py2 compat

Author: alimanfoo

zarr/compat.py

@@ -16,9 +16,16 @@
     class PermissionError(Exception):
         pass
 
+    def OrderedDict_move_to_end(od, key):
+        od[key] = od.pop(key)
+
+
 else:  # pragma: py2 no cover
 
     text_type = str
     binary_type = bytes
     from functools import reduce
     PermissionError = PermissionError
+
+    def OrderedDict_move_to_end(od, key):
+        od.move_to_end(key)

zarr/storage.py

@@ -28,10 +28,10 @@
                        normalize_storage_path, buffer_size,
                        normalize_fill_value, nolock, normalize_dtype)
 from zarr.meta import encode_array_metadata, encode_group_metadata
-from zarr.compat import PY2, binary_type
+from zarr.compat import PY2, binary_type, OrderedDict_move_to_end
 from numcodecs.registry import codec_registry
-from zarr.errors import (err_contains_group, err_contains_array, err_path_not_found,
-                         err_bad_compressor, err_fspath_exists_notdir, err_read_only)
+from zarr.errors import (err_contains_group, err_contains_array, err_bad_compressor,
+                         err_fspath_exists_notdir, err_read_only)
 
 
 array_meta_key = '.zarray'
@@ -1783,7 +1783,7 @@ def __getitem__(self, key):
                 # cache hit if no KeyError is raised
                 self.hits += 1
                 # treat the end as most recently used
-                self._values_cache.move_to_end(key)
+                OrderedDict_move_to_end(self._values_cache, key)
 
         except KeyError:
             # cache miss, retrieve value from the store

zarr/util.py

@@ -318,7 +318,10 @@ def buffer_size(v):
         return v.buffer_info()[1] * v.itemsize
     else:  # pragma: py2 no cover
         v = memoryview(v)
-        return reduce(operator.mul, v.shape, 1) * v.itemsize
+        if v.shape:
+            return reduce(operator.mul, v.shape) * v.itemsize
+        else:
+            return v.itemsize
 
 
 def info_text_report(items):