REF: de-duplicate consolidation methods (pandas-dev#42822)

Author: jbrockmendel

pandas/core/internals/array_manager.py

@@ -167,15 +167,6 @@ def set_axis(self, axis: int, new_labels: Index) -> None:
         axis = self._normalize_axis(axis)
         self._axes[axis] = new_labels
 
-    def consolidate(self: T) -> T:
-        return self
-
-    def is_consolidated(self) -> bool:
-        return True
-
-    def _consolidate_inplace(self) -> None:
-        pass
-
     def get_dtypes(self):
         return np.array([arr.dtype for arr in self.arrays], dtype="object")
 
@@ -1262,9 +1253,6 @@ def _can_hold_na(self) -> bool:
     def is_single_block(self) -> bool:
         return True
 
-    def _consolidate_check(self):
-        pass
-
     def fast_xs(self, loc: int) -> ArrayLike:
         raise NotImplementedError("Use series._values[loc] instead")
 

pandas/core/internals/base.py

@@ -33,6 +33,7 @@ class DataManager(PandasObject):
     def items(self) -> Index:
         raise AbstractMethodError(self)
 
+    @final
     def __len__(self) -> int:
         return len(self.items)
 
@@ -105,6 +106,7 @@ def _equal_values(self: T, other: T) -> bool:
         """
         raise AbstractMethodError(self)
 
+    @final
     def equals(self, other: object) -> bool:
         """
         Implementation for DataFrame.equals
@@ -129,13 +131,27 @@ def apply(
     ) -> T:
         raise AbstractMethodError(self)
 
+    @final
     def isna(self: T, func) -> T:
         return self.apply("apply", func=func)
 
+    # --------------------------------------------------------------------
+    # Consolidation: No-ops for all but BlockManager
+
+    def is_consolidated(self) -> bool:
+        return True
+
+    def consolidate(self: T) -> T:
+        return self
+
+    def _consolidate_inplace(self) -> None:
+        return
+
 
 class SingleDataManager(DataManager):
     ndim = 1
 
+    @final
     @property
     def array(self):
         """

pandas/core/internals/managers.py

@@ -465,19 +465,6 @@ def to_native_types(self: T, **kwargs) -> T:
         """
         return self.apply("to_native_types", **kwargs)
 
-    def is_consolidated(self) -> bool:
-        """
-        Return True if more than one block with the same dtype
-        """
-        if not self._known_consolidated:
-            self._consolidate_check()
-        return self._is_consolidated
-
-    def _consolidate_check(self) -> None:
-        dtypes = [blk.dtype for blk in self.blocks if blk._can_consolidate]
-        self._is_consolidated = len(dtypes) == len(set(dtypes))
-        self._known_consolidated = True
-
     @property
     def is_numeric_mixed_type(self) -> bool:
         return all(block.is_numeric for block in self.blocks)
@@ -623,13 +610,6 @@ def consolidate(self: T) -> T:
         bm._consolidate_inplace()
         return bm
 
-    def _consolidate_inplace(self) -> None:
-        if not self.is_consolidated():
-            self.blocks = tuple(_consolidate(self.blocks))
-            self._is_consolidated = True
-            self._known_consolidated = True
-            self._rebuild_blknos_and_blklocs()
-
     def reindex_indexer(
         self: T,
         new_axis: Index,
@@ -1551,6 +1531,29 @@ def _interleave(
 
         return result
 
+    # ----------------------------------------------------------------
+    # Consolidation
+
+    def is_consolidated(self) -> bool:
+        """
+        Return True if more than one block with the same dtype
+        """
+        if not self._known_consolidated:
+            self._consolidate_check()
+        return self._is_consolidated
+
+    def _consolidate_check(self) -> None:
+        dtypes = [blk.dtype for blk in self.blocks if blk._can_consolidate]
+        self._is_consolidated = len(dtypes) == len(set(dtypes))
+        self._known_consolidated = True
+
+    def _consolidate_inplace(self) -> None:
+        if not self.is_consolidated():
+            self.blocks = tuple(_consolidate(self.blocks))
+            self._is_consolidated = True
+            self._known_consolidated = True
+            self._rebuild_blknos_and_blklocs()
+
 
 class SingleBlockManager(BaseBlockManager, SingleDataManager):
     """manage a single block with"""
@@ -1710,15 +1713,6 @@ def array_values(self):
     def _can_hold_na(self) -> bool:
         return self._block._can_hold_na
 
-    def is_consolidated(self) -> bool:
-        return True
-
-    def _consolidate_check(self):
-        pass
-
-    def _consolidate_inplace(self):
-        pass
-
     def idelete(self, indexer) -> SingleBlockManager:
         """
         Delete single location from SingleBlockManager.