Module model_download 

Model download and management system.

This module handles:

• Model manifest with SHA256 checksums
• State machine for download lifecycle
• Resumable downloads with progress reporting
• SHA256 verification
• Atomic installation (temp dir -> rename)
• Model version upgrade detection

Note: The core types (ModelState, ModelFile, ModelManifest) are structurally identical to those in frankensearch_embed::model_manifest. They are kept locally for now due to build-system sync constraints. See frankensearch-embed for the canonical definitions.

Network Policy: No network calls occur without explicit user consent. The download system is consent-gated via ModelState::NeedsConsent.

Structs

DownloadProgress

Download progress information.

ModelAcquisitionPolicy

Policy inputs that constrain semantic model acquisition.

ModelCacheReport

Machine-readable report for semantic model cache lifecycle decisions.

ModelDownloader

Model downloader with resumption and verification.

ModelFile

A file in the model manifest.

ModelManifest

Model manifest describing a downloadable model.

Enums

DownloadError

Download error types.

ModelCacheState

Precise on-disk semantic model cache state.

ModelState

Model state machine for download lifecycle.

Constants

PLACEHOLDER_CHECKSUM

Placeholder checksum value used for unverified manifests.

Functions

check_model_installed

Check if a model is installed and verified against the given manifest.

check_version_mismatch

Check for model version mismatch.

classify_model_cache

Classify the local semantic model cache without performing network I/O.

compute_sha256

Compute SHA256 hash of a file.

model_file_path

Resolve a manifest file on disk.

normalize_mirror_base_url

Validate and normalize a mirror base URL for model downloads.

Type Aliases

ProgressCallback

Progress callback for downloads.