ILType.h

//
//  ILType.h
//  ILType
//
//  Created by ∞ on 18/04/10.
//  Copyright 2010 __MyCompanyName__. All rights reserved.
//

#import <Foundation/Foundation.h>

#if TARGET_OS_IPHONE
#import <MobileCoreServices/MobileCoreServices.h>
#import <CoreGraphics/CoreGraphics.h>
#else
#import <Carbon/Carbon.h>
#import <Quartz/Quartz.h>
#endif

@interface ILType : NSObject {
	NSString* UTI;
}

// These methods accept an argument that is either a NSString or a ILType.
// If it's of the right kind (for instance, passing a NSString to UTIWithType) the argument will be returned unchanged; otherwise, it will be transformed to the right type.
// Note that the CFStringRef returned by UTIWithType: uses ObjC rules (no need to release it).
// Additionally, both accept a nil parameter gracefully returning nil.
+ (CFStringRef) UTIWithType:(id) type;
+ (ILType*) typeWithType:(id) type;


// Designated initializer.
- initWithUTI:(id) uti;
+ typeWithUTI:(id) uti;

@property(readonly, nonatomic, copy) NSString* UTI;

// (id)-typed arguments can be either a ILType or a UTI NSString.
- (BOOL) conformsTo:(id) type; // self conforms to type?
- (BOOL) isConformingType:(id) type; // type conforms to self?

@property(readonly) NSDictionary* declaration;
@property(readonly) NSURL* definingBundleURL;

@property(readonly) NSString* localizedDescription;

// Returns a type object for the given tag of the given kind.
// 'kind' is one of the kUTTagClass… constants.
// The last argument can be a ILType or a NSString UTI object.
+ typeForTag:(NSString*) tag ofClass:(CFStringRef) kind conformingToType:(id) type;
// Same, but returns all applicable types.
+ (NSArray*) allTypesForTag:(NSString*) tag ofClass:(CFStringRef) kind conformingToType:(id) type;

// Returns the tag of the given class.
// 'kind' is one of the kUTTagClass… constants.
- (NSString*) preferredTagOfClass:(CFStringRef) kind;

@end

@interface ILType (ILTypeConvenienceMethods)

// The bundle that declares this type.
@property(readonly) NSBundle* definingBundle;

// An array of all types the receiver conforms to.
@property(readonly) NSArray* conformingToTypes;

// Use the kUTTagClass… objects as keys.
@property(readonly) NSDictionary* tagsByClass;

// Returns a path to an image representing files of this type. If there is an image with the given size or greater, it'll be returned; otherwise, a smaller image will be returned if specified, or nil if none.
- (NSString*) pathToRepresentingImageOfSize:(CGSize) s;

@end

ILType.m

//
//  ILType.m
//  ILType
//
//  Created by ∞ on 18/04/10.
//  Copyright 2010 __MyCompanyName__. All rights reserved.
//

#import "ILType.h"

@interface ILType ()

@property(copy, nonatomic, setter=private_setUTI:) NSString* UTI;

@end



@implementation ILType

+ (CFStringRef) UTIWithType:(id) type;
{
	if ([type isKindOfClass:[NSString class]])
		return (CFStringRef) type;
	else
		return (CFStringRef) [type UTI];
}

+ (ILType*) typeWithType:(id) type;
{
	if ([type isKindOfClass:[NSString class]])
		return [self typeWithUTI:type];
	else
		return type;
}

- initWithUTI:(id) uti;
{
	if ((self = [super init]))
		self.UTI = uti;
	
	return self;
}

+ typeWithUTI:(id) uti;
{
	return [[[self alloc] initWithUTI:uti] autorelease];
}

@synthesize UTI;

- (void) dealloc
{
	[UTI release];
	[super dealloc];
}

- (NSUInteger) hash;
{
	return [UTI hash] ^ [[self class] hash];
}

- (BOOL) isEqual:(id) o;
{
	return [o isKindOfClass:[ILType class]] && [[o UTI] isEqual:self.UTI];
}


- (BOOL) conformsTo:(id) type; // self conforms to type?
{
	return UTTypeConformsTo((CFStringRef) self.UTI, [[self class] UTIWithType:type]);
}

- (BOOL) isConformingType:(id) type; // type conforms to self?
{
	return UTTypeConformsTo([[self class] UTIWithType:type], (CFStringRef) self.UTI);
}


- (NSDictionary*) declaration;
{
	return [(id) UTTypeCopyDeclaration((CFStringRef) self.UTI) autorelease];
}

- (NSURL*) definingBundleURL;
{
	return [(id) UTTypeCopyDeclaringBundleURL((CFStringRef) self.UTI) autorelease];
}

- (NSString*) localizedDescription;
{
	return [(id) UTTypeCopyDescription((CFStringRef) self.UTI) autorelease];
}


+ typeForTag:(NSString*) tag ofClass:(CFStringRef) kind conformingToType:(id) type;
{
	return [self typeWithType:[(id)UTTypeCreatePreferredIdentifierForTag(kind, (CFStringRef) tag, [self UTIWithType:type]) autorelease]];
}

+ (NSArray*) allTypesForTag:(NSString*) tag ofClass:(CFStringRef) kind conformingToType:(id) type;
{
	NSArray* a = [(id)UTTypeCreateAllIdentifiersForTag(kind, (CFStringRef) tag, [self UTIWithType:type]) autorelease];
	
	NSMutableArray* types = [NSMutableArray arrayWithCapacity:[a count]];
	for (NSString* uti in a)
		[types addObject:[self typeWithUTI:uti]];
	
	return types;
}


- (NSString*) preferredTagOfClass:(CFStringRef) kind;
{
	return [(id)UTTypeCopyPreferredTagWithClass((CFStringRef) self.UTI, kind) autorelease];
}


@end


@implementation ILType (ILTypeConvenienceMethods)

- (NSBundle*) definingBundle;
{
	return [NSBundle bundleWithPath:[self.definingBundleURL path]];
}

- (NSArray*) conformingToTypes;
{
	NSMutableArray* a = [NSMutableArray array];
	for (NSString* uti in [self.declaration objectForKey:@"UTTypeConformsTo"])
		[a addObject:[[self class] typeWithUTI:uti]];
	
	return a;
}

- (NSDictionary*) tagsByClass;
{
	return [self.declaration objectForKey:@"UTTypeTagSpecification"];
}

- (NSString*) pathToRepresentingImageOfSize:(CGSize) s;
{
	NSString* path = nil;
	NSDictionary* d = self.declaration;
	
#if TARGET_OS_IPHONE
	if (s.width <= 64 || s.height <= 64)
		path = [d objectForKey:@"UTTypeSize64IconFile"];
	
	if (!path)
		path = [d objectForKey:@"UTTypeSize320IconFile"];
#else
	path = [d objectForKey:@"UTTypeIconFile"];
#endif
	
	if (path)
		path = [[self.definingBundle resourcePath] stringByAppendingPathComponent:path];
	
	return path;
}

@end