可控制生命周期的常驻线程

#import "AlwaysLiveThread.h"

@interface AlwaysLiveThread()
{
    CFRunLoopSourceContext context;
    CFRunLoopRef runLoop;
    CFRunLoopSourceRef runLoopSource;
}

@property (nonatomic, strong) NSThread *workThread;
@property (nonatomic, assign) BOOL isStarted;
@property (nonatomic, assign) BOOL isStoped;

@end

@implementation AlwaysLiveThread

- (instancetype)init {
    return [self initWithBlock:^{
        
    }];
}

- (instancetype)initWithBlock:(void (^)(void))block {
    self = [super init];
    if (self) {
        self.isStarted = NO;
        self.isStoped = NO;
        self.workThread = [[NSThread alloc] initWithTarget:self selector:@selector(startThreadByBlock:) object:block];
    }
    return self;
}

- (BOOL)startThisThread {
    BOOL isStarted = self.isStarted;
    if (!self.isStarted && !self.isStoped) {
        [self.workThread start];
    }
    return (!self.isStoped && !isStarted);
}

- (void)startThreadByBlock:(void (^)(void))block {
    if (!self.isStarted && !self.isStoped) {
        !block?:block();
        [self registerRunloopSourceThenRunning];
    }
}

- (void)registerRunloopSourceThenRunning {
    if (!self.isStarted && !self.isStoped) {
        self.isStarted = YES;
        runLoop = CFRunLoopGetCurrent();
        runLoopSource = CFRunLoopSourceCreate(NULL, 0, &context);
        CFRunLoopAddSource(runLoop, runLoopSource, kCFRunLoopDefaultMode);
        CFRunLoopRun();
    }
}

- (void)stopThisRunloopWhileDisableThread {
    if (!self.isStoped && self.isStarted) {
        CFRunLoopStop(runLoop);
        CFRunLoopRemoveSource(runLoop, runLoopSource, kCFRunLoopDefaultMode);
        CFRelease(runLoopSource);
        CFRelease(&context);
        self.isStoped = YES;
    }
}

- (void)workJob:(void (^)(void))block {
    [self performSelector:@selector(doNewJob:) onThread:self.workThread withObject:block waitUntilDone:NO];
}

- (void)doNewJob:(void (^)(void))block {
    !block?:block();
}

- (BOOL)stopThisThread {
    BOOL isStoped = self.isStoped;
    if (self.isStarted && !self.isStoped) {
        /// 放在线程内执行，主要是避免跨线程操作异常（比如调用启动后立即停止，导致数据访问异常）
        [self performSelector:@selector(stopThisRunloopWhileDisableThread) onThread:self.workThread withObject:nil waitUntilDone:NO];
    }
    return (self.isStarted && !isStoped);
}

- (void)dealloc {
#ifdef DEBUG
    NSLog(@"任务线程%@被销毁",self);
#endif
}

@end