chore: 更新版本至1.1.33并优化下载源处理逻辑

- 将项目版本从1.1.32更新至1.1.33
- 优化DownloadSource.add_source_to_candidate函数参数格式，提高可读性
- 调整process_files方法中循环顺序，优先处理已合并的源
- 添加空列表检查，避免处理无效数据
- 优化循环逻辑，在满足条件时提前退出循环
- 保持原有功能不变，仅改进代码结构和错误处理

Author: farfun

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "funread"
-version = "1.1.32"
+version = "1.1.33"
 description = "一个用于管理和处理阅读源（Legado 阅读 APP 的书源和 RSS 源）的 Python 工具库"
 readme = "README.md"
 requires-python = ">=3.8"

src/funread/legado/manage/download/base.py

@@ -98,7 +98,10 @@ def url_index(self, url: str) -> int:
 
     @staticmethod
     def add_source_to_candidate(
-        md5: str, fpath: str, source: Dict[str, Any], url_info: Optional[Dict[str, Any]] = None
+        md5: str,
+        fpath: str,
+        source: Dict[str, Any],
+        url_info: Optional[Dict[str, Any]] = None,
     ) -> None:
         """
         将源添加到候选列表
@@ -303,9 +306,11 @@ def export_sources(self, size: int = 1000) -> Iterator[List[Dict[str, Any]]]:
                     continue
 
                 # 从候选和已合并列表中提取源
-                for key in ("candidate", "merged"):
+                for key in ("merged", "candidate"):
                     if key not in data:
                         continue
+                    if len(data[key]) == 0:
+                        continue
                     for item in data[key][:3]:  # 每个文件最多取前3个
                         if "source" not in item or "md5_list" not in item:
                             continue
@@ -321,6 +326,7 @@ def export_sources(self, size: int = 1000) -> Iterator[List[Dict[str, Any]]]:
                         if len(dd) >= size:
                             yield dd
                             dd = []
+                    break
             except (IOError, json.JSONDecodeError, KeyError) as e:
                 logger.warning(f"Failed to process {file_path}: {e}")
                 continue