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// Copyright (c) 2017-2022 Cloudflare, Inc.
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// Licensed under the Apache 2.0 license found in the LICENSE file or at:
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//     https://opensource.org/licenses/Apache-2.0
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// Copyright Joyent and Node contributors. All rights reserved. MIT license.
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import type { IncomingMessage } from 'node:http';
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export type IncomingMessageCallback = (req: IncomingMessage) => void;
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interface OnceOptions {
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  preserveReturnValue?: boolean;
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}
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export function once<RT>(
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  this: unknown,
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  callback: (...allArgs: unknown[]) => RT,
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  options?: OnceOptions
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): (...all: unknown[]) => RT {
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  const preserveReturnValue = options?.preserveReturnValue ?? false;
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  let called = false;
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  let returnValue: RT;
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  return function (this: unknown, ...args: unknown[]): RT {
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    if (called) return returnValue;
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    called = true;
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    const result = Reflect.apply(callback, this, args);
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    returnValue = preserveReturnValue ? result : (undefined as RT);
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    return result;
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  };
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}
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export const kServerResponse = Symbol('ServerResponse');
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export const kIncomingMessage = Symbol('IncomingMessage');
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// RFC 7230 compliant header value splitting that respects quoted-string constructions
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// Returns only the first value up to the first comma (outside of quoted strings)
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// Spec: https://www.rfc-editor.org/rfc/rfc7230.html#appendix-B
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// Edge cases handled:
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// - Quoted strings with commas: 'text/plain; param="a, b"' -> 'text/plain; param="a, b"'
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// - Escaped quotes in strings: 'text/plain; param="a \"quoted\" value"' -> 'text/plain; param="a \"quoted\" value"'
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// - Multiple values: 'text/plain; f="a, b", text/html' -> 'text/plain; f="a, b"'
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// - Whitespace before commas: 'value1 \t , value2' -> 'value1'
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// - No commas: 'single-value' -> 'single-value'
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export function splitHeaderValue(value: string): string {
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  let inQuotes = false;
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  for (let i = 0; i < value.length; i++) {
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    const char = value[i];
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    if (char === '"') {
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      inQuotes = !inQuotes;
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    } else if (char === '\\' && inQuotes) {
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      i++; // Skip next character (it's escaped)
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    } else if (!inQuotes && char === ',') {
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      // Found unquoted comma, return
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      return value.slice(0, i);
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    }
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  }
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  return value;
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}