1 files changed, 197 insertions, 0 deletions
diff --git a/ext/node/polyfills/_fs/_fs_read.ts b/ext/node/polyfills/_fs/_fs_read.ts
new file mode 100644
index 000000000..d74445829
--- /dev/null
+++ b/ext/node/polyfills/_fs/_fs_read.ts
@@ -0,0 +1,197 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+import { Buffer } from "internal:deno_node/polyfills/buffer.ts";
+import { ERR_INVALID_ARG_TYPE } from "internal:deno_node/polyfills/internal/errors.ts";
+import {
+  validateOffsetLengthRead,
+  validatePosition,
+} from "internal:deno_node/polyfills/internal/fs/utils.mjs";
+import {
+  validateBuffer,
+  validateInteger,
+} from "internal:deno_node/polyfills/internal/validators.mjs";
+
+type readOptions = {
+  buffer: Buffer | Uint8Array;
+  offset: number;
+  length: number;
+  position: number | null;
+};
+
+type readSyncOptions = {
+  offset: number;
+  length: number;
+  position: number | null;
+};
+
+type BinaryCallback = (
+  err: Error | null,
+  bytesRead: number | null,
+  data?: Buffer,
+) => void;
+type Callback = BinaryCallback;
+
+export function read(fd: number, callback: Callback): void;
+export function read(
+  fd: number,
+  options: readOptions,
+  callback: Callback,
+): void;
+export function read(
+  fd: number,
+  buffer: Buffer | Uint8Array,
+  offset: number,
+  length: number,
+  position: number | null,
+  callback: Callback,
+): void;
+export function read(
+  fd: number,
+  optOrBufferOrCb?: Buffer | Uint8Array | readOptions | Callback,
+  offsetOrCallback?: number | Callback,
+  length?: number,
+  position?: number | null,
+  callback?: Callback,
+) {
+  let cb: Callback | undefined;
+  let offset = 0,
+    buffer: Buffer | Uint8Array;
+
+  if (typeof fd !== "number") {
+    throw new ERR_INVALID_ARG_TYPE("fd", "number", fd);
+  }
+
+  if (length == null) {
+    length = 0;
+  }
+
+  if (typeof offsetOrCallback === "function") {
+    cb = offsetOrCallback;
+  } else if (typeof optOrBufferOrCb === "function") {
+    cb = optOrBufferOrCb;
+  } else {
+    offset = offsetOrCallback as number;
+    validateInteger(offset, "offset", 0);
+    cb = callback;
+  }
+
+  if (
+    optOrBufferOrCb instanceof Buffer || optOrBufferOrCb instanceof Uint8Array
+  ) {
+    buffer = optOrBufferOrCb;
+  } else if (typeof optOrBufferOrCb === "function") {
+    offset = 0;
+    buffer = Buffer.alloc(16384);
+    length = buffer.byteLength;
+    position = null;
+  } else {
+    const opt = optOrBufferOrCb as readOptions;
+    if (
+      !(opt.buffer instanceof Buffer) && !(opt.buffer instanceof Uint8Array)
+    ) {
+      if (opt.buffer === null) {
+        // @ts-ignore: Intentionally create TypeError for passing test-fs-read.js#L87
+        length = opt.buffer.byteLength;
+      }
+      throw new ERR_INVALID_ARG_TYPE("buffer", [
+        "Buffer",
+        "TypedArray",
+        "DataView",
+      ], optOrBufferOrCb);
+    }
+    offset = opt.offset ?? 0;
+    buffer = opt.buffer ?? Buffer.alloc(16384);
+    length = opt.length ?? buffer.byteLength;
+    position = opt.position ?? null;
+  }
+
+  if (position == null) {
+    position = -1;
+  }
+
+  validatePosition(position);
+  validateOffsetLengthRead(offset, length, buffer.byteLength);
+
+  if (!cb) throw new ERR_INVALID_ARG_TYPE("cb", "Callback", cb);
+
+  (async () => {
+    try {
+      let nread: number | null;
+      if (typeof position === "number" && position >= 0) {
+        const currentPosition = await Deno.seek(fd, 0, Deno.SeekMode.Current);
+        // We use sync calls below to avoid being affected by others during
+        // these calls.
+        Deno.seekSync(fd, position, Deno.SeekMode.Start);
+        nread = Deno.readSync(fd, buffer);
+        Deno.seekSync(fd, currentPosition, Deno.SeekMode.Start);
+      } else {
+        nread = await Deno.read(fd, buffer);
+      }
+      cb(null, nread ?? 0, Buffer.from(buffer.buffer, offset, length));
+    } catch (error) {
+      cb(error as Error, null);
+    }
+  })();
+}
+
+export function readSync(
+  fd: number,
+  buffer: Buffer | Uint8Array,
+  offset: number,
+  length: number,
+  position: number | null,
+): number;
+export function readSync(
+  fd: number,
+  buffer: Buffer | Uint8Array,
+  opt: readSyncOptions,
+): number;
+export function readSync(
+  fd: number,
+  buffer: Buffer | Uint8Array,
+  offsetOrOpt?: number | readSyncOptions,
+  length?: number,
+  position?: number | null,
+): number {
+  let offset = 0;
+
+  if (typeof fd !== "number") {
+    throw new ERR_INVALID_ARG_TYPE("fd", "number", fd);
+  }
+
+  validateBuffer(buffer);
+
+  if (length == null) {
+    length = 0;
+  }
+
+  if (typeof offsetOrOpt === "number") {
+    offset = offsetOrOpt;
+    validateInteger(offset, "offset", 0);
+  } else {
+    const opt = offsetOrOpt as readSyncOptions;
+    offset = opt.offset ?? 0;
+    length = opt.length ?? buffer.byteLength;
+    position = opt.position ?? null;
+  }
+
+  if (position == null) {
+    position = -1;
+  }
+
+  validatePosition(position);
+  validateOffsetLengthRead(offset, length, buffer.byteLength);
+
+  let currentPosition = 0;
+  if (typeof position === "number" && position >= 0) {
+    currentPosition = Deno.seekSync(fd, 0, Deno.SeekMode.Current);
+    Deno.seekSync(fd, position, Deno.SeekMode.Start);
+  }
+
+  const numberOfBytesRead = Deno.readSync(fd, buffer);
+
+  if (typeof position === "number" && position >= 0) {
+    Deno.seekSync(fd, currentPosition, Deno.SeekMode.Start);
+  }
+
+  return numberOfBytesRead ?? 0;
+}