black_bindings.py

#!/usr/bin/python3
import os
import re
import subprocess
import sys
from concurrent.futures import ThreadPoolExecutor
from dataclasses import dataclass
from enum import Enum, auto

MARK_C_IN_PY = "##| "
MARK_PY_IN_C = "//| "


class Mode(Enum):
    C = auto()
    PY = auto()


@dataclass(frozen=True)
class LineWithMode:
    data: str
    mode: Mode


class OutputWriter:
    def __init__(self):
        self.content = []

    def write(self, line):
        self.content.append(line.rstrip())

    def getcontent(self):
        return "\n".join(self.content)


class PythonOutputWriter(OutputWriter):
    def write(self, line):
        if isinstance(line, str):
            super().write(line)
        elif line.mode == Mode.PY:
            super().write(line.data)
        else:  # line mode is C
            super().write(MARK_C_IN_PY + line.data)


class COutputWriter(OutputWriter):
    def write(self, line):
        if isinstance(line, str):
            super().write(line)
        elif line.mode == Mode.PY:
            super().write(MARK_PY_IN_C + line.data)
        else:  # line mode is C
            super().write(line.data)


def parse_line(line, defmode, mark, smark, markmode):
    sline = line.strip()
    if sline == smark or sline.startswith(mark):
        return LineWithMode(sline[len(mark) :], markmode)
    else:
        return LineWithMode(line, defmode)


def parse_lines(lines, defmode, mark, markmode):
    smark = mark.strip()
    return [parse_line(line, defmode, mark, smark, markmode) for line in lines]


def swap_comment_markers(content, input_mode):
    lines = content.rstrip().split("\n")

    if input_mode == Mode.C:
        parsed = parse_lines(lines, Mode.C, MARK_PY_IN_C, Mode.PY)
        writer = PythonOutputWriter()
    else:
        parsed = parse_lines(lines, Mode.PY, MARK_C_IN_PY, Mode.C)
        writer = COutputWriter()

    for line in parsed:
        writer.write(line)

    newcontent = writer.getcontent() + "\n"

    return newcontent


def process_one_file(fn):
    with open(fn, "r", encoding="utf-8") as f:
        c_content = f.read()

    if not "\n//| " in c_content:
        return

    py_content = swap_comment_markers(c_content, Mode.C)

    try:
        # Line length is 95 so that with "//| " the max is 99
        result = subprocess.run(
            ["black", "--pyi", "-l95", "-q", "-"],
            input=py_content,
            check=True,
            stdout=subprocess.PIPE,
            encoding="utf-8",
        )
    except subprocess.CalledProcessError as e:
        print(f"{fn}:0: Failed to process file ")
        raise

    new_py_content = result.stdout
    new_c_content = swap_comment_markers(new_py_content, Mode.PY)

    if new_c_content != c_content:
        with open(fn, "w", encoding="utf-8") as f:
            f.write(new_c_content)


if __name__ == "__main__":
    # Use a thread pool because most processing is inside black!
    executor = ThreadPoolExecutor(max_workers=os.cpu_count())
    futures = [executor.submit(process_one_file, fn) for fn in sys.argv[1:]]
    status = 0
    for f in futures:
        try:
            f.result()
        except Exception as e:
            print(e)
            status = 1
    executor.shutdown()
    raise SystemExit(status)