Crate arcbox_atomic_file 

Atomic file replacement with a durable rename.

Write a private temp sibling, fsync it, rename it over the destination, then fsync the parent directory so the rename itself survives a crash. Either the old contents or the new ones are visible at every instant; a reader never sees a truncated file.

Two failures, not one

The point of this crate is that the two ways it can fail mean different things, and callers legitimately treat them differently:

• AtomicWriteError::NotCommitted — the destination was never touched and the temp file is cleaned up. The caller simply failed.
• AtomicWriteError::DurabilityUncertain — the new contents are already visible, but the directory fsync confirming the rename did not complete, so a power loss could still resurrect the old ones.

A catalog that must not lie about what it persisted treats the second as an error; a record store that would rather keep the record and warn treats it as a warning. So this crate reports which happened and lets the caller decide, rather than picking one policy for everyone.

Enums

AtomicWriteError

How an atomic write failed.

Functions

write

Atomically replaces destination with bytes, durably.