Class JsonFile

Lib/test/libregrtest/runtests.py:23–63

@dataclasses.dataclass(slots=True, frozen=True)
class JsonFile:
    # file type depends on file_type:
    # - UNIX_FD: file descriptor (int)
    # - WINDOWS_HANDLE: handle (int)
    # - STDOUT: use process stdout (None)
    file: int | None
    file_type: str

    def configure_subprocess(self, popen_kwargs: dict[str, Any]) -> None:
        match self.file_type:
            case JsonFileType.UNIX_FD:
                # Unix file descriptor
                popen_kwargs['pass_fds'] = [self.file]
            case JsonFileType.WINDOWS_HANDLE:
                # Windows handle
                # We run mypy with `--platform=linux` so it complains about this:
                startupinfo = subprocess.STARTUPINFO()  # type: ignore[attr-defined]
                startupinfo.lpAttributeList = {"handle_list": [self.file]}
                popen_kwargs['startupinfo'] = startupinfo

    @contextlib.contextmanager
    def inherit_subprocess(self) -> Iterator[None]:
        if sys.platform == 'win32' and self.file_type == JsonFileType.WINDOWS_HANDLE:
            os.set_handle_inheritable(self.file, True)
            try:
                yield
            finally:
                os.set_handle_inheritable(self.file, False)
        else:
            yield

    def open(self, mode='r', *, encoding):
        if self.file_type == JsonFileType.STDOUT:
            raise ValueError("for STDOUT file type, just use sys.stdout")

        file = self.file
        if self.file_type == JsonFileType.WINDOWS_HANDLE:
            import msvcrt
            # Create a file descriptor from the handle
            file = msvcrt.open_osfhandle(file, os.O_WRONLY)
        return open(file, mode, encoding=encoding)


@dataclasses.dataclass(slots=True, frozen=True)