Adding timing capabilities to clean memory (#5)

Adding timing capabilities to clean memory
This will enable projects to time how long garbage collection is taking

ConsistencyManager/ConsistencyManager.swift

@@ -65,6 +65,22 @@ public class ConsistencyManager {
      */
     public var garbageCollectionInterval: NSTimeInterval = 300
 
+    // MARK: Constants
+
+    /**
+     This notification is fired whenever the asynchronous work of clean memory starts.
+     It's useful if you want to add timers to this work.
+     Called on an internal thread.
+    */
+    public static let kCleanMemoryAsynchronousWorkStarted = "com.linkedin.consistencyManager.kCleanMemoryAsynchronousWorkStarted"
+
+    /**
+     This notification is fired whenever the asynchronous work of clean memory finishes.
+     It's useful if you want to add timers to this work.
+     Called on an internal thread.
+     */
+    public static let kCleanMemoryAsynchronousWorkFinished = "com.linkedin.consistencyManager.kCleanMemoryAsynchronousWorkFinished"
+
     // MARK: - Private ivars
 
     /**
@@ -343,6 +359,7 @@ public class ConsistencyManager {
     */
     public func cleanMemory() {
         dispatch_async(dispatchQueue) {
+            NSNotificationCenter.defaultCenter().postNotificationName(ConsistencyManager.kCleanMemoryAsynchronousWorkStarted, object: self)
             for (key, var listenersArray) in self.listeners {
                 listenersArray.prune()
                 // If the array has no elements now, let's remove it from the dictionary
@@ -353,6 +370,7 @@ public class ConsistencyManager {
                     self.listeners[key] = listenersArray
                 }
             }
+            NSNotificationCenter.defaultCenter().postNotificationName(ConsistencyManager.kCleanMemoryAsynchronousWorkFinished, object: self)
         }
         // Remove any PausedListener structs from our local list if the internal listener is now nil
         pausedListeners = self.pausedListeners.filter { $0.listener != nil }

ConsistencyManagerTests/MemoryWarningTests.swift

@@ -13,7 +13,21 @@ import XCTest
 
 class MemoryWarningTests: ConsistencyManagerTestCase {
 
+    var cleanMemoryStartedTimes = [NSDate]()
+    var cleanMemoryFinishedTimes = [NSDate]()
+
+
     func testMemoryWarning() {
+        let testStart = NSDate()
+
+        NSNotificationCenter.defaultCenter().addObserverForName(ConsistencyManager.kCleanMemoryAsynchronousWorkStarted, object: nil, queue: nil) { _ in
+            self.cleanMemoryStartedTimes.append(NSDate())
+        }
+
+        NSNotificationCenter.defaultCenter().addObserverForName(ConsistencyManager.kCleanMemoryAsynchronousWorkFinished, object: nil, queue: nil) { _ in
+            self.cleanMemoryFinishedTimes.append(NSDate())
+        }
+
         let model = TestRequiredModel(id: "0", data: 0)
 
         // Setting this up with a block ensures that the listener will be released and is out of scope.
@@ -42,5 +56,11 @@ class MemoryWarningTests: ConsistencyManagerTestCase {
             XCTAssertEqual(listenersArray.count, 0)
         }
         // Else it's nil which is fine too
+
+        // Now, let's check we got the right start/finish times
+        XCTAssertEqual(cleanMemoryStartedTimes.count, 1)
+        XCTAssertEqual(cleanMemoryFinishedTimes.count, 1)
+        XCTAssertTrue(cleanMemoryStartedTimes[0].timeIntervalSince1970 <= cleanMemoryFinishedTimes[0].timeIntervalSince1970)
+        XCTAssertTrue(testStart.timeIntervalSince1970 <= cleanMemoryStartedTimes[0].timeIntervalSince1970)
     }
 }