Flatten file directories (fixes #159)

Sources/BaseDataTransaction.swift

@@ -0,0 +1,488 @@
+//
+//  BaseDataTransaction.swift
+//  CoreStore
+//
+//  Copyright © 2014 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: - BaseDataTransaction
+
+/**
+ The `BaseDataTransaction` is an abstract interface for `NSManagedObject` creates, updates, and deletes. All `BaseDataTransaction` subclasses manage a private `NSManagedObjectContext` which are direct children of the `NSPersistentStoreCoordinator`'s root `NSManagedObjectContext`. This means that all updates are saved first to the persistent store, and then propagated up to the read-only `NSManagedObjectContext`.
+ */
+public /*abstract*/ class BaseDataTransaction {
+    
+    // MARK: Object management
+    
+    /**
+     Indicates if the transaction has pending changes
+     */
+    public var hasChanges: Bool {
+        
+        return self.context.hasChanges
+    }
+    
+    /**
+     Creates a new `NSManagedObject` with the specified entity type.
+     
+     - parameter into: the `Into` clause indicating the destination `NSManagedObject` entity type and the destination configuration
+     - returns: a new `NSManagedObject` instance of the specified entity type.
+     */
+    public func create<T: NSManagedObject>(_ into: Into<T>) -> T {
+        
+        let entityClass = (into.entityClass as! T.Type)
+        CoreStore.assert(
+            self.isRunningInAllowedQueue(),
+            "Attempted to create an entity of type \(cs_typeName(entityClass)) outside its designated queue."
+        )
+        
+        let context = self.context
+        if into.inferStoreIfPossible {
+            
+            switch context.parentStack!.persistentStoreForEntityClass(
+                entityClass,
+                configuration: nil,
+                inferStoreIfPossible: true
+            ) {
+                
+            case (let persistentStore?, _):
+                let object = entityClass.createInContext(context)
+                context.assign(object, to: persistentStore)
+                return object
+                
+            case (nil, true):
+                CoreStore.abort("Attempted to create an entity of type \(cs_typeName(entityClass)) with ambiguous destination persistent store, but the configuration name was not specified.")
+                
+            default:
+                CoreStore.abort("Attempted to create an entity of type \(cs_typeName(entityClass)), but a destination persistent store containing the entity type could not be found.")
+            }
+        }
+        else {
+            
+            switch context.parentStack!.persistentStoreForEntityClass(
+                entityClass,
+                configuration: into.configuration
+                    ?? type(of: into).defaultConfigurationName,
+                inferStoreIfPossible: false
+            ) {
+                
+            case (let persistentStore?, _):
+                let object = entityClass.createInContext(context)
+                context.assign(object, to: persistentStore)
+                return object
+                
+            case (nil, true):
+                CoreStore.abort("Attempted to create an entity of type \(cs_typeName(entityClass)) with ambiguous destination persistent store, but the configuration name was not specified.")
+                
+            default:
+                if let configuration = into.configuration {
+                    
+                    CoreStore.abort("Attempted to create an entity of type \(cs_typeName(entityClass)) into the configuration \"\(configuration)\", which it doesn't belong to.")
+                }
+                else {
+                    
+                    CoreStore.abort("Attempted to create an entity of type \(cs_typeName(entityClass)) into the default configuration, which it doesn't belong to.")
+                }
+            }
+        }
+    }
+    
+    /**
+     Returns an editable proxy of a specified `NSManagedObject`.
+     
+     - parameter object: the `NSManagedObject` type to be edited
+     - returns: an editable proxy for the specified `NSManagedObject`.
+     */
+    public func edit<T: NSManagedObject>(_ object: T?) -> T? {
+        
+        CoreStore.assert(
+            self.isRunningInAllowedQueue(),
+            "Attempted to update an entity of type \(cs_typeName(object)) outside its designated queue."
+        )
+        guard let object = object else {
+            
+            return nil
+        }
+        return self.context.fetchExisting(object)
+    }
+    
+    /**
+     Returns an editable proxy of the object with the specified `NSManagedObjectID`.
+     
+     - parameter into: an `Into` clause specifying the entity type
+     - parameter objectID: the `NSManagedObjectID` for the object to be edited
+     - returns: an editable proxy for the specified `NSManagedObject`.
+     */
+    public func edit<T: NSManagedObject>(_ into: Into<T>, _ objectID: NSManagedObjectID) -> T? {
+        
+        CoreStore.assert(
+            self.isRunningInAllowedQueue(),
+            "Attempted to update an entity of type \(cs_typeName(into.entityClass)) outside its designated queue."
+        )
+        CoreStore.assert(
+            into.inferStoreIfPossible
+                || (into.configuration ?? Into.defaultConfigurationName) == objectID.persistentStore?.configurationName,
+            "Attempted to update an entity of type \(cs_typeName(into.entityClass)) but the specified persistent store do not match the `NSManagedObjectID`."
+        )
+        return self.fetchExisting(objectID) as? T
+    }
+    
+    /**
+     Deletes a specified `NSManagedObject`.
+     
+     - parameter object: the `NSManagedObject` to be deleted
+     */
+    public func delete(_ object: NSManagedObject?) {
+        
+        CoreStore.assert(
+            self.isRunningInAllowedQueue(),
+            "Attempted to delete an entity outside its designated queue."
+        )
+        guard let object = object else {
+            
+            return
+        }
+        self.context.fetchExisting(object)?.deleteFromContext()
+    }
+    
+    /**
+     Deletes the specified `NSManagedObject`s.
+     
+     - parameter object1: the `NSManagedObject` to be deleted
+     - parameter object2: another `NSManagedObject` to be deleted
+     - parameter objects: other `NSManagedObject`s to be deleted
+     */
+    public func delete(_ object1: NSManagedObject?, _ object2: NSManagedObject?, _ objects: NSManagedObject?...) {
+        
+        self.delete(([object1, object2] + objects).flatMap { $0 })
+    }
+    
+    /**
+     Deletes the specified `NSManagedObject`s.
+     
+     - parameter objects: the `NSManagedObject`s to be deleted
+     */
+    public func delete<S: Sequence>(_ objects: S) where S.Iterator.Element: NSManagedObject {
+        
+        CoreStore.assert(
+            self.isRunningInAllowedQueue(),
+            "Attempted to delete entities outside their designated queue."
+        )
+        
+        let context = self.context
+        objects.forEach { context.fetchExisting($0)?.deleteFromContext() }
+    }
+    
+    /**
+     Refreshes all registered objects `NSManagedObject`s in the transaction.
+     */
+    public func refreshAndMergeAllObjects() {
+        
+        CoreStore.assert(
+            self.isRunningInAllowedQueue(),
+            "Attempted to refresh entities outside their designated queue."
+        )
+        
+        self.context.refreshAndMergeAllObjects()
+    }
+    
+    
+    // MARK: Inspecting Pending Objects
+    
+    /**
+    Returns all pending `NSManagedObject`s that were inserted to the transaction. This method should not be called after the `commit()` method was called.
+    
+    - returns: a `Set` of pending `NSManagedObject`s that were inserted to the transaction.
+     */
+    public func insertedObjects() -> Set<NSManagedObject> {
+        
+        CoreStore.assert(
+            self.transactionQueue.cs_isCurrentExecutionContext(),
+            "Attempted to access inserted objects from a \(cs_typeName(self)) outside its designated queue."
+        )
+        CoreStore.assert(
+            !self.isCommitted,
+            "Attempted to access inserted objects from an already committed \(cs_typeName(self))."
+        )
+        
+        return self.context.insertedObjects
+    }
+    
+    /**
+     Returns all pending `NSManagedObject`s of the specified type that were inserted to the transaction. This method should not be called after the `commit()` method was called.
+     
+     - parameter entity: the `NSManagedObject` subclass to filter
+     - returns: a `Set` of pending `NSManagedObject`s of the specified type that were inserted to the transaction.
+     */
+    public func insertedObjects<T: NSManagedObject>(_ entity: T.Type) -> Set<T> {
+        
+        CoreStore.assert(
+            self.transactionQueue.cs_isCurrentExecutionContext(),
+            "Attempted to access inserted objects from a \(cs_typeName(self)) outside its designated queue."
+        )
+        CoreStore.assert(
+            !self.isCommitted,
+            "Attempted to access inserted objects from an already committed \(cs_typeName(self))."
+        )
+        
+        return Set(self.context.insertedObjects.flatMap { $0 as? T })
+    }
+    
+    /**
+     Returns all pending `NSManagedObjectID`s that were inserted to the transaction. This method should not be called after the `commit()` method was called.
+     
+     - returns: a `Set` of pending `NSManagedObjectID`s that were inserted to the transaction.
+     */
+    public func insertedObjectIDs() -> Set<NSManagedObjectID> {
+        
+        CoreStore.assert(
+            self.transactionQueue.cs_isCurrentExecutionContext(),
+            "Attempted to access inserted object IDs from a \(cs_typeName(self)) outside its designated queue."
+        )
+        CoreStore.assert(
+            !self.isCommitted,
+            "Attempted to access inserted objects IDs from an already committed \(cs_typeName(self))."
+        )
+        
+        return Set(self.context.insertedObjects.map { $0.objectID })
+    }
+    
+    /**
+     Returns all pending `NSManagedObjectID`s of the specified type that were inserted to the transaction. This method should not be called after the `commit()` method was called.
+     
+     - parameter entity: the `NSManagedObject` subclass to filter
+     - returns: a `Set` of pending `NSManagedObjectID`s of the specified type that were inserted to the transaction.
+     */
+    public func insertedObjectIDs<T: NSManagedObject>(_ entity: T.Type) -> Set<NSManagedObjectID> {
+        
+        CoreStore.assert(
+            self.transactionQueue.cs_isCurrentExecutionContext(),
+            "Attempted to access inserted object IDs from a \(cs_typeName(self)) outside its designated queue."
+        )
+        CoreStore.assert(
+            !self.isCommitted,
+            "Attempted to access inserted objects IDs from an already committed \(cs_typeName(self))."
+        )
+        
+        return Set(self.context.insertedObjects.filter { $0.isKind(of: entity) }.map { $0.objectID })
+    }
+    
+    /**
+     Returns all pending `NSManagedObject`s that were updated in the transaction. This method should not be called after the `commit()` method was called.
+     
+     - returns: a `Set` of pending `NSManagedObject`s that were updated to the transaction.
+     */
+    public func updatedObjects() -> Set<NSManagedObject> {
+        
+        CoreStore.assert(
+            self.transactionQueue.cs_isCurrentExecutionContext(),
+            "Attempted to access updated objects from a \(cs_typeName(self)) outside its designated queue."
+        )
+        CoreStore.assert(
+            !self.isCommitted,
+            "Attempted to access updated objects from an already committed \(cs_typeName(self))."
+        )
+        
+        return self.context.updatedObjects
+    }
+    
+    /**
+     Returns all pending `NSManagedObject`s of the specified type that were updated in the transaction. This method should not be called after the `commit()` method was called.
+     
+     - parameter entity: the `NSManagedObject` subclass to filter
+     - returns: a `Set` of pending `NSManagedObject`s of the specified type that were updated in the transaction.
+     */
+    public func updatedObjects<T: NSManagedObject>(_ entity: T.Type) -> Set<T> {
+        
+        CoreStore.assert(
+            self.transactionQueue.cs_isCurrentExecutionContext(),
+            "Attempted to access updated objects from a \(cs_typeName(self)) outside its designated queue."
+        )
+        CoreStore.assert(
+            !self.isCommitted,
+            "Attempted to access updated objects from an already committed \(cs_typeName(self))."
+        )
+        
+        return Set(self.context.updatedObjects.filter { $0.isKind(of: entity) }.map { $0 as! T })
+    }
+    
+    /**
+     Returns all pending `NSManagedObjectID`s that were updated in the transaction. This method should not be called after the `commit()` method was called.
+     
+     - returns: a `Set` of pending `NSManagedObjectID`s that were updated in the transaction.
+     */
+    public func updatedObjectIDs() -> Set<NSManagedObjectID> {
+        
+        CoreStore.assert(
+            self.transactionQueue.cs_isCurrentExecutionContext(),
+            "Attempted to access updated object IDs from a \(cs_typeName(self)) outside its designated queue."
+        )
+        CoreStore.assert(
+            !self.isCommitted,
+            "Attempted to access updated object IDs from an already committed \(cs_typeName(self))."
+        )
+        
+        return Set(self.context.updatedObjects.map { $0.objectID })
+    }
+    
+    /**
+     Returns all pending `NSManagedObjectID`s of the specified type that were updated in the transaction. This method should not be called after the `commit()` method was called.
+     
+     - parameter entity: the `NSManagedObject` subclass to filter
+     - returns: a `Set` of pending `NSManagedObjectID`s of the specified type that were updated in the transaction.
+     */
+    public func updatedObjectIDs<T: NSManagedObject>(_ entity: T.Type) -> Set<NSManagedObjectID> {
+        
+        CoreStore.assert(
+            self.transactionQueue.cs_isCurrentExecutionContext(),
+            "Attempted to access updated object IDs from a \(cs_typeName(self)) outside its designated queue."
+        )
+        CoreStore.assert(
+            !self.isCommitted,
+            "Attempted to access updated object IDs from an already committed \(cs_typeName(self))."
+        )
+        
+        return Set(self.context.updatedObjects.filter { $0.isKind(of: entity) }.map { $0.objectID })
+    }
+    
+    /**
+     Returns all pending `NSManagedObject`s that were deleted from the transaction. This method should not be called after the `commit()` method was called.
+     
+     - returns: a `Set` of pending `NSManagedObject`s that were deleted from the transaction.
+     */
+    public func deletedObjects() -> Set<NSManagedObject> {
+        
+        CoreStore.assert(
+            self.transactionQueue.cs_isCurrentExecutionContext(),
+            "Attempted to access deleted objects from a \(cs_typeName(self)) outside its designated queue."
+        )
+        CoreStore.assert(
+            !self.isCommitted,
+            "Attempted to access deleted objects from an already committed \(cs_typeName(self))."
+        )
+        
+        return self.context.deletedObjects
+    }
+    
+    /**
+     Returns all pending `NSManagedObject`s of the specified type that were deleted from the transaction. This method should not be called after the `commit()` method was called.
+     
+     - parameter entity: the `NSManagedObject` subclass to filter
+     - returns: a `Set` of pending `NSManagedObject`s of the specified type that were deleted from the transaction.
+     */
+    public func deletedObjects<T: NSManagedObject>(_ entity: T.Type) -> Set<T> {
+        
+        CoreStore.assert(
+            self.transactionQueue.cs_isCurrentExecutionContext(),
+            "Attempted to access deleted objects from a \(cs_typeName(self)) outside its designated queue."
+        )
+        CoreStore.assert(
+            !self.isCommitted,
+            "Attempted to access deleted objects from an already committed \(cs_typeName(self))."
+        )
+        
+        return Set(self.context.deletedObjects.filter { $0.isKind(of: entity) }.map { $0 as! T })
+    }
+    
+    /**
+     Returns all pending `NSManagedObjectID`s of the specified type that were deleted from the transaction. This method should not be called after the `commit()` method was called.
+     
+     - parameter entity: the `NSManagedObject` subclass to filter
+     - returns: a `Set` of pending `NSManagedObjectID`s of the specified type that were deleted from the transaction.
+     */
+    public func deletedObjectIDs() -> Set<NSManagedObjectID> {
+        
+        CoreStore.assert(
+            self.transactionQueue.cs_isCurrentExecutionContext(),
+            "Attempted to access deleted object IDs from a \(cs_typeName(self)) outside its designated queue."
+        )
+        CoreStore.assert(
+            !self.isCommitted,
+            "Attempted to access deleted object IDs from an already committed \(cs_typeName(self))."
+        )
+        
+        return Set(self.context.deletedObjects.map { $0.objectID })
+    }
+    
+    /**
+     Returns all pending `NSManagedObjectID`s of the specified type that were deleted from the transaction. This method should not be called after the `commit()` method was called.
+     
+     - parameter entity: the `NSManagedObject` subclass to filter
+     - returns: a `Set` of pending `NSManagedObjectID`s of the specified type that were deleted from the transaction.
+     */
+    public func deletedObjectIDs<T: NSManagedObject>(_ entity: T.Type) -> Set<NSManagedObjectID> {
+        
+        CoreStore.assert(
+            self.transactionQueue.cs_isCurrentExecutionContext(),
+            "Attempted to access deleted object IDs from a \(cs_typeName(self)) outside its designated queue."
+        )
+        CoreStore.assert(
+            !self.isCommitted,
+            "Attempted to access deleted object IDs from an already committed \(cs_typeName(self))."
+        )
+        
+        return Set(self.context.deletedObjects.filter { $0.isKind(of: entity) }.map { $0.objectID })
+    }
+    
+    
+    // MARK: Internal
+    
+    internal let context: NSManagedObjectContext
+    internal let transactionQueue: DispatchQueue
+    internal let childTransactionQueue = DispatchQueue.serial("com.corestore.datastack.childtransactionqueue")
+    internal let supportsUndo: Bool
+    internal let bypassesQueueing: Bool
+    internal var isCommitted = false
+    internal var result: SaveResult?
+    
+    internal init(mainContext: NSManagedObjectContext, queue: DispatchQueue, supportsUndo: Bool, bypassesQueueing: Bool) {
+        
+        let context = mainContext.temporaryContextInTransactionWithConcurrencyType(
+            queue == .main
+                ? .mainQueueConcurrencyType
+                : .privateQueueConcurrencyType
+        )
+        self.transactionQueue = queue
+        self.context = context
+        self.supportsUndo = supportsUndo
+        self.bypassesQueueing = bypassesQueueing
+        
+        context.parentTransaction = self
+        context.isTransactionContext = true
+        if !supportsUndo {
+            
+            context.undoManager = nil
+        }
+        else if context.undoManager == nil {
+            
+            context.undoManager = UndoManager()
+        }
+    }
+    
+    internal func isRunningInAllowedQueue() -> Bool {
+        
+        return self.bypassesQueueing || self.transactionQueue.cs_isCurrentExecutionContext()
+    }
+}