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[BSD] Restore support (gorakhargosh#641)
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* [BSD] Pass tests \o/

Changes in kqueue observer:
- Some refactoring to have the data flow be clearer
- Conform better to what the test suite expects
- Be a bit more correct

* [BSD] Restore support (changelog)

Fixes gorakhargosh#637

* [BSD] Restore support (review)
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@evilham
evilham committed Feb 7, 2020
1 parent 5572d85 commit 0fdd00f
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2 changes: 1 addition & 1 deletion changelog.rst
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Original file line number Diff line number Diff line change
Expand Up @@ -13,7 +13,7 @@ Changelog
``PatternMatchingEventHandler`` and ``RegexMatchingEventHandler``
- Improve tests support on non Windows/Linux platforms (`#633 <https://github.com/gorakhargosh/watchdog/pull/633>`__, `#639 <https://github.com/gorakhargosh/watchdog/pull/639>`__)
- Added FreeBSD CI support (`#532 <https://github.com/gorakhargosh/watchdog/pull/532>`__)
- [BSD] Restore partial support (`#638 <https://github.com/gorakhargosh/watchdog/pull/638>`__)
- [BSD] Restore support (`#638 <https://github.com/gorakhargosh/watchdog/pull/638>`__, `#641 <https://github.com/gorakhargosh/watchdog/pull/641>`__)
- Thanks to our beloved contributors: @BoboTiG, @evilham


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181 changes: 83 additions & 98 deletions src/watchdog/observers/kqueue.py
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Original file line number Diff line number Diff line change
Expand Up @@ -74,6 +74,7 @@
import errno
from stat import S_ISDIR
import os
import os.path
import select

from pathtools.path import absolute_path
Expand Down Expand Up @@ -522,128 +523,114 @@ def queue_event(self, event):
elif event.event_type == EVENT_TYPE_DELETED:
self._unregister_kevent(event.src_path)

def _queue_dirs_modified(self,
dirs_modified,
ref_snapshot,
new_snapshot):
def _gen_kqueue_events(self,
kev,
ref_snapshot,
new_snapshot):
"""
Queues events for directory modifications by scanning the directory
for changes.
A scan is a comparison between two snapshots of the same directory
taken at two different times. This also determines whether files
or directories were created, which updated the modified timestamp
for the directory.
"""
if dirs_modified:
for dir_modified in dirs_modified:
self.queue_event(DirModifiedEvent(dir_modified))
diff_events = new_snapshot - ref_snapshot
for file_created in diff_events.files_created:
self.queue_event(FileCreatedEvent(file_created))
for directory_created in diff_events.dirs_created:
self.queue_event(DirCreatedEvent(directory_created))

def _queue_events_except_renames_and_dir_modifications(self, event_list):
"""
Queues events from the kevent list returned from the call to
Generate events from the kevent list returned from the call to
:meth:`select.kqueue.control`.
.. NOTE:: Queues only the deletions, file modifications,
.. NOTE:: kqueue only tells us about deletions, file modifications,
attribute modifications. The other events, namely,
file creation, directory modification, file rename,
directory rename, directory creation, etc. are
determined by comparing directory snapshots.
"""
files_renamed = set()
dirs_renamed = set()
dirs_modified = set()

for kev in event_list:
descriptor = self._descriptors.get_for_fd(kev.ident)
src_path = descriptor.path

if is_deleted(kev):
if descriptor.is_directory:
self.queue_event(DirDeletedEvent(src_path))
else:
self.queue_event(FileDeletedEvent(src_path))
elif is_attrib_modified(kev):
if descriptor.is_directory:
self.queue_event(DirModifiedEvent(src_path))
else:
self.queue_event(FileModifiedEvent(src_path))
elif is_modified(kev):
if descriptor.is_directory:
descriptor = self._descriptors.get_for_fd(kev.ident)
src_path = descriptor.path

if is_renamed(kev):
# Kqueue does not specify the destination names for renames
# to, so we have to process these using the a snapshot
# of the directory.
for event in self._gen_renamed_events(src_path,
descriptor.is_directory,
ref_snapshot,
new_snapshot):
yield event
elif is_attrib_modified(kev):
if descriptor.is_directory:
yield DirModifiedEvent(src_path)
else:
yield FileModifiedEvent(src_path)
elif is_modified(kev):
if descriptor.is_directory:
if self.watch.is_recursive or self.watch.path == src_path:
# When a directory is modified, it may be due to
# sub-file/directory renames or new file/directory
# creation. We determine all this by comparing
# snapshots later.
dirs_modified.add(src_path)
else:
self.queue_event(FileModifiedEvent(src_path))
elif is_renamed(kev):
# Kqueue does not specify the destination names for renames
# to, so we have to process these after taking a snapshot
# of the directory.
if descriptor.is_directory:
dirs_renamed.add(src_path)
else:
files_renamed.add(src_path)
return files_renamed, dirs_renamed, dirs_modified

def _queue_renamed(self,
src_path,
is_directory,
ref_snapshot,
new_snapshot):
yield DirModifiedEvent(src_path)
else:
yield FileModifiedEvent(src_path)
elif is_deleted(kev):
if descriptor.is_directory:
yield DirDeletedEvent(src_path)
else:
yield FileDeletedEvent(src_path)

def _parent_dir_modified(self, src_path):
"""
Helper to generate a DirModifiedEvent on the parent of src_path.
"""
return DirModifiedEvent(os.path.dirname(src_path))

def _gen_renamed_events(self,
src_path,
is_directory,
ref_snapshot,
new_snapshot):
"""
Compares information from two directory snapshots (one taken before
the rename operation and another taken right after) to determine the
destination path of the file system object renamed, and adds
appropriate events to the event queue.
destination path of the file system object renamed, and yields
the appropriate events to be queued.
"""
try:
ref_stat_info = ref_snapshot.stat_info(src_path)
f_inode = ref_snapshot.inode(src_path)
except KeyError:
# Probably caught a temporary file/directory that was renamed
# and deleted. Fires a sequence of created and deleted events
# for the path.
if is_directory:
self.queue_event(DirCreatedEvent(src_path))
self.queue_event(DirDeletedEvent(src_path))
yield DirCreatedEvent(src_path)
yield DirDeletedEvent(src_path)
else:
self.queue_event(FileCreatedEvent(src_path))
self.queue_event(FileDeletedEvent(src_path))
yield FileCreatedEvent(src_path)
yield FileDeletedEvent(src_path)
# We don't process any further and bail out assuming
# the event represents deletion/creation instead of movement.
return

f_id = (ref_stat_info.st_ino, ref_stat_info.st_dev)
dest_path = new_snapshot.path(f_id)
dest_path = new_snapshot.path(f_inode)
if dest_path is not None:
dest_path = absolute_path(dest_path)
if is_directory:
event = DirMovedEvent(src_path, dest_path)
yield event
else:
yield FileMovedEvent(src_path, dest_path)
yield self._parent_dir_modified(src_path)
yield self._parent_dir_modified(dest_path)
if is_directory:
# TODO: Do we need to fire moved events for the items
# inside the directory tree? Does kqueue does this
# all by itself? Check this and then enable this code
# only if it doesn't already.
# A: It doesn't. So I've enabled this block.
if self.watch.is_recursive:
for sub_event in generate_sub_moved_events(src_path, dest_path):
self.queue_event(sub_event)
self.queue_event(event)
else:
self.queue_event(FileMovedEvent(src_path, dest_path))
yield sub_event
else:
# If the new snapshot does not have an inode for the
# old path, we haven't found the new name. Therefore,
# we mark it as deleted and remove unregister the path.
if is_directory:
self.queue_event(DirDeletedEvent(src_path))
yield DirDeletedEvent(src_path)
else:
self.queue_event(FileDeletedEvent(src_path))
yield FileDeletedEvent(src_path)
yield self._parent_dir_modified(src_path)

def _read_events(self, timeout=None):
"""
Expand Down Expand Up @@ -672,35 +659,33 @@ def queue_events(self, timeout):
with self._lock:
try:
event_list = self._read_events(timeout)
files_renamed, dirs_renamed, dirs_modified = (
self._queue_events_except_renames_and_dir_modifications(event_list))
# TODO: investigate why order appears to be reversed
event_list.reverse()

# Take a fresh snapshot of the directory and update the
# saved snapshot.
new_snapshot = DirectorySnapshot(self.watch.path,
self.watch.is_recursive)
ref_snapshot = self._snapshot
self._snapshot = new_snapshot
diff_events = new_snapshot - ref_snapshot

# Process events
for directory_created in diff_events.dirs_created:
self.queue_event(DirCreatedEvent(directory_created))
for file_created in diff_events.files_created:
self.queue_event(FileCreatedEvent(file_created))
for file_modified in diff_events.files_modified:
self.queue_event(FileModifiedEvent(file_modified))

for kev in event_list:
for event in self._gen_kqueue_events(kev,
ref_snapshot,
new_snapshot):
self.queue_event(event)

if files_renamed or dirs_renamed or dirs_modified:
for src_path in files_renamed:
self._queue_renamed(src_path,
False,
ref_snapshot,
new_snapshot)
for src_path in dirs_renamed:
self._queue_renamed(src_path,
True,
ref_snapshot,
new_snapshot)
self._queue_dirs_modified(dirs_modified,
ref_snapshot,
new_snapshot)
except OSError as e:
if e.errno == errno.EBADF:
# logging.debug(e)
pass
else:
if e.errno != errno.EBADF:
raise

def on_thread_stop(self):
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