[翻译] GCDObjC

[翻译] GCDObjC

GCDObjC

https://github.com/mjmsmith/gcdobjc

GCDObjC is an Objective-C wrapper for the most commonly used features of Grand Central Dispatch. It has four main aims:

GCDObjC 封装了GCD最常使用的一些特性,它有着如下的4点宗旨:

  • Organize the flat C API into appropriate classes.
  • Use intention-revealing names to distinguish between synchronous and asynchronous functions.
  • Use more convenient arguments such as time intervals.
  • Add convenience methods.
  • 将C语言级别的API转换成合适的对象类型
  • 使用见名知意的名字来区分同步和异步的方法
  • 用更便利的参数,如时间间隔
  • 添加一些便利的方法

Usage(使用)

GCDObjC requires ARC and iOS 6.0. (Prior to 6.0, dispatch objects were not considered Objective-C objects, and therefore required manual memory management.)

GCDObjC.h is the only header file that needs to be imported.

GCDObjC需要开启ARC以及iOS6.0(在6.0之前,dispatch对象不被当做Objective-C对象,所以需要手动管理内存)

GCDObjC.h是唯一需要包含的头文件。

For usage examples, see GCDObjCTests.m.

GCDQueue(GCD队列)

Queues are implemented in the GCDQueue class.

在GCDQueue类中实现了队列。

  • convenience accessors for global queues
  • 便利的系统相关队列
+ (GCDQueue *)mainQueue;
+ (GCDQueue *)globalQueue;
+ (GCDQueue *)highPriorityGlobalQueue;
+ (GCDQueue *)lowPriorityGlobalQueue;
+ (GCDQueue *)backgroundPriorityGlobalQueue;
  • creating serial and concurrent queues
  • 创建串行以及并发队列
- (instancetype)initSerial;
- (instancetype)initConcurrent;
  • queueing blocks for asynchronous execution
  • 队列的block用来执行异步操作
- (void)queueBlock:(dispatch_block_t)block;
- (void)queueBlock:(dispatch_block_t)block afterDelay:(double)seconds;
- (void)queueBlock:(dispatch_block_t)block inGroup:(GCDGroup *)group;
  • queueing blocks for synchronous execution
  • 队列的block用来执行同步操作
- (void)queueAndAwaitBlock:(dispatch_block_t)block;
- (void)queueAndAwaitBlock:(void (^)(size_t))block iterationCount:(size_t)count;
  • queueing barrier blocks for synchronous or asynchronous execution
  • 队列阻塞block用来执行同步或者异步操作
- (void)queueBarrierBlock:(dispatch_block_t)block;
- (void)queueAndAwaitBarrierBlock:(dispatch_block_t)block;
  • queueing notify blocks on groups
  • 用来监测groups的队列
- (void)queueNotifyBlock:(dispatch_block_t)block inGroup:(GCDGroup *)group;
  • suspending and resuming a queue
  • 挂起以及回复一个队列
- (void)suspend;
- (void)resume;

GCDSemaphore(GCD信号量)

Semaphores are implemented in the GCDSemaphore class.

GCDSemaphore类实现了信号量

  • creating semaphores
  • 创建信号量
- (instancetype)init;
- (instancetype)initWithValue:(long)value;
  • signaling and waiting on a semaphore
  • 发送以及等待一个信号量
- (BOOL)signal;
- (void)wait;
- (BOOL)wait:(double)seconds;

GCDGroup(GCD线程组)

Groups are implemented in the GCDGroup class.

GCDGroup实现了线程组。

  • creating groups
  • 创建组
- (instancetype)init;
  • entering and leaving a group
  • 加入以及脱离一个组
- (void)enter;
- (void)leave;
  • waiting on completion of a group
  • 等待一个线程组执行完毕
- (void)wait;
- (BOOL)wait:(double)seconds;

Macros(宏函数)

Two macros are provided for wrapping dispatch_once() calls.

给dispatch_once()调用提供了两个宏。

  • executing a block only once: GCDExecOnce(block)
  • 仅仅执行一次
for (int i = 0; i < 10; ++i) {
GCDExecOnce(^{ NSLog(@"This will only be logged once."); });
}
  • creating a singleton instance of a class: GCDSharedInstance(block)
  • 创建一个类的单例
+ (instancetype)sharedInstance {
GCDSharedInstance(^{ return [[self class] new]; });
}

The block supplied to GCDSharedInstance() must return an instance of the desired class.

GCDShardInstance()必须返回这个类的一个实例对象。

------------------------------------------------------------------------------------------------------

此类仅仅支持arc,所以是在arc环境下测试,简单易用,以测了所有的情况

------------------------------------------------------------------------------------------------------

串行主线程池

    [[GCDQueue mainQueue] queueBlock:^{
NSLog(@"");
}]; [[GCDQueue mainQueue] queueBlock:^{
NSLog(@"");
}]; [[GCDQueue mainQueue] queueBlock:^{
NSLog(@"");
}]; [[GCDQueue mainQueue] queueBlock:^{
NSLog(@"");
}];

2014-04-09 10:39:57.210 StudyGCD_new[10395:60b] 1
2014-04-09 10:39:57.210 StudyGCD_new[10395:60b] 2
2014-04-09 10:39:57.211 StudyGCD_new[10395:60b] 3
2014-04-09 10:39:57.211 StudyGCD_new[10395:60b] 4

串行主线程池与并发主线程池混用

    [[GCDQueue globalQueue] queueBlock:^{
// 系统并发线程池
// ... 处理阻塞操作 [[GCDQueue mainQueue] queueBlock:^{
// 系统串行主线程池
// ... 更新UI操作
}];
}];

自己创建的并发线程池

    GCDQueue *concurrentQueue = [[GCDQueue alloc] initConcurrent];

    [concurrentQueue queueBlock:^{
NSLog(@"");
}]; [concurrentQueue queueBlock:^{
NSLog(@"");
}]; [concurrentQueue queueBlock:^{
NSLog(@"");
}]; [concurrentQueue queueBlock:^{
NSLog(@"");
}];

2014-04-09 11:08:39.450 StudyGCD_new[10592:1303] 1
2014-04-09 11:08:39.450 StudyGCD_new[10592:3903] 4
2014-04-09 11:08:39.450 StudyGCD_new[10592:3807] 2
2014-04-09 11:08:39.450 StudyGCD_new[10592:3707] 3

自己创建的串行线程池

    GCDQueue *serialQueue = [[GCDQueue alloc] initSerial];

    [serialQueue queueBlock:^{
NSLog(@"");
}]; [serialQueue queueBlock:^{
NSLog(@"");
}]; [serialQueue queueBlock:^{
NSLog(@"");
}]; [serialQueue queueBlock:^{
NSLog(@"");
}];

2014-04-09 11:08:39.450 StudyGCD_new[10592:1303] 1
2014-04-09 11:08:39.450 StudyGCD_new[10592:3903] 2
2014-04-09 11:08:39.450 StudyGCD_new[10592:3807] 3
2014-04-09 11:08:39.450 StudyGCD_new[10592:3707] 4

主并发线程池延时1s执行

    NSLog(@"");

    [[GCDQueue globalQueue] queueBlock:^{
NSLog(@"Y.X.");
} afterDelay:.f]; NSLog(@"");

2014-04-09 11:11:46.349 StudyGCD_new[10640:1303] 1
2014-04-09 11:11:46.350 StudyGCD_new[10640:1303] 2
2014-04-09 11:11:47.350 StudyGCD_new[10640:1303] Y.X.

并发线程池中运行阻塞线程(queueAndAwaitBlock-dispatch_sync)

    GCDQueue *concurrentQueue = [[GCDQueue alloc] initConcurrent];

    [concurrentQueue queueAndAwaitBlock:^{
sleep();
NSLog(@"");
}]; [concurrentQueue queueAndAwaitBlock:^{
sleep();
NSLog(@"");
}]; [concurrentQueue queueAndAwaitBlock:^{
sleep();
NSLog(@"");
}]; [concurrentQueue queueBlock:^{
NSLog(@"");
}]; [concurrentQueue queueBlock:^{
NSLog(@"");
}]; [concurrentQueue queueAndAwaitBlock:^{
sleep();
NSLog(@"");
}];

2014-04-09 11:21:15.186 StudyGCD_new[10946:60b] 1
2014-04-09 11:21:16.188 StudyGCD_new[10946:60b] 2
2014-04-09 11:21:17.190 StudyGCD_new[10946:60b] 3
2014-04-09 11:21:17.191 StudyGCD_new[10946:3807]
2014-04-09 11:21:17.191 StudyGCD_new[10946:1303]
2014-04-09 11:21:18.192 StudyGCD_new[10946:60b] 6

并发线程池,等待执行多次完毕后接着往下执行(dispatch_apply)

    GCDQueue *concurrentQueue = [[GCDQueue alloc] initConcurrent];

    NSLog(@"1-1-1");

    [concurrentQueue queueAndAwaitBlock:^(size_t count) {
NSLog(@"%zu", count);
} iterationCount:]; NSLog(@"2-2-2");

2014-04-09 11:27:39.400 StudyGCD_new[11131:60b] 1-1-1
2014-04-09 11:27:39.401 StudyGCD_new[11131:60b] 1
2014-04-09 11:27:39.401 StudyGCD_new[11131:1303] 0
2014-04-09 11:27:39.401 StudyGCD_new[11131:3707] 2
2014-04-09 11:27:39.401 StudyGCD_new[11131:3903] 3
2014-04-09 11:27:39.403 StudyGCD_new[11131:60b] 2-2-2

并发线程池,设置障碍线程而按照队列的形式执行(dispatch_barrier_async)

    GCDQueue *concurrentQueue = [[GCDQueue alloc] initConcurrent];

    [concurrentQueue queueBarrierBlock:^{
NSLog(@"");
sleep();
}]; [concurrentQueue queueBarrierBlock:^{
NSLog(@"");
sleep();
}]; [concurrentQueue queueBlock:^{
NSLog(@"Y.X.");
sleep();
}]; [concurrentQueue queueBarrierBlock:^{
NSLog(@"");
sleep();
}]; [concurrentQueue queueBarrierBlock:^{
NSLog(@"");
sleep();
}];

2014-04-09 11:33:08.190 StudyGCD_new[11252:1303]
2014-04-09 11:33:09.192 StudyGCD_new[11252:1303]
2014-04-09 11:33:10.194 StudyGCD_new[11252:1303] Y.X.
2014-04-09 11:33:11.196 StudyGCD_new[11252:1303]
2014-04-09 11:33:12.198 StudyGCD_new[11252:1303]

线程组以及监听

    GCDQueue *concurrentQueue = [[GCDQueue alloc] initConcurrent];
GCDGroup *group = [[GCDGroup alloc] init]; [concurrentQueue queueBlock:^{
NSLog(@"");
} inGroup:group]; [concurrentQueue queueBlock:^{
NSLog(@"");
} inGroup:group]; [concurrentQueue queueBlock:^{
NSLog(@"");
} inGroup:group]; [concurrentQueue queueNotifyBlock:^{
NSLog(@"监测所有这个组中的子线程完成后执行此打印语句");
} inGroup:group];

2014-04-09 11:37:19.492 StudyGCD_new[11343:3707] 3
2014-04-09 11:37:19.492 StudyGCD_new[11343:3807] 2
2014-04-09 11:37:19.492 StudyGCD_new[11343:1303] 1
2014-04-09 11:37:19.493 StudyGCD_new[11343:3807] 监测所有这个组中的子线程完成后执行此打印语句

先讲解系统的dispatch_group_enter来等待所有的异步操作结束后再执行最后的block

    // 创建一个组
dispatch_group_t group = dispatch_group_create(); /*
dispatch_group_enter() * A call to this function must be balanced with a call to dispatch_group_leave.
* 调用了这个方法就必须使用dispatch_group_leave来达到平衡
*/ // 明确的标记一个block进入了一个组
dispatch_group_enter(group);
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, ), ^{
NSLog(@"1 starting");
sleep();
NSLog(@"1 complete"); // 明确的标记一个这个组中的block已经完成
dispatch_group_leave(group);
}); // 明确的标记一个block进入了一个组
dispatch_group_enter(group);
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, ), ^{
NSLog(@"2 starting");
sleep();
NSLog(@"2 complete"); // 明确的标记一个这个组中的block已经完成
dispatch_group_leave(group);
}); dispatch_async(dispatch_get_main_queue(), ^{
// 同步等待之前提交的block任务都完成了才会执行这里
dispatch_group_wait(group, DISPATCH_TIME_FOREVER);
NSLog(@"所有的进入group的都结束了,结束");
});

2014-04-09 13:10:32.518 StudyGCD_new[11864:1303] 1 starting
2014-04-09 13:10:32.518 StudyGCD_new[11864:3403] 2 starting
2014-04-09 13:10:33.520 StudyGCD_new[11864:1303] 1 complete
2014-04-09 13:10:36.521 StudyGCD_new[11864:3403] 2 complete
2014-04-09 13:10:36.522 StudyGCD_new[11864:60b] 所有的进入group的都结束了,结束

GCDGroup同步并发线程,更精简

    GCDGroup *group = [[GCDGroup alloc] init];

    [group enter];
[[GCDQueue globalQueue] queueBlock:^{
sleep();
NSLog(@"1结束");
[group leave];
}]; [group enter];
[[GCDQueue globalQueue] queueBlock:^{
sleep();
NSLog(@"2结束");
[group leave];
}]; [[GCDQueue globalQueue] queueBlock:^{
[group wait];
NSLog(@"1.2都执行结束了,进来了这里");
}];

2014-04-09 13:16:17.584 StudyGCD_new[11945:1303] 1结束
2014-04-09 13:16:18.584 StudyGCD_new[11945:3807] 2结束
2014-04-09 13:16:18.585 StudyGCD_new[11945:3707] 1.2都执行结束了,进来了这里

使用系统的信号量操作

    // 创建信号量
dispatch_semaphore_t sem = dispatch_semaphore_create(); dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, ), ^(void) {
NSLog(@"1开始"); // 模拟阻塞操作
sleep();
NSLog(@"1结束"); // 增加信号量
dispatch_semaphore_signal(sem); sleep();
dispatch_semaphore_signal(sem); sleep();
dispatch_semaphore_signal(sem); sleep();
dispatch_semaphore_signal(sem);
}); NSLog(@"阻塞吗?");
// 减少信号量
dispatch_semaphore_wait(sem, DISPATCH_TIME_FOREVER);
NSLog(@"阻塞了1!"); // 减少信号量
dispatch_semaphore_wait(sem, DISPATCH_TIME_FOREVER);
NSLog(@"阻塞了2!"); // 减少信号量
dispatch_semaphore_wait(sem, DISPATCH_TIME_FOREVER);
NSLog(@"阻塞了3!"); // 减少信号量
dispatch_semaphore_wait(sem, DISPATCH_TIME_FOREVER);
NSLog(@"阻塞了4!");

2014-04-09 13:31:10.135 StudyGCD_new[12198:1303] 1开始

2014-04-09 13:31:10.134 StudyGCD_new[12198:60b] 阻塞吗?

2014-04-09 13:31:12.137 StudyGCD_new[12198:1303] 1结束

2014-04-09 13:31:12.138 StudyGCD_new[12198:60b] 阻塞了1!

2014-04-09 13:31:13.139 StudyGCD_new[12198:60b] 阻塞了2!

2014-04-09 13:31:14.140 StudyGCD_new[12198:60b] 阻塞了3!

2014-04-09 13:31:15.141 StudyGCD_new[12198:60b] 阻塞了4!

信号量操作

    GCDSemaphore *semaphore = [[GCDSemaphore alloc] initWithValue:];

    [[GCDQueue globalQueue] queueBlock:^{
sleep();
[semaphore signal];
}]; [semaphore wait];
NSLog(@"结束");

2014-04-09 13:39:09.476 StudyGCD_new[12298:60b] 结束

 
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