Module flow 

The 10-step self-update flow. Pure functions + small helpers the crate::Updater composes.

The steps run in strict order — each precondition is checked and a failure leaves the disk in one of two states: the old binary untouched, or the new one fully verified and swapped in. No in-between.

Functions

cache_dir_for

Default cache dir — <project-cache-dir>/update/<version>/. Falls back to the system temp dir if directories-rs can’t resolve.

default_self_test_fn

Default SelfTestFn — exec <staged> --version with a 10 s timeout, return stdout. A non-zero exit or timeout surfaces as UpdateError::SelfTestFailed at the call site.

default_swap_fn

Default SwapFn — real self-replace call.

download_to_file

Stream asset into dest, returning the byte count. Emits Downloading progress events.

dry_run_outcome

Dry-run outcome shape — no swap.

extract_binary

Extract the binary matching tool_name from the archive at src into dest_dir. Returns the extracted binary’s path.

fetch_small_asset

Fully buffer an asset into memory. Returns the bytes. Used for signatures and checksum files, which are small.

mark_executable

Set POSIX executable bits on path. No-op on Windows.

parse_release_tag

Strip any leading v / V from a tag and parse as semver. Used for the check comparison and downgrade check.

swap_outcome

Swap outcome shape — after a successful self-replace.

Type Aliases

SelfTestFn

Self-test function — runs the staged binary with --version and returns its captured stdout. Lets tests avoid spawning a real child.

SwapFn

Swap function — lets tests substitute a double for self_replace::self_replace. Returns Ok iff the running binary has been replaced.