from __future__ import annotations
import logging
from datetime import datetime, timezone
from errno import ENOTEMPTY
from io import BytesIO
from pathlib import PurePath, PureWindowsPath
from typing import Any, ClassVar
from fsspec import AbstractFileSystem
from fsspec.implementations.local import LocalFileSystem
from fsspec.utils import stringify_path
logger = logging.getLogger("fsspec.memoryfs")
[docs]
class MemoryFileSystem(AbstractFileSystem):
"""A filesystem based on a dict of BytesIO objects
This is a global filesystem so instances of this class all point to the same
in memory filesystem.
"""
store: ClassVar[dict[str, Any]] = {} # global, do not overwrite!
pseudo_dirs = [""] # global, do not overwrite!
protocol = "memory"
root_marker = "/"
@classmethod
def _strip_protocol(cls, path):
if isinstance(path, PurePath):
if isinstance(path, PureWindowsPath):
return LocalFileSystem._strip_protocol(path)
else:
path = stringify_path(path)
if path.startswith("memory://"):
path = path[len("memory://") :]
if "::" in path or "://" in path:
return path.rstrip("/")
path = path.lstrip("/").rstrip("/")
return "/" + path if path else ""
def ls(self, path, detail=True, **kwargs):
path = self._strip_protocol(path)
if path in self.store:
# there is a key with this exact name
if not detail:
return [path]
return [
{
"name": path,
"size": self.store[path].size,
"type": "file",
"created": self.store[path].created.timestamp(),
}
]
paths = set()
starter = path + "/"
out = []
for p2 in tuple(self.store):
if p2.startswith(starter):
if "/" not in p2[len(starter) :]:
# exact child
out.append(
{
"name": p2,
"size": self.store[p2].size,
"type": "file",
"created": self.store[p2].created.timestamp(),
}
)
elif len(p2) > len(starter):
# implied child directory
ppath = starter + p2[len(starter) :].split("/", 1)[0]
if ppath not in paths:
out = out or []
out.append(
{
"name": ppath,
"size": 0,
"type": "directory",
}
)
paths.add(ppath)
for p2 in self.pseudo_dirs:
if p2.startswith(starter):
if "/" not in p2[len(starter) :]:
# exact child pdir
if p2 not in paths:
out.append({"name": p2, "size": 0, "type": "directory"})
paths.add(p2)
else:
# directory implied by deeper pdir
ppath = starter + p2[len(starter) :].split("/", 1)[0]
if ppath not in paths:
out.append({"name": ppath, "size": 0, "type": "directory"})
paths.add(ppath)
if not out:
if path in self.pseudo_dirs:
# empty dir
return []
raise FileNotFoundError(path)
if detail:
return out
return sorted([f["name"] for f in out])
def mkdir(self, path, create_parents=True, **kwargs):
path = self._strip_protocol(path)
if path in self.store or path in self.pseudo_dirs:
raise FileExistsError(path)
if self._parent(path).strip("/") and self.isfile(self._parent(path)):
raise NotADirectoryError(self._parent(path))
if create_parents and self._parent(path).strip("/"):
try:
self.mkdir(self._parent(path), create_parents, **kwargs)
except FileExistsError:
pass
if path and path not in self.pseudo_dirs:
self.pseudo_dirs.append(path)
def makedirs(self, path, exist_ok=False):
try:
self.mkdir(path, create_parents=True)
except FileExistsError:
if not exist_ok:
raise
def pipe_file(self, path, value, **kwargs):
"""Set the bytes of given file
Avoids copies of the data if possible
"""
self.open(path, "wb", data=value)
def rmdir(self, path):
path = self._strip_protocol(path)
if path == "":
# silently avoid deleting FS root
return
if path in self.pseudo_dirs:
if not self.ls(path):
self.pseudo_dirs.remove(path)
else:
raise OSError(ENOTEMPTY, "Directory not empty", path)
else:
raise FileNotFoundError(path)
def info(self, path, **kwargs):
logger.debug("info: %s", path)
path = self._strip_protocol(path)
if path in self.pseudo_dirs or any(
p.startswith(path + "/") for p in list(self.store) + self.pseudo_dirs
):
return {
"name": path,
"size": 0,
"type": "directory",
}
elif path in self.store:
filelike = self.store[path]
return {
"name": path,
"size": filelike.size,
"type": "file",
"created": getattr(filelike, "created", None),
}
else:
raise FileNotFoundError(path)
def _open(
self,
path,
mode="rb",
block_size=None,
autocommit=True,
cache_options=None,
**kwargs,
):
path = self._strip_protocol(path)
if path in self.pseudo_dirs:
raise IsADirectoryError(path)
parent = path
while len(parent) > 1:
parent = self._parent(parent)
if self.isfile(parent):
raise FileExistsError(parent)
if mode in ["rb", "ab", "r+b"]:
if path in self.store:
f = self.store[path]
if mode == "ab":
# position at the end of file
f.seek(0, 2)
else:
# position at the beginning of file
f.seek(0)
return f
else:
raise FileNotFoundError(path)
elif mode == "wb":
m = MemoryFile(self, path, kwargs.get("data"))
if not self._intrans:
m.commit()
return m
else:
name = self.__class__.__name__
raise ValueError(f"unsupported file mode for {name}: {mode!r}")
def cp_file(self, path1, path2, **kwargs):
path1 = self._strip_protocol(path1)
path2 = self._strip_protocol(path2)
if self.isfile(path1):
self.store[path2] = MemoryFile(
self, path2, self.store[path1].getvalue()
) # implicit copy
elif self.isdir(path1):
if path2 not in self.pseudo_dirs:
self.pseudo_dirs.append(path2)
else:
raise FileNotFoundError(path1)
def cat_file(self, path, start=None, end=None, **kwargs):
logger.debug("cat: %s", path)
path = self._strip_protocol(path)
try:
return bytes(self.store[path].getbuffer()[start:end])
except KeyError as e:
raise FileNotFoundError(path) from e
def _rm(self, path):
path = self._strip_protocol(path)
try:
del self.store[path]
except KeyError as e:
raise FileNotFoundError(path) from e
def modified(self, path):
path = self._strip_protocol(path)
try:
return self.store[path].modified
except KeyError as e:
raise FileNotFoundError(path) from e
def created(self, path):
path = self._strip_protocol(path)
try:
return self.store[path].created
except KeyError as e:
raise FileNotFoundError(path) from e
def isfile(self, path):
path = self._strip_protocol(path)
return path in self.store
def rm(self, path, recursive=False, maxdepth=None):
if isinstance(path, str):
path = self._strip_protocol(path)
else:
path = [self._strip_protocol(p) for p in path]
paths = self.expand_path(path, recursive=recursive, maxdepth=maxdepth)
for p in reversed(paths):
if self.isfile(p):
self.rm_file(p)
# If the expanded path doesn't exist, it is only because the expanded
# path was a directory that does not exist in self.pseudo_dirs. This
# is possible if you directly create files without making the
# directories first.
elif not self.exists(p):
continue
else:
self.rmdir(p)
class MemoryFile(BytesIO):
"""A BytesIO which can't close and works as a context manager
Can initialise with data. Each path should only be active once at any moment.
No need to provide fs, path if auto-committing (default)
"""
def __init__(self, fs=None, path=None, data=None):
logger.debug("open file %s", path)
self.fs = fs
self.path = path
self.created = datetime.now(tz=timezone.utc)
self.modified = datetime.now(tz=timezone.utc)
if data:
super().__init__(data)
self.seek(0)
@property
def size(self):
return self.getbuffer().nbytes
def __enter__(self):
return self
def close(self):
pass
def discard(self):
pass
def commit(self):
self.fs.store[self.path] = self
self.modified = datetime.now(tz=timezone.utc)