Swiftgram/Display/RuntimeUtils.m

#import "RuntimeUtils.h"

#import <objc/runtime.h>

@implementation RuntimeUtils

+ (void)swizzleInstanceMethodOfClass:(Class)targetClass currentSelector:(SEL)currentSelector newSelector:(SEL)newSelector {
    Method origMethod = nil, newMethod = nil;
    
    origMethod = class_getInstanceMethod(targetClass, currentSelector);
    newMethod = class_getInstanceMethod(targetClass, newSelector);
    if ((origMethod != nil) && (newMethod != nil)) {
        if(class_addMethod(targetClass, currentSelector, method_getImplementation(newMethod), method_getTypeEncoding(newMethod))) {
            class_replaceMethod(targetClass, newSelector, method_getImplementation(origMethod), method_getTypeEncoding(origMethod));
        } else {
            method_exchangeImplementations(origMethod, newMethod);
        }
    }
}

+ (void)swizzleInstanceMethodOfClass:(Class)targetClass currentSelector:(SEL)currentSelector withAnotherClass:(Class)anotherClass newSelector:(SEL)newSelector {
    Method origMethod = nil, newMethod = nil;
    
    origMethod = class_getInstanceMethod(targetClass, currentSelector);
    newMethod = class_getInstanceMethod(anotherClass, newSelector);
    if ((origMethod != nil) && (newMethod != nil)) {
        method_exchangeImplementations(origMethod, newMethod);
    }
}

+ (void)swizzleClassMethodOfClass:(Class)targetClass currentSelector:(SEL)currentSelector newSelector:(SEL)newSelector {
    Method origMethod = nil, newMethod = nil;
    
    origMethod = class_getClassMethod(targetClass, currentSelector);
    newMethod = class_getClassMethod(targetClass, newSelector);
    
    targetClass = object_getClass((id)targetClass);
    
    if ((origMethod != nil) && (newMethod != nil)) {
        if(class_addMethod(targetClass, currentSelector, method_getImplementation(newMethod), method_getTypeEncoding(newMethod))) {
            class_replaceMethod(targetClass, newSelector, method_getImplementation(origMethod), method_getTypeEncoding(origMethod));
        } else {
            method_exchangeImplementations(origMethod, newMethod);
        }
    }
}

@end

@implementation NSObject (AssociatedObject)

- (void)setAssociatedObject:(id)object forKey:(void const *)key
{
    [self setAssociatedObject:object forKey:key associationPolicy:NSObjectAssociationPolicyRetain];
}

- (void)setAssociatedObject:(id)object forKey:(void const *)key associationPolicy:(NSObjectAssociationPolicy)associationPolicy
{
    int policy = 0;
    switch (associationPolicy)
    {
        case NSObjectAssociationPolicyRetain:
            policy = OBJC_ASSOCIATION_RETAIN_NONATOMIC;
            break;
        case NSObjectAssociationPolicyCopy:
            policy = OBJC_ASSOCIATION_COPY_NONATOMIC;
            break;
        default:
            policy = OBJC_ASSOCIATION_RETAIN_NONATOMIC;
            break;
    }
    objc_setAssociatedObject(self, key, object, policy);
}

- (id)associatedObjectForKey:(void const *)key
{
    return objc_getAssociatedObject(self, key);
}

- (bool)checkObjectIsKindOfClass:(Class)targetClass {
    return [self isKindOfClass:targetClass];
}

- (void)setClass:(Class)newClass {
    object_setClass(self, newClass);
}

static Class freedomMakeClass(Class superclass, Class subclass, SEL *copySelectors, int copySelectorsCount)
{
    if (superclass == Nil || subclass == Nil)
        return nil;
    
    Class decoratedClass = objc_allocateClassPair(superclass, [[NSString alloc] initWithFormat:@"%@_%@", NSStringFromClass(superclass), NSStringFromClass(subclass)].UTF8String, 0);
    
    unsigned int count = 0;
    Method *methodList = class_copyMethodList(subclass, &count);
    if (methodList != NULL) {
        for (unsigned int i = 0; i < count; i++) {
            SEL methodName = method_getName(methodList[i]);
            class_addMethod(decoratedClass, methodName, method_getImplementation(methodList[i]), method_getTypeEncoding(methodList[i]));
        }
        
        free(methodList);
    }
    
    objc_registerClassPair(decoratedClass);
    
    return decoratedClass;
}

@end