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robertjpayne/NSManagedObjectArchiving.h

Created October 29, 2011 10:28
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  1. robertjpayne created this gist Oct 29, 2011.
    40 changes: 40 additions & 0 deletions NSManagedObjectArchiving.h
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    #import <Foundation/Foundation.h>

    @interface NSManagedObjectArchiver : NSObject

    /*
    * Takes a NSManagedObject and converts it to a NSData archive - it traverses all relationships ( including circular ) and archives it
    */
    + (NSData *)archivedDataWithRootObject:(NSManagedObject *)pObject;

    @end

    @interface NSManagedObjectUnarchiver : NSObject

    /*
    * Takes a NSData object from NSManagedObjectArchiver and re-creates the NSManagedObject
    * @param NSManagedObjectContext *context - required - provided context is used to obtain NSEntityDescriptions from. The entityName and entityVersionHash is checked to restore the correct entity.
    * @param BOOL insert - whether or not objects should be inserted into the provided context when created, if choose not to insert them you would need to insert them manually ( including relationships ) before they can be saved
    */
    + (NSManagedObject *)unarchiveObjectWithData:(NSData *)pData context:(NSManagedObjectContext *)pContext insert:(BOOL)pInsert;

    @end


    @interface NSManagedObject (NSManagedObjectCopying)

    /*
    * Makes a copy of an NSManagedObject - this is a shallow copy and does not traverse relationships
    * @param NSManagedObjectContext *context - required - provided context is used to obtain NSEntityDescriptions from.
    * @param BOOL insert - whether or not objects should be inserted into the provided context when created, if choose not to insert them you would need to insert them manually ( including relationships ) before they can be saved
    */
    - (id)copyUsingContext:(NSManagedObjectContext *)pContext insert:(BOOL)pInsert;

    /*
    * Makes a copy of an NSManagedObject - this is a deep copy and does traverse relationships ( including circular )
    * @param NSManagedObjectContext *context - required - provided context is used to obtain NSEntityDescriptions from.
    * @param BOOL insert - whether or not objects should be inserted into the provided context when created, if choose not to insert them you would need to insert them manually ( including relationships ) before they can be saved
    */
    - (id)copyIncludingRelationshipsUsingContext:(NSManagedObjectContext *)pContext insert:(BOOL)pInsert;

    @end
    228 changes: 228 additions & 0 deletions NSManagedObjectArchiving.m
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    #import "NSManagedObjectArchiving.h"

    @interface NSManagedObjectArchiver()

    @property (nonatomic, strong) NSMutableDictionary *objects;
    @property (nonatomic, strong) NSString *rootObjectIdentifier;

    - (id)identifierForObject:(NSManagedObject *)pObject;
    - (id)propertyListForObject:(NSManagedObject *)pObject;
    - (id)propertyListForRelationshipWithName:(NSString *)pRelationshipName inObject:(NSManagedObject *)pObject;

    @end

    @implementation NSManagedObjectArchiver

    #pragma mark - Properties

    @synthesize objects;
    @synthesize rootObjectIdentifier;

    #pragma mark - Initialization

    + (NSData *)archivedDataWithRootObject:(NSManagedObject *)pRootObject {
    NSManagedObjectArchiver *archiver = [[self alloc] init];
    archiver.rootObjectIdentifier = [archiver identifierForObject:pRootObject];
    [archiver propertyListForObject:pRootObject];
    return [NSKeyedArchiver archivedDataWithRootObject:[NSDictionary dictionaryWithObjectsAndKeys:
    archiver.objects, @"objects",
    archiver.rootObjectIdentifier, @"rootObjectIdentifier",
    nil]];
    }
    - (id)init {
    if((self = [super init])) {
    objects = [NSMutableDictionary dictionary];
    }
    return self;
    }

    #pragma mark - Actions

    - (id)identifierForObject:(NSManagedObject *)pObject {
    if(pObject == nil) {
    return [NSNull null];
    }
    return pObject.objectID.URIRepresentation.absoluteString;
    }
    - (id)propertyListForObject:(NSManagedObject *)pObject {
    if(pObject == nil) {
    return [NSNull null];
    }
    NSString *identifier = [self identifierForObject:pObject];
    id existingPropertyList = [self.objects objectForKey:identifier];
    if(existingPropertyList != nil) {
    return existingPropertyList;
    }
    NSEntityDescription *entityDescription = pObject.entity;

    NSMutableDictionary *propertyList = [NSMutableDictionary dictionary];
    [propertyList setObject:entityDescription.name forKey:@"entityName"];
    [propertyList setObject:entityDescription.versionHash forKey:@"entityVersionHash"];
    [propertyList setObject:identifier forKey:@"identifier"];
    [propertyList setObject:[pObject dictionaryWithValuesForKeys:entityDescription.attributeKeys] forKey:@"attributes"];

    [self.objects setObject:propertyList forKey:identifier];

    NSMutableDictionary *propertyListRelationships = [NSMutableDictionary dictionary];
    [propertyList setObject:propertyListRelationships forKey:@"relationships"];

    for(NSString *relationshipName in entityDescription.relationshipsByName) {
    [propertyListRelationships setObject:[self propertyListForRelationshipWithName:relationshipName inObject:pObject]
    forKey:relationshipName];
    }

    return propertyList;
    }
    - (id)propertyListForRelationshipWithName:(NSString *)pRelationshipName inObject:(NSManagedObject *)pObject {
    NSRelationshipDescription *relationshipDescription = [pObject.entity.relationshipsByName objectForKey:pRelationshipName];

    if(relationshipDescription.isToMany) {
    id src = [pObject valueForKey:pRelationshipName];
    id dst = nil;
    if(relationshipDescription.isOrdered) {
    dst = [NSMutableOrderedSet orderedSet];
    } else {
    dst = [NSMutableSet set];
    }
    for(NSManagedObject *object in src) {
    NSString *identifier = [self identifierForObject:object];
    [self propertyListForObject:object];
    [dst addObject:identifier];
    }
    return ([dst count] > 0) ? dst : [NSNull null];
    } else {
    NSString *identifier = [self identifierForObject:[pObject valueForKey:pRelationshipName]];
    [self propertyListForObject:[pObject valueForKey:pRelationshipName]];
    return identifier;
    }
    }

    @end


    @interface NSManagedObjectUnarchiver()

    @property (nonatomic, strong) NSManagedObjectContext *context;
    @property (nonatomic, assign) BOOL insert;
    @property (nonatomic, strong) NSMutableDictionary *entities;
    @property (nonatomic, strong) NSDictionary *archivedObjects;
    @property (nonatomic, strong) NSMutableDictionary *unarchivedObjects;

    - (NSManagedObject *)objectForIdentifier:(NSString *)pIdentifier;
    - (id)objectsForIdentifiers:(id)pIdentifiers;

    @end
    @implementation NSManagedObjectUnarchiver

    #pragma mark - Properties

    @synthesize context;
    @synthesize insert;
    @synthesize entities;
    @synthesize archivedObjects;
    @synthesize unarchivedObjects;

    #pragma mark - Initialization

    + (NSManagedObject *)unarchiveObjectWithData:(NSData *)pData context:(NSManagedObjectContext *)pContext insert:(BOOL)pInsert {
    NSManagedObjectUnarchiver *unarchiver = [[NSManagedObjectUnarchiver alloc] init];
    NSDictionary *dictionary = [NSKeyedUnarchiver unarchiveObjectWithData:pData];
    if(dictionary != nil && [dictionary isKindOfClass:[NSDictionary class]]) {
    unarchiver.context = pContext;
    unarchiver.insert = pInsert;
    unarchiver.archivedObjects = [dictionary objectForKey:@"objects"];
    return [unarchiver objectForIdentifier:[dictionary objectForKey:@"rootObjectIdentifier"]];
    }
    return nil;
    }
    - (id)init {
    if((self = [super init])) {
    unarchivedObjects = [NSMutableDictionary dictionary];
    }
    return self;
    }

    #pragma mark - Actions

    - (NSManagedObject *)objectForIdentifier:(NSString *)pIdentifier {
    if(pIdentifier == nil || ![pIdentifier isKindOfClass:[NSString class]]) {
    return nil;
    }
    NSManagedObject *unarchivedObject = [self.unarchivedObjects objectForKey:pIdentifier];
    if(unarchivedObject != nil) {
    return unarchivedObject;
    }

    NSDictionary *archivedObject = [self.archivedObjects objectForKey:pIdentifier];
    NSEntityDescription *entityDescription = [NSEntityDescription entityForName:[archivedObject objectForKey:@"entityName"] inManagedObjectContext:self.context];
    if(![entityDescription.versionHash isEqualToData:[archivedObject objectForKey:@"entityVersionHash"]]) {
    [NSException raise:@"Invalid archived data" format:@"Mismatching version hashes, archived managed object's entity version hash differs from version hash in the provided context."];
    return nil;
    }


    Class entityClass = NSClassFromString([entityDescription managedObjectClassName]);
    if(entityClass == nil) {
    [NSException raise:@"Invalid archived data" format:@"Cannot find custom class with name %@ for managed object with entity name %@", entityDescription.managedObjectClassName, entityDescription.name];
    return nil;
    }

    NSManagedObject *object = [[entityClass alloc] initWithEntity:entityDescription insertIntoManagedObjectContext:(self.insert) ? self.context : nil];
    [object setValuesForKeysWithDictionary:[archivedObject objectForKey:@"attributes"]];

    [self.unarchivedObjects setObject:object forKey:pIdentifier];

    NSDictionary *relationships = [archivedObject objectForKey:@"relationships"];
    for(NSString *relationshipName in relationships) {
    id relationshipValue = [relationships objectForKey:relationshipName];
    if([relationshipValue isKindOfClass:[NSString class]]) {
    relationshipValue = [self objectForIdentifier:relationshipValue];
    } else if([relationshipValue isKindOfClass:[NSOrderedSet class]] ||
    [relationshipValue isKindOfClass:[NSSet class]]) {
    relationshipValue = [self objectsForIdentifiers:relationshipValue];
    } else if([relationshipValue isKindOfClass:[NSNull class]]) {
    relationshipValue = nil;
    }
    [object setValue:relationshipValue forKey:relationshipName];
    }

    return object;
    }
    - (id)objectsForIdentifiers:(id)pIdentifiers {
    if(pIdentifiers == nil) {
    return nil;
    }
    id collection = nil;
    if([pIdentifiers isKindOfClass:[NSOrderedSet class]]) {
    collection = [NSMutableOrderedSet orderedSetWithCapacity:[pIdentifiers count]];
    } else if([pIdentifiers isKindOfClass:[NSSet class]]) {
    collection = [NSMutableSet setWithCapacity:[pIdentifiers count]];
    } else {
    return nil;
    }
    for(id identifier in pIdentifiers) {
    NSManagedObject *object = [self objectForIdentifier:identifier];
    if(object != nil) {
    [collection addObject:object];
    }
    }
    return ([collection count] > 0) ? collection : nil;
    }

    @end

    @implementation NSManagedObject (NSManagedObjectCopying)

    - (id)copyUsingContext:(NSManagedObjectContext *)pContext insert:(BOOL)pInsert {
    NSEntityDescription *entity = [NSEntityDescription entityForName:self.entity.name inManagedObjectContext:pContext];
    Class entityClass = NSClassFromString(entity.managedObjectClassName);
    NSManagedObject *copy = [[entityClass alloc] initWithEntity:entity insertIntoManagedObjectContext:((pInsert) ? pContext : nil)];
    [copy setValuesForKeysWithDictionary:[self dictionaryWithValuesForKeys:self.entity.attributeKeys]];
    return copy;
    }
    - (id)copyIncludingRelationshipsUsingContext:(NSManagedObjectContext *)pContext insert:(BOOL)pInsert {
    NSData *d = [NSManagedObjectArchiver archivedDataWithRootObject:self];
    return [NSManagedObjectUnarchiver unarchiveObjectWithData:d context:pContext insert:pInsert];
    }

    @end