Added unit tests for zeroing weak references

CoconutKit-test/CoconutKit-test.xcodeproj/project.pbxproj

@@ -32,6 +32,7 @@
 		6F4D6B6014EE7CD50002F09B /* GHUnitIOS.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 6F4D6B5F14EE7CD50002F09B /* GHUnitIOS.framework */; };
 		6F61D12E14161E4C004C91F5 /* NSTimeZone+HLSExtensionsTestCase.m in Sources */ = {isa = PBXBuildFile; fileRef = 6F61D12D14161E4C004C91F5 /* NSTimeZone+HLSExtensionsTestCase.m */; };
 		6F7B848B14CF32B20091EE4B /* UIActionSheet+HLSExtensions.m in Sources */ = {isa = PBXBuildFile; fileRef = 6F7B848A14CF32B20091EE4B /* UIActionSheet+HLSExtensions.m */; };
+		6F897873152B505D006C8231 /* HLSZeroingWeakRefTestCase.m in Sources */ = {isa = PBXBuildFile; fileRef = 6F897872152B505D006C8231 /* HLSZeroingWeakRefTestCase.m */; };
 		6F91452A14CEBDF100AFA609 /* UIBarButtonItem+HLSActionSheet.m in Sources */ = {isa = PBXBuildFile; fileRef = 6F91452914CEBDF100AFA609 /* UIBarButtonItem+HLSActionSheet.m */; };
 		6F91F77314F3EF0B00E95EFA /* UIViewController+HLSExtensions.m in Sources */ = {isa = PBXBuildFile; fileRef = 6F91F77214F3EF0B00E95EFA /* UIViewController+HLSExtensions.m */; };
 		6F93C4CE1404287400FEC9B0 /* HLSFloatTestCase.m in Sources */ = {isa = PBXBuildFile; fileRef = 6F93C4CD1404287400FEC9B0 /* HLSFloatTestCase.m */; };
@@ -172,6 +173,8 @@
 		6F61D12D14161E4C004C91F5 /* NSTimeZone+HLSExtensionsTestCase.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = "NSTimeZone+HLSExtensionsTestCase.m"; sourceTree = "<group>"; };
 		6F7B848914CF32B20091EE4B /* UIActionSheet+HLSExtensions.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = "UIActionSheet+HLSExtensions.h"; sourceTree = "<group>"; };
 		6F7B848A14CF32B20091EE4B /* UIActionSheet+HLSExtensions.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = "UIActionSheet+HLSExtensions.m"; sourceTree = "<group>"; };
+		6F897871152B505D006C8231 /* HLSZeroingWeakRefTestCase.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = HLSZeroingWeakRefTestCase.h; sourceTree = "<group>"; };
+		6F897872152B505D006C8231 /* HLSZeroingWeakRefTestCase.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = HLSZeroingWeakRefTestCase.m; sourceTree = "<group>"; };
 		6F91452714CEBDF100AFA609 /* HLSActionSheet+Friend.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = "HLSActionSheet+Friend.h"; sourceTree = "<group>"; };
 		6F91452814CEBDF100AFA609 /* UIBarButtonItem+HLSActionSheet.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = "UIBarButtonItem+HLSActionSheet.h"; sourceTree = "<group>"; };
 		6F91452914CEBDF100AFA609 /* UIBarButtonItem+HLSActionSheet.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = "UIBarButtonItem+HLSActionSheet.m"; sourceTree = "<group>"; };
@@ -518,6 +521,8 @@
 				6F93C4CD1404287400FEC9B0 /* HLSFloatTestCase.m */,
 				6F3B060A14BC4C2D0026F512 /* HLSValidatorsTestCase.h */,
 				6F3B060B14BC4C2D0026F512 /* HLSValidatorsTestCase.m */,
+				6F897871152B505D006C8231 /* HLSZeroingWeakRefTestCase.h */,
+				6F897872152B505D006C8231 /* HLSZeroingWeakRefTestCase.m */,
 				6F33351413FB7F80000FC9FD /* NSCalendar+HLSExtensionsTestCase.h */,
 				6F33351513FB7F80000FC9FD /* NSCalendar+HLSExtensionsTestCase.m */,
 				6F33351613FB7F80000FC9FD /* NSDate+HLSExtensionsTestCase.h */,
@@ -1008,6 +1013,7 @@
 				6FB991FE1523B18B00E13BED /* HLSZeroingWeakRef.m in Sources */,
 				6FDDEC131529776000CED462 /* UITextField+HLSExtensions.m in Sources */,
 				6FDDEC251529782500CED462 /* UITextView+HLSExtensions.m in Sources */,
+				6F897873152B505D006C8231 /* HLSZeroingWeakRefTestCase.m in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};

CoconutKit-test/Sources/Core/HLSZeroingWeakRefTestCase.h

@@ -0,0 +1,11 @@
+//
+//  HLSZeroingWeakRefTestCase.h
+//  CoconutKit-test
+//
+//  Created by Samuel Défago on 03.04.12.
+//  Copyright (c) 2012 Hortis. All rights reserved.
+//
+
+@interface HLSZeroingWeakRefTestCase : GHTestCase
+
+@end

CoconutKit-test/Sources/Core/HLSZeroingWeakRefTestCase.m

@@ -0,0 +1,39 @@
+//
+//  HLSZeroingWeakRefTestCase.m
+//  CoconutKit-test
+//
+//  Created by Samuel Défago on 03.04.12.
+//  Copyright (c) 2012 Hortis. All rights reserved.
+//
+
+#import "HLSZeroingWeakRefTestCase.h"
+
+@interface BasicClass : NSObject
+
+@end
+
+@implementation HLSZeroingWeakRefTestCase
+
+#pragma mark Tests
+
+- (void)testNonTollFreeBridgedObject
+{
+    BasicClass *basicClass = [[BasicClass alloc] init];
+    HLSZeroingWeakRef *zeroingWeakRef = [[[HLSZeroingWeakRef alloc] initWithObject:basicClass] autorelease];
+    GHAssertNotNil(zeroingWeakRef.object, @"Non-zeroed object reference");
+    [basicClass release];
+    GHAssertNil(zeroingWeakRef.object, @"Zeroed object reference");
+}
+
+- (void)testTollFreeBridgedObject
+{
+    NSNumber *number = [[NSNumber alloc] initWithInt:1012];
+    GHAssertThrows([[HLSZeroingWeakRef alloc] initWithObject:number], @"Cannot create from Core Foundation objects");
+    [number release];
+}
+
+@end
+
+@implementation BasicClass
+
+@end

CoconutKit/Sources/Core/HLSZeroingWeakRef.h

@@ -13,7 +13,17 @@
  * way to execute custom code before the reference is zeroed. This is especially useful when it makes
  * sense to proactively stop some process whose delegate gets deallocated, for example.
  *
- * HLSZeroingWeakRef instances must be retained by the objects which store them
+ * HLSZeroingWeakRef instances must be retained by the objects which store them.
+ *
+ * The current implementation of HLSZeroingWeakRef is fairly basic:
+ *   - zeroing weak references to toll-free bridged objects (NSString, NSURL, NSNumber, etc.) are not 
+ *     supported. Attempting to initialize a zeroing weak with a toll-free bridged object results in 
+ *     an exception being thrown
+ *   - thread-safety issues have been ignored
+ *
+ * This implementation should suffice in most cases (weak pointers to instances of custom Objective-C 
+ * classes, accessed from a single thread). In other cases, consider using Mike Ash implementation
+ * found at https://github.com/mikeash/MAZeroingWeakRef or ARC zeroing weak references.
  */
 @interface HLSZeroingWeakRef : NSObject {
 @private
@@ -22,8 +32,8 @@
 }
 
 /**
- * Initialize a weak reference to an object. When the object gets deallocated, the weak reference object
- * is automatically set to nil
+ * Initialize a weak reference to an Objective-C object (throws an exception if object is a toll-free
+ * bridged object)
  */
 - (id)initWithObject:(id)object;
 

CoconutKit/Sources/Core/HLSZeroingWeakRef.m

@@ -35,13 +35,24 @@ - (id)initWithObject:(id)object
         self.invocations = [NSMutableArray array];
         self.object = object;
 
-        if (self.object) {
+        if (object) {
             static NSString * const kSubclassPrefix = @"HLSZeroingWeakRef_";
 
+            // Access the real class, do not use [self class] here since can be faked
+            Class class = object_getClass(object);
+
+            // No support for Core Foundation objects (lead to infinite recursion)
+            // For more information, see
+            //   http://www.mikeash.com/pyblog/friday-qa-2010-01-22-toll-free-bridging-internals.html
+            if ([NSStringFromClass(class) hasPrefix: @"__NSCF"]) {
+                @throw [NSException exceptionWithName:NSInvalidArgumentException 
+                                               reason:@"Cannot create zeroing weak references to toll-free bridged objects"
+                                             userInfo:nil];
+            }
+
             // Dynamically subclass the object class to override -dealloc selectively, and use this class instead.
             // Another approach would involve swizzling -dealloc at the NSObject level, but this solution would 
             // incur an unacceptable overhead on all NSObjects
-            Class class = object_getClass(object);      // Access the real class, do not use [self class] here since can be faked
             NSString *className = [NSString stringWithUTF8String:class_getName(class)];
             if (! [className hasPrefix:kSubclassPrefix]) {
                 NSString *subclassName = [kSubclassPrefix stringByAppendingString:className];