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/*
* 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>
@interface BlockA : NSObject
@end
@implementation BlockA {
void (^_block_field)(void);
}
- (void)doSomethingThenCallback:(void (^)(void))my_block {
// null dereference, segfault if my_block is nil
my_block();
}
- (void)assignNilBad {
void (^my_block)(void) = ^() {
};
my_block = NULL;
my_block(); // Null deref
}
- (void)checkNotNilOk:(void (^)(void))my_block {
// ok to call this block!
if (my_block != nil) {
my_block();
}
}
- (void)paramAssignNilBad:(void (^)(void))my_block {
my_block = NULL;
my_block(); // Null deref
}
- (void)paramReassignNilBad:(void (^)(void))my_block_param {
void (^my_block)(void) = ^() {
};
my_block = NULL;
my_block_param = my_block;
my_block_param(); // Null deref
}
- (void)assignEmptyBlockOk:(void (^)(void))my_block_param {
void (^my_block)(void) = ^() {
};
my_block_param = my_block;
my_block_param(); // No error here
}
- (void)checkNotNilBlockAsArgOk:(BOOL)a
block_param:(void (^)(void))block_param {
void (^my_block)(void) = ^() {
if (block_param)
block_param(); // No error here
};
if (a) {
[self checkNotNilOk:^() {
my_block(); // No error here
}];
}
}
- (void)FN_ivarNilBlockBad {
_block_field(); // Ivar not nullable
}
- (int)check_nullifyOk {
int i = 7;
int* x = &i;
int (^my_block)(void) = ^() {
return *x; // we'll get a false NPE here if we nullify x too early.
};
return my_block();
}
@end
void calldoSomethingThenCallbackOk() {
BlockA* blockA = [BlockA alloc];
void (^my_block)(void) = ^() {
};
[blockA doSomethingThenCallback:my_block];
}
void calldoSomethingThenCallbackWithNilBad() {
BlockA* blockA = [BlockA alloc];
[blockA doSomethingThenCallback:nil];
}