feat(module): added checksum

Author: AndrewFossAWS

packages/types/src/checksum.ts

@@ -0,0 +1,60 @@
+/**
+ * An object that provides a checksum of data provided in chunks to `update`.
+ * The checksum may be performed incrementally as chunks are received or all
+ * at once when the checksum is finalized, depending on the underlying
+ * implementation.
+ *
+ * It's recommended to compute checksum incrementally to avoid reading the
+ * entire payload in memory.
+ *
+ * The constructor may accept an optional secret key while computing checksum
+ * value, when using HMAC. If provided, this secret key would be used when
+ * computing checksum.
+ */
+export interface Checksum {
+  /**
+   * Constant length of the digest created by the algorithm in bytes.
+   */
+  digestLength?: string;
+
+  /**
+   * Creates a new checksum object that contains a deep copy of the internal
+   * state of the current `Checksum` object.
+   * This is required by certain languages like Java.
+   */
+  copy?: () => Checksum;
+
+  /**
+   * Returns the digest of all of the data passed.
+   *
+   * This interface may be async, following digest interface standards
+   * for language.
+   * For the purpose of this document, we assume it's called synchronously.
+   */
+  digest: () => Promise<Uint8Array>;
+
+  /**
+   * Allows marking a checksum for checksums that support the ability
+   * to mark and reset.
+   *
+   * @param {number} readLimit - The maximum limit of bytes that can be read
+   *   before the mark position becomes invalid.
+   */
+  mark?: (readLimit: number) => void;
+
+  /**
+   * Resets the checksum to its initial value.
+   */
+  reset: () => void;
+
+  /**
+   * Adds a chunk of data for which checksum needs to be computed.
+   * This can be called many times with new data as it is streamed.
+   *
+   * Implementations may override this method which passes second param
+   * which makes Checksum object stateless.
+   *
+   * @param {Uint8Array} chunk - The buffer to update checksum with.
+   */
+  update(chunk: Uint8Array): void;
+}

packages/types/src/crypto.ts

@@ -4,6 +4,8 @@ export type SourceData = string | ArrayBuffer | ArrayBufferView;
  * An object that provides a hash of data provided in chunks to `update`. The
  * hash may be performed incrementally as chunks are received or all at once
  * when the hash is finalized, depending on the underlying implementation.
+ *
+ * @deprecated use {@link Checksum}
  */
 export interface Hash {
   /**
@@ -40,11 +42,3 @@ export interface HashConstructor {
 export interface StreamHasher<StreamType = any> {
   (hashCtor: HashConstructor, stream: StreamType): Promise<Uint8Array>;
 }
-
-/**
- * A function that returns a promise fulfilled with bytes from a
- * cryptographically secure pseudorandom number generator.
- */
-export interface randomValues {
-  (byteLength: number): Promise<Uint8Array>;
-}

packages/types/src/index.ts

@@ -1,5 +1,6 @@
 export * from "./abort";
 export * from "./auth";
+export * from "./checksum";
 export * from "./client";
 export * from "./command";
 export * from "./credentials";