Class _FunctionState

tools/cpplint.py:1679–1738

Tracks current function name and the number of lines in its body.

class _FunctionState:
    """Tracks current function name and the number of lines in its body."""

    _NORMAL_TRIGGER = 250  # for --v=0, 500 for --v=1, etc.
    _TEST_TRIGGER = 400  # about 50% more than _NORMAL_TRIGGER.

    def __init__(self):
        self.in_a_function = False
        self.lines_in_function = 0
        self.current_function = ""

    def Begin(self, function_name):
        """Start analyzing function body.

        Args:
          function_name: The name of the function being tracked.
        """
        self.in_a_function = True
        self.lines_in_function = 0
        self.current_function = function_name

    def Count(self):
        """Count line in current function body."""
        if self.in_a_function:
            self.lines_in_function += 1

    def Check(self, error, filename, linenum):
        """Report if too many lines in function body.

        Args:
          error: The function to call with any errors found.
          filename: The name of the current file.
          linenum: The number of the line to check.
        """
        if not self.in_a_function:
            return

        if re.match(r"T(EST|est)", self.current_function):
            base_trigger = self._TEST_TRIGGER
        else:
            base_trigger = self._NORMAL_TRIGGER
        trigger = base_trigger * 2 ** _VerboseLevel()

        if self.lines_in_function > trigger:
            error_level = int(math.log2(self.lines_in_function / base_trigger))
            # 50 => 0, 100 => 1, 200 => 2, 400 => 3, 800 => 4, 1600 => 5, ...
            error_level = min(error_level, 5)
            error(
                filename,
                linenum,
                "readability/fn_size",
                error_level,
                "Small and focused functions are preferred:"
                f" {self.current_function} has {self.lines_in_function} non-comment lines"
                f" (error triggered by exceeding {trigger} lines).",
            )

    def End(self):