/NSObjectSafe

Swizzle commonly used function of Foundation container to prevent nil crash

Primary LanguageObjective-C

NSObject-Safe

Update 2018.11.20

  • add thread-safe support

Update 2018.6.26

  • remove unused swizze for NSDictionary objectForKey:
  • more class cluster support
NSArray
    __NSArrayI_Transfer, __NSArrayReversed, __NSFrozenArrayM, __NSCFArray
NSString
    NSTaggedPointerString, __NSCFString, _NSCFConstantString
NSData
    NSConcreteData, NSConcreteMutableData, _NSZeroData, _NSInlineData, __NSCFData

Warn:

  • Compile NSObjectSafe.m with -fno-objc-arc, otherwise it will cause strange release error: [UIKeyboardLayoutStar release]: message sent to deallocated instance
  • Conflict with MultiDelegate

Desciption

  • Swizzle commonly used function of Foundation container to prevent nil crash
  • Hook forwardInvocation to catch unrecognized selector exception
  • Assert in Debug and log in Release

Usage:

  • involve NSObjectSafe.h/NSObjectSafe.m as build phases

unrecognized selector protection

  • NSSafeProxy: unrecognized selector [print:] sent to A
@interface A : NSObject
- (void)print:(NSString*)msg;
@end
@implementation A
@end

Object Literals

NSArray* item = nil;
NSArray * items = @[@"a",@"b", item ,@"c"];
NSLog(@"%@", items);

NSString* key = nil;
NSString* value = nil;
NSLog(@"%@", @{@"b":@"c",key:value, @"e":value});

Swizzle Functions:

  • NSObject(Swizzle):
+ (void)swizzleClassMethod:(SEL)origSelector withMethod:(SEL)newSelector;
- (void)swizzleInstanceMethod:(SEL)origSelector withMethod:(SEL)newSelector;
  • NSObject(Safe)
- (void) addObserver:(NSObject *)observer forKeyPath:(NSString *)keyPath 
						options:(NSKeyValueObservingOptions)options context:(void *)context;
- (void) removeObserver:(NSObject *)observer forKeyPath:(NSString *)keyPath;
  • NSString
+ (NSString*) stringWithUTF8String:(const char *)nullTerminatedCString;
+ (nullable instancetype) stringWithCString:(const char *)cString encoding:(NSStringEncoding)enc;
- (nullable instancetype) initWithCString:(const char *)nullTerminatedCString encoding:(NSStringEncoding)encoding;
- (NSString *)stringByAppendingString:(NSString *)aString;
  • NSMutableString
- (nullable instancetype) safeInitWithCString:(const char *)nullTerminatedCString encoding:(NSStringEncoding)encoding;
- (void) appendString:(NSString *)aString;
- (void) insertString:(NSString *)aString atIndex:(NSUInteger)loc;
- (void) deleteCharactersInRange:(NSRange)range;
- (NSString *)stringByAppendingString:(NSString *)aString;
  • NSArray
+ (instancetype) arrayWithObject:(id)anObject;
- (id) objectAtIndex:(NSUInteger)index;
  • NSMutableArray
- (void) addObject:(id)anObject;
- (id) objectAtIndex:(NSUInteger)index;
- (void) insertObject:(id)anObject atIndex:(NSUInteger)index;
- (void) removeObjectAtIndex:(NSUInteger)index;
- (void) replaceObjectAtIndex:(NSUInteger)index withObject:(id)anObject;
- (void) removeObjectsInRange:(NSRange)range;
  • NSDictionary
+ (instancetype) dictionaryWithObject:(id)object forKey:(id)key;
- (id) objectForKey:(id)aKey;
  • NSMutableDictionary
- (id) objectForKey:(id)aKey;
- (void) setObject:(id)anObject forKey:(id)aKey;
- (void) removeObjectForKey:(id)aKey;
  • NSSet
+ (instancetype)setWithObject:(id)object;
  • NSMutableSet
- (void) addObject:(id)object;
- (void) removeObject:(id)object;
  • NSOrderedSet
+ (instancetype)orderedSetWithObject:(id)object;
- (instancetype)initWithObject:(id)object;
- (id)objectAtIndex:(NSUInteger)idx;
  • NSMutableOrderedSet
- (id)objectAtIndex:(NSUInteger)idx;
- (void)addObject:(id)object;
- (void)insertObject:(id)object atIndex:(NSUInteger)idx;
- (void)removeObjectAtIndex:(NSUInteger)idx;
- (void)replaceObjectAtIndex:(NSUInteger)idx withObject:(id)object;
  • NSUserDefault
- (id) objectForKey:(NSString *)defaultName;
- (NSInteger) integerForKey:(NSString *)defaultName;
- (BOOL) boolForKey:(NSString *)defaultName;
- (void) setObject:(id)value forKey:(NSString*)aKey;
- (void) removeObjectForKey:(NSString*)aKey;