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| |
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|
|
| """Virtually every Python programmer has used Python for wrangling |
| disk contents, and ``fileutils`` collects solutions to some of the |
| most commonly-found gaps in the standard library. |
| """ |
|
|
|
|
| import os |
| import re |
| import sys |
| import stat |
| import errno |
| import fnmatch |
| from shutil import copy2, copystat, Error |
|
|
|
|
| __all__ = ['mkdir_p', 'atomic_save', 'AtomicSaver', 'FilePerms', |
| 'iter_find_files', 'copytree'] |
|
|
|
|
| FULL_PERMS = 0o777 |
| RW_PERMS = 438 |
| _SINGLE_FULL_PERM = 7 |
|
|
|
|
| def mkdir_p(path): |
| """Creates a directory and any parent directories that may need to |
| be created along the way, without raising errors for any existing |
| directories. This function mimics the behavior of the ``mkdir -p`` |
| command available in Linux/BSD environments, but also works on |
| Windows. |
| """ |
| try: |
| os.makedirs(path) |
| except OSError as exc: |
| if exc.errno == errno.EEXIST and os.path.isdir(path): |
| return |
| raise |
| return |
|
|
|
|
| class FilePerms: |
| """The :class:`FilePerms` type is used to represent standard POSIX |
| filesystem permissions: |
| |
| * Read |
| * Write |
| * Execute |
| |
| Across three classes of user: |
| |
| * Owning (u)ser |
| * Owner's (g)roup |
| * Any (o)ther user |
| |
| This class assists with computing new permissions, as well as |
| working with numeric octal ``777``-style and ``rwx``-style |
| permissions. Currently it only considers the bottom 9 permission |
| bits; it does not support sticky bits or more advanced permission |
| systems. |
| |
| Args: |
| user (str): A string in the 'rwx' format, omitting characters |
| for which owning user's permissions are not provided. |
| group (str): A string in the 'rwx' format, omitting characters |
| for which owning group permissions are not provided. |
| other (str): A string in the 'rwx' format, omitting characters |
| for which owning other/world permissions are not provided. |
| |
| There are many ways to use :class:`FilePerms`: |
| |
| >>> FilePerms(user='rwx', group='xrw', other='wxr') # note character order |
| FilePerms(user='rwx', group='rwx', other='rwx') |
| >>> int(FilePerms('r', 'r', '')) |
| 288 |
| >>> oct(288)[-3:] # XXX Py3k |
| '440' |
| |
| See also the :meth:`FilePerms.from_int` and |
| :meth:`FilePerms.from_path` classmethods for useful alternative |
| ways to construct :class:`FilePerms` objects. |
| """ |
| |
| class _FilePermProperty: |
| _perm_chars = 'rwx' |
| _perm_set = frozenset('rwx') |
| _perm_val = {'r': 4, 'w': 2, 'x': 1} |
|
|
| def __init__(self, attribute, offset): |
| self.attribute = attribute |
| self.offset = offset |
|
|
| def __get__(self, fp_obj, type_=None): |
| if fp_obj is None: |
| return self |
| return getattr(fp_obj, self.attribute) |
|
|
| def __set__(self, fp_obj, value): |
| cur = getattr(fp_obj, self.attribute) |
| if cur == value: |
| return |
| try: |
| invalid_chars = set(str(value)) - self._perm_set |
| except TypeError: |
| raise TypeError('expected string, not %r' % value) |
| if invalid_chars: |
| raise ValueError('got invalid chars %r in permission' |
| ' specification %r, expected empty string' |
| ' or one or more of %r' |
| % (invalid_chars, value, self._perm_chars)) |
|
|
| def sort_key(c): return self._perm_val[c] |
| new_value = ''.join(sorted(set(value), |
| key=sort_key, reverse=True)) |
| setattr(fp_obj, self.attribute, new_value) |
| self._update_integer(fp_obj, new_value) |
|
|
| def _update_integer(self, fp_obj, value): |
| mode = 0 |
| key = 'xwr' |
| for symbol in value: |
| bit = 2 ** key.index(symbol) |
| mode |= (bit << (self.offset * 3)) |
| fp_obj._integer |= mode |
|
|
| def __init__(self, user='', group='', other=''): |
| self._user, self._group, self._other = '', '', '' |
| self._integer = 0 |
| self.user = user |
| self.group = group |
| self.other = other |
|
|
| @classmethod |
| def from_int(cls, i): |
| """Create a :class:`FilePerms` object from an integer. |
| |
| >>> FilePerms.from_int(0o644) # note the leading zero-oh for octal |
| FilePerms(user='rw', group='r', other='r') |
| """ |
| i &= FULL_PERMS |
| key = ('', 'x', 'w', 'xw', 'r', 'rx', 'rw', 'rwx') |
| parts = [] |
| while i: |
| parts.append(key[i & _SINGLE_FULL_PERM]) |
| i >>= 3 |
| parts.reverse() |
| return cls(*parts) |
|
|
| @classmethod |
| def from_path(cls, path): |
| """Make a new :class:`FilePerms` object based on the permissions |
| assigned to the file or directory at *path*. |
| |
| Args: |
| path (str): Filesystem path of the target file. |
| |
| Here's an example that holds true on most systems: |
| |
| >>> import tempfile |
| >>> 'r' in FilePerms.from_path(tempfile.gettempdir()).user |
| True |
| """ |
| stat_res = os.stat(path) |
| return cls.from_int(stat.S_IMODE(stat_res.st_mode)) |
|
|
| def __int__(self): |
| return self._integer |
|
|
| |
| user = _FilePermProperty('_user', 2) |
| "Stores the ``rwx``-formatted *user* permission." |
| group = _FilePermProperty('_group', 1) |
| "Stores the ``rwx``-formatted *group* permission." |
| other = _FilePermProperty('_other', 0) |
| "Stores the ``rwx``-formatted *other* permission." |
|
|
| def __repr__(self): |
| cn = self.__class__.__name__ |
| return ('%s(user=%r, group=%r, other=%r)' |
| % (cn, self.user, self.group, self.other)) |
|
|
| |
|
|
|
|
| _TEXT_OPENFLAGS = os.O_RDWR | os.O_CREAT | os.O_EXCL |
| if hasattr(os, 'O_NOINHERIT'): |
| _TEXT_OPENFLAGS |= os.O_NOINHERIT |
| if hasattr(os, 'O_NOFOLLOW'): |
| _TEXT_OPENFLAGS |= os.O_NOFOLLOW |
| _BIN_OPENFLAGS = _TEXT_OPENFLAGS |
| if hasattr(os, 'O_BINARY'): |
| _BIN_OPENFLAGS |= os.O_BINARY |
|
|
|
|
| try: |
| import fcntl as fcntl |
| except ImportError: |
| def set_cloexec(fd): |
| "Dummy set_cloexec for platforms without fcntl support" |
| pass |
| else: |
| def set_cloexec(fd): |
| """Does a best-effort :func:`fcntl.fcntl` call to set a fd to be |
| automatically closed by any future child processes. |
| |
| Implementation from the :mod:`tempfile` module. |
| """ |
| try: |
| flags = fcntl.fcntl(fd, fcntl.F_GETFD, 0) |
| except OSError: |
| pass |
| else: |
| |
| flags |= fcntl.FD_CLOEXEC |
| fcntl.fcntl(fd, fcntl.F_SETFD, flags) |
| return |
|
|
|
|
| def atomic_save(dest_path, **kwargs): |
| """A convenient interface to the :class:`AtomicSaver` type. Example: |
| |
| >>> try: |
| ... with atomic_save("file.txt", text_mode=True) as fo: |
| ... _ = fo.write('bye') |
| ... 1/0 # will error |
| ... fo.write('bye') |
| ... except ZeroDivisionError: |
| ... pass # at least our file.txt didn't get overwritten |
| |
| See the :class:`AtomicSaver` documentation for details. |
| """ |
| return AtomicSaver(dest_path, **kwargs) |
|
|
|
|
| def path_to_unicode(path): |
| if isinstance(path, str): |
| return path |
| encoding = sys.getfilesystemencoding() or sys.getdefaultencoding() |
| return path.decode(encoding) |
|
|
|
|
| if os.name == 'nt': |
| import ctypes |
| from ctypes import c_wchar_p |
| from ctypes.wintypes import DWORD, LPVOID |
|
|
| _ReplaceFile = ctypes.windll.kernel32.ReplaceFile |
| _ReplaceFile.argtypes = [c_wchar_p, c_wchar_p, c_wchar_p, |
| DWORD, LPVOID, LPVOID] |
|
|
| def replace(src, dst): |
| |
| try: |
| |
| |
| os.rename(src, dst) |
| return |
| except OSError as we: |
| if we.errno == errno.EEXIST: |
| pass |
| else: |
| raise |
|
|
| src = path_to_unicode(src) |
| dst = path_to_unicode(dst) |
| res = _ReplaceFile(c_wchar_p(dst), c_wchar_p(src), |
| None, 0, None, None) |
| if not res: |
| raise OSError(f'failed to replace {dst!r} with {src!r}') |
| return |
|
|
| def atomic_rename(src, dst, overwrite=False): |
| "Rename *src* to *dst*, replacing *dst* if *overwrite is True" |
| if overwrite: |
| replace(src, dst) |
| else: |
| os.rename(src, dst) |
| return |
| else: |
| |
| def replace(src, dst): |
| |
| return os.rename(src, dst) |
|
|
| def atomic_rename(src, dst, overwrite=False): |
| "Rename *src* to *dst*, replacing *dst* if *overwrite is True" |
| if overwrite: |
| os.rename(src, dst) |
| else: |
| os.link(src, dst) |
| os.unlink(src) |
| return |
|
|
|
|
| _atomic_rename = atomic_rename |
|
|
| replace.__doc__ = """Similar to :func:`os.replace` in Python 3.3+, |
| this function will atomically create or replace the file at path |
| *dst* with the file at path *src*. |
| |
| On Windows, this function uses the ReplaceFile API for maximum |
| possible atomicity on a range of filesystems. |
| """ |
|
|
|
|
| class AtomicSaver: |
| """``AtomicSaver`` is a configurable `context manager`_ that provides |
| a writable :class:`file` which will be moved into place as long as |
| no exceptions are raised within the context manager's block. These |
| "part files" are created in the same directory as the destination |
| path to ensure atomic move operations (i.e., no cross-filesystem |
| moves occur). |
| |
| Args: |
| dest_path (str): The path where the completed file will be |
| written. |
| overwrite (bool): Whether to overwrite the destination file if |
| it exists at completion time. Defaults to ``True``. |
| file_perms (int): Integer representation of file permissions |
| for the newly-created file. Defaults are, when the |
| destination path already exists, to copy the permissions |
| from the previous file, or if the file did not exist, to |
| respect the user's configured `umask`_, usually resulting |
| in octal 0644 or 0664. |
| text_mode (bool): Whether to open the destination file in text |
| mode (i.e., ``'w'`` not ``'wb'``). Defaults to ``False`` (``wb``). |
| part_file (str): Name of the temporary *part_file*. Defaults |
| to *dest_path* + ``.part``. Note that this argument is |
| just the filename, and not the full path of the part |
| file. To guarantee atomic saves, part files are always |
| created in the same directory as the destination path. |
| overwrite_part (bool): Whether to overwrite the *part_file*, |
| should it exist at setup time. Defaults to ``False``, |
| which results in an :exc:`OSError` being raised on |
| pre-existing part files. Be careful of setting this to |
| ``True`` in situations when multiple threads or processes |
| could be writing to the same part file. |
| rm_part_on_exc (bool): Remove *part_file* on exception cases. |
| Defaults to ``True``, but ``False`` can be useful for |
| recovery in some cases. Note that resumption is not |
| automatic and by default an :exc:`OSError` is raised if |
| the *part_file* exists. |
| |
| Practically, the AtomicSaver serves a few purposes: |
| |
| * Avoiding overwriting an existing, valid file with a partially |
| written one. |
| * Providing a reasonable guarantee that a part file only has one |
| writer at a time. |
| * Optional recovery of partial data in failure cases. |
| |
| .. _context manager: https://docs.python.org/2/reference/compound_stmts.html#with |
| .. _umask: https://en.wikipedia.org/wiki/Umask |
| |
| """ |
| _default_file_perms = RW_PERMS |
|
|
| |
| def __init__(self, dest_path, **kwargs): |
| self.dest_path = dest_path |
| self.overwrite = kwargs.pop('overwrite', True) |
| self.file_perms = kwargs.pop('file_perms', None) |
| self.overwrite_part = kwargs.pop('overwrite_part', False) |
| self.part_filename = kwargs.pop('part_file', None) |
| self.rm_part_on_exc = kwargs.pop('rm_part_on_exc', True) |
| self.text_mode = kwargs.pop('text_mode', False) |
| self.buffering = kwargs.pop('buffering', -1) |
| if kwargs: |
| raise TypeError(f'unexpected kwargs: {kwargs.keys()!r}') |
|
|
| self.dest_path = os.path.abspath(self.dest_path) |
| self.dest_dir = os.path.dirname(self.dest_path) |
| if not self.part_filename: |
| self.part_path = dest_path + '.part' |
| else: |
| self.part_path = os.path.join(self.dest_dir, self.part_filename) |
| self.mode = 'w+' if self.text_mode else 'w+b' |
| self.open_flags = _TEXT_OPENFLAGS if self.text_mode else _BIN_OPENFLAGS |
|
|
| self.part_file = None |
|
|
| def _open_part_file(self): |
| do_chmod = True |
| file_perms = self.file_perms |
| if file_perms is None: |
| try: |
| |
| stat_res = os.stat(self.dest_path) |
| file_perms = stat.S_IMODE(stat_res.st_mode) |
| except OSError: |
| |
| file_perms = self._default_file_perms |
| do_chmod = False |
|
|
| fd = os.open(self.part_path, self.open_flags, file_perms) |
| set_cloexec(fd) |
| self.part_file = os.fdopen(fd, self.mode, self.buffering) |
|
|
| |
| |
| if do_chmod: |
| try: |
| os.chmod(self.part_path, file_perms) |
| except OSError: |
| self.part_file.close() |
| raise |
| return |
|
|
| def setup(self): |
| """Called on context manager entry (the :keyword:`with` statement), |
| the ``setup()`` method creates the temporary file in the same |
| directory as the destination file. |
| |
| ``setup()`` tests for a writable directory with rename permissions |
| early, as the part file may not be written to immediately (not |
| using :func:`os.access` because of the potential issues of |
| effective vs. real privileges). |
| |
| If the caller is not using the :class:`AtomicSaver` as a |
| context manager, this method should be called explicitly |
| before writing. |
| """ |
| if os.path.lexists(self.dest_path): |
| if not self.overwrite: |
| raise OSError(errno.EEXIST, |
| 'Overwrite disabled and file already exists', |
| self.dest_path) |
| if self.overwrite_part and os.path.lexists(self.part_path): |
| os.unlink(self.part_path) |
| self._open_part_file() |
| return |
|
|
| def __enter__(self): |
| self.setup() |
| return self.part_file |
|
|
| def __exit__(self, exc_type, exc_val, exc_tb): |
| if self.part_file: |
| |
| self.part_file.flush() |
| os.fsync(self.part_file.fileno()) |
| self.part_file.close() |
| if exc_type: |
| if self.rm_part_on_exc: |
| try: |
| os.unlink(self.part_path) |
| except Exception: |
| pass |
| return |
| try: |
| atomic_rename(self.part_path, self.dest_path, |
| overwrite=self.overwrite) |
| except OSError: |
| if self.rm_part_on_exc: |
| try: |
| os.unlink(self.part_path) |
| except Exception: |
| pass |
| raise |
| return |
|
|
|
|
| def iter_find_files(directory, patterns, ignored=None, include_dirs=False, max_depth=None): |
| """Returns a generator that yields file paths under a *directory*, |
| matching *patterns* using `glob`_ syntax (e.g., ``*.txt``). Also |
| supports *ignored* patterns. |
| |
| Args: |
| directory (str): Path that serves as the root of the |
| search. Yielded paths will include this as a prefix. |
| patterns (str or list): A single pattern or list of |
| glob-formatted patterns to find under *directory*. |
| ignored (str or list): A single pattern or list of |
| glob-formatted patterns to ignore. |
| include_dirs (bool): Whether to include directories that match |
| patterns, as well. Defaults to ``False``. |
| max_depth (int): traverse up to this level of subdirectory. |
| I.e., 0 for the specified *directory* only, 1 for *directory* |
| and one level of subdirectory. |
| |
| For example, finding Python files in the current directory: |
| |
| >>> _CUR_DIR = os.path.dirname(os.path.abspath(__file__)) |
| >>> filenames = sorted(iter_find_files(_CUR_DIR, '*.py')) |
| >>> os.path.basename(filenames[-1]) |
| 'urlutils.py' |
| |
| Or, Python files while ignoring emacs lockfiles: |
| |
| >>> filenames = iter_find_files(_CUR_DIR, '*.py', ignored='.#*') |
| |
| .. _glob: https://en.wikipedia.org/wiki/Glob_%28programming%29 |
| |
| """ |
| if isinstance(patterns, str): |
| patterns = [patterns] |
| pats_re = re.compile('|'.join([fnmatch.translate(p) for p in patterns])) |
|
|
| if not ignored: |
| ignored = [] |
| elif isinstance(ignored, str): |
| ignored = [ignored] |
| ign_re = re.compile('|'.join([fnmatch.translate(p) for p in ignored])) |
| start_depth = len(directory.split(os.path.sep)) |
| for root, dirs, files in os.walk(directory): |
| if max_depth is not None and (len(root.split(os.path.sep)) - start_depth) > max_depth: |
| continue |
| if include_dirs: |
| for basename in dirs: |
| if pats_re.match(basename): |
| if ignored and ign_re.match(basename): |
| continue |
| filename = os.path.join(root, basename) |
| yield filename |
|
|
| for basename in files: |
| if pats_re.match(basename): |
| if ignored and ign_re.match(basename): |
| continue |
| filename = os.path.join(root, basename) |
| yield filename |
| return |
|
|
|
|
| def copy_tree(src, dst, symlinks=False, ignore=None): |
| """The ``copy_tree`` function is an exact copy of the built-in |
| :func:`shutil.copytree`, with one key difference: it will not |
| raise an exception if part of the tree already exists. It achieves |
| this by using :func:`mkdir_p`. |
| |
| As of Python 3.8, you may pass :func:`shutil.copytree` the |
| `dirs_exist_ok=True` flag to achieve the same effect. |
| |
| Args: |
| src (str): Path of the source directory to copy. |
| dst (str): Destination path. Existing directories accepted. |
| symlinks (bool): If ``True``, copy symlinks rather than their |
| contents. |
| ignore (callable): A callable that takes a path and directory |
| listing, returning the files within the listing to be ignored. |
| |
| For more details, check out :func:`shutil.copytree` and |
| :func:`shutil.copy2`. |
| |
| """ |
| names = os.listdir(src) |
| if ignore is not None: |
| ignored_names = ignore(src, names) |
| else: |
| ignored_names = set() |
|
|
| mkdir_p(dst) |
| errors = [] |
| for name in names: |
| if name in ignored_names: |
| continue |
| srcname = os.path.join(src, name) |
| dstname = os.path.join(dst, name) |
| try: |
| if symlinks and os.path.islink(srcname): |
| linkto = os.readlink(srcname) |
| os.symlink(linkto, dstname) |
| elif os.path.isdir(srcname): |
| copytree(srcname, dstname, symlinks, ignore) |
| else: |
| |
| copy2(srcname, dstname) |
| |
| |
| except Error as e: |
| errors.extend(e.args[0]) |
| except OSError as why: |
| errors.append((srcname, dstname, str(why))) |
| try: |
| copystat(src, dst) |
| except OSError as why: |
| errors.append((src, dst, str(why))) |
| if errors: |
| raise Error(errors) |
|
|
|
|
| copytree = copy_tree |
|
|
|
|
| |
| class DummyFile: |
| |
| |
| def __init__(self, path, mode='r', buffering=None): |
| self.name = path |
| self.mode = mode |
| self.closed = False |
| self.errors = None |
| self.isatty = False |
| self.encoding = None |
| self.newlines = None |
| self.softspace = 0 |
|
|
| def close(self): |
| self.closed = True |
|
|
| def fileno(self): |
| return -1 |
|
|
| def flush(self): |
| if self.closed: |
| raise ValueError('I/O operation on a closed file') |
| return |
|
|
| def next(self): |
| raise StopIteration() |
|
|
| def read(self, size=0): |
| if self.closed: |
| raise ValueError('I/O operation on a closed file') |
| return '' |
|
|
| def readline(self, size=0): |
| if self.closed: |
| raise ValueError('I/O operation on a closed file') |
| return '' |
|
|
| def readlines(self, size=0): |
| if self.closed: |
| raise ValueError('I/O operation on a closed file') |
| return [] |
|
|
| def seek(self): |
| if self.closed: |
| raise ValueError('I/O operation on a closed file') |
| return |
|
|
| def tell(self): |
| if self.closed: |
| raise ValueError('I/O operation on a closed file') |
| return 0 |
|
|
| def truncate(self): |
| if self.closed: |
| raise ValueError('I/O operation on a closed file') |
| return |
|
|
| def write(self, string): |
| if self.closed: |
| raise ValueError('I/O operation on a closed file') |
| return |
|
|
| def writelines(self, list_of_strings): |
| if self.closed: |
| raise ValueError('I/O operation on a closed file') |
| return |
|
|
| def __next__(self): |
| raise StopIteration() |
|
|
| def __enter__(self): |
| if self.closed: |
| raise ValueError('I/O operation on a closed file') |
| return |
|
|
| def __exit__(self, exc_type, exc_val, exc_tb): |
| return |
|
|
|
|
| def rotate_file(filename, *, keep: int = 5): |
| """ |
| If *filename.ext* exists, it will be moved to *filename.1.ext*, |
| with all conflicting filenames being moved up by one, dropping any files beyond *keep*. |
| |
| After rotation, *filename* will be available for creation as a new file. |
| |
| Fails if *filename* is not a file or if *keep* is not > 0. |
| """ |
| if keep < 1: |
| raise ValueError(f'expected "keep" to be >=1, not {keep}') |
| if not os.path.exists(filename): |
| return |
| if not os.path.isfile(filename): |
| raise ValueError(f'expected {filename} to be a file') |
|
|
| fn_root, fn_ext = os.path.splitext(filename) |
| kept_names = [] |
| for i in range(1, keep + 1): |
| if fn_ext: |
| kept_names.append(f'{fn_root}.{i}{fn_ext}') |
| else: |
| kept_names.append(f'{fn_root}.{i}') |
|
|
| fns = [filename] + kept_names |
| for orig_name, kept_name in reversed(list(zip(fns, fns[1:]))): |
| if not os.path.exists(orig_name): |
| continue |
| os.rename(orig_name, kept_name) |
|
|
| if os.path.exists(kept_names[-1]): |
| os.remove(kept_names[-1]) |
|
|
| return |
|
|