Refetch monitors when persistent stores are added/removed. Allow unsafe transactions to create their own monitors

CoreStore/Internal/CoreStoreFetchedResultsController.swift

@@ -0,0 +1,101 @@
+//
+//  CoreStoreFetchedResultsController.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: - CoreStoreFetchedResultsController
+
+@available(OSX, unavailable)
+internal final class CoreStoreFetchedResultsController<T: NSManagedObject>: NSFetchedResultsController {
+    
+    
+    // MARK: Internal
+    
+    internal convenience init<T>(dataStack: DataStack, fetchRequest: NSFetchRequest, from: From<T>? = nil, sectionBy: SectionBy? = nil, fetchClauses: [FetchClause]) {
+        
+        self.init(
+            context: dataStack.mainContext,
+            fetchRequest: fetchRequest,
+            from: from,
+            sectionBy: sectionBy,
+            fetchClauses: fetchClauses
+        )
+    }
+    
+    internal init<T>(context: NSManagedObjectContext, fetchRequest: NSFetchRequest, from: From<T>? = nil, sectionBy: SectionBy? = nil, fetchClauses: [FetchClause]) {
+        
+        from?.applyToFetchRequest(fetchRequest, context: context, applyAffectedStores: false)
+        for clause in fetchClauses {
+            
+            clause.applyToFetchRequest(fetchRequest)
+        }
+        
+        if let from = from {
+            
+            self.reapplyAffectedStores = {
+                
+                return from.applyAffectedStoresForFetchedRequest(fetchRequest, context: context)
+            }
+        }
+        else {
+            
+            guard let from = (fetchRequest.entity.flatMap { $0.managedObjectClassName }).flatMap(NSClassFromString).flatMap(From.init) else {
+                
+                fatalError("Attempted to create an \(typeName(NSFetchedResultsController)) without a  From clause or an NSEntityDescription.")
+            }
+            
+            self.reapplyAffectedStores = {
+                
+                return from.applyAffectedStoresForFetchedRequest(fetchRequest, context: context)
+            }
+        }
+        
+        super.init(
+            fetchRequest: fetchRequest,
+            managedObjectContext: context,
+            sectionNameKeyPath: sectionBy?.sectionKeyPath,
+            cacheName: nil
+        )
+    }
+    
+    internal func performFetchFromSpecifiedStores() throws {
+        
+        if !self.reapplyAffectedStores() {
+            
+            CoreStore.log(
+                .Warning,
+                message: "Attempted to perform a fetch on an \(typeName(NSFetchedResultsController)) but could not find any persistent store for the entity \(typeName(self.fetchRequest.entityName))"
+            )
+        }
+        try self.performFetch()
+    }
+    
+    
+    // MARK: Private
+    
+    private let reapplyAffectedStores: () -> Bool
+}