move the shuffer into def sample_iter_reader

ppocr/data/det/dataset_traversal.py

@@ -36,18 +36,17 @@ class TrainReader(object):
             "absence process_function in Reader"
         self.process = create_module(params['process_function'])(params)
 
-    def __call__(self, process_id):
+    def __call__(self, process_id):     
         with open(self.label_file_path, "rb") as fin:
-            label_infor_list = fin.readlines()        
+            label_infor_list = fin.readlines()
         img_num = len(label_infor_list)
-        img_id_list = list(range(img_num))        
-        if sys.platform == "win32":
-            random.shuffle(img_id_list)
+        img_id_list = list(range(img_num))
+        if sys.platform == "win32" and self.num_workers != 1:
             print("multiprocess is not fully compatible with Windows."
                   "num_workers will be 1.")
             self.num_workers = 1
-                
-        def sample_iter_reader():            
+        def sample_iter_reader():
+            random.shuffle(img_id_list)
             for img_id in range(process_id, img_num, self.num_workers):
                 label_infor = label_infor_list[img_id_list[img_id]]
                 outs = self.process(label_infor)