Module ui_bundle_resolver 

red ui bundle resolver — pin→URL resolution, HTTPS download, SHA-256 verification, tgz extraction, and local cache management.

Implements the runtime download path described in ADR 0050:

1. The pinned red-ui version and its bundle SHA-256 are build-time constants set by CI (RED_UI_PINNED_VERSION / RED_UI_PINNED_SHA256).
2. resolve_ui_bundle checks ~/.cache/reddb/ui/<version>/ for a cached bundle whose manifest matches the pin. Cache hit → returns the directory immediately (no network call).
3. On a cache miss it downloads the GitHub release asset, verifies the SHA-256 (refuses on mismatch), extracts the tgz into a staging directory, writes a manifest, and atomically promotes the staging directory to the live version directory.
4. Offline first-run with no cached bundle fails with a clear, actionable io::Error message.

The UiBundleFetcher trait makes the network layer injectable for tests.

Structs

HttpFetcher

Production fetcher — HTTPS via ureq with rustls, per ADR 0050.

Constants

RED_UI_PINNED_SHA256

SHA-256 (lower-case hex) of the ui-dist.tgz for the pinned version. CI sets this alongside RED_UI_PINNED_VERSION.

RED_UI_PINNED_VERSION

Exact red-ui version this red binary was tested against. CI that validates the red↔red-ui pair sets this before the release build.

Traits

UiBundleFetcher

Abstraction over the network layer so tests can inject a fake without making real HTTP calls.

Functions

reddb_user_cache_root

Compute ~/.cache/reddb (XDG-aware on Linux, standard on macOS/Windows).

release_asset_url

GitHub release asset URL for a given red-ui version.

resolve_ui_bundle

Ensure the pinned red-ui bundle is cached and return its directory.