Use alternate TextEncoder/TextDecoder implementation (denoland#1281)

This is faster and smaller.

js/blob.ts

@@ -1,6 +1,7 @@
 // Copyright 2018 the Deno authors. All rights reserved. MIT license.
 import * as domTypes from "./dom_types";
 import { containsOnlyASCII } from "./util";
+import { TextEncoder } from "./text_encoding";
 
 const bytesSymbol = Symbol("bytes");
 

js/dom_types.ts

@@ -13,6 +13,8 @@ See the Apache Version 2.0 License for specific language governing permissions
 and limitations under the License.
 *******************************************************************************/
 
+export type BufferSource = ArrayBufferView | ArrayBuffer;
+
 export type HeadersInit =
  | Headers
  | Array<[string, string]>

js/fetch.ts

@@ -4,7 +4,7 @@ import * as flatbuffers from "./flatbuffers";
 import { sendAsync } from "./dispatch";
 import * as msg from "gen/msg_generated";
 import * as domTypes from "./dom_types";
-import { TextDecoder } from "./text_encoding";
+import { TextDecoder, TextEncoder } from "./text_encoding";
 import { DenoBlob } from "./blob";
 import { Headers } from "./headers";
 import * as io from "./io";

js/globals.ts

@@ -29,8 +29,6 @@ import { libdeno } from "./libdeno";
 declare global {
  const console: consoleTypes.Console;
  const setTimeout: typeof timers.setTimeout;
- // tslint:disable-next-line:variable-name
- const TextEncoder: typeof textEncoding.TextEncoder;
 }
 
 // A reference to the global object.
@@ -69,7 +67,7 @@ export type Headers = domTypes.Headers;
 window.FormData = formData.FormData as domTypes.FormDataConstructor;
 export type FormData = domTypes.FormData;
 
-// While these are classes, they have their global instance types created in
-// other type definitions, therefore we do not have to include them here.
 window.TextEncoder = textEncoding.TextEncoder;
+export type TextEncoder = textEncoding.TextEncoder;
 window.TextDecoder = textEncoding.TextDecoder;
+export type TextDecoder = textEncoding.TextDecoder;

js/text_encoding.ts

@@ -1,5 +1,29 @@
-// Copyright 2018 the Deno authors. All rights reserved. MIT license.
+// The following code is based off of text-encoding at:
+// https://github.com/inexorabletash/text-encoding
+//
+// Anyone is free to copy, modify, publish, use, compile, sell, or
+// distribute this software, either in source code form or as a compiled
+// binary, for any purpose, commercial or non-commercial, and by any
+// means.
+//
+// In jurisdictions that recognize copyright laws, the author or authors
+// of this software dedicate any and all copyright interest in the
+// software to the public domain. We make this dedication for the benefit
+// of the public at large and to the detriment of our heirs and
+// successors. We intend this dedication to be an overt act of
+// relinquishment in perpetuity of all present and future rights to this
+// software under copyright law.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+// IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
+// OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+// OTHER DEALINGS IN THE SOFTWARE.
+
 import * as base64 from "base64-js";
+import * as domTypes from "./dom_types";
 import { DenoError, ErrorKind } from "./errors";
 
 /** Decodes a string of data which has been encoded using base-64. */
@@ -43,29 +67,299 @@ export function btoa(s: string): string {
  return result;
 }
 
-// @types/text-encoding relies on lib.dom.d.ts for some interfaces. We do not
-// want to include lib.dom.d.ts (due to size) into deno's global type scope.
-// Therefore this hack: add a few of the missing interfaces in
-// @types/text-encoding to the global scope before importing.
+interface Decoder {
+ handler(stream: Stream, byte: number): number | number[] | null;
+}
+
+interface Encoder {
+ handler(codePoint: number): number | number[];
+}
+
+const CONTINUE = null;
+const END_OF_STREAM = -1;
+const FINISHED = -1;
+
+function codePointsToString(codePoints: number[]): string {
+ let s = "";
+ for (const cp of codePoints) {
+ s += String.fromCodePoint(cp);
+ }
+ return s;
+}
+
+function decoderError(fatal: boolean): number | never {
+ if (fatal) {
+ throw new TypeError("Decoder error.");
+ }
+ return 0xfffd; // default code point
+}
+
+function inRange(a: number, min: number, max: number) {
+ return min <= a && a <= max;
+}
+
+function stringToCodePoints(input: string): number[] {
+ const u: number[] = [];
+ for (const c of input) {
+ u.push(c.codePointAt(0)!);
+ }
+ return u;
+}
+
+class Stream {
+ private _tokens: number[];
+ constructor(tokens: number[] | Uint8Array) {
+ this._tokens = [].slice.call(tokens);
+ this._tokens.reverse();
+ }
+
+ endOfStream(): boolean {
+ return !this._tokens.length;
+ }
+
+ read(): number {
+ return !this._tokens.length ? END_OF_STREAM : this._tokens.pop()!;
+ }
+
+ prepend(token: number | number[]): void {
+ if (Array.isArray(token)) {
+ while (token.length) {
+ this._tokens.push(token.pop()!);
+ }
+ } else {
+ this._tokens.push(token);
+ }
+ }
+
+ push(token: number | number[]): void {
+ if (Array.isArray(token)) {
+ while (token.length) {
+ this._tokens.unshift(token.shift()!);
+ }
+ } else {
+ this._tokens.unshift(token);
+ }
+ }
+}
+
+class UTF8Decoder implements Decoder {
+ private _codePoint = 0;
+ private _bytesSeen = 0;
+ private _bytesNeeded = 0;
+ private _fatal: boolean;
+ private _lowerBoundary = 0x80;
+ private _upperBoundary = 0xbf;
+
+ constructor(options = { fatal: false }) {
+ this._fatal = options.fatal;
+ }
+
+ handler(stream: Stream, byte: number): number | null {
+ if (byte === END_OF_STREAM && this._bytesNeeded !== 0) {
+ this._bytesNeeded = 0;
+ return decoderError(this._fatal);
+ }
+
+ if (byte === END_OF_STREAM) {
+ return FINISHED;
+ }
+
+ if (this._bytesNeeded === 0) {
+ if (inRange(byte, 0x00, 0x7f)) {
+ // Single byte code point
+ return byte;
+ } else if (inRange(byte, 0xc2, 0xdf)) {
+ // Two byte code point
+ this._bytesNeeded = 1;
+ this._codePoint = byte & 0x1f;
+ } else if (inRange(byte, 0xe0, 0xef)) {
+ // Three byte code point
+ if (byte === 0xe0) {
+ this._lowerBoundary = 0xa0;
+ } else if (byte === 0xed) {
+ this._upperBoundary = 0x9f;
+ }
+ this._bytesNeeded = 2;
+ this._codePoint = byte & 0xf;
+ } else if (inRange(byte, 0xf0, 0xf4)) {
+ if (byte === 0xf0) {
+ this._lowerBoundary = 0x90;
+ } else if (byte === 0xf4) {
+ this._upperBoundary = 0x8f;
+ }
+ this._bytesNeeded = 3;
+ this._codePoint = byte & 0x7;
+ } else {
+ return decoderError(this._fatal);
+ }
+ return CONTINUE;
+ }
+
+ if (!inRange(byte, this._lowerBoundary, this._upperBoundary)) {
+ // Byte out of range, so encoding error
+ this._codePoint = 0;
+ this._bytesNeeded = 0;
+ this._bytesSeen = 0;
+ stream.prepend(byte);
+ return decoderError(this._fatal);
+ }
+
+ this._lowerBoundary = 0x80;
+ this._upperBoundary = 0xbf;
+
+ this._codePoint = (this._codePoint << 6) | (byte & 0x3f);
+
+ this._bytesSeen++;
+
+ if (this._bytesSeen !== this._bytesNeeded) {
+ return CONTINUE;
+ }
+
+ const codePoint = this._codePoint;
+
+ this._codePoint = 0;
+ this._bytesNeeded = 0;
+ this._bytesSeen = 0;
+
+ return codePoint;
+ }
+}
+
+class UTF8Encoder implements Encoder {
+ handler(codePoint: number): number | number[] {
+ if (codePoint === END_OF_STREAM) {
+ return FINISHED;
+ }
 
-declare global {
- type BufferSource = ArrayBufferView | ArrayBuffer;
+ if (inRange(codePoint, 0x00, 0x7f)) {
+ return codePoint;
+ }
+
+ let count: number;
+ let offset: number;
+ if (inRange(codePoint, 0x0080, 0x07ff)) {
+ count = 1;
+ offset = 0xc0;
+ } else if (inRange(codePoint, 0x0800, 0xffff)) {
+ count = 2;
+ offset = 0xe0;
+ } else if (inRange(codePoint, 0x10000, 0x10ffff)) {
+ count = 3;
+ offset = 0xf0;
+ } else {
+ throw TypeError(`Code point out of range: \\x${codePoint.toString(16)}`);
+ }
+
+ const bytes = [(codePoint >> (6 * count)) + offset];
+
+ while (count > 0) {
+ const temp = codePoint >> (6 * (count - 1));
+ bytes.push(0x80 | (temp & 0x3f));
+ count--;
+ }
 
- interface TextDecodeOptions {
- stream?: boolean;
+ return bytes;
  }
+}
 
- interface TextDecoderOptions {
- fatal?: boolean;
- ignoreBOM?: boolean;
+export interface TextDecodeOptions {
+ stream?: false;
+}
+
+export interface TextDecoderOptions {
+ fatal?: boolean;
+ ignoreBOM?: false;
+}
+
+export class TextDecoder {
+ /** Returns encoding's name, lowercased. */
+ readonly encoding = "utf-8";
+ /** Returns `true` if error mode is "fatal", and `false` otherwise. */
+ readonly fatal: boolean = false;
+ /** Returns `true` if ignore BOM flag is set, and `false` otherwise. */
+ readonly ignoreBOM = false;
+
+ constructor(
+ label: "utf-8" = "utf-8",
+ options: TextDecoderOptions = { fatal: false }
+ ) {
+ if (label !== "utf-8") {
+ throw new TypeError("Only UTF8 decoding supported.");
+ }
+ if (options.ignoreBOM) {
+ throw new TypeError("Ignoring the BOM not supported.");
+ }
+ if (options.fatal) {
+ this.fatal = true;
+ }
  }
 
- interface TextDecoder {
- readonly encoding: string;
- readonly fatal: boolean;
- readonly ignoreBOM: boolean;
- decode(input?: BufferSource, options?: TextDecodeOptions): string;
+ /** Returns the result of running encoding's decoder. */
+ decode(
+ input?: domTypes.BufferSource,
+ options: TextDecodeOptions = { stream: false }
+ ): string {
+ if (options.stream) {
+ throw new TypeError("Stream not supported.");
+ }
+
+ let bytes: Uint8Array;
+ if (typeof input === "object" && input instanceof ArrayBuffer) {
+ bytes = new Uint8Array(input);
+ } else if (
+ typeof input === "object" &&
+ "buffer" in input &&
+ input.buffer instanceof ArrayBuffer
+ ) {
+ bytes = new Uint8Array(input.buffer, input.byteOffset, input.byteLength);
+ } else {
+ bytes = new Uint8Array(0);
+ }
+
+ const decoder = new UTF8Decoder({ fatal: this.fatal });
+ const inputStream = new Stream(bytes);
+ const output: number[] = [];
+
+ while (true) {
+ const result = decoder.handler(inputStream, inputStream.read());
+ if (result === FINISHED) {
+ break;
+ }
+
+ if (result !== CONTINUE) {
+ output.push(result);
+ }
+ }
+
+ if (output.length > 0 && output[0] === 0xfeff) {
+ output.shift();
+ }
+
+ return codePointsToString(output);
  }
 }
 
-export { TextEncoder, TextDecoder } from "text-encoding";
+export class TextEncoder {
+ /** Returns "utf-8". */
+ readonly encoding = "utf-8";
+ /** Returns the result of running UTF-8's encoder. */
+ encode(input = ""): Uint8Array {
+ const encoder = new UTF8Encoder();
+ const inputStream = new Stream(stringToCodePoints(input));
+ const output: number[] = [];
+
+ while (true) {
+ const result = encoder.handler(inputStream.read());
+ if (result === FINISHED) {
+ break;
+ }
+ if (Array.isArray(result)) {
+ output.push.apply(output, result);
+ } else {
+ output.push(result);
+ }
+ }
+
+ return new Uint8Array(output);
+ }
+}