Drop JRSwizzle dependency.

SwipeBack.podspec

@@ -10,6 +10,5 @@ Pod::Spec.new do |s|
   s.platform     = :ios, '7.0'
   s.requires_arc = true
   s.source_files = 'SwipeBack/*.{h,m}'
-  s.frameworks   = 'UIKit', 'Foundation', 'QuartzCore'
-  s.dependency 'JRSwizzle', '~> 1.0'
+  s.frameworks   = 'UIKit', 'Foundation'
 end

SwipeBack/UINavigationController+SwipeBack.h

@@ -24,6 +24,8 @@
 
 #import <UIKit/UIKit.h>
 
+void __swipeback_swizzle(Class cls, SEL originalSelector);
+
 @interface UINavigationController (SwipeBack) <UIGestureRecognizerDelegate>
 
 @property (nonatomic, assign) BOOL swipeBackEnabled; // default is `YES`

SwipeBack/UINavigationController+SwipeBack.m

@@ -22,37 +22,53 @@
 // SOFTWARE.
 //
 
-
-#import <JRSwizzle/JRSwizzle.h>
 #import <objc/runtime.h>
-
 #import "UINavigationController+SwipeBack.h"
 
 
+void __swipeback_swizzle(Class cls, SEL originalSelector) {
+    NSString *originalName = NSStringFromSelector(originalSelector);
+    NSString *alternativeName = [NSString stringWithFormat:@"swizzled_%@", originalName];
+
+    SEL alternativeSelector = NSSelectorFromString(alternativeName);
+
+    Method originalMethod = class_getInstanceMethod(cls, originalSelector);
+    Method alternativeMethod = class_getInstanceMethod(cls, alternativeSelector);
+
+    class_addMethod(cls,
+                    originalSelector,
+                    class_getMethodImplementation(cls, originalSelector),
+                    method_getTypeEncoding(originalMethod));
+    class_addMethod(cls,
+                    alternativeSelector,
+                    class_getMethodImplementation(cls, alternativeSelector),
+                    method_getTypeEncoding(alternativeMethod));
+
+    method_exchangeImplementations(class_getInstanceMethod(cls, originalSelector),
+                                   class_getInstanceMethod(cls, alternativeSelector));
+}
+
+
 @implementation UINavigationController (SwipeBack)
 
 + (void)load
 {
     static dispatch_once_t onceToken;
     dispatch_once(&onceToken, ^{
-        [self jr_swizzleMethod:@selector(viewDidLoad)
-                    withMethod:@selector(hack_viewDidLoad)
-                         error:nil];
-        [self jr_swizzleMethod:@selector(pushViewController:animated:)
-                    withMethod:@selector(hack_pushViewController:animated:)
-                         error:nil];
+        __swipeback_swizzle(self, @selector(viewDidLoad));
+        __swipeback_swizzle(self, @selector(pushViewController:animated:));
     });
 }
 
-- (void)hack_viewDidLoad
+- (void)swizzled_viewDidLoad
 {
-    [self hack_viewDidLoad];
+    [self swizzled_viewDidLoad];
     self.interactivePopGestureRecognizer.delegate = self.swipeBackEnabled ? self : nil;
 }
 
-- (void)hack_pushViewController:(UIViewController *)viewController animated:(BOOL)animated
+- (void)swizzled_pushViewController:(UIViewController *)viewController animated:(BOOL)animated
 {
-    [self hack_pushViewController:viewController animated:animated];
+    [self swizzled_pushViewController:viewController animated:animated];
     self.interactivePopGestureRecognizer.enabled = NO;
 }
 

SwipeBack/UIViewController+SwipeBack.m

@@ -22,28 +22,32 @@
 // SOFTWARE.
 //
 
-
-#import <JRSwizzle/JRSwizzle.h>
-
+#import <objc/runtime.h>
 #import "UINavigationController+SwipeBack.h"
 #import "UIViewController+SwipeBack.h"
 
-
 @implementation UIViewController (SwipeBack)
 
 + (void)load
 {
     static dispatch_once_t onceToken;
     dispatch_once(&onceToken, ^{
-        [self jr_swizzleMethod:@selector(viewDidAppear:)
-                    withMethod:@selector(hack_viewDidAppear:)
-                         error:nil];
+        __swipeback_swizzle(self, @selector(viewDidAppear:));
+//        [self swizzle:@selector(viewDidAppear:)];
     });
 }
 
-- (void)hack_viewDidAppear:(BOOL)animated
++ (void)swizzle:(SEL)selector
+{
+    NSString *name = [NSString stringWithFormat:@"swizzled_%@", NSStringFromSelector(selector)];
+    Method m1 = class_getInstanceMethod(self, selector);
+    Method m2 = class_getInstanceMethod(self, NSSelectorFromString(name));
+    method_exchangeImplementations(m1, m2);
+}
+
+- (void)swizzled_viewDidAppear:(BOOL)animated
 {
-    [self hack_viewDidAppear:animated];
+    [self swizzled_viewDidAppear:animated];
     self.navigationController.interactivePopGestureRecognizer.enabled = YES;
 }