Initial commit

2026-08-07 22:13:25 -05:00
commit 8006fd67f3
40 changed files with 11017 additions and 0 deletions
--- a/shared/utils/drop-contract.ts
+++ b/shared/utils/drop-contract.ts
@@ -0,0 +1,121 @@
+import {
+  CHUNK_SIZE,
+  EXPIRY_VALUES,
+  GCM_TAG_BYTES,
+  MAX_CHUNK_BODY,
+  MAX_MANIFEST_BODY,
+  MAX_MANIFEST_PLAINTEXT,
+  PROTOCOL_VERSION,
+  READ_VALUES,
+  LEASE_IDLE_MS,
+  UPLOAD_RESERVATION_MS,
+  type ExpiryChoice,
+  type ReadChoice,
+  type ReserveRequest,
+} from "../types/drop";
+export const ROOM_ID_PATTERN = /^[23456789ABCDEFGHJKLMNPQRSTUVWXYZ]{32}$/u;
+export const B64URL_PATTERN = /^[A-Za-z0-9_-]+$/u;
+const MAX_CHUNKS = 0xfffffffe;
+export const EXPIRY_MS: Record<ExpiryChoice, number> = {
+  "1h": 3600000,
+  "2h": 7200000,
+  "6h": 21600000,
+  "12h": 43200000,
+  "24h": 86400000,
+  "7d": 604800000,
+};
+export function isExpiry(value: unknown): value is ExpiryChoice {
+  return (
+    typeof value === "string" &&
+    (EXPIRY_VALUES as readonly string[]).includes(value)
+  );
+}
+export function isReadLimit(value: unknown): value is ReadChoice {
+  return (
+    value === null ||
+    (typeof value === "number" && READ_VALUES.includes(value as never))
+  );
+}
+export function isBase64Url(value: unknown, bytes?: number): value is string {
+  return (
+    typeof value === "string" &&
+    value.length > 0 &&
+    value.length <= 512 &&
+    B64URL_PATTERN.test(value) &&
+    (!bytes ||
+      Math.ceil((value.length * 6) / 8) === bytes ||
+      value.length === Math.ceil((bytes * 8) / 6))
+  );
+}
+export function decodeBase64Url(value: string): Uint8Array {
+  if (!B64URL_PATTERN.test(value) || value.length % 4 === 1)
+    throw new Error("Invalid base64url");
+  const normalized = value
+    .replaceAll("-", "+")
+    .replaceAll("_", "/")
+    .padEnd(Math.ceil(value.length / 4) * 4, "=");
+  const binary = atob(normalized);
+  return Uint8Array.from(binary, (c) => c.charCodeAt(0));
+}
+export function validateRoomId(id: unknown): asserts id is string {
+  if (typeof id !== "string" || !ROOM_ID_PATTERN.test(id))
+    throw new Error("Invalid drop id");
+}
+export function validateReservation(input: unknown): ReserveRequest {
+  if (!input || typeof input !== "object" || Array.isArray(input))
+    throw new Error("Invalid reservation");
+  const value = input as Record<string, unknown>;
+  const allowed = [
+    "version",
+    "chunkSize",
+    "chunkCount",
+    "noncePrefix",
+    "expiresIn",
+    "maxReads",
+  ];
+  if (Object.keys(value).some((key) => !allowed.includes(key)))
+    throw new Error("Unknown reservation field");
+  const chunkCount = value.chunkCount;
+  if (
+    value.version !== PROTOCOL_VERSION ||
+    value.chunkSize !== CHUNK_SIZE ||
+    !Number.isSafeInteger(chunkCount) ||
+    (chunkCount as number) < 1 ||
+    (chunkCount as number) > MAX_CHUNKS
+  )
+    throw new Error("Invalid chunk geometry");
+  if (
+    !isExpiry(value.expiresIn) ||
+    !isReadLimit(value.maxReads) ||
+    !isBase64Url(value.noncePrefix, 8)
+  )
+    throw new Error("Invalid reservation policy");
+  if (decodeBase64Url(value.noncePrefix as string).byteLength !== 8)
+    throw new Error("Invalid nonce prefix");
+  return value as unknown as ReserveRequest;
+}
+export function validateChunkIndex(index: unknown, count: number): number {
+  const parsed = typeof index === "number" ? index : Number(index);
+  if (!Number.isSafeInteger(parsed) || parsed < 0 || parsed >= count)
+    throw new Error("Invalid chunk index");
+  return parsed;
+}
+export function validateChunkBodyLength(length: number, final: boolean): void {
+  if (
+    !Number.isSafeInteger(length) ||
+    length < (final ? GCM_TAG_BYTES : MAX_CHUNK_BODY) ||
+    length > MAX_CHUNK_BODY
+  )
+    throw new Error("Invalid chunk body length");
+}
+export function validateManifestBodyLength(length: number): void {
+  if (
+    !Number.isSafeInteger(length) ||
+    length <= GCM_TAG_BYTES ||
+    length > MAX_MANIFEST_BODY
+  )
+    throw new Error("Invalid manifest body length");
+}
+export function expiresInMs(value: ExpiryChoice): number {
+  return EXPIRY_MS[value];
+}