RestKit/Code/CoreData/RKManagedObjectMappingOperation.m

//
//  RKManagedObjectMappingOperation.m
//  RestKit
//
//  Created by Blake Watters on 5/31/11.
//  Copyright 2011 Two Toasters
//  
//  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 "RKManagedObjectMappingOperation.h"
#import "RKManagedObjectMapping.h"
#import "NSManagedObject+ActiveRecord.h"
#import "RKDynamicObjectMappingMatcher.h"
#import "RKLog.h"

// Set Logging Component
#undef RKLogComponent
#define RKLogComponent lcl_cRestKitCoreData

@implementation RKManagedObjectMappingOperation

- (void)connectRelationship:(NSString *)relationshipName {
    NSDictionary* relationshipsAndPrimaryKeyAttributes = [(RKManagedObjectMapping*)self.objectMapping relationshipsAndPrimaryKeyAttributes];
    id primaryKeyObject = [relationshipsAndPrimaryKeyAttributes objectForKey:relationshipName];
    NSString* primaryKeyAttribute = nil;
    if ([primaryKeyObject isKindOfClass:[RKDynamicObjectMappingMatcher class]]) {
        RKLogTrace(@"Found a dynamic matcher attempting to connect relationshipName: %@", relationshipName);
        RKDynamicObjectMappingMatcher* matcher = (RKDynamicObjectMappingMatcher*)primaryKeyObject;
        if ([matcher isMatchForData:self.destinationObject]) {
            primaryKeyAttribute = matcher.primaryKeyAttribute;
            RKLogTrace(@"Dynamic matched succeeded. Proceeding to connect relationshipName '%@' using primaryKeyAttribute '%@'", relationshipName, primaryKeyAttribute);
        } else {
            RKLogTrace(@"Dynamic matcher match failed. Skipping connection of relationshipName: %@", relationshipName);
            return;
        }
    } else if ([primaryKeyObject isKindOfClass:[NSString class]]) {
        primaryKeyAttribute = (NSString*)primaryKeyObject;
    }
    NSAssert(primaryKeyAttribute, @"Cannot connect relationship without primaryKeyAttribute");

    RKObjectRelationshipMapping* relationshipMapping = [self.objectMapping mappingForRelationship:relationshipName];
    RKObjectMappingDefinition *mapping = relationshipMapping.mapping;
    NSAssert(mapping, @"Attempted to connect relationship for keyPath '%@' without a relationship mapping defined.");
    if (! [mapping isKindOfClass:[RKObjectMapping class]]) {
        RKLogWarning(@"Can only connect relationships for RKObjectMapping relationships. Found %@: Skipping...", NSStringFromClass([mapping class]));
        return;
    }
    RKManagedObjectMapping *objectMapping = (RKManagedObjectMapping *) mapping;
    NSAssert(relationshipMapping, @"Unable to find relationship mapping '%@' to connect by primaryKey", relationshipName);
    NSAssert([relationshipMapping isKindOfClass:[RKObjectRelationshipMapping class]], @"Expected mapping for %@ to be a relationship mapping", relationshipName);
    NSAssert([relationshipMapping.mapping isKindOfClass:[RKManagedObjectMapping class]], @"Can only connect RKManagedObjectMapping relationships");
    NSString* primaryKeyAttributeOfRelatedObject = [(RKManagedObjectMapping*)objectMapping primaryKeyAttribute];
    NSAssert(primaryKeyAttributeOfRelatedObject, @"Cannot connect relationship: mapping for %@ has no primary key attribute specified", NSStringFromClass(objectMapping.objectClass));
    id valueOfLocalPrimaryKeyAttribute = [self.destinationObject valueForKey:primaryKeyAttribute];
    if (valueOfLocalPrimaryKeyAttribute) {
        id relatedObject = nil;
        if ([valueOfLocalPrimaryKeyAttribute conformsToProtocol:@protocol(NSFastEnumeration)]) {
            RKLogTrace(@"Connecting has-many relationship at keyPath '%@' to object with primaryKey attribute '%@'", relationshipName, primaryKeyAttributeOfRelatedObject);
            NSPredicate *predicate = [NSPredicate predicateWithFormat:@"%K IN %@", primaryKeyAttributeOfRelatedObject, valueOfLocalPrimaryKeyAttribute];
            NSArray *objects = [objectMapping.objectClass findAllWithPredicate:predicate inContext:[self.destinationObject managedObjectContext]];
            relatedObject = [NSSet setWithArray:objects];
        } else {
            RKLogTrace(@"Connecting has-one relationship at keyPath '%@' to object with primaryKey attribute '%@'", relationshipName, primaryKeyAttributeOfRelatedObject);
            relatedObject = [objectMapping.objectClass findFirstByAttribute:primaryKeyAttributeOfRelatedObject withValue:valueOfLocalPrimaryKeyAttribute inContext:[self.destinationObject managedObjectContext]];
        }      
        if (relatedObject) {                
            RKLogDebug(@"Connected relationship '%@' to object with primary key value '%@': %@", relationshipName, valueOfLocalPrimaryKeyAttribute, relatedObject);
        } else {
RKLogDebug(@"Failed to find instance of '%@' to connect relationship '%@' with primary key value '%@'", [[objectMapping entity] name], relationshipName, valueOfLocalPrimaryKeyAttribute);
        }
        RKLogTrace(@"setValue of %@ forKeyPath %@", relatedObject, relationshipName);
        [self.destinationObject setValue:relatedObject forKeyPath:relationshipName];
    } else {
        RKLogTrace(@"Failed to find primary key value for attribute '%@'", primaryKeyAttribute);
    }
}

- (void)connectRelationships {
    if ([self.objectMapping isKindOfClass:[RKManagedObjectMapping class]]) {
        NSDictionary* relationshipsAndPrimaryKeyAttributes = [(RKManagedObjectMapping*)self.objectMapping relationshipsAndPrimaryKeyAttributes];
		RKLogTrace(@"relationshipsAndPrimaryKeyAttributes: %@", relationshipsAndPrimaryKeyAttributes);
        for (NSString* relationshipName in relationshipsAndPrimaryKeyAttributes) {
            if (self.queue) {
                RKLogTrace(@"Enqueueing relationship connection using operation queue");
                __block RKManagedObjectMappingOperation *selfRef = self;
                [self.queue addOperationWithBlock:^{
                    [selfRef connectRelationship:relationshipName];
                }];
            } else {
                [self connectRelationship:relationshipName];
            }
        }
    }
}

- (BOOL)performMapping:(NSError **)error {
    BOOL success = [super performMapping:error];
    [self connectRelationships];
    return success;
}

@end