71 lines
1.8 KiB
TypeScript
71 lines
1.8 KiB
TypeScript
import { Checksum, SourceData } from "@aws-sdk/types";
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import { isEmptyData, convertToBuffer } from "@aws-crypto/util";
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import {
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EMPTY_DATA_SHA_256,
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SHA_256_HASH,
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SHA_256_HMAC_ALGO,
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} from "./constants";
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import { locateWindow } from "@aws-sdk/util-locate-window";
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export class Sha256 implements Checksum {
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private readonly secret?: SourceData;
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private key: Promise<CryptoKey> | undefined;
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private toHash: Uint8Array = new Uint8Array(0);
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constructor(secret?: SourceData) {
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this.secret = secret;
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this.reset();
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}
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update(data: SourceData): void {
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if (isEmptyData(data)) {
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return;
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}
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const update = convertToBuffer(data);
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const typedArray = new Uint8Array(
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this.toHash.byteLength + update.byteLength
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);
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typedArray.set(this.toHash, 0);
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typedArray.set(update, this.toHash.byteLength);
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this.toHash = typedArray;
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}
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digest(): Promise<Uint8Array> {
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if (this.key) {
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return this.key.then((key) =>
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locateWindow()
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.crypto.subtle.sign(SHA_256_HMAC_ALGO, key, this.toHash)
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.then((data) => new Uint8Array(data))
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);
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}
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if (isEmptyData(this.toHash)) {
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return Promise.resolve(EMPTY_DATA_SHA_256);
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}
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return Promise.resolve()
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.then(() =>
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locateWindow().crypto.subtle.digest(SHA_256_HASH, this.toHash)
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)
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.then((data) => Promise.resolve(new Uint8Array(data)));
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}
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reset(): void {
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this.toHash = new Uint8Array(0);
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if (this.secret && this.secret !== void 0) {
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this.key = new Promise((resolve, reject) => {
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locateWindow()
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.crypto.subtle.importKey(
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"raw",
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convertToBuffer(this.secret as SourceData),
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SHA_256_HMAC_ALGO,
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false,
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["sign"]
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)
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.then(resolve, reject);
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});
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this.key.catch(() => {});
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}
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}
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}
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