Backport Basilisk internal userscripts

browser/internaluserscripts/bundled-scripts/textdecoderstream-polyfill.user.js

@@ -0,0 +1,179 @@
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+// ==UserScript==
+// @name         TextDecoderStream Polyfill (best-effort)
+// @namespace    internal-userscripts
+// @description  Minimal TextDecoderStream implementation backed by TransformStream.
+// @match        *://*/*
+// @grant        none
+// @run-at       document-start
+// ==/UserScript==
+(function () {
+  "use strict";
+
+  var global = typeof window !== "undefined" ? window : null;
+  if (!global) {
+    return;
+  }
+
+  var existingCtor = global.TextDecoderStream;
+  if (typeof existingCtor === "function") {
+    try {
+      var probe = new existingCtor();
+      if (probe && probe.readable && probe.writable) {
+        return;
+      }
+    } catch (e) {
+      if (String(e).indexOf("not yet implemented") === -1) {
+        return;
+      }
+    }
+  }
+
+  if (typeof global.TransformStream !== "function") {
+    return;
+  }
+  if (typeof global.TextDecoder !== "function") {
+    return;
+  }
+
+  function isObject(value) {
+    return value !== null && (typeof value === "object" || typeof value === "function");
+  }
+
+  function streamBrandCheckException(name) {
+    return new TypeError("TextDecoderStream.prototype." + name +
+      " can only be used on a TextDecoderStream");
+  }
+
+  function isTextDecoderStream(value) {
+    return isObject(value) && value._isTextDecoderStream === true;
+  }
+
+  function normalizeOptions(options) {
+    var normalized = {
+      fatal: false,
+      ignoreBOM: false
+    };
+
+    if (!isObject(options)) {
+      return normalized;
+    }
+
+    normalized.fatal = !!options.fatal;
+    normalized.ignoreBOM = !!options.ignoreBOM;
+    return normalized;
+  }
+
+  function PolyfillTextDecoderStream(label, options) {
+    if (!(this instanceof PolyfillTextDecoderStream)) {
+      throw new TypeError("TextDecoderStream must be constructed with 'new'");
+    }
+
+    var normalizedOptions = normalizeOptions(options);
+    var effectiveLabel = label === undefined ? "utf-8" : label;
+
+    var decoder;
+    try {
+      decoder = new global.TextDecoder(effectiveLabel, {
+        fatal: normalizedOptions.fatal,
+        ignoreBOM: normalizedOptions.ignoreBOM
+      });
+    } catch (e) {
+      decoder = new global.TextDecoder(effectiveLabel, {
+        fatal: normalizedOptions.fatal
+      });
+    }
+
+    this._decoder = decoder;
+    this._encoding = typeof decoder.encoding === "string"
+      ? decoder.encoding
+      : String(effectiveLabel).toLowerCase();
+    this._fatal = typeof decoder.fatal === "boolean"
+      ? decoder.fatal
+      : normalizedOptions.fatal;
+    this._ignoreBOM = typeof decoder.ignoreBOM === "boolean"
+      ? decoder.ignoreBOM
+      : normalizedOptions.ignoreBOM;
+
+    this._transform = new global.TransformStream({
+      transform: function (chunk, controller) {
+        var output = decoder.decode(chunk, { stream: true });
+        if (output.length > 0) {
+          controller.enqueue(output);
+        }
+      },
+      flush: function (controller) {
+        var output = decoder.decode();
+        if (output.length > 0) {
+          controller.enqueue(output);
+        }
+      }
+    });
+
+    this._readable = this._transform.readable;
+    this._writable = this._transform.writable;
+    this._isTextDecoderStream = true;
+  }
+
+  Object.defineProperty(PolyfillTextDecoderStream.prototype, "encoding", {
+    get: function () {
+      if (!isTextDecoderStream(this)) {
+        throw streamBrandCheckException("encoding");
+      }
+      return this._encoding;
+    },
+    enumerable: true,
+    configurable: true
+  });
+
+  Object.defineProperty(PolyfillTextDecoderStream.prototype, "fatal", {
+    get: function () {
+      if (!isTextDecoderStream(this)) {
+        throw streamBrandCheckException("fatal");
+      }
+      return this._fatal;
+    },
+    enumerable: true,
+    configurable: true
+  });
+
+  Object.defineProperty(PolyfillTextDecoderStream.prototype, "ignoreBOM", {
+    get: function () {
+      if (!isTextDecoderStream(this)) {
+        throw streamBrandCheckException("ignoreBOM");
+      }
+      return this._ignoreBOM;
+    },
+    enumerable: true,
+    configurable: true
+  });
+
+  Object.defineProperty(PolyfillTextDecoderStream.prototype, "readable", {
+    get: function () {
+      if (!isTextDecoderStream(this)) {
+        throw streamBrandCheckException("readable");
+      }
+      return this._readable;
+    },
+    enumerable: true,
+    configurable: true
+  });
+
+  Object.defineProperty(PolyfillTextDecoderStream.prototype, "writable", {
+    get: function () {
+      if (!isTextDecoderStream(this)) {
+        throw streamBrandCheckException("writable");
+      }
+      return this._writable;
+    },
+    enumerable: true,
+    configurable: true
+  });
+
+  global.TextDecoderStream = PolyfillTextDecoderStream;
+  try {
+    global.__internalUserscriptsTextDecoderStreamPolyfill = true;
+  } catch (e) {}
+})();