You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
49 lines
935 B
49 lines
935 B
/*
|
|
* Copyright (c) Facebook, Inc. and its affiliates.
|
|
*
|
|
* This source code is licensed under the MIT license found in the
|
|
* LICENSE file in the root directory of this source tree.
|
|
*/
|
|
#import <Foundation/NSObject.h>
|
|
|
|
@protocol BarDelegate<NSObject>
|
|
@optional
|
|
- (void)optionalFunction;
|
|
@end
|
|
|
|
@interface Bar : NSObject
|
|
@property(weak, nonatomic) id<BarDelegate> delegate;
|
|
- (void)action;
|
|
@end
|
|
|
|
@implementation Bar
|
|
- (void)unsafeAction {
|
|
[self.delegate optionalFunction];
|
|
}
|
|
|
|
- (void)safeAction {
|
|
id<BarDelegate> delegate = self.delegate;
|
|
if ([delegate respondsToSelector:@selector(optionalFunction)]) {
|
|
[self.delegate optionalFunction];
|
|
}
|
|
}
|
|
@end
|
|
|
|
@interface Foo : NSObject<BarDelegate>
|
|
- (void)doSomething;
|
|
@end
|
|
|
|
@implementation Foo
|
|
- (void)doSomething {
|
|
Bar* x = [Bar new];
|
|
x.delegate = self;
|
|
[x unsafeAction];
|
|
}
|
|
@end
|
|
|
|
int main(int argc, const char* argv[]) {
|
|
Foo* y = [Foo new];
|
|
[y doSomething];
|
|
return 0;
|
|
}
|