buffer: introduce File

PR-URL: #45139 Fixes: #39015 Reviewed-By: Yagiz Nizipli <yagiz@nizipli.com> Reviewed-By: Minwoo Jung <nodecorelab@gmail.com> Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
nodejs · Jan 3, 2023 · 3a7f3d5 · 3a7f3d5
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diff --git a/benchmark/blob/file.js b/benchmark/blob/file.js
@@ -0,0 +1,34 @@
+'use strict';
+const common = require('../common.js');
+const { File } = require('buffer');
+
+const bench = common.createBenchmark(main, {
+  bytes: [128, 1024, 1024 ** 2],
+  n: [1e6],
+  operation: ['text', 'arrayBuffer']
+});
+
+const options = {
+  lastModified: Date.now() - 1e6,
+};
+
+async function run(n, bytes, operation) {
+  const buff = Buffer.allocUnsafe(bytes);
+  const source = new File(buff, 'dummy.txt', options);
+  bench.start();
+  for (let i = 0; i < n; i++) {
+    switch (operation) {
+      case 'text':
+        await source.text();
+        break;
+      case 'arrayBuffer':
+        await source.arrayBuffer();
+        break;
+    }
+  }
+  bench.end(n);
+}
+
+function main(conf) {
+  run(conf.n, conf.bytes, conf.operation).catch(console.log);
+}
diff --git a/doc/api/buffer.md b/doc/api/buffer.md
@@ -5009,6 +5009,56 @@ changes:
 
 See [`Buffer.from(string[, encoding])`][`Buffer.from(string)`].
 
+## Class: `File`
+
+<!-- YAML
+added: REPLACEME
+-->
+
+> Stability: 1 - Experimental
+
+* Extends: {Blob}
+
+A [`File`][] provides information about files.
+
+### `new buffer.File(sources, fileName[, options])`
+
+<!-- YAML
+added: REPLACEME
+-->
+
+* `sources` {string\[]|ArrayBuffer\[]|TypedArray\[]|DataView\[]|Blob\[]|File\[]}
+  An array of string, {ArrayBuffer}, {TypedArray}, {DataView}, {File}, or {Blob}
+  objects, or any mix of such objects, that will be stored within the `File`.
+* `fileName` {string} The name of the file.
+* `options` {Object}
+  * `endings` {string} One of either `'transparent'` or `'native'`. When set
+    to `'native'`, line endings in string source parts will be converted to
+    the platform native line-ending as specified by `require('node:os').EOL`.
+  * `type` {string} The File content-type.
+  * `lastModified` {number} The last modified date of the file.
+    **Default:** `Date.now()`.
+
+### `file.name`
+
+<!-- YAML
+added: REPLACEME
+-->
+
+* Type: {string}
+
+The name of the `File`.
+
+### `file.lastModified`
+
+<!-- YAML
+added: REPLACEME
+-->
+
+* Type: {number}
+
+The last modified date of the `File`.
+
 ## `node:buffer` module APIs
 
 While, the `Buffer` object is available as a global, there are additional
@@ -5355,6 +5405,7 @@ introducing security vulnerabilities into an application.
 [`ERR_INVALID_ARG_VALUE`]: errors.md#err_invalid_arg_value
 [`ERR_INVALID_BUFFER_SIZE`]: errors.md#err_invalid_buffer_size
 [`ERR_OUT_OF_RANGE`]: errors.md#err_out_of_range
+[`File`]: https://developer.mozilla.org/en-US/docs/Web/API/File
 [`JSON.stringify()`]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify
 [`SharedArrayBuffer`]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/SharedArrayBuffer
 [`String.prototype.indexOf()`]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/indexOf

diff --git a/lib/buffer.js b/lib/buffer.js
@@ -126,6 +126,10 @@ const {
   resolveObjectURL,
 } = require('internal/blob');
 
+const {
+  File,
+} = require('internal/file');
+
 FastBuffer.prototype.constructor = Buffer;
 Buffer.prototype = FastBuffer.prototype;
 addBufferPrototypeMethods(Buffer.prototype);
@@ -1320,6 +1324,7 @@ function atob(input) {
 
 module.exports = {
   Blob,
+  File,
   resolveObjectURL,
   Buffer,
   SlowBuffer,

diff --git a/lib/internal/file.js b/lib/internal/file.js
@@ -0,0 +1,113 @@
+'use strict';
+
+const {
+  DateNow,
+  NumberIsNaN,
+  ObjectDefineProperties,
+  SymbolToStringTag,
+} = primordials;
+
+const {
+  Blob,
+} = require('internal/blob');
+
+const {
+  customInspectSymbol: kInspect,
+  emitExperimentalWarning,
+  kEnumerableProperty,
+  kEmptyObject,
+  toUSVString,
+} = require('internal/util');
+
+const {
+  codes: {
+    ERR_INVALID_THIS,
+    ERR_MISSING_ARGS,
+  },
+} = require('internal/errors');
+
+const {
+  inspect,
+} = require('internal/util/inspect');
+
+class File extends Blob {
+  /** @type {string} */
+  #name;
+
+  /** @type {number} */
+  #lastModified;
+
+  constructor(fileBits, fileName, options = kEmptyObject) {
+    emitExperimentalWarning('buffer.File');
+
+    if (arguments.length < 2) {
+      throw new ERR_MISSING_ARGS('fileBits', 'fileName');
+    }
+
+    super(fileBits, options);
+
+    let { lastModified } = options ?? kEmptyObject;
+
+    if (lastModified !== undefined) {
+      // Using Number(...) will not throw an error for bigints.
+      lastModified = +lastModified;
+
+      if (NumberIsNaN(lastModified)) {
+        lastModified = 0;
+      }
+    } else {
+      lastModified = DateNow();
+    }
+
+    this.#name = toUSVString(fileName);
+    this.#lastModified = lastModified;
+  }
+
+  get name() {
+    if (!this || !(#name in this)) {
+      throw new ERR_INVALID_THIS('File');
+    }
+
+    return this.#name;
+  }
+
+  get lastModified() {
+    if (!this || !(#name in this)) {
+      throw new ERR_INVALID_THIS('File');
+    }
+
+    return this.#lastModified;
+  }
+
+  [kInspect](depth, options) {
+    if (depth < 0) {
+      return this;
+    }
+
+    const opts = {
+      ...options,
+      depth: options.depth == null ? null : options.depth - 1,
+    };
+
+    return `File ${inspect({
+      size: this.size,
+      type: this.type,
+      name: this.#name,
+      lastModified: this.#lastModified,
+    }, opts)}`;
+  }
+}
+
+ObjectDefineProperties(File.prototype, {
+  name: kEnumerableProperty,
+  lastModified: kEnumerableProperty,
+  [SymbolToStringTag]: {
+    __proto__: null,
+    configurable: true,
+    value: 'File',
+  }
+});
+
+module.exports = {
+  File,
+};
diff --git a/test/fixtures/wpt/FileAPI/file/File-constructor.any.js b/test/fixtures/wpt/FileAPI/file/File-constructor.any.js
@@ -0,0 +1,155 @@
+// META: title=File constructor
+
+const to_string_obj = { toString: () => 'a string' };
+const to_string_throws = { toString: () => { throw new Error('expected'); } };
+
+test(function() {
+  assert_true("File" in globalThis, "globalThis should have a File property.");
+}, "File interface object exists");
+
+test(t => {
+  assert_throws_js(TypeError, () => new File(),
+                   'Bits argument is required');
+  assert_throws_js(TypeError, () => new File([]),
+                   'Name argument is required');
+}, 'Required arguments');
+
+function test_first_argument(arg1, expectedSize, testName) {
+  test(function() {
+    var file = new File(arg1, "dummy");
+    assert_true(file instanceof File);
+    assert_equals(file.name, "dummy");
+    assert_equals(file.size, expectedSize);
+    assert_equals(file.type, "");
+    // assert_false(file.isClosed); XXX: File.isClosed doesn't seem to be implemented
+    assert_not_equals(file.lastModified, "");
+  }, testName);
+}
+
+test_first_argument([], 0, "empty fileBits");
+test_first_argument(["bits"], 4, "DOMString fileBits");
+test_first_argument(["𝓽𝓮𝔁𝓽"], 16, "Unicode DOMString fileBits");
+test_first_argument([new String('string object')], 13, "String object fileBits");
+test_first_argument([new Blob()], 0, "Empty Blob fileBits");
+test_first_argument([new Blob(["bits"])], 4, "Blob fileBits");
+test_first_argument([new File([], 'world.txt')], 0, "Empty File fileBits");
+test_first_argument([new File(["bits"], 'world.txt')], 4, "File fileBits");
+test_first_argument([new ArrayBuffer(8)], 8, "ArrayBuffer fileBits");
+test_first_argument([new Uint8Array([0x50, 0x41, 0x53, 0x53])], 4, "Typed array fileBits");
+test_first_argument(["bits", new Blob(["bits"]), new Blob(), new Uint8Array([0x50, 0x41]),
+                     new Uint16Array([0x5353]), new Uint32Array([0x53534150])], 16, "Various fileBits");
+test_first_argument([12], 2, "Number in fileBits");
+test_first_argument([[1,2,3]], 5, "Array in fileBits");
+test_first_argument([{}], 15, "Object in fileBits"); // "[object Object]"
+if (globalThis.document !== undefined) {
+  test_first_argument([document.body], 24, "HTMLBodyElement in fileBits"); // "[object HTMLBodyElement]"
+}
+test_first_argument([to_string_obj], 8, "Object with toString in fileBits");
+test_first_argument({[Symbol.iterator]() {
+  let i = 0;
+  return {next: () => [
+    {done:false, value:'ab'},
+    {done:false, value:'cde'},
+    {done:true}
+  ][i++]};
+}}, 5, 'Custom @@iterator');
+
+[
+  'hello',
+  0,
+  null
+].forEach(arg => {
+  test(t => {
+    assert_throws_js(TypeError, () => new File(arg, 'world.html'),
+                     'Constructor should throw for invalid bits argument');
+  }, `Invalid bits argument: ${JSON.stringify(arg)}`);
+});
+
+test(t => {
+  assert_throws_js(Error, () => new File([to_string_throws], 'name.txt'),
+                   'Constructor should propagate exceptions');
+}, 'Bits argument: object that throws');
+
+
+function test_second_argument(arg2, expectedFileName, testName) {
+  test(function() {
+    var file = new File(["bits"], arg2);
+    assert_true(file instanceof File);
+    assert_equals(file.name, expectedFileName);
+  }, testName);
+}
+
+test_second_argument("dummy", "dummy", "Using fileName");
+test_second_argument("dummy/foo", "dummy/foo",
+                     "No replacement when using special character in fileName");
+test_second_argument(null, "null", "Using null fileName");
+test_second_argument(1, "1", "Using number fileName");
+test_second_argument('', '', "Using empty string fileName");
+if (globalThis.document !== undefined) {
+  test_second_argument(document.body, '[object HTMLBodyElement]', "Using object fileName");
+}
+
+// testing the third argument
+[
+  {type: 'text/plain', expected: 'text/plain'},
+  {type: 'text/plain;charset=UTF-8', expected: 'text/plain;charset=utf-8'},
+  {type: 'TEXT/PLAIN', expected: 'text/plain'},
+  {type: '𝓽𝓮𝔁𝓽/𝔭𝔩𝔞𝔦𝔫', expected: ''},
+  {type: 'ascii/nonprintable\u001F', expected: ''},
+  {type: 'ascii/nonprintable\u007F', expected: ''},
+  {type: 'nonascii\u00EE', expected: ''},
+  {type: 'nonascii\u1234', expected: ''},
+  {type: 'nonparsable', expected: 'nonparsable'}
+].forEach(testCase => {
+  test(t => {
+    var file = new File(["bits"], "dummy", { type: testCase.type});
+    assert_true(file instanceof File);
+    assert_equals(file.type, testCase.expected);
+  }, `Using type in File constructor: ${testCase.type}`);
+});
+test(function() {
+  var file = new File(["bits"], "dummy", { lastModified: 42 });
+  assert_true(file instanceof File);
+  assert_equals(file.lastModified, 42);
+}, "Using lastModified");
+test(function() {
+  var file = new File(["bits"], "dummy", { name: "foo" });
+  assert_true(file instanceof File);
+  assert_equals(file.name, "dummy");
+}, "Misusing name");
+test(function() {
+  var file = new File(["bits"], "dummy", { unknownKey: "value" });
+  assert_true(file instanceof File);
+  assert_equals(file.name, "dummy");
+}, "Unknown properties are ignored");
+
+[
+  123,
+  123.4,
+  true,
+  'abc'
+].forEach(arg => {
+  test(t => {
+    assert_throws_js(TypeError, () => new File(['bits'], 'name.txt', arg),
+                     'Constructor should throw for invalid property bag type');
+  }, `Invalid property bag: ${JSON.stringify(arg)}`);
+});
+
+[
+  null,
+  undefined,
+  [1,2,3],
+  /regex/,
+  function() {}
+].forEach(arg => {
+  test(t => {
+    assert_equals(new File(['bits'], 'name.txt', arg).size, 4,
+                  'Constructor should accept object-ish property bag type');
+  }, `Unusual but valid property bag: ${arg}`);
+});
+
+test(t => {
+  assert_throws_js(Error,
+                   () => new File(['bits'], 'name.txt', {type: to_string_throws}),
+                   'Constructor should propagate exceptions');
+}, 'Property bag propagates exceptions');