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Cours/venv/lib/python3.12/site-packages/watchdog/observers/inotify_c.py

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from __future__ import annotations
import contextlib
import ctypes
import ctypes.util
import errno
import os
import struct
import threading
from ctypes import c_char_p, c_int, c_uint32
from functools import reduce
from typing import TYPE_CHECKING
from watchdog.utils import UnsupportedLibcError
if TYPE_CHECKING:
from collections.abc import Generator
libc = ctypes.CDLL(None)
if not hasattr(libc, "inotify_init") or not hasattr(libc, "inotify_add_watch") or not hasattr(libc, "inotify_rm_watch"):
error = f"Unsupported libc version found: {libc._name}" # noqa:SLF001
raise UnsupportedLibcError(error)
inotify_add_watch = ctypes.CFUNCTYPE(c_int, c_int, c_char_p, c_uint32, use_errno=True)(("inotify_add_watch", libc))
inotify_rm_watch = ctypes.CFUNCTYPE(c_int, c_int, c_uint32, use_errno=True)(("inotify_rm_watch", libc))
inotify_init = ctypes.CFUNCTYPE(c_int, use_errno=True)(("inotify_init", libc))
class InotifyConstants:
# User-space events
IN_ACCESS = 0x00000001 # File was accessed.
IN_MODIFY = 0x00000002 # File was modified.
IN_ATTRIB = 0x00000004 # Meta-data changed.
IN_CLOSE_WRITE = 0x00000008 # Writable file was closed.
IN_CLOSE_NOWRITE = 0x00000010 # Unwritable file closed.
IN_OPEN = 0x00000020 # File was opened.
IN_MOVED_FROM = 0x00000040 # File was moved from X.
IN_MOVED_TO = 0x00000080 # File was moved to Y.
IN_CREATE = 0x00000100 # Subfile was created.
IN_DELETE = 0x00000200 # Subfile was deleted.
IN_DELETE_SELF = 0x00000400 # Self was deleted.
IN_MOVE_SELF = 0x00000800 # Self was moved.
# Helper user-space events.
IN_MOVE = IN_MOVED_FROM | IN_MOVED_TO # Moves.
# Events sent by the kernel to a watch.
IN_UNMOUNT = 0x00002000 # Backing file system was unmounted.
IN_Q_OVERFLOW = 0x00004000 # Event queued overflowed.
IN_IGNORED = 0x00008000 # File was ignored.
# Special flags.
IN_ONLYDIR = 0x01000000 # Only watch the path if it's a directory.
IN_DONT_FOLLOW = 0x02000000 # Do not follow a symbolic link.
IN_EXCL_UNLINK = 0x04000000 # Exclude events on unlinked objects
IN_MASK_ADD = 0x20000000 # Add to the mask of an existing watch.
IN_ISDIR = 0x40000000 # Event occurred against directory.
IN_ONESHOT = 0x80000000 # Only send event once.
# All user-space events.
IN_ALL_EVENTS = reduce(
lambda x, y: x | y,
[
IN_ACCESS,
IN_MODIFY,
IN_ATTRIB,
IN_CLOSE_WRITE,
IN_CLOSE_NOWRITE,
IN_OPEN,
IN_MOVED_FROM,
IN_MOVED_TO,
IN_DELETE,
IN_CREATE,
IN_DELETE_SELF,
IN_MOVE_SELF,
],
)
# Flags for ``inotify_init1``
IN_CLOEXEC = 0x02000000
IN_NONBLOCK = 0x00004000
# Watchdog's API cares only about these events.
WATCHDOG_ALL_EVENTS = reduce(
lambda x, y: x | y,
[
InotifyConstants.IN_MODIFY,
InotifyConstants.IN_ATTRIB,
InotifyConstants.IN_MOVED_FROM,
InotifyConstants.IN_MOVED_TO,
InotifyConstants.IN_CREATE,
InotifyConstants.IN_DELETE,
InotifyConstants.IN_DELETE_SELF,
InotifyConstants.IN_DONT_FOLLOW,
InotifyConstants.IN_CLOSE_WRITE,
InotifyConstants.IN_CLOSE_NOWRITE,
InotifyConstants.IN_OPEN,
],
)
class InotifyEventStruct(ctypes.Structure):
"""Structure representation of the inotify_event structure
(used in buffer size calculations)::
struct inotify_event {
__s32 wd; /* watch descriptor */
__u32 mask; /* watch mask */
__u32 cookie; /* cookie to synchronize two events */
__u32 len; /* length (including nulls) of name */
char name[0]; /* stub for possible name */
};
"""
_fields_ = (
("wd", c_int),
("mask", c_uint32),
("cookie", c_uint32),
("len", c_uint32),
("name", c_char_p),
)
EVENT_SIZE = ctypes.sizeof(InotifyEventStruct)
DEFAULT_NUM_EVENTS = 2048
DEFAULT_EVENT_BUFFER_SIZE = DEFAULT_NUM_EVENTS * (EVENT_SIZE + 16)
class Inotify:
"""Linux inotify(7) API wrapper class.
:param path:
The directory path for which we want an inotify object.
:type path:
:class:`bytes`
:param recursive:
``True`` if subdirectories should be monitored; ``False`` otherwise.
"""
def __init__(self, path: bytes, *, recursive: bool = False, event_mask: int | None = None) -> None:
# The file descriptor associated with the inotify instance.
inotify_fd = inotify_init()
if inotify_fd == -1:
Inotify._raise_error()
self._inotify_fd = inotify_fd
self._lock = threading.Lock()
# Stores the watch descriptor for a given path.
self._wd_for_path: dict[bytes, int] = {}
self._path_for_wd: dict[int, bytes] = {}
self._path = path
# Default to all events
if event_mask is None:
event_mask = WATCHDOG_ALL_EVENTS
self._event_mask = event_mask
self._is_recursive = recursive
if os.path.isdir(path):
self._add_dir_watch(path, event_mask, recursive=recursive)
else:
self._add_watch(path, event_mask)
self._moved_from_events: dict[int, InotifyEvent] = {}
@property
def event_mask(self) -> int:
"""The event mask for this inotify instance."""
return self._event_mask
@property
def path(self) -> bytes:
"""The path associated with the inotify instance."""
return self._path
@property
def is_recursive(self) -> bool:
"""Whether we are watching directories recursively."""
return self._is_recursive
@property
def fd(self) -> int:
"""The file descriptor associated with the inotify instance."""
return self._inotify_fd
def clear_move_records(self) -> None:
"""Clear cached records of MOVED_FROM events"""
self._moved_from_events = {}
def source_for_move(self, destination_event: InotifyEvent) -> bytes | None:
"""The source path corresponding to the given MOVED_TO event.
If the source path is outside the monitored directories, None
is returned instead.
"""
if destination_event.cookie in self._moved_from_events:
return self._moved_from_events[destination_event.cookie].src_path
return None
def remember_move_from_event(self, event: InotifyEvent) -> None:
"""Save this event as the source event for future MOVED_TO events to
reference.
"""
self._moved_from_events[event.cookie] = event
def add_watch(self, path: bytes) -> None:
"""Adds a watch for the given path.
:param path:
Path to begin monitoring.
"""
with self._lock:
self._add_watch(path, self._event_mask)
def remove_watch(self, path: bytes) -> None:
"""Removes a watch for the given path.
:param path:
Path string for which the watch will be removed.
"""
with self._lock:
wd = self._wd_for_path.pop(path)
del self._path_for_wd[wd]
if inotify_rm_watch(self._inotify_fd, wd) == -1:
Inotify._raise_error()
def close(self) -> None:
"""Closes the inotify instance and removes all associated watches."""
with self._lock:
if self._path in self._wd_for_path:
wd = self._wd_for_path[self._path]
inotify_rm_watch(self._inotify_fd, wd)
# descriptor may be invalid because file was deleted
with contextlib.suppress(OSError):
os.close(self._inotify_fd)
def read_events(self, *, event_buffer_size: int = DEFAULT_EVENT_BUFFER_SIZE) -> list[InotifyEvent]:
"""Reads events from inotify and yields them."""
# HACK: We need to traverse the directory path
# recursively and simulate events for newly
# created subdirectories/files. This will handle
# mkdir -p foobar/blah/bar; touch foobar/afile
def _recursive_simulate(src_path: bytes) -> list[InotifyEvent]:
events = []
for root, dirnames, filenames in os.walk(src_path):
for dirname in dirnames:
with contextlib.suppress(OSError):
full_path = os.path.join(root, dirname)
wd_dir = self._add_watch(full_path, self._event_mask)
e = InotifyEvent(
wd_dir,
InotifyConstants.IN_CREATE | InotifyConstants.IN_ISDIR,
0,
dirname,
full_path,
)
events.append(e)
for filename in filenames:
full_path = os.path.join(root, filename)
wd_parent_dir = self._wd_for_path[os.path.dirname(full_path)]
e = InotifyEvent(
wd_parent_dir,
InotifyConstants.IN_CREATE,
0,
filename,
full_path,
)
events.append(e)
return events
event_buffer = None
while True:
try:
event_buffer = os.read(self._inotify_fd, event_buffer_size)
except OSError as e:
if e.errno == errno.EINTR:
continue
if e.errno == errno.EBADF:
return []
raise
break
with self._lock:
event_list = []
for wd, mask, cookie, name in Inotify._parse_event_buffer(event_buffer):
if wd == -1:
continue
wd_path = self._path_for_wd[wd]
src_path = os.path.join(wd_path, name) if name else wd_path # avoid trailing slash
inotify_event = InotifyEvent(wd, mask, cookie, name, src_path)
if inotify_event.is_moved_from:
self.remember_move_from_event(inotify_event)
elif inotify_event.is_moved_to:
move_src_path = self.source_for_move(inotify_event)
if move_src_path in self._wd_for_path:
moved_wd = self._wd_for_path[move_src_path]
del self._wd_for_path[move_src_path]
self._wd_for_path[inotify_event.src_path] = moved_wd
self._path_for_wd[moved_wd] = inotify_event.src_path
if self.is_recursive:
for _path in self._wd_for_path.copy():
if _path.startswith(move_src_path + os.path.sep.encode()):
moved_wd = self._wd_for_path.pop(_path)
_move_to_path = _path.replace(move_src_path, inotify_event.src_path)
self._wd_for_path[_move_to_path] = moved_wd
self._path_for_wd[moved_wd] = _move_to_path
src_path = os.path.join(wd_path, name)
inotify_event = InotifyEvent(wd, mask, cookie, name, src_path)
if inotify_event.is_ignored:
# Clean up book-keeping for deleted watches.
path = self._path_for_wd.pop(wd)
if self._wd_for_path[path] == wd:
del self._wd_for_path[path]
event_list.append(inotify_event)
if self.is_recursive and inotify_event.is_directory and inotify_event.is_create:
# TODO: When a directory from another part of the
# filesystem is moved into a watched directory, this
# will not generate events for the directory tree.
# We need to coalesce IN_MOVED_TO events and those
# IN_MOVED_TO events which don't pair up with
# IN_MOVED_FROM events should be marked IN_CREATE
# instead relative to this directory.
try:
self._add_watch(src_path, self._event_mask)
except OSError:
continue
event_list.extend(_recursive_simulate(src_path))
return event_list
# Non-synchronized methods.
def _add_dir_watch(self, path: bytes, mask: int, *, recursive: bool) -> None:
"""Adds a watch (optionally recursively) for the given directory path
to monitor events specified by the mask.
:param path:
Path to monitor
:param recursive:
``True`` to monitor recursively.
:param mask:
Event bit mask.
"""
if not os.path.isdir(path):
raise OSError(errno.ENOTDIR, os.strerror(errno.ENOTDIR), path)
self._add_watch(path, mask)
if recursive:
for root, dirnames, _ in os.walk(path):
for dirname in dirnames:
full_path = os.path.join(root, dirname)
if os.path.islink(full_path):
continue
self._add_watch(full_path, mask)
def _add_watch(self, path: bytes, mask: int) -> int:
"""Adds a watch for the given path to monitor events specified by the
mask.
:param path:
Path to monitor
:param mask:
Event bit mask.
"""
wd = inotify_add_watch(self._inotify_fd, path, mask)
if wd == -1:
Inotify._raise_error()
self._wd_for_path[path] = wd
self._path_for_wd[wd] = path
return wd
@staticmethod
def _raise_error() -> None:
"""Raises errors for inotify failures."""
err = ctypes.get_errno()
if err == errno.ENOSPC:
raise OSError(errno.ENOSPC, "inotify watch limit reached")
if err == errno.EMFILE:
raise OSError(errno.EMFILE, "inotify instance limit reached")
if err != errno.EACCES:
raise OSError(err, os.strerror(err))
@staticmethod
def _parse_event_buffer(event_buffer: bytes) -> Generator[tuple[int, int, int, bytes]]:
"""Parses an event buffer of ``inotify_event`` structs returned by
inotify::
struct inotify_event {
__s32 wd; /* watch descriptor */
__u32 mask; /* watch mask */
__u32 cookie; /* cookie to synchronize two events */
__u32 len; /* length (including nulls) of name */
char name[0]; /* stub for possible name */
};
The ``cookie`` member of this struct is used to pair two related
events, for example, it pairs an IN_MOVED_FROM event with an
IN_MOVED_TO event.
"""
i = 0
while i + 16 <= len(event_buffer):
wd, mask, cookie, length = struct.unpack_from("iIII", event_buffer, i)
name = event_buffer[i + 16 : i + 16 + length].rstrip(b"\0")
i += 16 + length
yield wd, mask, cookie, name
class InotifyEvent:
"""Inotify event struct wrapper.
:param wd:
Watch descriptor
:param mask:
Event mask
:param cookie:
Event cookie
:param name:
Base name of the event source path.
:param src_path:
Full event source path.
"""
def __init__(self, wd: int, mask: int, cookie: int, name: bytes, src_path: bytes) -> None:
self._wd = wd
self._mask = mask
self._cookie = cookie
self._name = name
self._src_path = src_path
@property
def src_path(self) -> bytes:
return self._src_path
@property
def wd(self) -> int:
return self._wd
@property
def mask(self) -> int:
return self._mask
@property
def cookie(self) -> int:
return self._cookie
@property
def name(self) -> bytes:
return self._name
@property
def is_modify(self) -> bool:
return self._mask & InotifyConstants.IN_MODIFY > 0
@property
def is_close_write(self) -> bool:
return self._mask & InotifyConstants.IN_CLOSE_WRITE > 0
@property
def is_close_nowrite(self) -> bool:
return self._mask & InotifyConstants.IN_CLOSE_NOWRITE > 0
@property
def is_open(self) -> bool:
return self._mask & InotifyConstants.IN_OPEN > 0
@property
def is_access(self) -> bool:
return self._mask & InotifyConstants.IN_ACCESS > 0
@property
def is_delete(self) -> bool:
return self._mask & InotifyConstants.IN_DELETE > 0
@property
def is_delete_self(self) -> bool:
return self._mask & InotifyConstants.IN_DELETE_SELF > 0
@property
def is_create(self) -> bool:
return self._mask & InotifyConstants.IN_CREATE > 0
@property
def is_moved_from(self) -> bool:
return self._mask & InotifyConstants.IN_MOVED_FROM > 0
@property
def is_moved_to(self) -> bool:
return self._mask & InotifyConstants.IN_MOVED_TO > 0
@property
def is_move(self) -> bool:
return self._mask & InotifyConstants.IN_MOVE > 0
@property
def is_move_self(self) -> bool:
return self._mask & InotifyConstants.IN_MOVE_SELF > 0
@property
def is_attrib(self) -> bool:
return self._mask & InotifyConstants.IN_ATTRIB > 0
@property
def is_ignored(self) -> bool:
return self._mask & InotifyConstants.IN_IGNORED > 0
@property
def is_directory(self) -> bool:
# It looks like the kernel does not provide this information for
# IN_DELETE_SELF and IN_MOVE_SELF. In this case, assume it's a dir.
# See also: https://github.com/seb-m/pyinotify/blob/2c7e8f8/python2/pyinotify.py#L897
return self.is_delete_self or self.is_move_self or self._mask & InotifyConstants.IN_ISDIR > 0
@property
def key(self) -> tuple[bytes, int, int, int, bytes]:
return self._src_path, self._wd, self._mask, self._cookie, self._name
def __eq__(self, inotify_event: object) -> bool:
if not isinstance(inotify_event, InotifyEvent):
return NotImplemented
return self.key == inotify_event.key
def __ne__(self, inotify_event: object) -> bool:
if not isinstance(inotify_event, InotifyEvent):
return NotImplemented
return self.key != inotify_event.key
def __hash__(self) -> int:
return hash(self.key)
@staticmethod
def _get_mask_string(mask: int) -> str:
masks = []
for c in dir(InotifyConstants):
if c.startswith("IN_") and c not in {"IN_ALL_EVENTS", "IN_MOVE"}:
c_val = getattr(InotifyConstants, c)
if mask & c_val:
masks.append(c)
return "|".join(masks)
def __repr__(self) -> str:
return (
f"<{type(self).__name__}: src_path={self.src_path!r}, wd={self.wd},"
f" mask={self._get_mask_string(self.mask)}, cookie={self.cookie},"
f" name={os.fsdecode(self.name)!r}>"
)
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