Initial import of verae-archive-worm from zapier monorepo

src/archive.js

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+/**
+ * In-process WORM archive: append-only records + bloom.
+ * @module archive
+ */
+
+import { Bloom } from './bloom.js';
+
+export class WormArchive {
+  /**
+   * @param {string} archiveId
+   */
+  constructor(archiveId) {
+    this.archiveId = archiveId;
+    this.bloom = new Bloom();
+    /** @type {Map<string, object[]>} */
+    this.byHash = new Map();
+  }
+
+  /**
+   * @param {{ sha256: string, kind: string, record: object }} put
+   */
+  put(put) {
+    const key = String(put.sha256).toLowerCase();
+    const list = this.byHash.get(key) ?? [];
+    list.push({ kind: put.kind, record: put.record, archiveId: this.archiveId, storedAt: new Date().toISOString() });
+    this.byHash.set(key, list);
+    this.bloom.add(key);
+  }
+
+  /**
+   * Bloom miss → null (caller must stay silent). Hit → records (may be empty if false positive).
+   * @param {string} sha256
+   * @returns {object[]|null}
+   */
+  query(sha256) {
+    const key = String(sha256).toLowerCase();
+    if (!this.bloom.mightHave(key)) return null;
+    return this.byHash.get(key) ?? [];
+  }
+}

src/bloom.js

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+/**
+ * Tiny Bloom filter for SHA256 membership (false positives ok).
+ * @module bloom
+ */
+
+import { createHash } from 'node:crypto';
+
+export class Bloom {
+  /**
+   * @param {number} [m=16384] bit count
+   * @param {number} [k=4] hash rounds
+   */
+  constructor(m = 16384, k = 4) {
+    this.m = m;
+    this.k = k;
+    this.bits = Buffer.alloc(Math.ceil(m / 8));
+  }
+
+  /**
+   * @param {string} s
+   * @returns {number[]}
+   */
+  hashes(s) {
+    const digest = createHash('sha256').update(String(s)).digest();
+    const out = [];
+    for (let i = 0; i < this.k; i += 1) {
+      const n = digest.readUInt32BE((i * 4) % 28);
+      out.push(n % this.m);
+    }
+    return out;
+  }
+
+  add(s) {
+    for (const i of this.hashes(s)) {
+      this.bits[i >> 3] |= 1 << (i & 7);
+    }
+  }
+
+  /**
+   * @param {string} s
+   * @returns {boolean} maybe (never a guaranteed yes)
+   */
+  mightHave(s) {
+    return this.hashes(s).every((i) => (this.bits[i >> 3] & (1 << (i & 7))) !== 0);
+  }
+}