┌──────────────────────────────────────────────────┐
   │  c o d e c h u — f s                             │
   │   .                                              │
   │   ├── atomic_write()    safe.tmp -> fsync -> mv  │
   │   ├── move_to_trash()   ~/.local/share/Trash/    │
   │   ├── walk()            cancellable + loop-safe  │
   │   └── mountpoint()      /proc/mounts aware       │
   └──────────────────────────────────────────────────┘

Filesystem primitives for tools that must not lose data.

codechu-fs

Stdlib-only filesystem helpers — atomic writes, XDG trash, cancellable walks, mount discovery — extracted from the Disk Cleaner toolchain. Zero third-party dependencies. Python 3.10+.

What it gives you

• atomic_write — tempfile in the same dir, fsync, then rename. Preserves existing permissions. Either bytes or text (with encoding).
• move_to_trash — freedesktop XDG Trash Specification compliant. Honors XDG_DATA_HOME, writes a .trashinfo, resolves name collisions.
• walk — os.walk with three things os.walk is missing: a cancel Event for cooperative shutdown, an on_error callback (no silent swallow), and symlink-loop detection when following links.
• recursive_size — sum of bytes under a directory, cancellable.
• mountpoint — the mount that contains a path, parsed from /proc/mounts on Linux with a st_dev fallback elsewhere.
• is_safe_path — path-traversal guard for user-supplied inputs.
• temp_dir — context-managed temp directory, auto-removed.

Install

pip install codechu-fs

Quick examples

from pathlib import Path
from threading import Event
from codechu_fs import (
    atomic_write, move_to_trash, walk, recursive_size,
    mountpoint, is_safe_path, temp_dir,
)

# Durable write — never leaves a half-written file even if you crash mid-write.
atomic_write("/etc/myapp/config.json", b'{"k":1}\n')
atomic_write("notes.txt", "hello\n", encoding="utf-8")

# Send a file to the desktop trash (recoverable from the file manager).
trashed = move_to_trash("/tmp/junk.log")
print("now at:", trashed)

# Cancellable walk — stop instantly when the user clicks Cancel.
cancel = Event()
for dirpath, dirnames, filenames in walk("/var/log", cancel=cancel):
    if some_condition():
        cancel.set()

# Total size of a directory tree (skips unreadable files).
print(recursive_size(Path.home() / "Downloads"))

# What partition is this on?
print(mountpoint("/var/log/syslog"))   # → /var, or / on most systems

# Safe extraction of an untrusted filename.
if is_safe_path(user_input, base="/srv/uploads"):
    ...

# Scratch space that always cleans up.
with temp_dir(prefix="myapp-") as scratch:
    (scratch / "work.bin").write_bytes(b"...")

Design

• Pure stdlib. Zero third-party dependencies. Seven small modules.
• Defensive. walk never swallows errors silently. atomic_write fsyncs before rename. move_to_trash rolls back its .trashinfo on failure.
• Cancellable. Every traversal accepts a threading.Event. Long scans on slow disks remain responsive in GUI apps.

Tests

pip install -e ".[dev]"
pytest -q

Documentation

• API reference — every public symbol, signatures, edge cases
• Recipes — five idiomatic patterns for CLIs and GUIs

License

MIT — see LICENSE.