[Add] progress bar when loading history data

vnpy/app/cta_strategy/backtesting.py

@@ -1,5 +1,5 @@
 from collections import defaultdict
-from datetime import date, datetime
+from datetime import date, datetime, timedelta
 from typing import Callable
 from itertools import product
 from functools import lru_cache
@@ -211,22 +211,44 @@ class BacktestingEngine:
         """"""
         self.output("开始加载历史数据")
 
+        if not self.end:
+            self.end = datetime.now()
+
+        # Load 30 days of data each time and allow for progress update
+        progress_delta = timedelta(days=30)
+        total_delta = self.end - self.start
+
+        start = self.start
+        end = self.start + progress_delta
+        progress = 0
+
+        while start < self.end:
             if self.mode == BacktestingMode.BAR:
-            self.history_data = load_bar_data(
+                data = load_bar_data(
                     self.symbol,
                     self.exchange,
                     self.interval,
-                self.start,
+                    start,
-                self.end
+                    end
                 )
             else:
-            self.history_data = load_tick_data(
+                data = load_tick_data(
                     self.symbol,
                     self.exchange,
-                self.start,
+                    start,
-                self.end
+                    end
                 )
 
+            self.history_data.extend(data)
+            
+            progress += progress_delta / total_delta
+            progress = min(progress, 1)
+            progress_bar = "#" * int(progress * 10)
+            self.output(f"加载进度：{progress_bar} [{progress:.0%}]")
+            
+            start = end
+            end += progress_delta
+        
         self.output(f"历史数据加载完成，数据量：{len(self.history_data)}")
 
     def run_backtesting(self):