}
	
	return self ;
}

-(NSString*)description
{
	NSMutableString * result = [ NSMutableString string ] ;
	__block NSString * separator = @"" ;
	[ self.properties enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop) {
		[ result appendFormat:@"%@%@=%@", separator, key, obj ] ;
		separator = @"," ;
	}];
	
	result = [ NSString stringWithFormat:@"<%@<%p>>{%@}", [ self class ], self, result ] ;
	return result ;
}

-(id)valueForKey:(NSString *)key
{
	id result = [ self.properties valueForKey:key ] ;
	if ( !result )
	{
		result = [ self defaultValueForKey:key ] ;
	}
	
	return result ;
}

-(id)defaultValueForKey:(NSString *)key
{
//	DebugLog(@"%@<%p> Returning 'nil' default value for key %@\n", [ self class ], self, key);
	return nil ;
}

@end