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denoland-deno/ext/node/polyfills/internal_binding/_timingSafeEqual.ts
Bartek Iwańczuk d47147fb6a
feat(ext/node): embed std/node into the snapshot (#17724)
This commit moves "deno_std/node" in "ext/node" crate. The code is
transpiled and snapshotted during the build process.

During the first pass a minimal amount of work was done to create the
snapshot, a lot of code in "ext/node" depends on presence of "Deno"
global. This code will be gradually fixed in the follow up PRs to migrate
it to import relevant APIs from "internal:" modules.

Currently the code from snapshot is not used in any way, and all
Node/npm compatibility still uses code from 
"https://deno.land/std/node" (or from the location specified by 
"DENO_NODE_COMPAT_URL"). This will also be handled in a follow 
up PRs.

---------

Co-authored-by: crowlkats <crowlkats@toaxl.com>
Co-authored-by: Divy Srivastava <dj.srivastava23@gmail.com>
Co-authored-by: Yoshiya Hinosawa <stibium121@gmail.com>
2023-02-14 17:38:45 +01:00

43 lines
1.2 KiB
TypeScript

// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
import { Buffer } from "internal:deno_node/polyfills/buffer.ts";
function assert(cond) {
if (!cond) {
throw new Error("assertion failed");
}
}
/** Compare to array buffers or data views in a way that timing based attacks
* cannot gain information about the platform. */
function stdTimingSafeEqual(
a: ArrayBufferView | ArrayBufferLike | DataView,
b: ArrayBufferView | ArrayBufferLike | DataView,
): boolean {
if (a.byteLength !== b.byteLength) {
return false;
}
if (!(a instanceof DataView)) {
a = new DataView(ArrayBuffer.isView(a) ? a.buffer : a);
}
if (!(b instanceof DataView)) {
b = new DataView(ArrayBuffer.isView(b) ? b.buffer : b);
}
assert(a instanceof DataView);
assert(b instanceof DataView);
const length = a.byteLength;
let out = 0;
let i = -1;
while (++i < length) {
out |= a.getUint8(i) ^ b.getUint8(i);
}
return out === 0;
}
export const timingSafeEqual = (
a: Buffer | DataView | ArrayBuffer,
b: Buffer | DataView | ArrayBuffer,
): boolean => {
if (a instanceof Buffer) a = new DataView(a.buffer);
if (a instanceof Buffer) b = new DataView(a.buffer);
return stdTimingSafeEqual(a, b);
};