ios异步中实现按序下载队列

HFSingleonH 头件这里写链接内容

#define HFSingletonH(name) + (instancetype)shared##name;// .m文件#if __has_feature(objc_arc)#define HFSingletonM(name) \static id _instace; \\+ (id)allocWithZone:(struct _NSZone *)zone \{ \static dispatch_once_t onceToken; \dispatch_once(&onceToken, ^{ \_instace = [super allocWithZone:zone]; \}); \return _instace; \} \\+ (instancetype)shared##name \{ \static dispatch_once_t onceToken; \dispatch_once(&onceToken, ^{ \_instace = [[self alloc] init]; \}); \return _instace; \} \\- (id)copyWithZone:(NSZone *)zone \{ \return _instace; \}#else#define HFSingletonM(name) \static id _instace; \\+ (id)allocWithZone:(struct _NSZone *)zone \{ \static dispatch_once_t onceToken; \dispatch_once(&onceToken, ^{ \_instace = [super allocWithZone:zone]; \}); \return _instace; \} \\+ (instancetype)shared##name \{ \static dispatch_once_t onceToken; \dispatch_once(&onceToken, ^{ \_instace = [[self alloc] init]; \}); \return _instace; \} \\- (id)copyWithZone:(NSZone *)zone \{ \return _instace; \} \\- (oneway void)release { } \- (id)retain { return self; } \- (NSUInteger)retainCount { return 1;} \- (id)autorelease { return self;}#endif

头文件

#import <Foundation/Foundation.h>#include "SingletonMacro.h"@interface VRImageDownloader : NSObjectHFSingletonH(VRImageDownloader)     //单例- (void) addDownTasks:(id)item target:(id)tag completed:(void (^)(int result, char *filename, id tag))completedBlock;@end

实现

#include <pthread.h>pthread_mutex_t  _downMutex;typedef void (^completedBlock)(int result, char *filename, id tag);@interface VRImageDownloader ()@property (strong, nonatomic) dispatch_queue_t barrierQueue;@property (strong, nonatomic) NSThread *downThread;@property (strong, nonatomic) NSMutableArray *arrTask;@end@implementation VRImageDownloaderHFSingletonM(VRImageDownloader)- (instancetype) init{    self = [super init];    if(self){        [self setup];    }    return self;}- (void) setup{    pthread_mutex_init(&_downMutex, NULL);    _barrierQueue = dispatch_queue_create("com.xxx.socketdownQueue", DISPATCH_QUEUE_CONCURRENT);    _arrTask = [[NSMutableArray alloc] initWithCapacity:10];    _downThread = [[NSThread alloc] initWithTarget:self                                          selector:@selector(DownThumbThread)                                            object:nil];    [_downThread start];}- (void) DownThumbThread{    [[NSThread currentThread] setName:@"DownThread"];    __weak __typeof(self)wself = self;    int downRet;    while(true){        //取队列中有没有数据，如果没有，则Sleep        __block NSDictionary *dic;        dispatch_barrier_sync(wself.barrierQueue, ^{            if([wself.arrTask count] >0){                dic = wself.arrTask[0];                [wself.arrTask removeObjectAtIndex:0];            }        });        if(dic !=nil){            //下载            completedBlock completedBlock ;            Model *model;            model = dic[@"item"];            completedBlock = dic[@"block"];            XXXManager *cloudManager = [[XXXManager alloc] init];                pthread_mutex_lock(&_downMutex);  //由于下载是异步的，等待上一次完成，            [cloudManager requestDown:@"" mediaModel:model progressBlock:^(int progress) {                dispatch_async_on_main_queue(^{                    if(completedBlock){                        completedBlock(progress, (char*)"0", model);                    }                });            } completion:^(Model *sqlModel, NSError *error) {                dispatch_async_on_main_queue(^{                    if(completedBlock){                        completedBlock(downRet, (char*)"", model);                    }                        pthread_mutex_unlock(&_downMutex);//上一次完成了                });            }];            usleep(100);   //让线程调度一下，内存不会自动释放下        }else{            usleep(10000);        }        dic = nil;    }}- (void) addDownTasks:(id)item target:(id)tag completed:(void (^)(int result, char *filename, id tag))completedBlock{    __weak __typeof(self)wself = self;    __block int ret=0;    dispatch_barrier_sync(wself.barrierQueue, ^{        NSDictionary *dic;        id obj;        for(obj in item){            dic = @{@"tag":tag, @"block":completedBlock,@"item":obj};            [_arrTask addObject:dic];        }    });}