Single-instance mode compatible with ARC and MRC, and compatible with arcmrc

Single-instance mode compatible with ARC and MRC, and compatible with arcmrc

I. single-instance implementation under ARC

Note: The method of user instantiation controls a single execution, while opening the initialization method of the Singleton.

-(instancetype)init{    self=[super init];    if(self){        static dispatch_once_t onceToken;        dispatch_once(&onceToken, ^{        });    }    return self;    }static id instance; +(instancetype)allocWithZone:(struct _NSZone *)zone{     static dispatch_once_t onceToken;    dispatch_once(&onceToken, ^{     instance=[super allocWithZone:zone];     }); return instance;}   + (instancetype) shareAudio{    static dispatch_once_t onceToken;    dispatch_once(&onceToken, ^{     instance=[[self alloc]init];     });     return instance; }  +(id)copyWithZone:(struct _NSZone *)zone{     return instance;}

Ii. single-instance implementation in MRC

Note: The method of user instantiation controls a single execution, and the initialization method of the Singleton is enabled. Because MRC is currently used, the method of controlling the parameter memory management needs to be executed at a time. Therefore, this method needs to be added compared with ARC:

static id instance; +(instancetype)allocWithZone:(struct _NSZone *)zone{     static dispatch_once_t onceToken;     dispatch_once(&onceToken, ^{         instance=[super allocWithZone:zone];     });     return instance; }   + (instancetype) shareAudio{    static dispatch_once_t onceToken;     dispatch_once(&onceToken, ^{         instance=[[self alloc]init];     });     return instance; } -(oneway void)release{ }  -(instancetype)autorelease{     return instance; }  -(instancetype)retain{     return instance; }  -(NSUInteger)retainCount{     return 1; }

Iii. Compatibility with macro definitions of MRC and ARC

Note: To facilitate later reference, you can extract a singleton as a macro definition. In view of the current manual count and automatic count, Conditional compilation is introduced:

# If! _ Has_feature (objc_arc) ===== current is ARC # else ===== current is MRC # endifCode:# Define singleton_h (name) + (instancetype) share ## name; # if! _ Has_feature (objc_arc) # define singleton_m (name) \ static id instance; \ + (instancetype) allocWithZone :( struct _ NSZone *) zone {\ static dispatch_once_t onceToken; \ dispatch_once (& onceToken, ^ {\ instance = [super allocWithZone: zone] ;\}); \ return instance ;\}\\ + (instancetype) share ## name {\ static dispatch_once_t onceToken; \ dispatch_once (& onceToken, ^ {\ instance = [[self alloc] init] ;\}); \ return instance; \}\-(oneway void) release {\}\\-(instancetype) autorelease {\ return instance ;\}\\-(instancetype) retain {\ return instance; \}\+ (id) copyWithZone :( struct _ NSZone *) zone {\ return instance; \}\-(NSUInteger) retainCount {\ return 1; \}# else # define singleton_m (name) \ static id instance; \ + (instancetype) allocWithZone :( struct _ NSZone *) zone {\ static deleoncetoken; \ dispatch_once (& onceToken, ^ {\ instance = [super allocWithZone: zone] ;\}); \ return instance ;\}\\+ (instancetype) share ## name {\ static dispatch_once_t onceToken; \ dispatch_once (& onceToken, ^ {\ instance = [[self alloc] init] ;\}); \ return instance ;\}\+ (id) copyWithZone :( struct _ NSZone *) zone {\ return instance ;\}# endif

Iv. File Reference

1. Reference singleton_h (audio) in the. h file );

2. Reference singleton_m (audio) in the. m file );