here we go

HardcoreData/NSManagedObjectContext+HardcoreData.swift

@@ -0,0 +1,302 @@
+//
+//  NSManagedObjectContext+HardcoreData.swift
+//  HardcoreData
+//
+//  Copyright (c) 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
+import GCDKit
+
+private var _HardcoreData_NSManagedObjectContext_shouldCascadeSavesToParent: Void?
+
+public extension NSManagedObjectContext {
+    
+    // MARK: - Public
+    
+    // MARK: Transactions
+    
+    public func temporaryContext() -> NSManagedObjectContext {
+        
+        let context = NSManagedObjectContext(concurrencyType: .PrivateQueueConcurrencyType)
+        context.parentContext = self
+        context.setupForHardcoreDataWithContextName("com.hardcoredata.temporarycontext")
+        context.shouldCascadeSavesToParent = true
+        
+        return context
+    }
+    
+    
+    // MARK: Querying
+    
+    public func findFirst<T: NSManagedObject>(entity: T.Type) -> T? {
+        
+        return self.findFirst(T.self, predicate: NSPredicate(value: true))
+    }
+    
+    public func findFirst<T: NSManagedObject>(entity: T.Type, predicate: NSPredicate) -> T? {
+        
+        let fetchRequest = NSFetchRequest()
+        fetchRequest.entity = NSEntityDescription.entityForName(
+            entity.entityName,
+            inManagedObjectContext: self)
+        fetchRequest.fetchLimit = 1
+        
+        var fetchResults: [T]?
+        self.performBlockAndWait {
+            
+            var error: NSError?
+            fetchResults = self.executeFetchRequest(fetchRequest, error: &error) as? [T]
+            if fetchResults == nil {
+                
+                HardcoreData.handleError(
+                    error!,
+                    message: "Failed executing fetch request.")
+            }
+        }
+        
+        return fetchResults?.first
+    }
+
+    public func findAll<T: NSManagedObject>(entity: T.Type) -> [T]? {
+        
+        return self.findAll(QueryDescriptor<T>(entity: entity))
+    }
+    
+    public func findAll<T: NSManagedObject>(query: QueryDescriptor<T>) -> [T]? {
+        
+        let fetchRequest = NSFetchRequest()
+        fetchRequest.entity = NSEntityDescription.entityForName(
+            query.entityName,
+            inManagedObjectContext: self)
+        
+        var fetchResults: [T]?
+        self.performBlockAndWait {
+            
+            var error: NSError?
+            fetchResults = self.executeFetchRequest(fetchRequest, error: &error) as? [T]
+            if fetchResults == nil {
+                
+                HardcoreData.handleError(
+                    error!,
+                    message: "Failed executing fetch request.")
+            }
+        }
+        
+        return fetchResults
+    }
+    
+    
+    // MARK: - Internal
+    
+    internal func saveSynchronously() -> SaveResult {
+        
+        var result: SaveResult = SaveResult(hasChanges: false)
+        if !self.hasChanges {
+            
+            self.reset()
+            return result
+        }
+        
+        self.performBlockAndWait {
+            [unowned self] () -> () in
+            
+            var saveError: NSError?
+            if self.save(&saveError) {
+                
+                if self.shouldCascadeSavesToParent {
+                    
+                    if let parentContext = self.parentContext {
+                        
+                        switch parentContext.saveSynchronously() {
+                            
+                        case .Success(let hasChanges):
+                            result = SaveResult(hasChanges: true)
+                        case .Failure(let error):
+                            result = SaveResult(error)
+                        }
+                        return
+                    }
+                }
+                
+                result = SaveResult(hasChanges: true)
+            }
+            else if let error = saveError {
+                
+                HardcoreData.handleError(
+                    error,
+                    message: "Failed to save NSManagedObjectContext.")
+                result = SaveResult(error)
+            }
+            else {
+                
+                result = SaveResult(hasChanges: false)
+            }
+        }
+        
+        return result
+    }
+    
+    internal func saveAsynchronouslyWithCompletion(completion: ((result: SaveResult) -> ())?) {
+        
+        if !self.hasChanges {
+            
+            self.reset()
+            if let completion = completion {
+                
+                GCDBlock.async(.Main) {
+                    
+                    completion(result: SaveResult(hasChanges: false))
+                }
+            }
+            return
+        }
+        
+        self.performBlock {
+            [unowned self] () -> () in
+            
+            var saveError: NSError?
+            if self.save(&saveError) {
+                
+                if self.shouldCascadeSavesToParent {
+                    
+                    if let parentContext = self.parentContext {
+                        
+                        parentContext.saveAsynchronouslyWithCompletion(completion)
+                        return
+                    }
+                }
+                
+                if let completion = completion {
+                    
+                    GCDBlock.async(.Main) {
+                        
+                        completion(result: SaveResult(hasChanges: true))
+                    }
+                }
+            }
+            else if let error = saveError {
+                
+                HardcoreData.handleError(
+                    error,
+                    message: "Failed to save NSManagedObjectContext.")
+                if let completion = completion {
+                    
+                    GCDBlock.async(.Main) {
+                        
+                        completion(result: SaveResult(error))
+                    }
+                }
+            }
+            else if let completion = completion {
+                
+                GCDBlock.async(.Main) {
+                    
+                    completion(result: SaveResult(hasChanges: false))
+                }
+            }
+        }
+    }
+    
+    internal class func rootSavingContextForCoordinator(coordinator: NSPersistentStoreCoordinator) -> NSManagedObjectContext {
+        
+        let context = NSManagedObjectContext(concurrencyType: .PrivateQueueConcurrencyType)
+        context.persistentStoreCoordinator = coordinator
+        context.mergePolicy = NSMergeByPropertyObjectTrumpMergePolicy
+        context.setupForHardcoreDataWithContextName("com.hardcoredata.rootcontext")
+        
+        return context
+    }
+    
+    internal class func mainContextForRootContext(rootContext: NSManagedObjectContext) -> NSManagedObjectContext {
+        
+        let context = NSManagedObjectContext(concurrencyType: .MainQueueConcurrencyType)
+        context.parentContext = rootContext
+        context.setupForHardcoreDataWithContextName("com.hardcoredata.maincontext")
+        context.shouldCascadeSavesToParent = true
+        context.registerForNotificationsWithName(
+            NSManagedObjectContextDidSaveNotification,
+            fromObject: rootContext,
+            targetQueue: NSOperationQueue.mainQueue()) {
+            [unowned context] (note) -> () in
+                
+            context.mergeChangesFromContextDidSaveNotification(note)
+        }
+        
+        return context
+    }
+    
+    
+    // MARK: - Private
+    
+    private var shouldCascadeSavesToParent: Bool {
+        
+        get {
+            
+            if let value = objc_getAssociatedObject(self, &_HardcoreData_NSManagedObjectContext_shouldCascadeSavesToParent) as? NSNumber {
+                
+                return value.boolValue
+            }
+            return false
+        }
+        set {
+            
+            objc_setAssociatedObject(
+                self,
+                &_HardcoreData_NSManagedObjectContext_shouldCascadeSavesToParent,
+                newValue,
+                objc_AssociationPolicy(OBJC_ASSOCIATION_ASSIGN))
+        }
+    }
+    
+    private func setupForHardcoreDataWithContextName(contextName: String) {
+        
+        if self.respondsToSelector("setName:") {
+            
+            self.name = contextName
+        }
+        
+        self.registerForNotificationsWithName(NSManagedObjectContextWillSaveNotification, fromObject: self) {
+            (note) -> () in
+            
+            let context: NSManagedObjectContext = note.object as NSManagedObjectContext
+            let insertedObjects = context.insertedObjects
+            if insertedObjects.count <= 0 {
+                
+                return
+            }
+            
+            var permanentIDError: NSError?
+            if context.obtainPermanentIDsForObjects(insertedObjects.allObjects, error: &permanentIDError) {
+                
+                return
+            }
+            
+            if let error = permanentIDError {
+                
+                HardcoreData.handleError(
+                    error,
+                    message: "Failed to obtain permanent IDs for inserted objects.")
+            }
+        }
+    }
+}