Added a very complicated AsyncIterableReader class.

The class was already implemented in
"https://deno.land/std@0.144.0/streams/conversion.ts".  So, I litterally
lost 1 day of work!  I hate myself.

vendor/deno.land/std@0.188.0/http/_negotiation/language.ts

@@ -0,0 +1,144 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+/*!
+ * Adapted directly from negotiator at https://github.com/jshttp/negotiator/
+ * which is licensed as follows:
+ *
+ * (The MIT License)
+ *
+ * Copyright (c) 2012-2014 Federico Romero
+ * Copyright (c) 2012-2014 Isaac Z. Schlueter
+ * Copyright (c) 2014-2015 Douglas Christopher Wilson
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * 'Software'), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * 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 OR COPYRIGHT HOLDERS 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 { compareSpecs, isQuality, Specificity } from "./common.ts";
+
+interface LanguageSpecificity extends Specificity {
+  prefix: string;
+  suffix?: string;
+  full: string;
+}
+
+const SIMPLE_LANGUAGE_REGEXP = /^\s*([^\s\-;]+)(?:-([^\s;]+))?\s*(?:;(.*))?$/;
+
+function parseLanguage(
+  str: string,
+  i: number,
+): LanguageSpecificity | undefined {
+  const match = SIMPLE_LANGUAGE_REGEXP.exec(str);
+  if (!match) {
+    return undefined;
+  }
+
+  const [, prefix, suffix] = match;
+  const full = suffix ? `${prefix}-${suffix}` : prefix;
+
+  let q = 1;
+  if (match[3]) {
+    const params = match[3].split(";");
+    for (const param of params) {
+      const [key, value] = param.trim().split("=");
+      if (key === "q") {
+        q = parseFloat(value);
+        break;
+      }
+    }
+  }
+
+  return { prefix, suffix, full, q, i };
+}
+
+function parseAcceptLanguage(accept: string): LanguageSpecificity[] {
+  const accepts = accept.split(",");
+  const result: LanguageSpecificity[] = [];
+
+  for (let i = 0; i < accepts.length; i++) {
+    const language = parseLanguage(accepts[i].trim(), i);
+    if (language) {
+      result.push(language);
+    }
+  }
+  return result;
+}
+
+function specify(
+  language: string,
+  spec: LanguageSpecificity,
+  i: number,
+): Specificity | undefined {
+  const p = parseLanguage(language, i);
+  if (!p) {
+    return undefined;
+  }
+  let s = 0;
+  if (spec.full.toLowerCase() === p.full.toLowerCase()) {
+    s |= 4;
+  } else if (spec.prefix.toLowerCase() === p.prefix.toLowerCase()) {
+    s |= 2;
+  } else if (spec.full.toLowerCase() === p.prefix.toLowerCase()) {
+    s |= 1;
+  } else if (spec.full !== "*") {
+    return;
+  }
+
+  return { i, o: spec.i, q: spec.q, s };
+}
+
+function getLanguagePriority(
+  language: string,
+  accepted: LanguageSpecificity[],
+  index: number,
+): Specificity {
+  let priority: Specificity = { i: -1, o: -1, q: 0, s: 0 };
+  for (const accepts of accepted) {
+    const spec = specify(language, accepts, index);
+    if (
+      spec &&
+      ((priority.s ?? 0) - (spec.s ?? 0) || priority.q - spec.q ||
+          (priority.o ?? 0) - (spec.o ?? 0)) < 0
+    ) {
+      priority = spec;
+    }
+  }
+  return priority;
+}
+
+export function preferredLanguages(
+  accept = "*",
+  provided?: string[],
+): string[] {
+  const accepts = parseAcceptLanguage(accept);
+
+  if (!provided) {
+    return accepts
+      .filter(isQuality)
+      .sort(compareSpecs)
+      .map((spec) => spec.full);
+  }
+
+  const priorities = provided
+    .map((type, index) => getLanguagePriority(type, accepts, index));
+
+  return priorities
+    .filter(isQuality)
+    .sort(compareSpecs)
+    .map((priority) => provided[priorities.indexOf(priority)]);
+}