def _maybe_memory_map(
handle: FileOrBuffer,
memory_map: bool,
encoding: str,
mode: str,
errors: str | None,
decode: bool,
) -> tuple[FileOrBuffer, bool, list[Buffer]]:
"""Try to memory map file/buffer."""
handles: list[Buffer] = []
memory_map &= hasattr(handle, "fileno") or isinstance(handle, str)
if not memory_map:
return handle, memory_map, handles
# need to open the file first
if isinstance(handle, str):
if encoding and "b" not in mode:
# Encoding
handle = open(handle,
mode,
encoding=encoding,
errors=errors,
newline="")
else:
# Binary mode
handle = open(handle, mode)
handles.append(handle)
try:
# error: Argument 1 to "_MMapWrapper" has incompatible type "Union[IO[Any],
# RawIOBase, BufferedIOBase, TextIOBase, mmap]"; expected "IO[Any]"
wrapped = cast(
mmap.mmap,
_MMapWrapper(handle, encoding, errors,
decode), # type: ignore[arg-type]
)
handle.close()
handles.remove(handle)
handles.append(wrapped)
handle = wrapped
except Exception:
# we catch any errors that may have occurred
# because that is consistent with the lower-level
# functionality of the C engine (pd.read_csv), so
# leave the file handler as is then
memory_map = False
return handle, memory_map, handles
def _maybe_memory_map(
handle: FileOrBuffer,
memory_map: bool,
encoding: str,
mode: str,
errors: Optional[str],
) -> Tuple[FileOrBuffer, bool, List[Buffer]]:
"""Try to memory map file/buffer."""
handles: List[Buffer] = []
memory_map &= hasattr(handle, "fileno") or isinstance(handle, str)
if not memory_map:
return handle, memory_map, handles
# need to open the file first
if isinstance(handle, str):
if encoding and "b" not in mode:
# Encoding
handle = open(handle,
mode,
encoding=encoding,
errors=errors,
newline="")
else:
# Binary mode
handle = open(handle, mode)
handles.append(handle)
try:
wrapped = cast(mmap.mmap,
_MMapWrapper(handle)) # type: ignore[arg-type]
handle.close()
handles.remove(handle)
handles.append(wrapped)
handle = wrapped
except Exception:
# we catch any errors that may have occurred
# because that is consistent with the lower-level
# functionality of the C engine (pd.read_csv), so
# leave the file handler as is then
memory_map = False
return handle, memory_map, handles