TB 41803: Add some developer tools for working on tor-browser.

#!/usr/bin/python

"""

Pre-process a git todo file before passing it on to an editor.

"""

import sys

import os

import subprocess

import re

EDITOR_ENV_NAME = "GIT_REBASE_FIXUP_PREPROCESSOR_USER_EDITOR"

try:

    editor = os.environ[EDITOR_ENV_NAME]

except KeyError:

    print(f"Missing {EDITOR_ENV_NAME} in environment", file=sys.stderr)

    exit(1)

if len(sys.argv) < 2:

    print("Missing filename argument", file=sys.stderr)

    exit(1)

filename = sys.argv[1]

class TodoLine:

    """

    Represents a line in the git todo file.

    """

    _PICK_REGEX = re.compile(r"^pick [a-f0-9]+ (?P<fixups>(fixup! )*)(?P<title>.*)")

    def __init__(self, line):

        """

        Create a new line with the given text content.

        """

        self._line = line

        self._make_fixup = False

        match = self._PICK_REGEX.match(line)

        if match:

            self._is_pick = True

            self._num_fixups = len(match.group("fixups")) / len("fixup! ")

            self._title = match.group("title")

        else:

            self._is_pick = False

            self._num_fixups = False

            self._title = None

    def add_to_list_try_fixup(self, existing_lines):

        """

        Add the TodoLine to the given list of other TodoLine, trying to fix up

        one of the existing lines.

        """

        if not self._num_fixups:  # Not a fixup line.

            existing_lines.append(self)

            return

        # Search from the end of the list upwards.

        for index in reversed(range(len(existing_lines))):

            other = existing_lines[index]

            if (

                other._is_pick

                and self._num_fixups == other._num_fixups + 1

                and other._title == self._title

            ):

                self._make_fixup = True

                existing_lines.insert(index + 1, self)

                return

        # No line found to fixup.

        existing_lines.append(self)

    def get_text(self):

        """

        Get the text for the line to save.

        """

        line = self._line

        if self._make_fixup:

            line = line.replace("pick", "fixup", 1)

        return line

todo_lines = []

with open(filename, "r", encoding="utf8") as todo_file:

    for line in todo_file:

        TodoLine(line).add_to_list_try_fixup(todo_lines)

with open(filename, "w", encoding="utf8") as todo_file:

    for line in todo_lines:

        todo_file.write(line.get_text())

exit(subprocess.run([editor, *sys.argv[1:]], check=False).returncode)