fix: python2 compatible and flake8 style

Author: lihsai0

qiniu/http/regions_provider.py

@@ -205,7 +205,6 @@ def _file_path(self):
 elif is_windows:
     import msvcrt
 
-
     class _FileLocker:
         def __init__(self, fd):
             self._fd = fd
@@ -235,13 +234,13 @@ def __enter__(self):
                 open_flags = os.O_EXCL | os.O_RDWR | os.O_CREAT
                 fd = os.open(self.lock_file_path, open_flags)
                 os.close(fd)
-            except FileExistsError:
+            except IOError:
                 raise FileAlreadyLocked('File {0} already locked'.format(self._file_path))
 
         def __exit__(self, exc_type, exc_val, exc_tb):
             try:
                 os.remove(self.lock_file_path)
-            except FileNotFoundError:
+            except IOError:
                 pass
 
         @property

tests/cases/test_http/test_regions_provider.py

@@ -294,21 +294,20 @@ def test_shrink_with_ignore_expired_regions(self, cached_regions_provider):
         list(cached_regions_provider)  # trigger __shrink_cache()
         assert len(cached_regions_provider._cache_scope.memo_cache[origin_cache_key]) > 0
 
-    def test_file_locker(self, temp_file_path):
-        handled_cnt = 0
-        skipped_cnt = 0
+    def test_file_locker(self, temp_file_path, use_ref):
+        handled_cnt = use_ref(0)
+        skipped_cnt = use_ref(0)
 
 
         def process_file(_n):
-            nonlocal handled_cnt, skipped_cnt
             try:
                 with open(temp_file_path, 'w') as f, _FileThreadingLocker(f), _FileLocker(f):
                     time.sleep(1)
-                    handled_cnt += 1
+                    handled_cnt.value += 1
             except FileAlreadyLocked:
-                skipped_cnt += 1
+                skipped_cnt.value += 1
 
 
         ThreadPool(4).map(process_file, range(20))
-        assert handled_cnt + skipped_cnt == 20
-        assert 0 < handled_cnt <= 4
+        assert handled_cnt.value + skipped_cnt.value == 20
+        assert 0 < handled_cnt.value <= 4