added ability to query aggregates and attributes straight from the persistent store

HardcoreData/ManagedObjectListController.swift

@@ -0,0 +1,125 @@
+//
+//  ManagedObjectListController.swift
+//  HardcoreData
+//
+//  Copyright (c) 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
+import GCDKit
+
+
+// MARK: - ManagedObjectListController
+
+public final class ManagedObjectListController<T: NSManagedObject>: NSFetchedResultsControllerDelegate {
+    
+    // MARK: Public
+    
+    public typealias EntityType = T
+    
+    public func addObserver<U: ManagedObjectListObserver where U.EntityType == EntityType>(observer: U) {
+        
+        HardcoreData.assert(GCDQueue.Main.isCurrentExecutionContext(), "Attempted to add a <\(U.self)> outside the main queue.")
+        
+        self.observers.addObject(observer)
+    }
+    
+    public func removeObserver<U: ManagedObjectListObserver where U.EntityType == EntityType>(observer: U) {
+        
+        HardcoreData.assert(GCDQueue.Main.isCurrentExecutionContext(), "Attempted to remove a <\(U.self)> outside the main queue.")
+        
+        self.observers.removeObject(observer)
+    }
+    
+    
+    // MARK: NSFetchedResultsControllerDelegate
+    
+    private func controller(controller: NSFetchedResultsController, didChangeObject anObject: AnyObject, atIndexPath indexPath: NSIndexPath?, forChangeType type: NSFetchedResultsChangeType, newIndexPath: NSIndexPath?) {
+        
+    }
+    
+    private func controller(controller: NSFetchedResultsController, didChangeSection sectionInfo: NSFetchedResultsSectionInfo, atIndex sectionIndex: Int, forChangeType type: NSFetchedResultsChangeType) {
+        
+    }
+    
+    private func controllerWillChangeContent(controller: NSFetchedResultsController) {
+        
+    }
+    
+    private func controllerDidChangeContent(controller: NSFetchedResultsController) {
+        
+    }
+    
+    private func controller(controller: NSFetchedResultsController, sectionIndexTitleForSectionName sectionName: String?) -> String? {
+        
+        return nil
+    }
+    
+    
+    // MARK: Internal
+    
+    internal init(dataStack: DataStack, entity: T.Type, sectionNameKeyPath: KeyPath?, cacheResults: Bool, queryClauses: [FetchClause]) {
+        
+        let context = dataStack.mainContext
+        
+        let fetchRequest = NSFetchRequest()
+        fetchRequest.entity = context.entityDescriptionForEntityClass(entity)
+        fetchRequest.fetchLimit = 0
+        fetchRequest.resultType = .ManagedObjectResultType
+        
+        for clause in queryClauses {
+            
+            clause.applyToFetchRequest(fetchRequest)
+        }
+        
+        let fetchedResultsController = NSFetchedResultsController(
+            fetchRequest: fetchRequest,
+            managedObjectContext: context,
+            sectionNameKeyPath: sectionNameKeyPath,
+            cacheName: (cacheResults
+                ? "\(ManagedObjectListController<T>.self).\(NSUUID())"
+                : nil)
+        )
+        
+        
+        self.fetchedResultsController = fetchedResultsController
+        self.parentStack = dataStack
+        self.observers = NSHashTable.weakObjectsHashTable()
+        
+        fetchedResultsController.delegate = self
+        
+        var error: NSError?
+        if !fetchedResultsController.performFetch(&error) {
+            
+            HardcoreData.handleError(
+                error ?? NSError(hardcoreDataErrorCode: .UnknownError),
+                "Failed to perform fetch on \(NSFetchedResultsController.self)")
+        }
+    }
+    
+    
+    // MARK: Private
+    
+    private let fetchedResultsController: NSFetchedResultsController
+    private weak var parentStack: DataStack?
+    private let observers: NSHashTable
+}