Objective-C的runtime应用

// 获取类的类名
const char * class_getName ( Class cls );
Raw

// 获取类的父类
Class class_getSuperclass ( Class cls );
 
// 判断给定的Class是否是一个元类
BOOL class_isMetaClass ( Class cls );

// 获取实例大小
size_t class_getInstanceSize ( Class cls );

// 获取类中指定名称实例成员变量的信息
Ivar class_getInstanceVariable ( Class cls, const char *name );
 
// 获取类成员变量的信息
Ivar class_getClassVariable ( Class cls, const char *name );
 
// 添加成员变量
BOOL class_addIvar ( Class cls, const char *name, size_t size, uint8_t alignment, const char *types );
 
// 获取整个成员变量列表
Ivar * class_copyIvarList ( Class cls, unsigned int *outCount );

// 获取指定的属性
objc_property_t class_getProperty ( Class cls, const char *name );
 
// 获取属性列表
objc_property_t * class_copyPropertyList ( Class cls, unsigned int *outCount );
 
// 为类添加属性
BOOL class_addProperty ( Class cls, const char *name, const objc_property_attribute_t *attributes, unsigned int attributeCount );
 
// 替换类的属性
void class_replaceProperty ( Class cls, const char *name, const objc_property_attribute_t *attributes, unsigned int attributeCount );

const uint8_t * class_getIvarLayout ( Class cls );
void class_setIvarLayout ( Class cls, const uint8_t *layout );
const uint8_t * class_getWeakIvarLayout ( Class cls );
void class_setWeakIvarLayout ( Class cls, const uint8_t *layout );
Raw

// 添加方法
BOOL class_addMethod ( Class cls, SEL name, IMP imp, const char *types );
 
// 获取实例方法
Method class_getInstanceMethod ( Class cls, SEL name );
 
// 获取类方法
Method class_getClassMethod ( Class cls, SEL name );
 
// 获取所有方法的数组
Method * class_copyMethodList ( Class cls, unsigned int *outCount );
 
// 替代方法的实现
IMP class_replaceMethod ( Class cls, SEL name, IMP imp, const char *types );
 
// 返回方法的具体实现
IMP class_getMethodImplementation ( Class cls, SEL name );
IMP class_getMethodImplementation_stret ( Class cls, SEL name );
 
// 类实例是否响应指定的selector
BOOL class_respondsToSelector ( Class cls, SEL sel );

void myMethodIMP(id self, SEL _cmd)
{
    // implementation ....
}

// 添加协议
BOOL class_addProtocol ( Class cls, Protocol *protocol );
 
// 返回类是否实现指定的协议
BOOL class_conformsToProtocol ( Class cls, Protocol *protocol );
 
// 返回类实现的协议列表
Protocol * class_copyProtocolList ( Class cls, unsigned int *outCount );

// 获取版本号
int class_getVersion ( Class cls );
 
// 设置版本号
void class_setVersion ( Class cls, int version );


// 通常我们不直接使用这两个函数
Class objc_getFutureClass ( const char *name );
void objc_setFutureClass ( Class cls, const char *name );

@interface MyClass : NSObject <NSCopying, NSCoding>

@property (nonatomic, strong) NSArray *array;

@property (nonatomic, copy) NSString *string;

- (void)method1;

- (void)method2;

+ (void)classMethod;

@end

@interface MyClass () {
    NSInteger       _instance1;
    
    NSString *_instance2;
}

@property (nonatomic, assign) NSUInteger integer;

- (void)method3WithArg1:(NSInteger)arg1 arg2:(NSString *)arg2;

@end

@implementation MyClass
+ (void)classMethod {

}

- (void)method1 {
    NSLog(@"call method method1");
}

- (void)method2 {
}

- (void)method3WithArg1:(NSInteger)arg1 arg2:(NSString *)arg2 {
    NSLog(@"arg1 : %ld, arg2 : %@", arg1, arg2);
}
@end

- (void)runtimeTest1 {
    MyClass *myClass = [[MyClass alloc] init];
    unsigned int outCount = 0;
    
    Class cls = [myClass class];
    
    // 类名
    NSLog(@"-----%@-----", @"类名");
    NSLog(@"class name: %s \n", class_getName(cls));
    
    // 父类
    NSLog(@" ");
    NSLog(@"-----%@-----", @"父类");
    NSLog(@"super class name: %s", class_getName(class_getSuperclass(cls)));
    
    // 是否是元类
    NSLog(@" ");
    NSLog(@"-----%@-----", @"是否是元类");
    NSLog(@"MyClass is %@ a meta-class", (class_isMetaClass(cls) ? @"" : @"not"));
    
    Class meta_class = objc_getMetaClass(class_getName(cls));
    NSLog(@"%s's meta-class is %s", class_getName(cls), class_getName(meta_class));
    
    // 变量实例大小
    NSLog(@" ");
    NSLog(@"-----%@-----", @"变量实例大小");
    NSLog(@"instance size: %zu", class_getInstanceSize(cls));
    
    // 成员变量
    NSLog(@" ");
    NSLog(@"-----%@-----", @"成员变量");
    Ivar *ivars = class_copyIvarList(cls, &outCount);
    for (int i = 0; i < outCount; i++) {
        Ivar ivar = ivars[i];
        NSLog(@"instance variable's name: %s at index: %d", ivar_getName(ivar), i);
    }
    
    free(ivars);
    
    Ivar string = class_getInstanceVariable(cls, "_string");
    if (string != NULL) {
        NSLog(@"instace variable %s", ivar_getName(string));
    }
    
    // 属性操作
    NSLog(@" ");
    NSLog(@"-----%@-----", @"属性操作");
    objc_property_t * properties = class_copyPropertyList(cls, &outCount);
    for (int i = 0; i < outCount; i++) {
        objc_property_t property = properties[i];
        NSLog(@"property's name: %s", property_getName(property));
    }
    
    free(properties);
    
    objc_property_t array = class_getProperty(cls, "array");
    if (array != NULL) {
        NSLog(@"property %s", property_getName(array));
    }
    
    
    // 方法操作
    NSLog(@" ");
    NSLog(@"-----%@-----", @"方法操作");
    Method *methods = class_copyMethodList(cls, &outCount);
    for (int i = 0; i < outCount; i++) {
        Method method = methods[i];
        NSLog(@"method's signature: %s", sel_getName(method_getName(method)));
    }
    
    free(methods);
    
    Method method1 = class_getInstanceMethod(cls, @selector(method1));
    if (method1 != NULL) {
        NSLog(@"method %s", sel_getName(method_getName(method1)));
    }
    
    Method classMethod = class_getClassMethod(cls, @selector(classMethod));
    if (classMethod != NULL) {
        NSLog(@"class method : %s", sel_getName(method_getName(classMethod)));
    }
    
    NSLog(@"MyClass is%@ responsd to selector: method3WithArg1:arg2:", class_respondsToSelector(cls, @selector(method3WithArg1:arg2:)) ? @"" : @" not");
    
    IMP imp = class_getMethodImplementation(cls, @selector(method1));
    imp();
    
    // 协议
    NSLog(@" ");
    NSLog(@"-----%@-----", @"协议");
    Protocol * __unsafe_unretained * protocols = class_copyProtocolList(cls, &outCount);
    Protocol * protocol;
    for (int i = 0; i < outCount; i++) {
        protocol = protocols[i];
        NSLog(@"protocol name: %s", protocol_getName(protocol));
    }
    
    NSLog(@"MyClass is%@ responsed to protocol %s", class_conformsToProtocol(cls, protocol) ? @"" : @" not", protocol_getName(protocol));
}

// 创建一个新类和元类
Class objc_allocateClassPair ( Class superclass, const char *name, size_t extraBytes );
 
// 销毁一个类及其相关联的类
void objc_disposeClassPair ( Class cls );
 
// 在应用中注册由objc_allocateClassPair创建的类
void objc_registerClassPair ( Class cls );

- (void)runtimeTest2 {
    Class cls = objc_allocateClassPair(MyClass.class, "MySubClass", 0);
    class_addMethod(cls, @selector(submethod1), (IMP)imp_submethod1, "v@:");
    class_replaceMethod(cls, @selector(method1), (IMP)imp_submethod1, "v@:");
    class_addIvar(cls, "_ivar1", sizeof(NSString *), log(sizeof(NSString *)), "i");
    
    objc_property_attribute_t type = {"T", "@\"NSString\""};
    objc_property_attribute_t ownership = { "C", "" };
    objc_property_attribute_t backingivar = { "V", "_ivar1"};
    objc_property_attribute_t attrs[] = {type, ownership, backingivar};
    
    class_addProperty(cls, "property2", attrs, 3);
    objc_registerClassPair(cls);
    
    id instance = [[cls alloc] init];
    [instance performSelector:@selector(submethod1)];
    [instance performSelector:@selector(method1)];
}

void imp_submethod1(id self,SEL _cmd){
    NSLog(@"run sub method1:%p",_cmd);
}

// 创建类实例
id class_createInstance ( Class cls, size_t extraBytes );
 
// 在指定位置创建类实例
id objc_constructInstance ( Class cls, void *bytes );
 
// 销毁类实例
void * objc_destructInstance ( id obj );
Raw

- (void)runtimeTest3 {
    id theObject = class_createInstance(NSString.class, sizeof(unsigned));
    id str1 = [theObject init];
    
    NSLog(@"%@", [str1 class]);
    
    id str2 = [[NSString alloc] initWithString:@"test"];
    NSLog(@"%@", [str2 class]);
}

// 返回指定对象的一份拷贝
id object_copy ( id obj, size_t size );
 
// 释放指定对象占用的内存
id object_dispose ( id obj );

- (void)runtimeTest4 {
    NSObject *a = [[NSObject alloc] init];
    id newB = object_copy(a, class_getInstanceSize(MyClass.class));
    object_setClass(newB, MyClass.class);
    object_dispose(a);
}

// 修改类实例的实例变量的值
Ivar object_setInstanceVariable ( id obj, const char *name, void *value );
 
// 获取对象实例变量的值
Ivar object_getInstanceVariable ( id obj, const char *name, void **outValue );
 
// 返回指向给定对象分配的任何额外字节的指针
void * object_getIndexedIvars ( id obj );
 
// 返回对象中实例变量的值
id object_getIvar ( id obj, Ivar ivar );
 
// 设置对象中实例变量的值
void object_setIvar ( id obj, Ivar ivar, id value );

// 返回给定对象的类名
const char * object_getClassName ( id obj );
 
// 返回对象的类
Class object_getClass ( id obj );
 
// 设置对象的类
Class object_setClass ( id obj, Class cls );

// 获取已注册的类定义的列表
int objc_getClassList ( Class *buffer, int bufferCount );
 
// 创建并返回一个指向所有已注册类的指针列表
Class * objc_copyClassList ( unsigned int *outCount );
 
// 返回指定类的类定义
Class objc_lookUpClass ( const char *name );
Class objc_getClass ( const char *name );
Class objc_getRequiredClass ( const char *name );
 
// 返回指定类的元类
Class objc_getMetaClass ( const char *name );

- (void)runtimeTest5 {
    int numClasses;
    Class * classes = NULL;
    
    numClasses = objc_getClassList(NULL, 0);
    if (numClasses > 0) {
        classes = malloc(sizeof(Class) * numClasses);
        numClasses = objc_getClassList(classes, numClasses);
        
        NSLog(@"number of classes: %d", numClasses);
        
        for (int i = 0; i < numClasses; i++) {
            
            Class cls = classes[i];
            NSLog(@"class name: %s", class_getName(cls));
        }
        
        free(classes);
    }
}