BPXLUUIDHandler.m

//	
//  BPXLUUIDHandler.m
//  UUIDHandler
//
//  Created by Doug Russell on 2/29/12.
//  Copyright (c) 2012 Black Pixel. All rights reserved.
//  
//  Licensed under the Apache License, Version 2.0 (the "License");
//  you may not use this file except in compliance with the License.
//  You may obtain a copy of the License at
//  
//  http://www.apache.org/licenses/LICENSE-2.0
//  
//  Unless required by applicable law or agreed to in writing, software
//  distributed under the License is distributed on an "AS IS" BASIS,
//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//  See the License for the specific language governing permissions and
//  limitations under the License.
//  

#import "BPXLUUIDHandler.h"

#ifndef ARCLOGIC
#define ARCLOGIC

#ifdef HASARC
#undef HASARC
#endif
#ifdef HASWEAK
#undef HASWEAK
#endif
#ifdef STRONG
#undef STRONG
#endif
#ifdef __STRONG
#undef __STRONG
#endif
#ifdef WEAK
#undef WEAK
#endif
#ifdef __WEAK
#undef __WEAK
#endif
#ifdef __BRIDGE
#undef __BRIDGE
#endif

#define HASARC __has_feature(objc_arc)

#define HASWEAK __has_feature(objc_arc_weak)

#if HASARC
	#define IF_ARC(ARCBlock, NOARCBlock) ARCBlock
	#define NO_ARC(NoARCBlock) 
	#define __BRIDGE __bridge
	#define STRONG strong
	#define __STRONG __strong
	#if HASWEAK
		#define __WEAK __weak
		#define WEAK weak
		#define NO_WEAK(NoWeakBlock) 
	#else
		#define WEAK assign
		#define __WEAK __unsafe_unretained
		#define NO_WEAK(NoWeakBlock) NoWeakBlock
	#endif
#else
	#define IF_ARC(ARCBlock, NOARCBlock) NOARCBlock
	#define NO_ARC(NoARCBlock) NoARCBlock
	#define __BRIDGE 
	#define STRONG retain
	#define __STRONG 
	#define WEAK assign
	#define __WEAK 
	#define NO_WEAK(NoWeakBlock) NoWeakBlock
#endif

#endif

@implementation BPXLUUIDHandler

static CFStringRef account = CFSTR("bpxl_uuid_account");
static CFStringRef service = CFSTR("bpxl_uuid_service");

static CFMutableDictionaryRef CreateKeychainQueryDictionary(void)
{
	CFMutableDictionaryRef query = CFDictionaryCreateMutable(kCFAllocatorDefault, 4, &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks);
	CFDictionarySetValue(query, kSecClass, kSecClassGenericPassword);
	CFDictionarySetValue(query, kSecAttrAccount, account);
	CFDictionarySetValue(query, kSecAttrService, service);
#if !TARGET_IPHONE_SIMULATOR
	if ([BPXLUUIDHandler accessGroup])
	{
		CFDictionarySetValue(query, kSecAttrAccessGroup, (__BRIDGE CFTypeRef)[BPXLUUIDHandler accessGroup]);
	}
#endif
	return query;
}

+ (NSString *)generateUUID
{
#if TARGET_IPHONE_SIMULATOR
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wdeprecated-declarations"
	return [[UIDevice currentDevice] uniqueIdentifier];
#pragma clang diagnostic pop
#endif
	CFUUIDRef uuidRef = CFUUIDCreate(NULL);
	CFStringRef uuidStringRef = CFUUIDCreateString(NULL, uuidRef);
	CFRelease(uuidRef);
	NSString *uuid;
	IF_ARC(
		   uuid = objc_retainedObject(uuidStringRef);
		   ,
		   uuid = [(NSString *)uuidStringRef autorelease];
		   )
	return uuid;
}

+ (NSString *)storeUUID:(BOOL)itemExists
{
	// Build a query
	CFMutableDictionaryRef query = CreateKeychainQueryDictionary();
	
	NSString *uuid = [[self class] generateUUID];
	
	CFDataRef dataRef;
	IF_ARC(
		   // This CFBridgingRetain will erroneously raise a static analyzer warning in Xcode 4.2.x,
		   // The warning is fixed in 4.3+
		   dataRef = CFBridgingRetain([uuid dataUsingEncoding:NSUTF8StringEncoding]);
		   , 
		   dataRef = CFRetain([uuid dataUsingEncoding:NSUTF8StringEncoding]);
		   )
	OSStatus status;
	if (itemExists)
	{
		CFMutableDictionaryRef passwordDictionaryRef = CFDictionaryCreateMutable(kCFAllocatorDefault, 4, &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks);
		CFDictionarySetValue(passwordDictionaryRef, kSecValueData, dataRef);
		status = SecItemUpdate(query, passwordDictionaryRef);
		CFRelease(passwordDictionaryRef);
	}
	else 
	{
		CFDictionarySetValue(query, kSecValueData, dataRef);
		status = SecItemAdd(query, NULL);
	}
	
	if (status != noErr)
	{
		NSLog(@"BPXLUUIDHandler Keychain Save Error: %ld", status);
		uuid = nil;
	}
	
	CFRelease(dataRef);
	CFRelease(query);
	
	return uuid;
}

static NSString *_uuid = nil;
+ (NSString *)UUID
{
	if (_uuid != nil)
		return _uuid;
	
	// Build a query
	CFMutableDictionaryRef query = CreateKeychainQueryDictionary();
	
	// See if the attribute exists
	CFTypeRef attributeResult = NULL;
	OSStatus status = SecItemCopyMatching(query, (CFTypeRef *)&attributeResult);
	if (attributeResult != NULL)
		CFRelease(attributeResult);
	
	if (status != noErr) 
	{
		CFRelease(query);
		if (status == errSecItemNotFound) // If there's no entry, store one
		{
			return [[self class] storeUUID:NO];
		}
		else // Any other error, log it and return nil
		{
			NSLog(@"BPXLUUIDHandler Unhandled Keychain Error %ld", status);
			return nil;
		}
	}
	
	// Fetch stored attribute
	CFDictionaryRemoveValue(query, kSecReturnAttributes);
	CFDictionarySetValue(query, kSecReturnData, (id)kCFBooleanTrue);
	CFTypeRef resultData = NULL;
	status = SecItemCopyMatching(query, &resultData);
	
	if (status != noErr) 
	{
		CFRelease(query);
		if (status == errSecItemNotFound) // If there's no entry, store one
		{
			return [[self class] storeUUID:NO];
		}
		else // Any other error, log it and return nil
		{
			NSLog(@"BPXLUUIDHandler Unhandled Keychain Error %ld", status);
			return nil;
		}
	}
	
	if (resultData != NULL) 
	{
		IF_ARC(
			   _uuid = [[NSString alloc] initWithData:objc_retainedObject(resultData) encoding:NSUTF8StringEncoding];
			   ,
			   _uuid = [[NSString alloc] initWithData:(NSData *)resultData encoding:NSUTF8StringEncoding];
			   CFRelease(resultData);
		)
	}
	
	CFRelease(query);
	
	return _uuid;
}

+ (void)reset
{
	NO_ARC([_uuid release];)
	_uuid = nil;
	
	// Build a query
	CFMutableDictionaryRef query = CreateKeychainQueryDictionary();
	
	// See if the attribute exists
	CFTypeRef attributeResult = NULL;
	CFDictionarySetValue(query, kSecReturnAttributes, (id)kCFBooleanTrue);
	OSStatus status = SecItemCopyMatching(query, (CFTypeRef *)&attributeResult);
	if (attributeResult != NULL)
		CFRelease(attributeResult);
	
	if (status == errSecItemNotFound) 
	{
		CFRelease(query);
		return;
	}
	
	status = SecItemDelete(query);
	if (status != noErr)
	{
		NSLog(@"BPXLUUIDHandler Keychain Delete Error: %ld", status);
	}
	CFRelease(query);
}

static NSString *_accessGroup = nil;
+ (NSString *)accessGroup
{
	return _accessGroup;
}

+ (void)setAccessGroup:(NSString *)accessGroup
{
	NO_ARC(
		   [accessGroup retain];
		   [_accessGroup release];
		   )
	_accessGroup = accessGroup;
}

@end