private function parseAttributes()

in src/parser/html/PhutilHTMLParser.php [237:432]

• 115 lines of code
• 31 McCabe index (conditional complexity)

  private function parseAttributes($attributes) {
    $state = 'key';

    $whitespace = array(
      ' ' => true,
      "\n" => true,
      "\t" => true,
      "\r" => true,
    );

    $map = array();
    $len = strlen($attributes);
    $key_pos = null;
    for ($ii = 0; $ii < $len; $ii++) {
      $c = $attributes[$ii];
      $is_space = isset($whitespace[$c]);

      switch ($state) {
        case 'key':
          // We're looking for the start of an attribute name.

          // Skip over any whitespace.
          if ($is_space) {
            break;
          }

          // If we see "<tag =...", that isn't valid. Treat this tag as
          // content.
          if ($c === '=') {
            return null;
          }

          // If we see a quotation mark with no attribute name, that isn't
          // valid. Treat this tag as content.
          if ($c === '"') {
            return null;
          }

          // Any other character marks the beginning of an attribute name.
          // Switch the parser state to "name" to parse the name.
          $name_pos = $ii;
          $state = 'name';
          break;
        case 'name':
          // We're looking for the end of an attribute name.

          // Finding a "=" or a space character ends the attribute name.
          // Save it, then figure out what to do with the parser state.
          if ($c === '=' || $is_space) {
            $name_value = substr($attributes, $name_pos, $ii - $name_pos);
            $name_value = phutil_utf8_strtolower($name_value);

            // If this attribute already exists, the tag is invalid. This means
            // the input is something like "<tag a=1 a=2>".
            if (isset($map[$name_value])) {
              return null;
            }
          }

          // If we find an "=", that's the end of the name. Next, we're going
          // to parse a value.
          if ($c === '=') {
            $state = 'value';
            break;
          }

          // If we find whitespace, that's the end of the name. We're going
          // to look for an "=".
          if ($is_space) {
            $state = 'equals';
            break;
          }

          break;
        case 'equals':
          // We've parsed the name of an attribute and are looking for an
          // "=" character.

          // Skip over any whitespace.
          if ($is_space) {
            break;
          }

          // This is the "=" we're looking for, so we're good to go.
          if ($c === '=') {
            $state = 'value';
            break;
          }

          // If this is anything else, this is an attribute name with no
          // value. Treat it as "true" and move on. This corresponds to an
          // input like "<input disabled>".
          $map[$name_value] = true;
          $name_pos = $ii;
          $state = 'name';
          break;
        case 'value':
          // We've parsed an "=" and are looking for the start of a value.

          // Skip over any whitespace.
          if ($is_space) {
            break;
          }

          // Don't accept "<tag a==" to mean that key "a" has a value of
          // "=", since this is silly. To specify a value beginning with "=",
          // you have to quote it.
          if ($c === '=') {
            return null;
          }

          // Anything else is a value.
          $value_pos = $ii;

          // This is a quotation mark, so parse a quoted value.
          if ($c === '"') {
            $value_pos = $value_pos + 1;
            $state = 'quoted';
          } else {
            $state = 'unquoted';
          }
          break;
        case 'quoted':
          // We've started parsing a quoted value, so look for the closing
          // quote.

          // We found the closing quote, so pull out the actual value.
          if ($c === '"') {
            $attr_value = substr($attributes, $value_pos, $ii - $value_pos);

            $map[$name_value] = $attr_value;
            $state = 'key';
            break;
          }

          // Anything else is more text in the quoted value.
          break;
        case 'unquoted':
          // We've started parsing an unquoted value, so look for terminating
          // whitespace.

          // We've found some whitespace, so pull out the actual value.
          if ($is_space) {
            $attr_value = substr($attributes, $value_pos, $ii - $value_pos);

            $map[$name_value] = $attr_value;
            $state = 'key';
            break;
          }

          // Anything else is more text in the unquoted value.
          break;
      }
    }

    switch ($state) {
      case 'key':
        // We were looking for the start of an attribute name, so there's
        // nothing to clean up.
        break;
      case 'name':
        // We were looking for the end of an attribute name. Treat whatever
        // we found as a name.
        $name_value = substr($attributes, $name_pos, $len - $name_pos);

        if (isset($map[$name_value])) {
          return null;
        }

        $map[$name_value] = true;
        break;
      case 'equals':
      case 'value':
        // We found an attribute name followed by whitespace or an "=". Treat
        // whatever we found as a valid attribute name with no value.

        if (isset($map[$name_value])) {
          return null;
        }

        $map[$name_value] = true;
        break;
      case 'quoted':
      case 'unquoted':
        // We were parsing a value but ran out of characters before we found
        // the delimiter or closing quote. Treat whatever we found as a quoted
        // value.

        $attr_value = substr($attributes, $value_pos, $len - $name_pos);

        $map[$name_value] = $attr_value;
        break;
    }

    return $map;
  }