cdk-s3-vectors/node_modules/@aws-crypto/sha256-browser/src/webCryptoSha256.ts

A CDK construct library for Amazon S3 Vectors. This construct simplifies the creation of vector buckets, vector indexes with full configuration options, and Amazon Bedrock knowledge bases using S3 Vectors as the underlying vector store.

import { Checksum, SourceData } from "@aws-sdk/types";
import { isEmptyData, convertToBuffer } from "@aws-crypto/util";
import {
  EMPTY_DATA_SHA_256,
  SHA_256_HASH,
  SHA_256_HMAC_ALGO,
} from "./constants";
import { locateWindow } from "@aws-sdk/util-locate-window";

export class Sha256 implements Checksum {
  private readonly secret?: SourceData;
  private key: Promise<CryptoKey> | undefined;
  private toHash: Uint8Array = new Uint8Array(0);

  constructor(secret?: SourceData) {
    this.secret = secret;
    this.reset();
  }

  update(data: SourceData): void {
    if (isEmptyData(data)) {
      return;
    }

    const update = convertToBuffer(data);
    const typedArray = new Uint8Array(
      this.toHash.byteLength + update.byteLength
    );
    typedArray.set(this.toHash, 0);
    typedArray.set(update, this.toHash.byteLength);
    this.toHash = typedArray;
  }

  digest(): Promise<Uint8Array> {
    if (this.key) {
      return this.key.then((key) =>
        locateWindow()
          .crypto.subtle.sign(SHA_256_HMAC_ALGO, key, this.toHash)
          .then((data) => new Uint8Array(data))
      );
    }

    if (isEmptyData(this.toHash)) {
      return Promise.resolve(EMPTY_DATA_SHA_256);
    }

    return Promise.resolve()
      .then(() =>
        locateWindow().crypto.subtle.digest(SHA_256_HASH, this.toHash)
      )
      .then((data) => Promise.resolve(new Uint8Array(data)));
  }

  reset(): void {
    this.toHash = new Uint8Array(0);
    if (this.secret && this.secret !== void 0) {
      this.key = new Promise((resolve, reject) => {
        locateWindow()
            .crypto.subtle.importKey(
            "raw",
            convertToBuffer(this.secret as SourceData),
            SHA_256_HMAC_ALGO,
            false,
            ["sign"]
        )
            .then(resolve, reject);
      });
      this.key.catch(() => {});
    }
  }
}