REF: de-duplicate CoW helpers (#53899)

Author: jbrockmendel

pandas/core/internals/blocks.py

@@ -583,20 +583,6 @@ def _maybe_copy(self, using_cow: bool, inplace: bool) -> Self:
  blk = self if inplace else self.copy()
  return blk
 
- @final
- def _get_values_and_refs(self, using_cow, inplace):
- if using_cow:
- if inplace and not self.refs.has_reference():
- refs = self.refs
- new_values = self.values
- else:
- refs = None
- new_values = self.values.copy()
- else:
- refs = None
- new_values = self.values if inplace else self.values.copy()
- return new_values, refs
-
  @final
  def _get_refs_and_copy(self, using_cow: bool, inplace: bool):
  refs = None
@@ -738,11 +724,10 @@ def _replace_regex(
 
  rx = re.compile(to_replace)
 
- new_values, refs = self._get_values_and_refs(using_cow, inplace)
+ block = self._maybe_copy(using_cow, inplace)
 
- replace_regex(new_values, rx, value, mask)
+ replace_regex(block.values, rx, value, mask)
 
- block = self.make_block(new_values, refs=refs)
  return block.convert(copy=False, using_cow=using_cow)
 
  @final