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
from fsspec import AbstractFileSystem
from fsspec.implementations.local import LocalFileSystem
from fsspec.utils import stringify_path, tokenize
logger = logging.getLogger("fsspec.memoryfs")
[docs]
class MemoryFileSystem(AbstractFileSystem):
"""A filesystem based on a dict of BytesIO objects
By default, instances share a global in-memory filesystem. Pass
``global_store=False, skip_instance_cache=True`` to create a new instance
with an independent store instead.
"""
store: dict[str, Any] = {} # shared by default
pseudo_dirs = [""] # shared by default
protocol = "memory"
root_marker = "/"
[docs]
def __init__(self, *args, global_store=True, **kwargs):
"""Create a memory filesystem.
Parameters
----------
global_store: bool
Share files and directories with other default instances. If False,
each instance starts with an empty, independent store. The normal
instance cache still applies; pass ``skip_instance_cache=True``
to create a new instance on every call. Pickling an
independent filesystem copies its files and directories; pickling a
global filesystem retains the reference to the global store.
"""
super().__init__(*args, **kwargs)
self.global_store = global_store
if not global_store:
self.store = {}
self.pseudo_dirs = [""]
@property
def _fs_token(self):
if self.global_store:
return super()._fs_token
return tokenize(super()._fs_token, id(self))
def __reduce__(self):
reduced = super().__reduce__()
if self.global_store:
return reduced
factory, (cls, args, kwargs) = reduced
# Restore into a new instance even when the source is cached.
kwargs = {**kwargs, "skip_instance_cache": True}
# Pickle's memo preserves the cycle through each MemoryFile.fs.
return (
factory,
(cls, args, kwargs),
{"store": self.store, "pseudo_dirs": self.pseudo_dirs},
)
@classmethod
def _strip_protocol(cls, path):
if isinstance(path, PurePath):
if isinstance(path, PureWindowsPath):
return LocalFileSystem._strip_protocol(path)
else:
path = stringify_path(path)
path = path.removeprefix("memory://")
if "::" in path or "://" in path:
return path.rstrip("/")
path = path.lstrip("/").rstrip("/")
return "/" + path if path else ""
def find(self, path, maxdepth=None, withdirs=False, detail=False, **kwargs):
# The base implementation calls ls() once per directory, and each ls()
# scans the whole store, giving O(n_dirs * n_entries) behaviour
# for a tree. Since the store is a flat mapping of every path, the same
# result can be produced with a single pass over it.
if maxdepth is not None and maxdepth < 1:
raise ValueError("maxdepth must be at least 1")
path = self._strip_protocol(path)
if path in self.store:
# path is itself a file
if not detail:
return [path]
filelike = self.store[path]
return {
path: {
"name": path,
"size": filelike.size,
"type": "file",
"created": filelike.created.timestamp(),
}
}
# Uniform prefix so that the search root "" (the filesystem root) and a
# nested path are handled the same way; rel depth is rel.count("/") + 1.
prefix = path + "/" if path else "/"
out = {}
dirs = {}
def add_ancestor_dirs(name):
# Register every directory implied between ``path`` and ``name`` that
# is within maxdepth, mirroring how walk() surfaces implied dirs.
idx = name.rfind("/")
while idx > len(path):
parent = name[:idx]
if parent in dirs:
break
rel = parent[len(prefix) :]
if maxdepth is None or rel.count("/") + 1 <= maxdepth:
dirs[parent] = {"name": parent, "size": 0, "type": "directory"}
idx = parent.rfind("/")
# `store` may be shared by multiple MemoryFileSystem instances, so iterate a
# snapshot: a concurrent create/delete would otherwise raise
# "dictionary changed size during iteration". ls() does the same.
for name, filelike in tuple(self.store.items()):
if not name.startswith(prefix):
continue
rel = name[len(prefix) :]
if withdirs:
add_ancestor_dirs(name)
if maxdepth is not None and rel.count("/") + 1 > maxdepth:
continue
out[name] = {
"name": name,
"size": filelike.size,
"type": "file",
"created": filelike.created.timestamp(),
}
if withdirs:
# Explicitly-created (possibly empty) directories live in pseudo_dirs.
for pdir in self.pseudo_dirs:
if pdir and pdir.startswith(prefix):
add_ancestor_dirs(pdir + "/")
out.update(dirs)
# Mirror the base find(): include the search root itself when it is
# a directory (needed for posix glob compliance).
if path != "" and self.isdir(path):
out[path] = self.info(path)
names = sorted(out)
return {name: out[name] for name in names} if detail else names
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, mode="overwrite", **kwargs):
"""Set the bytes of given file
Avoids copies of the data if possible
"""
mode = "xb" if mode == "create" else "wb"
self.open(path, mode=mode, 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 "x" in mode and self.exists(path):
raise FileExistsError
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", "a+b"]:
if path in self.store:
f = self.store[path]
if "a" in mode:
# position at the end of file
f.seek(0, 2)
else:
# position at the beginning of file
f.seek(0)
return f
elif "a" in mode:
# append modes create the file if it does not exist, matching
# builtin open() and LocalFileSystem
m = MemoryFile(self, path, kwargs.get("data"))
if not self._intrans:
m.commit()
# position at the end of file, like the existing-file path above
m.seek(0, 2)
return m
else:
raise FileNotFoundError(path)
elif mode in {"wb", "w+b", "xb", "x+b"}:
if "x" in mode and self.exists(path):
raise FileExistsError
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)
# A non-recursive expand keeps a literal path whether or not it exists,
# so record what exists before anything is deleted.
existed = {p for p in paths if self.exists(p)}
for p in reversed(paths):
if self.isfile(p):
self.rm_file(p)
elif not self.exists(p):
# A directory that is not in self.pseudo_dirs only exists while it
# has files under it, so deleting those files earlier in this loop
# makes it vanish. That is expected; a path that never existed is
# not, and raises like rm_file and the other filesystems do.
if p not in existed:
raise FileNotFoundError(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)