带你读《2022技术人的百宝黑皮书》——淘宝iOS扫一扫架构升级 - 设计模式的应用（3）

  @implementation TBPipelineManager
  - (TBPipelineManager *(^)(id<TBPipelineDataCreatorDelegate> dataCreator))addDataCreator {
  @weakify
  return ^(id<TBPipelineDataCreatorDelegate> dataCreator) {
  @strongify
  if (dataCreator) {
  [self.dataGenArr addObject:dataCreator];
 }
 return self;
 };
 }
- (TBPipelineManager *(^)(id<TBPipelineDelegate> pipeline))addPipeline {
  @weakify
  return ^(id<TBPipelineDelegate> pipeline) {
  @strongify
  if (pipeline) {
  [self.pipelineArr addObject:pipeline]; 20
  //每一次add的同时，我们做链式标记（通过runtime给每个处理加Next）
  if (self.pCurPipeline) {
  NSObject *cur = (NSObject *)self.pCurPipeline;
  cur.tb_nextPipeline = pipeline;
 }
 self.pCurPipeline = pipeline;
 }
 return self;
 };
 }
  - (void)setThrowDataBlock:(void (^)(id _Nonnull))throwDataBlock {
  _throwDataBlock = throwDataBlock; 34
  @weakify
  //Creator的数组，依次对 Block 回调进行赋值，当业务方调用此 Block 时，就是开始处理数据的时候
   [self.dataGenArr enumerateObjectsUsingBlock:^(id<TBPipelineDataCreatorDelegate> _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
  obj.generateDataBlock = ^(id<TBPipelineBaseDataProtocol> data, NSInteger dataId) {
  @strongify
data.dataId = dataId;
//开始递归处理数据
[self handleData:data];
   -  (void)handleData:(id)data {
[self recurPipeline:self.pipelineArr.firstObject data:data];
}
- (void)recurPipeline:(id<TBPipelineDelegate>)pipeline data:(id)data { if (!pipeline) {
return;
}
//递归让pipeline处理数据@weakify
[pipeline receiveData:data throwDataBlock:^(id _Nonnull throwData) { @strongify
NSObject *cur = (NSObject *)pipeline; if (cur.tb_nextPipeline) {
[self recurPipeline:cur.tb_nextPipeline data:throwData];
} else {
!self.throwDataBlock?:self.throwDataBlock(throwData);
}
}];
}
@end

1 @protocol TBPipelineDelegate <NSObject>
2 //如果有错误，直接抛出
3 - (void)receiveData:(id)data throwDataBlock:(void(^)(id data))block;
4 @end

//以A类型码码处理单元为例@implementation TBGen3Pipeline
- (void)receiveData:(id <TBCodeDataDelegate>)data throwDataBlock:(void (^)(id data))block { TBScanResult *result = data.scanResult;
NSString *scanType = result.resultType;
NSString *scanData = result.data;
if ([scanType isEqualToString:TBScanResultTypeA]) {
//跳转逻辑
...
//可以处理，终止递归BlockInPipeline();
} else {
//不满足处理条件，继续递归：由下一个 Pipeline 继续处理PassNextPipeline(data);
}
}
@end

- (void)setupPipeline {
//创建 manager 和 creator
self.manager = TBPipelineManager.new; self.dataCreator = TBDataCreator.new;
//创建 pipeline
TBCodeTypeAPipelie *codeTypeAPipeline = TBCodeTypeAPipelie.new; TBCodeTypeBPipelie *codeTypeBPipeline = TBCodeTypeBPipelie.new;
//...
TBCodeTypeFPipelie *codeTypeFPipeline = TBCodeTypeFPipelie.new;