Merge branch 'develop' into corestore4_develop

# Conflicts:
#	CoreStore.podspec
#	Sources/CoreStoreImportableAttributeType.swift
#	Sources/CoreStoreQueryableAttributeType.swift
#	Sources/Info.plist
#	Sources/NSManagedObjectModel+Setup.swift

Sources/CustomSchemaMappingProvider.swift

@@ -0,0 +1,658 @@
+//
+//  CustomSchemaMappingProvider.swift
+//  CoreStore
+//
+//  Copyright © 2017 John Rommel Estropia
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in all
+//  copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+//  SOFTWARE.
+//
+
+import CoreData
+import Foundation
+
+
+// MARK: - CustomSchemaMappingProvider
+
+open class CustomSchemaMappingProvider: Hashable, SchemaMappingProvider {
+    
+    public let sourceVersion: ModelVersion
+    public let destinationVersion: ModelVersion
+    
+    public required init(from sourceVersion: ModelVersion, to destinationVersion: ModelVersion, entityMappings: Set<CustomMapping> = []) {
+        
+        CoreStore.assert(
+            cs_lazy {
+                
+                let sources = entityMappings.flatMap({ $0.entityMappingSourceEntity })
+                let destinations = entityMappings.flatMap({ $0.entityMappingDestinationEntity })
+                return sources.count == Set(sources).count
+                    && destinations.count == Set(destinations).count
+            },
+            "Duplicate source/destination entities found in provided \"entityMappings\" argument."
+        )
+        self.sourceVersion = sourceVersion
+        self.destinationVersion = destinationVersion
+        self.entityMappings = entityMappings
+    }
+    
+    
+    // MARK: - CustomMapping
+    
+    public enum CustomMapping: Hashable {
+        
+        public typealias Transformer = (_ sourceObject: UnsafeSourceObject, _ createDestinationObject: () -> UnsafeDestinationObject) throws -> Void
+        
+        case deleteEntity(sourceEntity: EntityName)
+        case insertEntity(destinationEntity: EntityName)
+        case copyEntity(sourceEntity: EntityName, destinationEntity: EntityName)
+        case transformEntity(sourceEntity: EntityName, destinationEntity: EntityName, transformer: Transformer)
+        
+        static func inferredTransformation(_ sourceObject: UnsafeSourceObject, _ createDestinationObject: () -> UnsafeDestinationObject) throws -> Void {
+            
+            let destinationObject = createDestinationObject()
+            destinationObject.enumerateAttributes { (attribute, sourceAttribute) in
+                
+                if let sourceAttribute = sourceAttribute {
+                    
+                    destinationObject[attribute] = sourceObject[sourceAttribute]
+                }
+            }
+        }
+        
+        var entityMappingSourceEntity: EntityName? {
+            
+            switch self {
+                
+            case .deleteEntity(let sourceEntity),
+                 .copyEntity(let sourceEntity, _),
+                 .transformEntity(let sourceEntity, _, _):
+                return sourceEntity
+                
+            case .insertEntity:
+                return nil
+            }
+        }
+        
+        var entityMappingDestinationEntity: EntityName? {
+            
+            switch self {
+                
+            case .insertEntity(let destinationEntity),
+                 .copyEntity(_, let destinationEntity),
+                 .transformEntity(_, let destinationEntity, _):
+                return destinationEntity
+                
+            case .deleteEntity:
+                return nil
+            }
+        }
+        
+        
+        // MARK: Equatable
+        
+        public static func == (lhs: CustomMapping, rhs: CustomMapping) -> Bool {
+            
+            switch (lhs, rhs) {
+                
+            case (.deleteEntity(let sourceEntity1), .deleteEntity(let sourceEntity2)):
+                return sourceEntity1 == sourceEntity2
+                
+            case (.insertEntity(let destinationEntity1), .insertEntity(let destinationEntity2)):
+                return destinationEntity1 == destinationEntity2
+                
+            case (.copyEntity(let sourceEntity1, let destinationEntity1), .copyEntity(let sourceEntity2, let destinationEntity2)):
+                return sourceEntity1 == sourceEntity2
+                    && destinationEntity1 == destinationEntity2
+                
+            case (.transformEntity(let sourceEntity1, let destinationEntity1, _), .transformEntity(let sourceEntity2, let destinationEntity2, _)):
+                return sourceEntity1 == sourceEntity2
+                    && destinationEntity1 == destinationEntity2
+                
+            default:
+                return false
+            }
+        }
+        
+        
+        // MARK: Hashable
+        
+        public var hashValue: Int {
+            
+            switch self {
+                
+            case .deleteEntity(let sourceEntity):
+                return sourceEntity.hashValue
+                
+            case .insertEntity(let destinationEntity):
+                return destinationEntity.hashValue
+                
+            case .copyEntity(let sourceEntity, let destinationEntity):
+                return sourceEntity.hashValue
+                    ^ destinationEntity.hashValue
+                
+            case .transformEntity(let sourceEntity, let destinationEntity, _):
+                return sourceEntity.hashValue
+                    ^ destinationEntity.hashValue
+            }
+        }
+    }
+    
+    
+    // MARK: - UnsafeSourceObject
+    
+    public final class UnsafeSourceObject {
+        
+        public subscript(attribute: KeyPath) -> Any? {
+            
+            return self.rawObject.cs_accessValueForKVCKey(attribute)
+        }
+        
+        public subscript(attribute: NSAttributeDescription) -> Any? {
+            
+            return self.rawObject.cs_accessValueForKVCKey(attribute.name)
+        }
+        
+        public func enumerateAttributes(_ closure: (_ attribute: NSAttributeDescription) -> Void) {
+            
+            for case let attribute as NSAttributeDescription in self.rawObject.entity.properties {
+                
+                closure(attribute)
+            }
+        }
+        
+        
+        // MARK: Internal
+        
+        internal init(_ rawObject: NSManagedObject) {
+            
+            self.rawObject = rawObject
+        }
+        
+        
+        // MARK: Private
+        
+        private let rawObject: NSManagedObject
+    }
+    
+    
+    // MARK: - UnsafeDestinationObject
+    
+    public final class UnsafeDestinationObject {
+        
+        public subscript(attribute: KeyPath) -> Any? {
+            
+            get { return self.rawObject.cs_accessValueForKVCKey(attribute) }
+            set { self.rawObject.cs_setValue(newValue, forKVCKey: attribute) }
+        }
+        
+        public subscript(attribute: NSAttributeDescription) -> Any? {
+            
+            get { return self.rawObject.cs_accessValueForKVCKey(attribute.name) }
+            set { self.rawObject.cs_setValue(newValue, forKVCKey: attribute.name) }
+        }
+        
+        public func enumerateAttributes(_ closure: (_ attribute: NSAttributeDescription, _ sourceAttribute: NSAttributeDescription?) -> Void) {
+            
+            for case let attribute as NSAttributeDescription in self.rawObject.entity.properties {
+                
+                closure(attribute, self.sourceAttributesByDestinationKey[attribute.name])
+            }
+        }
+        
+        
+        // MARK: Internal
+        
+        internal init(_ rawObject: NSManagedObject, _ sourceAttributesByDestinationKey: [KeyPath: NSAttributeDescription]) {
+            
+            self.rawObject = rawObject
+            self.sourceAttributesByDestinationKey = sourceAttributesByDestinationKey
+        }
+        
+        
+        // MARK: Private
+        
+        private let rawObject: NSManagedObject
+        private let sourceAttributesByDestinationKey: [KeyPath: NSAttributeDescription]
+    }
+    
+    
+    // MARK: Equatable
+    
+    public static func == (lhs: CustomSchemaMappingProvider, rhs: CustomSchemaMappingProvider) -> Bool {
+        
+        return lhs.sourceVersion == rhs.sourceVersion
+            && lhs.destinationVersion == rhs.destinationVersion
+            && type(of: lhs) == type(of: rhs)
+    }
+    
+    
+    // MARK: Hashable
+    
+    public var hashValue: Int {
+        
+        return self.sourceVersion.hashValue
+            ^ self.destinationVersion.hashValue
+    }
+    
+    
+    // MARK: SchemaMappingProvider
+    
+    public func createMappingModel(from sourceSchema: DynamicSchema, to destinationSchema: DynamicSchema, storage: LocalStorage) throws -> (mappingModel: NSMappingModel, migrationType: MigrationType) {
+        
+        let sourceModel = sourceSchema.rawModel()
+        let destinationModel = destinationSchema.rawModel()
+        
+        let mappingModel = NSMappingModel()
+        
+        let (deleteMappings, insertMappings, copyMappings, transformMappings) = self.resolveEntityMappings(
+            sourceModel: sourceModel,
+            destinationModel: destinationModel
+        )
+        func expression(forSource sourceEntity: NSEntityDescription) -> NSExpression {
+            
+            return NSExpression(format: "FETCH(FUNCTION($\(NSMigrationManagerKey), \"fetchRequestForSourceEntityNamed:predicateString:\" , \"\(sourceEntity.name!)\", \"\(NSPredicate(value: true))\"), $\(NSMigrationManagerKey).\(#keyPath(NSMigrationManager.sourceContext)), \(false))")
+        }
+        
+        let sourceEntitiesByName = sourceModel.entitiesByName
+        let destinationEntitiesByName = destinationModel.entitiesByName
+        
+        var entityMappings: [NSEntityMapping] = []
+        for case .deleteEntity(let sourceEntityName) in deleteMappings {
+            
+            let sourceEntity = sourceEntitiesByName[sourceEntityName]!
+            
+            let entityMapping = NSEntityMapping()
+            entityMapping.sourceEntityName = sourceEntity.name
+            entityMapping.sourceEntityVersionHash = sourceEntity.versionHash
+            entityMapping.mappingType = .removeEntityMappingType
+            entityMapping.sourceExpression = expression(forSource: sourceEntity)
+            
+            entityMappings.append(entityMapping)
+        }
+        for case .insertEntity(let destinationEntityName) in insertMappings {
+            
+            let destinationEntity = destinationEntitiesByName[destinationEntityName]!
+            
+            let entityMapping = NSEntityMapping()
+            entityMapping.destinationEntityName = destinationEntity.name
+            entityMapping.destinationEntityVersionHash = destinationEntity.versionHash
+            entityMapping.mappingType = .addEntityMappingType
+            entityMapping.attributeMappings = autoreleasepool { () -> [NSPropertyMapping] in
+                
+                var attributeMappings: [NSPropertyMapping] = []
+                for (_, destinationAttribute) in destinationEntity.attributesByName {
+                    
+                    let propertyMapping = NSPropertyMapping()
+                    propertyMapping.name = destinationAttribute.name
+                    attributeMappings.append(propertyMapping)
+                }
+                return attributeMappings
+            }
+            entityMapping.relationshipMappings = autoreleasepool { () -> [NSPropertyMapping] in
+                
+                var relationshipMappings: [NSPropertyMapping] = []
+                for (_, destinationRelationship) in destinationEntity.relationshipsByName {
+                    
+                    let propertyMapping = NSPropertyMapping()
+                    propertyMapping.name = destinationRelationship.name
+                    relationshipMappings.append(propertyMapping)
+                }
+                return relationshipMappings
+            }
+            entityMappings.append(entityMapping)
+        }
+        for case .copyEntity(let sourceEntityName, let destinationEntityName) in copyMappings {
+            
+            let sourceEntity = sourceEntitiesByName[sourceEntityName]!
+            let destinationEntity = destinationEntitiesByName[destinationEntityName]!
+            
+            let entityMapping = NSEntityMapping()
+            entityMapping.sourceEntityName = sourceEntity.name
+            entityMapping.sourceEntityVersionHash = sourceEntity.versionHash
+            entityMapping.destinationEntityName = destinationEntity.name
+            entityMapping.destinationEntityVersionHash = destinationEntity.versionHash
+            entityMapping.mappingType = .copyEntityMappingType
+            entityMapping.sourceExpression = expression(forSource: sourceEntity)
+            entityMapping.attributeMappings = autoreleasepool { () -> [NSPropertyMapping] in
+                
+                let sourceAttributes = sourceEntity.cs_resolvedAttributeRenamingIdentities()
+                let destinationAttributes = destinationEntity.cs_resolvedAttributeRenamingIdentities()
+                
+                var attributeMappings: [NSPropertyMapping] = []
+                for (renamingIdentifier, destination) in destinationAttributes {
+                    
+                    let sourceAttribute = sourceAttributes[renamingIdentifier]!.attribute
+                    let destinationAttribute = destination.attribute
+                    let propertyMapping = NSPropertyMapping()
+                    propertyMapping.name = destinationAttribute.name
+                    propertyMapping.valueExpression = NSExpression(format: "$\(NSMigrationSourceObjectKey).\(sourceAttribute.name)")
+                    attributeMappings.append(propertyMapping)
+                }
+                return attributeMappings
+            }
+            let entityMappingName = entityMapping.name!
+            entityMapping.relationshipMappings = autoreleasepool { () -> [NSPropertyMapping] in
+                
+                let destinationRelationships = destinationEntity.cs_resolvedRelationshipRenamingIdentities()
+                var relationshipMappings: [NSPropertyMapping] = []
+                for (_, destination) in destinationRelationships {
+                    
+                    let destinationRelationship = destination.relationship
+                    let propertyMapping = NSPropertyMapping()
+                    propertyMapping.name = destinationRelationship.name
+                    propertyMapping.valueExpression = NSExpression(format: "FUNCTION($\(NSMigrationManagerKey), \"\(#selector(NSMigrationManager.destinationInstances(forEntityMappingName:sourceInstances:)))\" , \"\(entityMappingName)\", $\(NSMigrationSourceObjectKey))[0]")
+                    relationshipMappings.append(propertyMapping)
+                }
+                return relationshipMappings
+            }
+            entityMappings.append(entityMapping)
+        }
+        for case .transformEntity(let sourceEntityName, let destinationEntityName, let transformEntity) in transformMappings {
+            
+            let sourceEntity = sourceEntitiesByName[sourceEntityName]!
+            let destinationEntity = destinationEntitiesByName[destinationEntityName]!
+            
+            let entityMapping = NSEntityMapping()
+            entityMapping.sourceEntityName = sourceEntity.name
+            entityMapping.sourceEntityVersionHash = sourceEntity.versionHash
+            entityMapping.destinationEntityName = destinationEntity.name
+            entityMapping.destinationEntityVersionHash = destinationEntity.versionHash
+            entityMapping.mappingType = .customEntityMappingType
+            entityMapping.sourceExpression = expression(forSource: sourceEntity)
+            entityMapping.entityMigrationPolicyClassName = NSStringFromClass(CustomEntityMigrationPolicy.self)
+            
+            var userInfo: [AnyHashable: Any] = [
+                CustomEntityMigrationPolicy.UserInfoKey.transformer: transformEntity
+            ]
+            autoreleasepool {
+                
+                let sourceAttributes = sourceEntity.cs_resolvedAttributeRenamingIdentities()
+                let destinationAttributes = destinationEntity.cs_resolvedAttributeRenamingIdentities()
+                
+                let transformedRenamingIdentifiers = Set(destinationAttributes.keys)
+                    .intersection(sourceAttributes.keys)
+
+                var sourceAttributesByDestinationKey: [KeyPath: NSAttributeDescription] = [:]
+                for renamingIdentifier in transformedRenamingIdentifiers {
+                    
+                    let sourceAttribute = sourceAttributes[renamingIdentifier]!.attribute
+                    let destinationAttribute = destinationAttributes[renamingIdentifier]!.attribute
+                    sourceAttributesByDestinationKey[destinationAttribute.name] = sourceAttribute
+                }
+                userInfo[CustomEntityMigrationPolicy.UserInfoKey.sourceAttributesByDestinationKey] = sourceAttributesByDestinationKey
+            }
+            let entityMappingName = entityMapping.name!
+            entityMapping.relationshipMappings = autoreleasepool { () -> [NSPropertyMapping] in
+                
+                let destinationRelationships = destinationEntity.cs_resolvedRelationshipRenamingIdentities()
+                var relationshipMappings: [NSPropertyMapping] = []
+                for (_, destination) in destinationRelationships {
+                    
+                    let destinationRelationship = destination.relationship
+                    let propertyMapping = NSPropertyMapping()
+                    propertyMapping.name = destinationRelationship.name
+                    propertyMapping.valueExpression = NSExpression(format: "FUNCTION($\(NSMigrationManagerKey), \"\(#selector(NSMigrationManager.destinationInstances(forEntityMappingName:sourceInstances:)))\" , \"\(entityMappingName)\", $\(NSMigrationSourceObjectKey))[0]")
+                    relationshipMappings.append(propertyMapping)
+                }
+                return relationshipMappings
+            }
+            entityMapping.userInfo = userInfo
+            entityMappings.append(entityMapping)
+        }
+        
+        mappingModel.entityMappings = entityMappings
+        return (
+            mappingModel,
+            .heavyweight(
+                sourceVersion: self.sourceVersion,
+                destinationVersion: self.destinationVersion
+            )
+        )
+    }
+    
+    
+    // MARK: Private
+    
+    // MARK: - CustomEntityMigrationPolicy
+    
+    private final class CustomEntityMigrationPolicy: NSEntityMigrationPolicy {
+        
+        // MARK: NSEntityMigrationPolicy
+        
+        override func createDestinationInstances(forSource sInstance: NSManagedObject, in mapping: NSEntityMapping, manager: NSMigrationManager) throws {
+            
+            let userInfo = mapping.userInfo!
+            let transformer = userInfo[CustomEntityMigrationPolicy.UserInfoKey.transformer]! as! CustomMapping.Transformer
+            let sourceAttributesByDestinationKey = userInfo[CustomEntityMigrationPolicy.UserInfoKey.sourceAttributesByDestinationKey] as! [KeyPath: NSAttributeDescription]
+            
+            var dInstance: NSManagedObject?
+            try transformer(
+                UnsafeSourceObject(sInstance),
+                {
+                    let rawObject = NSEntityDescription.insertNewObject(
+                        forEntityName: mapping.destinationEntityName!,
+                        into: manager.destinationContext
+                    )
+                    dInstance = rawObject
+                    return UnsafeDestinationObject(rawObject, sourceAttributesByDestinationKey)
+                }
+            )
+            if let dInstance = dInstance {
+                
+                manager.associate(
+                    sourceInstance: sInstance,
+                    withDestinationInstance: dInstance,
+                    for: mapping
+                )
+            }
+        }
+        
+        override func createRelationships(forDestination dInstance: NSManagedObject, in mapping: NSEntityMapping, manager: NSMigrationManager) throws {
+            
+            try super.createRelationships(forDestination: dInstance, in: mapping, manager: manager)
+        }
+        
+        
+        // MARK: FilePrivate
+        
+        fileprivate enum UserInfoKey {
+            
+            fileprivate static let transformer = "CoreStore.CustomEntityMigrationPolicy.transformer"
+            fileprivate static let sourceAttributesByDestinationKey = "CoreStore.CustomEntityMigrationPolicy.sourceAttributesByDestinationKey"
+        }
+    }
+    
+    
+    // MARK: -
+    
+    private let entityMappings: Set<CustomMapping>
+    
+    private func resolveEntityMappings(sourceModel: NSManagedObjectModel, destinationModel: NSManagedObjectModel) -> (delete: Set<CustomMapping>, insert: Set<CustomMapping>, copy: Set<CustomMapping>, transform: Set<CustomMapping>) {
+        
+        var deleteMappings: Set<CustomMapping> = []
+        var insertMappings: Set<CustomMapping> = []
+        var copyMappings: Set<CustomMapping> = []
+        var transformMappings: Set<CustomMapping> = []
+        var allMappedSourceKeys: [KeyPath: KeyPath] = [:]
+        var allMappedDestinationKeys: [KeyPath: KeyPath] = [:]
+        
+        let sourceRenamingIdentifiers = sourceModel.cs_resolvedRenamingIdentities()
+        let sourceEntityNames = sourceModel.entitiesByName
+        let destinationRenamingIdentifiers = destinationModel.cs_resolvedRenamingIdentities()
+        let destinationEntityNames = destinationModel.entitiesByName
+        
+        let removedRenamingIdentifiers = Set(sourceRenamingIdentifiers.keys)
+            .subtracting(destinationRenamingIdentifiers.keys)
+        let addedRenamingIdentifiers = Set(destinationRenamingIdentifiers.keys)
+            .subtracting(sourceRenamingIdentifiers.keys)
+        let transformedRenamingIdentifiers = Set(destinationRenamingIdentifiers.keys)
+            .subtracting(addedRenamingIdentifiers)
+            .subtracting(removedRenamingIdentifiers)
+        
+        // First pass: resolve source-destination entities
+        for mapping in self.entityMappings {
+            
+            switch mapping {
+                
+            case .deleteEntity(let sourceEntity):
+                CoreStore.assert(
+                    sourceEntityNames[sourceEntity] != nil,
+                    "A \(cs_typeName(CustomMapping.self)) with value '\(mapping)' passed to \(cs_typeName(CustomSchemaMappingProvider.self)) could not be mapped to any \(cs_typeName(NSEntityDescription.self)) from the source \(cs_typeName(NSManagedObjectModel.self))."
+                )
+                CoreStore.assert(
+                    allMappedSourceKeys[sourceEntity] == nil,
+                    "Duplicate \(cs_typeName(CustomMapping.self))s found for source entity name \"\(sourceEntity)\" in \(cs_typeName(CustomSchemaMappingProvider.self))."
+                )
+                deleteMappings.insert(mapping)
+                allMappedSourceKeys[sourceEntity] = ""
+                
+            case .insertEntity(let destinationEntity):
+                CoreStore.assert(
+                    destinationEntityNames[destinationEntity] != nil,
+                    "A \(cs_typeName(CustomMapping.self)) with value '\(mapping)' passed to \(cs_typeName(CustomSchemaMappingProvider.self)) could not be mapped to any \(cs_typeName(NSEntityDescription.self)) from the destination \(cs_typeName(NSManagedObjectModel.self))."
+                )
+                CoreStore.assert(
+                    allMappedDestinationKeys[destinationEntity] == nil,
+                    "Duplicate \(cs_typeName(CustomMapping.self))s found for destination entity name \"\(destinationEntity)\" in \(cs_typeName(CustomSchemaMappingProvider.self))."
+                )
+                insertMappings.insert(mapping)
+                allMappedDestinationKeys[destinationEntity] = ""
+                
+            case .transformEntity(let sourceEntity, let destinationEntity, _):
+                CoreStore.assert(
+                    sourceEntityNames[sourceEntity] != nil,
+                    "A \(cs_typeName(CustomMapping.self)) with value '\(mapping)' passed to \(cs_typeName(CustomSchemaMappingProvider.self)) could not be mapped to any \(cs_typeName(NSEntityDescription.self)) from the source \(cs_typeName(NSManagedObjectModel.self))."
+                )
+                CoreStore.assert(
+                    destinationEntityNames[destinationEntity] != nil,
+                    "A \(cs_typeName(CustomMapping.self)) with value '\(mapping)' passed to \(cs_typeName(CustomSchemaMappingProvider.self)) could not be mapped to any \(cs_typeName(NSEntityDescription.self)) from the destination \(cs_typeName(NSManagedObjectModel.self))."
+                )
+                CoreStore.assert(
+                    allMappedSourceKeys[sourceEntity] == nil,
+                    "Duplicate \(cs_typeName(CustomMapping.self))s found for source entity name \"\(sourceEntity)\" in \(cs_typeName(CustomSchemaMappingProvider.self))."
+                )
+                CoreStore.assert(
+                    allMappedDestinationKeys[destinationEntity] == nil,
+                    "Duplicate \(cs_typeName(CustomMapping.self))s found for destination entity name \"\(destinationEntity)\" in \(cs_typeName(CustomSchemaMappingProvider.self))."
+                )
+                transformMappings.insert(mapping)
+                allMappedSourceKeys[sourceEntity] = destinationEntity
+                allMappedDestinationKeys[destinationEntity] = sourceEntity
+                
+            case .copyEntity(let sourceEntity, let destinationEntity):
+                CoreStore.assert(
+                    sourceEntityNames[sourceEntity] != nil,
+                    "A \(cs_typeName(CustomMapping.self)) with value '\(mapping)' passed to \(cs_typeName(CustomSchemaMappingProvider.self)) could not be mapped to any \(cs_typeName(NSEntityDescription.self)) from the source \(cs_typeName(NSManagedObjectModel.self))."
+                )
+                CoreStore.assert(
+                    destinationEntityNames[destinationEntity] != nil,
+                    "A \(cs_typeName(CustomMapping.self)) with value '\(mapping)' passed to \(cs_typeName(CustomSchemaMappingProvider.self)) could not be mapped to any \(cs_typeName(NSEntityDescription.self)) from the destination \(cs_typeName(NSManagedObjectModel.self))."
+                )
+                CoreStore.assert(
+                    sourceEntityNames[sourceEntity]!.versionHash == destinationEntityNames[destinationEntity]!.versionHash,
+                    "A \(cs_typeName(CustomMapping.self)) with value '\(mapping)' was passed to \(cs_typeName(CustomSchemaMappingProvider.self)) but the \(cs_typeName(NSEntityDescription.self))'s \"versionHash\" of the source and destination entities do not match."
+                )
+                CoreStore.assert(
+                    allMappedSourceKeys[sourceEntity] == nil,
+                    "Duplicate \(cs_typeName(CustomMapping.self))s found for source entity name \"\(sourceEntity)\" in \(cs_typeName(CustomSchemaMappingProvider.self))."
+                )
+                CoreStore.assert(
+                    allMappedDestinationKeys[destinationEntity] == nil,
+                    "Duplicate \(cs_typeName(CustomMapping.self))s found for destination entity name \"\(destinationEntity)\" in \(cs_typeName(CustomSchemaMappingProvider.self))."
+                )
+                copyMappings.insert(mapping)
+                allMappedSourceKeys[sourceEntity] = destinationEntity
+                allMappedDestinationKeys[destinationEntity] = sourceEntity
+            }
+            
+            for renamingIdentifier in transformedRenamingIdentifiers {
+                
+                let sourceEntity = sourceRenamingIdentifiers[renamingIdentifier]!.entity
+                let destinationEntity = destinationRenamingIdentifiers[renamingIdentifier]!.entity
+                let sourceEntityName = sourceEntity.name!
+                let destinationEntityName = destinationEntity.name!
+                switch (allMappedSourceKeys[sourceEntityName], allMappedDestinationKeys[destinationEntityName]) {
+                    
+                case (nil, nil):
+                    if sourceEntity.versionHash == destinationEntity.versionHash {
+                        
+                        copyMappings.insert(
+                            .copyEntity(
+                                sourceEntity: sourceEntityName,
+                                destinationEntity: destinationEntityName
+                            )
+                        )
+                    }
+                    else {
+                        
+                        transformMappings.insert(
+                            .transformEntity(
+                                sourceEntity: sourceEntityName,
+                                destinationEntity: destinationEntityName,
+                                transformer: CustomMapping.inferredTransformation
+                            )
+                        )
+                    }
+                    allMappedSourceKeys[sourceEntityName] = destinationEntityName
+                    allMappedDestinationKeys[destinationEntityName] = sourceEntityName
+                    
+                case (""?, nil):
+                    insertMappings.insert(.insertEntity(destinationEntity: destinationEntityName))
+                    allMappedDestinationKeys[destinationEntityName] = ""
+                    
+                case (nil, ""?):
+                    deleteMappings.insert(.deleteEntity(sourceEntity: sourceEntityName))
+                    allMappedSourceKeys[sourceEntityName] = ""
+                    
+                default:
+                    continue
+                }
+            }
+            for renamingIdentifier in removedRenamingIdentifiers {
+                
+                let sourceEntity = sourceRenamingIdentifiers[renamingIdentifier]!.entity
+                let sourceEntityName = sourceEntity.name!
+                switch allMappedSourceKeys[sourceEntityName] {
+                    
+                case nil:
+                    deleteMappings.insert(.deleteEntity(sourceEntity: sourceEntityName))
+                    allMappedSourceKeys[sourceEntityName] = ""
+                    
+                default:
+                    continue
+                }
+            }
+            for renamingIdentifier in addedRenamingIdentifiers {
+                
+                let destinationEntity = destinationRenamingIdentifiers[renamingIdentifier]!.entity
+                let destinationEntityName = destinationEntity.name!
+                switch allMappedDestinationKeys[destinationEntityName] {
+                    
+                case nil:
+                    insertMappings.insert(.insertEntity(destinationEntity: destinationEntityName))
+                    allMappedDestinationKeys[destinationEntityName] = ""
+                    
+                default:
+                    continue
+                }
+            }
+        }
+        return (deleteMappings, insertMappings, copyMappings, transformMappings)
+    }
+}