path: root/pre_commit/util.py

from __future__ import annotations

import contextlib
import errno
import importlib.resources
import os.path
import shutil
import stat
import subprocess
import sys
from collections.abc import Generator
from types import TracebackType
from typing import Any
from typing import Callable

from pre_commit import parse_shebang


def force_bytes(exc: Any) -> bytes:
    with contextlib.suppress(TypeError):
        return bytes(exc)
    with contextlib.suppress(Exception):
        return str(exc).encode()
    return f'<unprintable {type(exc).__name__} object>'.encode()


@contextlib.contextmanager
def clean_path_on_failure(path: str) -> Generator[None, None, None]:
    """Cleans up the directory on an exceptional failure."""
    try:
        yield
    except BaseException:
        if os.path.exists(path):
            rmtree(path)
        raise


def resource_text(filename: str) -> str:
    files = importlib.resources.files('pre_commit.resources')
    return files.joinpath(filename).read_text()


def make_executable(filename: str) -> None:
    original_mode = os.stat(filename).st_mode
    new_mode = original_mode | stat.S_IXUSR | stat.S_IXGRP | stat.S_IXOTH
    os.chmod(filename, new_mode)


class CalledProcessError(RuntimeError):
    def __init__(
            self,
            returncode: int,
            cmd: tuple[str, ...],
            stdout: bytes,
            stderr: bytes | None,
    ) -> None:
        super().__init__(returncode, cmd, stdout, stderr)
        self.returncode = returncode
        self.cmd = cmd
        self.stdout = stdout
        self.stderr = stderr

    def __bytes__(self) -> bytes:
        def _indent_or_none(part: bytes | None) -> bytes:
            if part:
                return b'\n    ' + part.replace(b'\n', b'\n    ').rstrip()
            else:
                return b' (none)'

        return b''.join((
            f'command: {self.cmd!r}\n'.encode(),
            f'return code: {self.returncode}\n'.encode(),
            b'stdout:', _indent_or_none(self.stdout), b'\n',
            b'stderr:', _indent_or_none(self.stderr),
        ))

    def __str__(self) -> str:
        return self.__bytes__().decode()


def _setdefault_kwargs(kwargs: dict[str, Any]) -> None:
    for arg in ('stdin', 'stdout', 'stderr'):
        kwargs.setdefault(arg, subprocess.PIPE)


def _oserror_to_output(e: OSError) -> tuple[int, bytes, None]:
    return 1, force_bytes(e).rstrip(b'\n') + b'\n', None


def cmd_output_b(
        *cmd: str,
        check: bool = True,
        **kwargs: Any,
) -> tuple[int, bytes, bytes | None]:
    _setdefault_kwargs(kwargs)

    try:
        cmd = parse_shebang.normalize_cmd(cmd, env=kwargs.get('env'))
    except parse_shebang.ExecutableNotFoundError as e:
        returncode, stdout_b, stderr_b = e.to_output()
    else:
        try:
            proc = subprocess.Popen(cmd, **kwargs)
        except OSError as e:
            returncode, stdout_b, stderr_b = _oserror_to_output(e)
        else:
            stdout_b, stderr_b = proc.communicate()
            returncode = proc.returncode

    if check and returncode:
        raise CalledProcessError(returncode, cmd, stdout_b, stderr_b)

    return returncode, stdout_b, stderr_b


def cmd_output(*cmd: str, **kwargs: Any) -> tuple[int, str, str | None]:
    returncode, stdout_b, stderr_b = cmd_output_b(*cmd, **kwargs)
    stdout = stdout_b.decode() if stdout_b is not None else None
    stderr = stderr_b.decode() if stderr_b is not None else None
    return returncode, stdout, stderr


if sys.platform != 'win32':  # pragma: win32 no cover
    from os import openpty
    import termios

    class Pty:
        def __init__(self) -> None:
            self.r: int | None = None
            self.w: int | None = None

        def __enter__(self) -> Pty:
            self.r, self.w = openpty()

            # tty flags normally change \n to \r\n
            attrs = termios.tcgetattr(self.w)
            assert isinstance(attrs[1], int)
            attrs[1] &= ~(termios.ONLCR | termios.OPOST)
            termios.tcsetattr(self.w, termios.TCSANOW, attrs)

            return self

        def close_w(self) -> None:
            if self.w is not None:
                os.close(self.w)
                self.w = None

        def close_r(self) -> None:
            assert self.r is not None
            os.close(self.r)
            self.r = None

        def __exit__(
                self,
                exc_type: type[BaseException] | None,
                exc_value: BaseException | None,
                traceback: TracebackType | None,
        ) -> None:
            self.close_w()
            self.close_r()

    def cmd_output_p(
            *cmd: str,
            check: bool = True,
            **kwargs: Any,
    ) -> tuple[int, bytes, bytes | None]:
        assert check is False
        assert kwargs['stderr'] == subprocess.STDOUT, kwargs['stderr']
        _setdefault_kwargs(kwargs)

        try:
            cmd = parse_shebang.normalize_cmd(cmd)
        except parse_shebang.ExecutableNotFoundError as e:
            return e.to_output()

        with open(os.devnull) as devnull, Pty() as pty:
            assert pty.r is not None
            kwargs.update({'stdin': devnull, 'stdout': pty.w, 'stderr': pty.w})
            try:
                proc = subprocess.Popen(cmd, **kwargs)
            except OSError as e:
                return _oserror_to_output(e)

            pty.close_w()

            buf = b''
            while True:
                try:
                    bts = os.read(pty.r, 4096)
                except OSError as e:
                    if e.errno == errno.EIO:
                        bts = b''
                    else:
                        raise
                else:
                    buf += bts
                if not bts:
                    break

        return proc.wait(), buf, None
else:  # pragma: no cover
    cmd_output_p = cmd_output_b


def _handle_readonly(
        func: Callable[[str], object],
        path: str,
        exc: OSError,
) -> None:
    if (
            func in (os.rmdir, os.remove, os.unlink) and
            exc.errno in {errno.EACCES, errno.EPERM}
    ):
        for p in (path, os.path.dirname(path)):
            os.chmod(p, os.stat(p).st_mode | stat.S_IWUSR)
        func(path)
    else:
        raise


if sys.version_info < (3, 12):  # pragma: <3.12 cover
    def _handle_readonly_old(
        func: Callable[[str], object],
        path: str,
        excinfo: tuple[type[OSError], OSError, TracebackType],
    ) -> None:
        return _handle_readonly(func, path, excinfo[1])

    def rmtree(path: str) -> None:
        shutil.rmtree(path, ignore_errors=False, onerror=_handle_readonly_old)
else:  # pragma: >=3.12 cover
    def rmtree(path: str) -> None:
        """On windows, rmtree fails for readonly dirs."""
        shutil.rmtree(path, ignore_errors=False, onexc=_handle_readonly)


def win_exe(s: str) -> str:
    return s if sys.platform != 'win32' else f'{s}.exe'