Module mem_cache 

Read-mem cache resolution, published-config reads, and the install-to-cache side effect.

Every sealed-archive byte entering the cache goes through validate_and_normalize_archive — the install path reads the submitted archive, hands the bytes to the validator, and writes the validator’s canonical_bytes via a temp-plus-atomic-rename so no partial archive ever lands on disk. Steady-state loads (through read_published_config or the entity loader) trust the cached bytes: they were canonical at write time and re-validation on every load would just pay for the same work twice.

The cache base path resolves via dirs::data_dir() so the same path works on macOS (~/Library/Application Support/memstead/mems), Linux ($XDG_DATA_HOME/memstead/mems or ~/.local/share/memstead/mems), and Windows (%APPDATA%\memstead\mems). For tests, MEMSTEAD_MEM_CACHE overrides the base so temp dirs can stand in without touching the user’s real data directory.

Structs

CacheInstallOutcome

Install a sealed mem archive into the global cache and register it in a writable mem’s config. Accepts the .mem archive format.

Enums

InstallError

MountRegistration

What happened on the mount-registration side of an install.

Constants

CACHE_OVERRIDE_ENV

Env var that overrides <data_dir>/memstead/mems for tests.

Functions

install_to_cache

Validate an archive and land it in the global content-addressed cache — the cache-side half of memstead install, with no config or mount side effects (the caller registers the returned archive as a workspace-level read-only mount). Shares the validator, the shadow-name gate, and the content-addressed atomic-rename write with the historical combined path.

mem_cache_dir

Resolve the global mem-cache directory.

read_published_config

Read the whitelisted .memstead/config.json from a cached archive.

register_cached_archive

Register a cached archive (the outcome of install_to_cache) as a workspace-level read-only mount on the live engine — the shared back half of memstead install and the MCP server’s --read-mem boot flag. Idempotent per content: an existing read-only mount under the same name is a no-op when it already points at this cache file, and an in-place refresh (unregister + re-register) when the content changed. The caller persists the mount state (engine.persist_state()) after a Registered / Refreshed outcome.