Function parseContentDispositionAttribute

lib/web/fetch/formdata-parser.js:209–308

* Parses content-disposition attributes (e.g., name="value" or filename*=utf-8''encoded) * @param {Buffer} input * @param {{ position: number }} position * @returns {{ name: string, value: string, extended: boolean } | null}

(input, position)

 * @returns {{ name: string, value: string, extended: boolean } | null}
 */
function parseContentDispositionAttribute (input, position) {
  // Skip leading semicolon and whitespace
  if (input[position.position] === 0x3b /* ; */) {
    position.position++
  }

  // Skip whitespace
  collectASequenceOfBytes(
    (char) => char === 0x20 || char === 0x09,
    input,
    position
  )

  // Collect attribute name (token characters)
  const attributeName = collectASequenceOfBytes(
    (char) => isToken(char) && char !== 0x3d && char !== 0x2a, // not = or *
    input,
    position
  )

  if (attributeName.length === 0) {
    return null
  }

  const attrNameStr = attributeName.toString('ascii').toLowerCase()

  // Check for extended notation (attribute*)
  const isExtended = input[position.position] === 0x2a /* * */
  if (isExtended) {
    position.position++ // skip *
  }

  // Expect = sign
  if (input[position.position] !== 0x3d /* = */) {
    return null
  }
  position.position++ // skip =

  // Skip whitespace
  collectASequenceOfBytes(
    (char) => char === 0x20 || char === 0x09,
    input,
    position
  )

  let value

  if (isExtended) {
    // Extended attribute format: charset'language'encoded-value
    const headerValue = collectASequenceOfBytes(
      (char) => char !== 0x20 && char !== 0x0d && char !== 0x0a && char !== 0x3b, // not space, CRLF, or ;
      input,
      position
    )

    // Check for utf-8'' prefix (case insensitive)
    if (
      (headerValue[0] !== 0x75 && headerValue[0] !== 0x55) || // u or U