site/node_modules/micromark-core-commonmark/lib/autolink.js

/**
 * @typedef {import('micromark-util-types').Construct} Construct
 * @typedef {import('micromark-util-types').State} State
 * @typedef {import('micromark-util-types').TokenizeContext} TokenizeContext
 * @typedef {import('micromark-util-types').Tokenizer} Tokenizer
 */

import {
  asciiAlpha,
  asciiAlphanumeric,
  asciiAtext,
  asciiControl
} from 'micromark-util-character'
/** @type {Construct} */
export const autolink = {
  name: 'autolink',
  tokenize: tokenizeAutolink
}

/**
 * @this {TokenizeContext}
 * @type {Tokenizer}
 */
function tokenizeAutolink(effects, ok, nok) {
  let size = 0
  return start

  /**
   * Start of an autolink.
   *
   * ```markdown
   * > | a<https://example.com>b
   *      ^
   * > | a<user@example.com>b
   *      ^
   * ```
   *
   * @type {State}
   */
  function start(code) {
    effects.enter('autolink')
    effects.enter('autolinkMarker')
    effects.consume(code)
    effects.exit('autolinkMarker')
    effects.enter('autolinkProtocol')
    return open
  }

  /**
   * After `<`, at protocol or atext.
   *
   * ```markdown
   * > | a<https://example.com>b
   *       ^
   * > | a<user@example.com>b
   *       ^
   * ```
   *
   * @type {State}
   */
  function open(code) {
    if (asciiAlpha(code)) {
      effects.consume(code)
      return schemeOrEmailAtext
    }
    return emailAtext(code)
  }

  /**
   * At second byte of protocol or atext.
   *
   * ```markdown
   * > | a<https://example.com>b
   *        ^
   * > | a<user@example.com>b
   *        ^
   * ```
   *
   * @type {State}
   */
  function schemeOrEmailAtext(code) {
    // ASCII alphanumeric and `+`, `-`, and `.`.
    if (code === 43 || code === 45 || code === 46 || asciiAlphanumeric(code)) {
      // Count the previous alphabetical from `open` too.
      size = 1
      return schemeInsideOrEmailAtext(code)
    }
    return emailAtext(code)
  }

  /**
   * In ambiguous protocol or atext.
   *
   * ```markdown
   * > | a<https://example.com>b
   *        ^
   * > | a<user@example.com>b
   *        ^
   * ```
   *
   * @type {State}
   */
  function schemeInsideOrEmailAtext(code) {
    if (code === 58) {
      effects.consume(code)
      size = 0
      return urlInside
    }

    // ASCII alphanumeric and `+`, `-`, and `.`.
    if (
      (code === 43 || code === 45 || code === 46 || asciiAlphanumeric(code)) &&
      size++ < 32
    ) {
      effects.consume(code)
      return schemeInsideOrEmailAtext
    }
    size = 0
    return emailAtext(code)
  }

  /**
   * After protocol, in URL.
   *
   * ```markdown
   * > | a<https://example.com>b
   *             ^
   * ```
   *
   * @type {State}
   */
  function urlInside(code) {
    if (code === 62) {
      effects.exit('autolinkProtocol')
      effects.enter('autolinkMarker')
      effects.consume(code)
      effects.exit('autolinkMarker')
      effects.exit('autolink')
      return ok
    }

    // ASCII control, space, or `<`.
    if (code === null || code === 32 || code === 60 || asciiControl(code)) {
      return nok(code)
    }
    effects.consume(code)
    return urlInside
  }

  /**
   * In email atext.
   *
   * ```markdown
   * > | a<user.name@example.com>b
   *              ^
   * ```
   *
   * @type {State}
   */
  function emailAtext(code) {
    if (code === 64) {
      effects.consume(code)
      return emailAtSignOrDot
    }
    if (asciiAtext(code)) {
      effects.consume(code)
      return emailAtext
    }
    return nok(code)
  }

  /**
   * In label, after at-sign or dot.
   *
   * ```markdown
   * > | a<user.name@example.com>b
   *                 ^       ^
   * ```
   *
   * @type {State}
   */
  function emailAtSignOrDot(code) {
    return asciiAlphanumeric(code) ? emailLabel(code) : nok(code)
  }

  /**
   * In label, where `.` and `>` are allowed.
   *
   * ```markdown
   * > | a<user.name@example.com>b
   *                   ^
   * ```
   *
   * @type {State}
   */
  function emailLabel(code) {
    if (code === 46) {
      effects.consume(code)
      size = 0
      return emailAtSignOrDot
    }
    if (code === 62) {
      // Exit, then change the token type.
      effects.exit('autolinkProtocol').type = 'autolinkEmail'
      effects.enter('autolinkMarker')
      effects.consume(code)
      effects.exit('autolinkMarker')
      effects.exit('autolink')
      return ok
    }
    return emailValue(code)
  }

  /**
   * In label, where `.` and `>` are *not* allowed.
   *
   * Though, this is also used in `emailLabel` to parse other values.
   *
   * ```markdown
   * > | a<user.name@ex-ample.com>b
   *                    ^
   * ```
   *
   * @type {State}
   */
  function emailValue(code) {
    // ASCII alphanumeric or `-`.
    if ((code === 45 || asciiAlphanumeric(code)) && size++ < 63) {
      const next = code === 45 ? emailValue : emailLabel
      effects.consume(code)
      return next
    }
    return nok(code)
  }
}