feat(ingest): content-addressed blob store

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

lib/ingest/blob_store.js

@@ -0,0 +1,34 @@
+import crypto from 'node:crypto';
+import fs from 'node:fs/promises';
+import path from 'node:path';
+
+export class BlobStore {
+  constructor(root) { this.root = root; }
+
+  async hash(buf) {
+    return crypto.createHash('sha256').update(buf).digest('hex');
+  }
+
+  path(sha) {
+    return path.join(this.root, sha.slice(0, 2), sha);
+  }
+
+  async write(buf) {
+    const sha = await this.hash(buf);
+    const dest = this.path(sha);
+    try {
+      await fs.access(dest);
+    } catch {
+      await fs.mkdir(path.dirname(dest), { recursive: true });
+      await fs.writeFile(dest, buf);
+    }
+    return { sha, path: dest };
+  }
+}
+
+let _default = null;
+export function defaultStore() {
+  const root = process.env.BLOB_ROOT || '/var/lib/void/blobs';
+  if (!_default || _default.root !== root) _default = new BlobStore(root);
+  return _default;
+}

tests/ingest/blob_store.test.js

@@ -0,0 +1,38 @@
+import { describe, it, expect, beforeEach } from 'vitest';
+import fs from 'node:fs/promises';
+import path from 'node:path';
+import os from 'node:os';
+import { BlobStore } from '../../lib/ingest/blob_store.js';
+
+let root, store;
+beforeEach(async () => {
+  root = await fs.mkdtemp(path.join(os.tmpdir(), 'void-blob-'));
+  store = new BlobStore(root);
+});
+
+describe('blob_store', () => {
+  it('hashes content and resolves a sharded path', async () => {
+    const buf = Buffer.from('void');
+    const sha = await store.hash(buf);
+    expect(sha).toMatch(/^[0-9a-f]{64}$/);
+    const p = store.path(sha);
+    expect(p.startsWith(root)).toBe(true);
+    expect(p.includes(sha.slice(0, 2))).toBe(true);
+  });
+
+  it('write is idempotent on identical content', async () => {
+    const buf = Buffer.from('void');
+    const a = await store.write(buf);
+    const b = await store.write(buf);
+    expect(a.path).toBe(b.path);
+    expect(a.sha).toBe(b.sha);
+    const onDisk = await fs.readFile(a.path);
+    expect(onDisk.equals(buf)).toBe(true);
+  });
+
+  it('distinct content gets distinct paths', async () => {
+    const a = await store.write(Buffer.from('void-one'));
+    const b = await store.write(Buffer.from('void-two'));
+    expect(a.path).not.toBe(b.path);
+  });
+});