Files
RestKit/Code/CoreData/RKFetchRequestManagedObjectCache.m
Blake Watters 79e31b524a Refactored managed object caches and connection support to enable connecting by multiple atributes that are specified as arrays.
* Migrated the caches to return `NSSet` to eliminate duplicate objects when your cache keys overlap
* Introduced new recursive strategy for building cache keys in `RKInMemoryManagedObjectCache`
* Added support for array cache key values in `RKFetchRequestManagedObjectCache`
* Re-enabled a slew of tests that were disabled during 0.20 development
2012-12-06 23:43:34 -05:00

88 lines
3.6 KiB
Objective-C

//
// RKFetchRequestMappingCache.m
// RestKit
//
// Created by Jeff Arena on 1/24/12.
// Copyright (c) 2009-2012 RestKit. All rights reserved.
//
#import "RKFetchRequestManagedObjectCache.h"
#import "RKLog.h"
#import "RKPropertyInspector.h"
#import "RKPropertyInspector+CoreData.h"
#import "RKObjectUtilities.h"
// Set Logging Component
#undef RKLogComponent
#define RKLogComponent RKlcl_cRestKitCoreData
/*
NOTE: At the moment this cache key assume that the structure of the values for each key in the `attributeValues` in constant
i.e. if you have `userID`, it will always be a single value, or `userIDs` will always be an array.
It will need to be reimplemented if changes in attribute values occur during the life of a single cache
*/
static NSString *RKPredicateCacheKeyForAttributes(NSArray *attributeNames)
{
return [[attributeNames sortedArrayUsingSelector:@selector(localizedCaseInsensitiveCompare:)] componentsJoinedByString:@":"];
}
// NOTE: We build a dynamic format string here because `NSCompoundPredicate` does not support use of substiution variables
static NSPredicate *RKPredicateWithSubsitutionVariablesForAttributeValues(NSDictionary *attributeValues)
{
NSArray *attributeNames = [attributeValues allKeys];
NSMutableArray *formatFragments = [NSMutableArray arrayWithCapacity:[attributeNames count]];
[attributeValues enumerateKeysAndObjectsUsingBlock:^(NSString *attributeName, id value, BOOL *stop) {
NSString *formatFragment = RKObjectIsCollection(value)
? [NSString stringWithFormat:@"%@ IN $%@", attributeName, attributeName]
: [NSString stringWithFormat:@"%@ = $%@", attributeName, attributeName];
[formatFragments addObject:formatFragment];
}];
return [NSPredicate predicateWithFormat:[formatFragments componentsJoinedByString:@" AND "]];
}
@interface RKFetchRequestManagedObjectCache ()
@property (nonatomic, strong) NSCache *predicateCache;
@end
@implementation RKFetchRequestManagedObjectCache
- (id)init
{
self = [super init];
if (self) {
self.predicateCache = [NSCache new];
}
return self;
}
- (NSSet *)managedObjectsWithEntity:(NSEntityDescription *)entity
attributeValues:(NSDictionary *)attributeValues
inManagedObjectContext:(NSManagedObjectContext *)managedObjectContext
{
NSAssert(entity, @"Cannot find existing managed object without a target class");
NSAssert(attributeValues, @"Cannot retrieve cached objects without attribute values to identify them with.");
NSAssert(managedObjectContext, @"Cannot find existing managed object with a nil context");
NSString *predicateCacheKey = RKPredicateCacheKeyForAttributes([attributeValues allKeys]);
NSPredicate *substitutionPredicate = [self.predicateCache objectForKey:predicateCacheKey];
if (! substitutionPredicate) {
substitutionPredicate = RKPredicateWithSubsitutionVariablesForAttributeValues(attributeValues);
[self.predicateCache setObject:substitutionPredicate forKey:predicateCacheKey];
}
NSFetchRequest *fetchRequest = [NSFetchRequest fetchRequestWithEntityName:[entity name]];
fetchRequest.predicate = [substitutionPredicate predicateWithSubstitutionVariables:attributeValues];
NSError *error = nil;
NSArray *objects = [managedObjectContext executeFetchRequest:fetchRequest error:&error];
if (! objects) {
RKLogError(@"Failed to execute fetch request due to error: %@", error);
}
RKLogDebug(@"Found objects '%@' using fetchRequest '%@'", objects, fetchRequest);
return [NSSet setWithArray:objects];
}
@end