// Declare the interface of the class
@interface MyVehicle : NSObject
// Declare the properties
@property NSString *vehicleType;
@property int numberOfWheels;
// Declare the methods
- (void)startEngine;
- (void)addWheels:(int)value;
@end
클래스
@implementation MyVehicle : NSObject
// No need to indicate the properties, only define methods
- (void)startEngine {
NSLog(@"Engine started");
}
- (void)addWheels:(int)value {
self.numberOfWheels += value;
}
@end
객체 및 메소드 호출
클래스의 인스턴스를 생성하기 위해 alloc 메소드를 호출합니다. 이 메소드는 각 속성에 메모리를 할당하고 해당 할당을 0으로 초기화합니다. 그런 다음 **init**이 호출되어 속성을 필요한 값으로 초기화합니다.
// Something like this:
MyVehicle *newVehicle = [[MyVehicle alloc] init];
// Which is usually expressed as:
MyVehicle *newVehicle = [MyVehicle new];
// To call a method
// [myClassInstance nameOfTheMethodFirstParam:param1 secondParam:param2]
[newVehicle addWheels:4];
클래스 메서드
클래스 메서드는 인스턴스 메서드와는 다른 더하기 기호 (+)를 사용하여 정의됩니다. NSString 클래스의 stringWithString 메서드와 같이 사용됩니다.
+ (id)stringWithString:(NSString *)aString;
Setter & Getter
속성을 설정하고 얻기 위해서는 도트 표기법을 사용하거나 마치 메소드를 호출하는 것처럼 할 수 있습니다:
// Set
newVehicle.numberOfWheels = 2;
[newVehicle setNumberOfWheels:3];
// Get
NSLog(@"Number of wheels: %i", newVehicle.numberOfWheels);
NSLog(@"Number of wheels: %i", [newVehicle numberOfWheels]);
인스턴스 변수
세터 및 게터 메서드 대신 인스턴스 변수를 사용할 수도 있습니다. 이 변수들은 속성과 동일한 이름을 가지지만 "_"로 시작합니다.
Objective-C is a programming language commonly used for macOS and iOS development. Understanding the basics of Objective-C can be helpful for macOS security and privilege escalation.
Objective-C Basics
Objective-C is an object-oriented programming language that extends the C programming language. It adds features such as dynamic typing, message passing, and runtime reflection.
Classes and Objects
In Objective-C, classes are used to define objects. An object is an instance of a class. Classes define the properties and behaviors of objects.
Methods and Messages
Methods are functions defined within a class that perform specific tasks. In Objective-C, methods are called by sending messages to objects. Messages are requests for objects to perform a specific method.
Properties
Properties are attributes of an object. They define the state of an object and can be accessed and modified using getter and setter methods.
Memory Management
Objective-C uses reference counting for memory management. When an object is created, its reference count is set to 1. When the object is no longer needed, its reference count is decremented. When the reference count reaches 0, the object is deallocated.
Inheritance
Objective-C supports inheritance, allowing classes to inherit properties and behaviors from other classes. This promotes code reuse and modularity.
Categories
Categories allow you to add methods to existing classes without modifying their original implementation. This can be useful for extending the functionality of built-in classes.
Protocols
Protocols define a set of methods that a class can implement. They are similar to interfaces in other programming languages and allow for polymorphism.
Conclusion
Understanding the basics of Objective-C is essential for macOS security and privilege escalation. It provides a foundation for analyzing and exploiting vulnerabilities in macOS applications.
기본 클래스는 불변이므로 기존 문자열에 문자열을 추가하려면 새로운 NSString을 생성해야 합니다.
NSString *bookDescription = [NSString stringWithFormat:@"%@ by %@ was published in %@", bookTitle, bookAuthor, bookPublicationYear];
또는 가변 문자열 클래스를 사용할 수도 있습니다:
NSMutableString *mutableString = [NSMutableString stringWithString:@"The book "];
[mutableString appendString:bookTitle];
[mutableString appendString:@" was written by "];
[mutableString appendString:bookAuthor];
[mutableString appendString:@" and published in "];
[mutableString appendString:bookPublicationYear];
번호
// character literals.
NSNumber *theLetterZ = @'Z'; // equivalent to [NSNumber numberWithChar:'Z']
// integral literals.
NSNumber *fortyTwo = @42; // equivalent to [NSNumber numberWithInt:42]
NSNumber *fortyTwoUnsigned = @42U; // equivalent to [NSNumber numberWithUnsignedInt:42U]
NSNumber *fortyTwoLong = @42L; // equivalent to [NSNumber numberWithLong:42L]
NSNumber *fortyTwoLongLong = @42LL; // equivalent to [NSNumber numberWithLongLong:42LL]
// floating point literals.
NSNumber *piFloat = @3.141592654F; // equivalent to [NSNumber numberWithFloat:3.141592654F]
NSNumber *piDouble = @3.1415926535; // equivalent to [NSNumber numberWithDouble:3.1415926535]
// BOOL literals.
NSNumber *yesNumber = @YES; // equivalent to [NSNumber numberWithBool:YES]
NSNumber *noNumber = @NO; // equivalent to [NSNumber numberWithBool:NO]
블록은 객체로 동작하는 함수이므로 함수에 전달하거나 배열이나 사전에 저장할 수 있습니다. 또한 값이 주어지면 값으로 표현될 수 있으므로 람다와 유사합니다.
returnType (^blockName)(argumentType1, argumentType2, ...) = ^(argumentType1 param1, argumentType2 param2, ...){
//Perform operations here
};
// For example
int (^suma)(int, int) = ^(int a, int b){
return a+b;
};
NSLog(@"3+4 = %d", suma(3,4));
함수의 매개변수로 사용될 블록 유형을 정의하는 것도 가능합니다:
// Define the block type
typedef void (^callbackLogger)(void);
// Create a bloack with the block type
callbackLogger myLogger = ^{
NSLog(@"%@", @"This is my block");
};
// Use it inside a function as a param
void genericLogger(callbackLogger blockParam) {
NSLog(@"%@", @"This is my function");
blockParam();
}
genericLogger(myLogger);
// Call it inline
genericLogger(^{
NSLog(@"%@", @"This is my second block");
});
파일
// Manager to manage files
NSFileManager *fileManager = [NSFileManager defaultManager];
// Check if file exists:
if ([fileManager fileExistsAtPath:@"/path/to/file.txt" ] == YES) {
NSLog (@"File exists");
}
// copy files
if ([fileManager copyItemAtPath: @"/path/to/file1.txt" toPath: @"/path/to/file2.txt" error:nil] == YES) {
NSLog (@"Copy successful");
}
// Check if the content of 2 files match
if ([fileManager contentsEqualAtPath:@"/path/to/file1.txt" andPath:@"/path/to/file2.txt"] == YES) {
NSLog (@"File contents match");
}
// Delete file
if ([fileManager removeItemAtPath:@"/path/to/file1.txt" error:nil]) {
NSLog(@"Removed successfully");
}
NSString 대신 NSURL 객체를 사용하여 파일을 관리하는 것도 가능합니다. 메서드 이름은 유사하지만 Path 대신 URL을 사용합니다.
