Flatten file directories (fixes #159)

Sources/From.swift

@@ -0,0 +1,253 @@
+//
+//  From.swift
+//  CoreStore
+//
+//  Copyright © 2015 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 Foundation
+import CoreData
+
+
+// MARK: - From
+
+/**
+ A `From` clause specifies the source entity and source persistent store for fetch and query methods. A common usage is to just indicate the entity:
+ ```
+ let person = transaction.fetchOne(From<MyPersonEntity>())
+ ```
+ For cases where multiple `NSPersistentStore`s contain the same entity, the source configuration's name needs to be specified as well:
+ ```
+ let person = transaction.fetchOne(From<MyPersonEntity>("Configuration1"))
+ ```
+ */
+public struct From<T: NSManagedObject> {
+    
+    /**
+     The associated `NSManagedObject` entity class
+     */
+    public let entityClass: AnyClass
+    
+    /**
+     The `NSPersistentStore` configuration names to associate objects from.
+     May contain `String`s to pertain to named configurations, or `nil` to pertain to the default configuration
+     */
+    public let configurations: [String?]?
+    
+    /**
+     Initializes a `From` clause.
+     ```
+     let people = transaction.fetchAll(From<MyPersonEntity>())
+     ```
+     */
+    public init() {
+        
+        self.init(entityClass: T.self, configurations: nil)
+    }
+    
+    /**
+     Initializes a `From` clause with the specified entity type.
+     ```
+     let people = transaction.fetchAll(From<MyPersonEntity>())
+     ```
+     - parameter entity: the associated `NSManagedObject` type
+     */
+    public init(_ entity: T.Type) {
+        
+        self.init(entityClass: entity, configurations: nil)
+    }
+    
+    /**
+     Initializes a `From` clause with the specified entity class.
+     ```
+     let people = transaction.fetchAll(From<MyPersonEntity>())
+     ```
+     - parameter entityClass: the associated `NSManagedObject` entity class
+     */
+    public init(_ entityClass: AnyClass) {
+        
+        CoreStore.assert(
+            entityClass is T.Type,
+            "Attempted to create generic type \(cs_typeName(From<T>.self)) with entity class \(cs_typeName(entityClass))"
+        )
+        self.init(entityClass: entityClass, configurations: nil)
+    }
+    
+    /**
+     Initializes a `From` clause with the specified configurations.
+     ```
+     let people = transaction.fetchAll(From<MyPersonEntity>(nil, "Configuration1"))
+     ```
+     - parameter configuration: the `NSPersistentStore` configuration name to associate objects from. This parameter is required if multiple configurations contain the created `NSManagedObject`'s entity type. Set to `nil` to use the default configuration.
+     - parameter otherConfigurations: an optional list of other configuration names to associate objects from (see `configuration` parameter)
+     */
+    public init(_ configuration: String?, _ otherConfigurations: String?...) {
+        
+        self.init(entityClass: T.self, configurations: [configuration] + otherConfigurations)
+    }
+    
+    /**
+     Initializes a `From` clause with the specified configurations.
+     ```
+     let people = transaction.fetchAll(From<MyPersonEntity>(["Configuration1", "Configuration2"]))
+     ```
+     - parameter configurations: a list of `NSPersistentStore` configuration names to associate objects from. This parameter is required if multiple configurations contain the created `NSManagedObject`'s entity type. Set to `nil` to use the default configuration.
+     */
+    public init(_ configurations: [String?]) {
+        
+        self.init(entityClass: T.self, configurations: configurations)
+    }
+    
+    /**
+     Initializes a `From` clause with the specified configurations.
+     ```
+     let people = transaction.fetchAll(From(MyPersonEntity.self, nil, "Configuration1"))
+     ```
+     - parameter entity: the associated `NSManagedObject` type
+     - parameter configuration: the `NSPersistentStore` configuration name to associate objects from. This parameter is required if multiple configurations contain the created `NSManagedObject`'s entity type. Set to `nil` to use the default configuration.
+     - parameter otherConfigurations: an optional list of other configuration names to associate objects from (see `configuration` parameter)
+     */
+    public init(_ entity: T.Type, _ configuration: String?, _ otherConfigurations: String?...) {
+        
+        self.init(entityClass: entity, configurations: [configuration] + otherConfigurations)
+    }
+    
+    /**
+     Initializes a `From` clause with the specified configurations.
+     ```
+     let people = transaction.fetchAll(From(MyPersonEntity.self, ["Configuration1", "Configuration1"]))
+     ```
+     - parameter entity: the associated `NSManagedObject` type
+     - parameter configurations: a list of `NSPersistentStore` configuration names to associate objects from. This parameter is required if multiple configurations contain the created `NSManagedObject`'s entity type. Set to `nil` to use the default configuration.
+     */
+    public init(_ entity: T.Type, _ configurations: [String?]) {
+        
+        self.init(entityClass: entity, configurations: configurations)
+    }
+    
+    /**
+     Initializes a `From` clause with the specified configurations.
+     ```
+     let people = transaction.fetchAll(From(MyPersonEntity.self, nil, "Configuration1"))
+     ```
+     - parameter entity: the associated `NSManagedObject` entity class
+     - parameter configuration: the `NSPersistentStore` configuration name to associate objects from. This parameter is required if multiple configurations contain the created `NSManagedObject`'s entity type. Set to `nil` to use the default configuration.
+     - parameter otherConfigurations: an optional list of other configuration names to associate objects from (see `configuration` parameter)
+     */
+    public init(_ entityClass: AnyClass, _ configuration: String?, _ otherConfigurations: String?...) {
+        
+        CoreStore.assert(
+            entityClass is T.Type,
+            "Attempted to create generic type \(cs_typeName(From<T>.self)) with entity class \(cs_typeName(entityClass))"
+        )
+        self.init(entityClass: entityClass, configurations: [configuration] + otherConfigurations)
+    }
+    
+    /**
+     Initializes a `From` clause with the specified configurations.
+     ```
+     let people = transaction.fetchAll(From(MyPersonEntity.self, ["Configuration1", "Configuration1"]))
+     ```
+     - parameter entity: the associated `NSManagedObject` entity class
+     - parameter configurations: a list of `NSPersistentStore` configuration names to associate objects from. This parameter is required if multiple configurations contain the created `NSManagedObject`'s entity type. Set to `nil` to use the default configuration.
+     */
+    public init(_ entityClass: AnyClass, _ configurations: [String?]) {
+        
+        CoreStore.assert(
+            entityClass is T.Type,
+            "Attempted to create generic type \(cs_typeName(From<T>.self)) with entity class \(cs_typeName(entityClass))"
+        )
+        self.init(entityClass: entityClass, configurations: configurations)
+    }
+    
+    
+    // MARK: Internal
+    
+    internal func applyToFetchRequest<ResultType: NSFetchRequestResult>(_ fetchRequest: NSFetchRequest<ResultType>, context: NSManagedObjectContext, applyAffectedStores: Bool = true) -> Bool {
+        
+        fetchRequest.entity = context.entityDescriptionForEntityClass(self.entityClass)
+        guard applyAffectedStores else {
+            
+            return true
+        }
+        if self.applyAffectedStoresForFetchedRequest(fetchRequest, context: context) {
+            
+            return true
+        }
+        CoreStore.log(
+            .warning,
+            message: "Attempted to perform a fetch but could not find any persistent store for the entity \(cs_typeName(fetchRequest.entityName))"
+        )
+        return false
+    }
+    
+    internal func applyAffectedStoresForFetchedRequest<U: NSFetchRequestResult>(_ fetchRequest: NSFetchRequest<U>, context: NSManagedObjectContext) -> Bool {
+        
+        let stores = self.findPersistentStores(context)
+        fetchRequest.affectedStores = stores
+        return stores?.isEmpty == false
+    }
+    
+    internal func downcast() -> From<NSManagedObject> {
+        
+        return From<NSManagedObject>(
+            entityClass: self.entityClass,
+            configurations: self.configurations,
+            findPersistentStores: self.findPersistentStores
+        )
+    }
+    
+    
+    // MARK: Private
+    
+    private let findPersistentStores: (_ context: NSManagedObjectContext) -> [NSPersistentStore]?
+    
+    private init(entityClass: AnyClass, configurations: [String?]?) {
+        
+        self.entityClass = entityClass
+        self.configurations = configurations
+        if let configurations = configurations {
+            
+            let configurationsSet = Set(configurations.map { $0 ?? Into.defaultConfigurationName })
+            self.findPersistentStores = { (context: NSManagedObjectContext) -> [NSPersistentStore]? in
+                
+                return context.parentStack?.persistentStoresForEntityClass(entityClass)?.filter {
+                    
+                    return configurationsSet.contains($0.configurationName)
+                }
+            }
+        }
+        else {
+            
+            self.findPersistentStores = { (context: NSManagedObjectContext) -> [NSPersistentStore]? in
+                
+                return context.parentStack?.persistentStoresForEntityClass(entityClass)
+            }
+        }
+    }
+    
+    private init(entityClass: AnyClass, configurations: [String?]?, findPersistentStores: @escaping (_ context: NSManagedObjectContext) -> [NSPersistentStore]?) {
+        
+        self.entityClass = entityClass
+        self.configurations = configurations
+        self.findPersistentStores = findPersistentStores
+    }
+}