@prof-bilal/atlas-hashing

SHA-256 hashing and change detection for CodeAtlas. This module powers incremental updates: it hashes every file, persists the hashes as a JSON snapshot, and can tell you exactly which files changed, were deleted, or are new between runs.

Implements HashPort from @prof-bilal/atlas-core.

Features

• SHA-256 digest for every file (getHash) and for raw strings (hashContent).
• Snapshots — persist hashes to a versioned JSON file (saveSnapshot / loadSnapshot).
• Change detection — compareHashes classifies every known path as changed, added, deleted, or unchanged.
• getChangedFiles returns the paths needing re-processing (changed + added).

Usage

import { HashService } from "@prof-bilal/atlas-hashing";

const hasher = new HashService();

// 1. Hash all current files into a snapshot.
const current = await hasher.buildSnapshot(["/repo/a.ts", "/repo/b.ts"]);
await hasher.saveSnapshot(current.value, "/repo/.codeatlas/hashes.json");

// 2. On a later run, compare with the stored snapshot.
const previous = await hasher.loadSnapshot("/repo/.codeatlas/hashes.json");
const diff = hasher.compareHashes(previous.value, current.value);

Storage

Hashes are stored as JSON (.codeatlas/hashes.json), with a version field for future migrations. SQLite can be added later behind the same port.

Public API

• hashContent(content) — SHA-256 hex of a string.
• getHash(path) — SHA-256 hex of a file on disk.
• buildSnapshot(paths) — build a snapshot from a set of file paths.
• compareHashes(previous, current) — classify changed/added/deleted/unchanged.
• getChangedFiles(previous, current) — list of files to re-process.
• saveSnapshot(snapshot, path) / loadSnapshot(path) — JSON persistence.
• HashService — the HashPort implementation.