Method: GraphQL::Language::Lexer#advance

Defined in:
lib/graphql/language/lexer.rb

#advance ⇒ Object 



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# File 'lib/graphql/language/lexer.rb', line 30

def advance
  @scanner.skip(IGNORE_REGEXP)
  if @scanner.eos?
    @finished = true
    return false
  end
  @tokens_count += 1
  if @tokens_count > @max_tokens
    raise_parse_error("This query is too large to execute.")
  end
  @pos = @scanner.pos
  next_byte = @string.getbyte(@pos)
  next_byte_is_for = FIRST_BYTES[next_byte]
  case next_byte_is_for
  when ByteFor::PUNCTUATION
    @scanner.pos += 1
    PUNCTUATION_NAME_FOR_BYTE[next_byte]
  when ByteFor::NAME
    if len = @scanner.skip(KEYWORD_REGEXP)
      case len
      when 2
        :ON
      when 12
        :SUBSCRIPTION
      else
        pos = @pos

        # Use bytes 2 and 3 as a unique identifier for this keyword
        bytes = (@string.getbyte(pos + 2) << 8) | @string.getbyte(pos + 1)
        KEYWORD_BY_TWO_BYTES[_hash(bytes)]
      end
    else
      @scanner.skip(IDENTIFIER_REGEXP)
      :IDENTIFIER
    end
  when ByteFor::IDENTIFIER
    @scanner.skip(IDENTIFIER_REGEXP)
    :IDENTIFIER
  when ByteFor::NUMBER
    if len = @scanner.skip(NUMERIC_REGEXP)

      if GraphQL.reject_numbers_followed_by_names
        new_pos = @scanner.pos
        peek_byte = @string.getbyte(new_pos)
        next_first_byte = FIRST_BYTES[peek_byte]
        if next_first_byte == ByteFor::NAME || next_first_byte == ByteFor::IDENTIFIER
          number_part = token_value
          name_part = @scanner.scan(IDENTIFIER_REGEXP)
          raise_parse_error("Name after number is not allowed (in `#{number_part}#{name_part}`)")
        end
      end
      # Check for a matched decimal:
      @scanner[1] ? :FLOAT : :INT
    else
      # Attempt to find the part after the `-`
      value = @scanner.scan(/-\s?[a-z0-9]*/i)
      invalid_byte_for_number_error_message = "Expected type 'number', but it was malformed#{value.nil? ? "" : ": #{value.inspect}"}."
      raise_parse_error(invalid_byte_for_number_error_message)
    end
  when ByteFor::ELLIPSIS
    if @string.getbyte(@pos + 1) != 46 || @string.getbyte(@pos + 2) != 46
      raise_parse_error("Expected `...`, actual: #{@string[@pos..@pos + 2].inspect}")
    end
    @scanner.pos += 3
    :ELLIPSIS
  when ByteFor::STRING
    if @scanner.skip(BLOCK_STRING_REGEXP) || @scanner.skip(QUOTED_STRING_REGEXP)
      :STRING
    else
      raise_parse_error("Expected string or block string, but it was malformed")
    end
  else
    @scanner.pos += 1
    :UNKNOWN_CHAR
  end
rescue ArgumentError => err
  if err.message == "invalid byte sequence in UTF-8"
    raise_parse_error("Parse error on bad Unicode escape sequence", nil, nil)
  end
end