CoreStore/Sources/Saving and Processing/NSManagedObject+Transaction.swift

//
//  NSManagedObject+Transaction.swift
//  CoreStore
//
//  Copyright © 2016 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: - NSManagedObject

public extension NSManagedObject {
    
    /**
     Returns this object's parent `UnsafeDataTransaction` instance if it was created from one. Returns `nil` if the parent transaction is either an `AsynchronousDataTransaction` or a `SynchronousDataTransaction`, or if the object is not managed by CoreStore.
     
     When using an `UnsafeDataTransaction` and passing around a temporary object, you can use this property to execute fetches and updates to the transaction without having to pass around both the object and the transaction instances.
     
     Note that the internal reference to the transaction is `weak`, and it is still the developer's responsibility to retain a strong reference to the `UnsafeDataTransaction`.
     */
    @nonobjc
    public var unsafeDataTransaction: UnsafeDataTransaction? {
        
        return self.managedObjectContext?.parentTransaction as? UnsafeDataTransaction
    }
    
    
    // MARK: Internal
    
    internal dynamic class func createInContext(context: NSManagedObjectContext) -> Self {
        
        return self.init(
            entity: context.entityDescriptionForEntityType(self)!,
            insertIntoManagedObjectContext: context
        )
    }
    
    internal func deleteFromContext() {
        
        self.managedObjectContext?.deleteObject(self)
    }
}