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") 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) 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 (global) 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` is shared by every MemoryFileSystem instance, 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) 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)