fix(ext/node): Add fs.readv, fs.readvSync (#23166)

Part of #18218.

Implements `fs.readv` and `fs.readvSync` and enables the corresponding
`node_compat` tests.

1 files changed, 130 insertions, 0 deletions

diff --git a/ext/node/polyfills/_fs/_fs_readv.ts b/ext/node/polyfills/_fs/_fs_readv.ts
new file mode 100644
index 000000000..7d87c51f7
--- /dev/null
+++ b/ext/node/polyfills/_fs/_fs_readv.ts
@@ -0,0 +1,130 @@
+// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
+
+// TODO(petamoriken): enable prefer-primordials for node polyfills
+// deno-lint-ignore-file prefer-primordials
+
+import {
+  ERR_INVALID_ARG_TYPE,
+  type ErrnoException,
+} from "ext:deno_node/internal/errors.ts";
+import {
+  getValidatedFd,
+  validateBufferArray,
+} from "ext:deno_node/internal/fs/utils.mjs";
+import { maybeCallback } from "ext:deno_node/_fs/_fs_common.ts";
+import { validateInteger } from "ext:deno_node/internal/validators.mjs";
+import * as io from "ext:deno_io/12_io.js";
+import * as fs from "ext:deno_fs/30_fs.js";
+
+type Callback = (
+  err: ErrnoException | null,
+  bytesRead: number,
+  buffers: readonly ArrayBufferView[],
+) => void;
+
+export function readv(
+  fd: number,
+  buffers: readonly ArrayBufferView[],
+  callback: Callback,
+): void;
+export function readv(
+  fd: number,
+  buffers: readonly ArrayBufferView[],
+  position: number | Callback,
+  callback?: Callback,
+): void {
+  if (typeof fd !== "number") {
+    throw new ERR_INVALID_ARG_TYPE("fd", "number", fd);
+  }
+  fd = getValidatedFd(fd);
+  validateBufferArray(buffers);
+  const cb = maybeCallback(callback || position) as Callback;
+  let pos: number | null = null;
+  if (typeof position === "number") {
+    validateInteger(position, "position", 0);
+    pos = position;
+  }
+
+  if (buffers.length === 0) {
+    process.nextTick(cb, null, 0, buffers);
+    return;
+  }
+
+  const innerReadv = async (
+    fd: number,
+    buffers: readonly ArrayBufferView[],
+    position: number | null,
+  ) => {
+    if (typeof position === "number") {
+      await fs.seek(fd, position, io.SeekMode.Start);
+    }
+
+    let readTotal = 0;
+    let readInBuf = 0;
+    let bufIdx = 0;
+    let buf = buffers[bufIdx];
+    while (bufIdx < buffers.length) {
+      const nread = await io.read(fd, buf);
+      if (nread === null) {
+        break;
+      }
+      readInBuf += nread;
+      if (readInBuf === buf.byteLength) {
+        readTotal += readInBuf;
+        readInBuf = 0;
+        bufIdx += 1;
+        buf = buffers[bufIdx];
+      }
+    }
+    readTotal += readInBuf;
+
+    return readTotal;
+  };
+
+  innerReadv(fd, buffers, pos).then(
+    (numRead) => {
+      cb(null, numRead, buffers);
+    },
+    (err) => cb(err, -1, buffers),
+  );
+}
+
+export function readvSync(
+  fd: number,
+  buffers: readonly ArrayBufferView[],
+  position: number | null = null,
+): number {
+  if (typeof fd !== "number") {
+    throw new ERR_INVALID_ARG_TYPE("fd", "number", fd);
+  }
+  fd = getValidatedFd(fd);
+  validateBufferArray(buffers);
+  if (buffers.length === 0) {
+    return 0;
+  }
+  if (typeof position === "number") {
+    validateInteger(position, "position", 0);
+    fs.seekSync(fd, position, io.SeekMode.Start);
+  }
+
+  let readTotal = 0;
+  let readInBuf = 0;
+  let bufIdx = 0;
+  let buf = buffers[bufIdx];
+  while (bufIdx < buffers.length) {
+    const nread = io.readSync(fd, buf);
+    if (nread === null) {
+      break;
+    }
+    readInBuf += nread;
+    if (readInBuf === buf.byteLength) {
+      readTotal += readInBuf;
+      readInBuf = 0;
+      bufIdx += 1;
+      buf = buffers[bufIdx];
+    }
+  }
+  readTotal += readInBuf;
+
+  return readTotal;
+}