Module preflight

Structs§

HostFacts: What the caller measures through Win32, so this module stays testable off Windows.
Preflight: What execute reuses, so no archive is opened twice.

check_space 🔒: Room for what is written plus copies of what it replaces, doubled as if every file replaced one its size, which errs on the safe side.
check_writable: Whether this account can write to game_dir, asked when the user settles on it and before anything is installed, so it removes whatever the probe created: a folder the user then abandons keeps no trace.
preflight: Everything that can fail is checked before the first file is touched, since a failure after an uninstall leaves neither the old content nor the new.
probe_writable 🔒: Creates the state directory and a probe file in it.
verified_files 🔒: The files of the payload named by sha256, checked against it; by digest rather than through the index, which holds only the newest version, so a restore can name an older one.