Enforcing class objects as arguments

ASHook/ASHook+BlockInsert.h

@@ -14,20 +14,20 @@
  * Runs the given block on the target just before the given selector gets called.
  *
  * @param block The block that will run.
- * @param hookTarget The instance or class where the selector can be found.
+ * @param hookTarget The class object where the selector can be found.
  * @param hookSelector The original selector that will trigger the block.
  *
  */
-+ (void)runBlock:(void (^)(__unsafe_unretained id _self))block onTarget:(id)hookTarget beforeInstanceSelector:(SEL)hookSelector;
++ (void)runBlock:(void (^)(__unsafe_unretained id _self))block onTarget:(Class)hookTarget beforeInstanceSelector:(SEL)hookSelector;
 
 /**
  * Runs the given block on the target just before the given selector gets called.
  *
  * @param block The block that will run.
- * @param hookTarget The instance or class where the selector can be found.
+ * @param hookTarget The class object where the selector can be found.
  * @param hookSelector The original selector that will trigger the block.
  *
  */
-+ (void)runBlock:(void (^)(__unsafe_unretained id _self))block onTarget:(id)hookTarget beforeClassSelector:(SEL)hookSelector;
++ (void)runBlock:(void (^)(__unsafe_unretained id _self))block onTarget:(Class)hookTarget beforeClassSelector:(SEL)hookSelector;
 
 @end

ASHook/ASHook+BlockInsert.m

@@ -13,7 +13,7 @@
 
 @interface ASHook ()
 
-+ (void)swizzle:(id)swizzleTarget
++ (void)swizzle:(Class)swizzleTarget
        selector:(SEL)originalSelector
     newSelector:(SEL)newSelector
  originalMethod:(Method)originalMethod
@@ -25,18 +25,19 @@ @implementation ASHook (BlockInsert)
 
 #pragma mark - Public methods
 
-+ (void)runBlock:(void (^)(__unsafe_unretained id _self))block onTarget:(id)hookTarget beforeInstanceSelector:(SEL)hookSelector {
-    id target = [hookTarget class];
-    Method originalMethod = class_getInstanceMethod(target, hookSelector);
-    SEL newSelector = [self insertBlock:block onTarget:target originalSelector:hookSelector originalMethod:originalMethod];
++ (void)runBlock:(void (^)(__unsafe_unretained id _self))block onTarget:(Class)hookTarget beforeInstanceSelector:(SEL)hookSelector {
+    assert((hookTarget && hookTarget == [hookTarget class]) && "Plese use a class as the target.");
+    Method originalMethod = class_getInstanceMethod(hookTarget, hookSelector);
+    SEL newSelector = [self insertBlock:block onTarget:hookTarget originalSelector:hookSelector originalMethod:originalMethod];
     if (newSelector) {
-        Method newMethod = class_getInstanceMethod(target, newSelector);
-        [ASHook swizzle:target selector:hookSelector newSelector:newSelector originalMethod:originalMethod newMethod:newMethod];
+        Method newMethod = class_getInstanceMethod(hookTarget, newSelector);
+        [ASHook swizzle:hookTarget selector:hookSelector newSelector:newSelector originalMethod:originalMethod newMethod:newMethod];
     }
 }
 
-+ (void)runBlock:(void (^)(__unsafe_unretained id _self))block onTarget:(id)hookTarget beforeClassSelector:(SEL)hookSelector {
-    id target = object_getClass([hookTarget class]);
++ (void)runBlock:(void (^)(__unsafe_unretained id _self))block onTarget:(Class)hookTarget beforeClassSelector:(SEL)hookSelector {
+    assert((hookTarget && hookTarget == [hookTarget class]) && "Plese use a class as the target.");
+    id target = object_getClass(hookTarget);
     Method originalMethod = class_getClassMethod(target, hookSelector);
     SEL newSelector = [self insertBlock:block onTarget:target originalSelector:hookSelector originalMethod:originalMethod];
     if (newSelector) {
@@ -49,7 +50,7 @@ + (void)runBlock:(void (^)(__unsafe_unretained id _self))block onTarget:(id)hook
 
 /*! @brief Creating and adding a new implementation for the original method with the block included. */
 + (SEL)insertBlock:(void (^)(__unsafe_unretained id _self))block
-          onTarget:(id)target
+          onTarget:(Class)target
 originalSelector:(SEL)originalSelector
   originalMethod:(Method)originalMethod {
     NSString *swizzledMethodSuffix = @"_ASMethodSwizzled";

ASHook/ASHook+MethodSwizzler.h

@@ -13,21 +13,21 @@
 /**
  * Replaces the implementations of the two given instance selectors in a class object.
  *
- * @param swizzleTarget The target (instance or class) where you want to replace selectors.
+ * @param swizzleTarget The target class object where you want to replace selectors.
  * @param originalSelector The original selector that is to be replaced.
  * @param newSelector The new selector will replace the original selector's implementation.
  *
  */
-+ (void)swizzle:(id)swizzleTarget instanceSelector:(SEL)originalSelector withInstanceSelector:(SEL)newSelector;
++ (void)swizzle:(Class)swizzleTarget instanceSelector:(SEL)originalSelector withInstanceSelector:(SEL)newSelector;
 
 /**
  * Replaces the implementations of the two given class selectors in a class object.
  *
- * @param swizzleTarget The target (instance or class) where you want to replace selectors.
+ * @param swizzleTarget The target class object where you want to replace selectors.
  * @param originalSelector The original selector that is to be replaced.
  * @param newSelector The new selector will replace the original selector's implementation.
  *
  */
-+ (void)swizzle:(id)swizzleTarget classSelector:(SEL)originalSelector withClassSelector:(SEL)newSelector;
++ (void)swizzle:(Class)swizzleTarget classSelector:(SEL)originalSelector withClassSelector:(SEL)newSelector;
 
 @end

ASHook/ASHook+MethodSwizzler.m

@@ -14,23 +14,24 @@ @implementation ASHook (MethodSwizzler)
 
 #pragma mark - Public methods
 
-+ (void)swizzle:(id)swizzleTarget instanceSelector:(SEL)originalSelector withInstanceSelector:(SEL)newSelector {
-    id target = [swizzleTarget class];
-    Method originalMethod = class_getInstanceMethod(target, originalSelector);
-    Method newMethod = class_getInstanceMethod(target, newSelector);
-    [self swizzle:target selector:originalSelector newSelector:newSelector originalMethod:originalMethod newMethod:newMethod];
++ (void)swizzle:(Class)swizzleTarget instanceSelector:(SEL)originalSelector withInstanceSelector:(SEL)newSelector {
+    assert((swizzleTarget && swizzleTarget == [swizzleTarget class]) && "Plese use a class as the target.");
+    Method originalMethod = class_getInstanceMethod(swizzleTarget, originalSelector);
+    Method newMethod = class_getInstanceMethod(swizzleTarget, newSelector);
+    [self swizzle:swizzleTarget selector:originalSelector newSelector:newSelector originalMethod:originalMethod newMethod:newMethod];
 }
 
-+ (void)swizzle:(id)swizzleTarget classSelector:(SEL)originalSelector withClassSelector:(SEL)newSelector {
-    id target = object_getClass([swizzleTarget class]);
++ (void)swizzle:(Class)swizzleTarget classSelector:(SEL)originalSelector withClassSelector:(SEL)newSelector {
+    assert((swizzleTarget && swizzleTarget == [swizzleTarget class]) && "Plese use a class as the target.");
+    id target = object_getClass(swizzleTarget);
     Method originalMethod = class_getClassMethod(target, originalSelector);
     Method newMethod = class_getClassMethod(target, newSelector);
     [self swizzle:target selector:originalSelector newSelector:newSelector originalMethod:originalMethod newMethod:newMethod];
 }
 
 #pragma mark - Private methods
 
-+ (void)swizzle:(id)target
++ (void)swizzle:(Class)target
        selector:(SEL)originalSelector
     newSelector:(SEL)newSelector
  originalMethod:(Method)originalMethod

ASHookDemo/ASHookDemo/AppDelegate.m

@@ -34,6 +34,11 @@ + (void)initialize {
     [ASHook runBlock:^(__unsafe_unretained id _self) {
         NSLog(@"alloc will run on %@ - will there be any funny messages in it?", _self);
     } onTarget:[EvilSingleton class] beforeClassSelector:@selector(alloc)];
+
+    // Example 5: Lifecycle
+    [ASHook swizzle:[[EvilSingleton sharedInstance] class] instanceSelector:@selector(shouldSingletonsBeUsedInAproject) withInstanceSelector:@selector(printNever)];
+    NSLog(@"Should I use singletons?");
+    [[EvilSingleton sharedInstance] shouldSingletonsBeUsedInAproject];
 }
 
 - (void)applicationDidFinishLaunching:(NSNotification *)notification {