Crate rusty_sponge 

rusty-sponge

A Rust port of the moreutils sponge utility: soak up all of stdin and write it atomically to a file. The library is the canonical surface; the CLI binary is a thin wrapper around run.

Quick start

use rusty_sponge::{SpongeBuilder, Target, CompatibilityMode};
use std::io::Cursor;
use std::path::PathBuf;

let mut sponge = SpongeBuilder::new()
    .target(Target::File(PathBuf::from("output.txt")))
    .append(false)
    .compat(CompatibilityMode::Default)
    .build()?;

sponge.run(Cursor::new(b"hello\nworld\n"))?;

Stability (lockstep SemVer)

The library and binary share a single crate version. Within the 0.x series, minor version bumps may introduce breaking changes per standard Cargo semantics. Every public enum and struct is #[non_exhaustive] so that variant additions are not breaking changes once 1.0 lands.

Atomic-safety guarantee

When writing to a regular non-symlink file, Sponge::run writes to a sibling tempfile in the target’s parent directory and atomically renames into place. Mid-write failures (panic, IO error, signal) leave the original file untouched. Symlink targets and the cross-volume fallback path explicitly forgo this guarantee — see the crate README for the full compatibility statement.

Re-exports

pub use error::Error;

Modules

atomic

Atomic in-place file rewrite: sibling tempfile + atomic rename.

buffer

Hybrid in-memory + tempfile-spill buffer for soaking up stdin.

cli

Command-line interface for rusty-sponge.

error

Library-level error type for rusty_sponge.

mode

Compatibility mode resolution.

signal

Signal-driven cleanup so an in-progress sibling tempfile is removed before the process exits on SIGINT/SIGTERM/SIGHUP (Unix) or CTRL_C_EVENT / CTRL_BREAK_EVENT / CTRL_CLOSE_EVENT (Windows).

strict

Strict moreutils-compat mode entry point.

writethrough

Non-atomic write-through path for symlink and reparse-point targets (FR-010).

Structs

Sponge

Runtime engine for one sponge invocation. Constructed via SpongeBuilder.

SpongeBuilder

Builder for Sponge. All chain methods are #[must_use].

Enums

CompatibilityMode

Whether to apply Default-mode ergonomic extensions or Strict moreutils parity.

Target

Where the buffered input should be delivered.

Constants

DEFAULT_SPILL_THRESHOLD

Default spill threshold (128 MiB).

Functions

run

Binary entry-point helper used by both src/main.rs and src/bin/sponge.rs.