Current File : //lib/calibre/calibre/db/delete_service.py
#!/usr/bin/env python3
__license__ = 'GPL v3'
__copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
import os, tempfile, shutil, errno, time, atexit
from threading import Thread
from calibre.constants import ismacos
from calibre.ptempfile import remove_dir
from calibre.utils.filenames import remove_dir_if_empty
from calibre.utils.recycle_bin import delete_tree, delete_file
from polyglot.queue import Queue
class DeleteService(Thread):
''' Provide a blocking file delete implementation with support for the
recycle bin. On windows, deleting files to the recycle bin spins the event
loop, which can cause locking errors in the main thread. We get around this
by only moving the files/folders to be deleted out of the library in the
main thread, they are deleted to recycle bin in a separate worker thread.
This has the added advantage that doing a restore from the recycle bin won't
cause metadata.db and the file system to get out of sync. Also, deleting
becomes much faster, since in the common case, the move is done by a simple
os.rename(). The downside is that if the user quits calibre while a long
move to recycle bin is happening, the files may not all be deleted.'''
daemon = True
def __init__(self):
Thread.__init__(self)
self.requests = Queue()
if ismacos:
from calibre_extensions.cocoa import enable_cocoa_multithreading
enable_cocoa_multithreading()
def shutdown(self, timeout=20):
self.requests.put(None)
self.join(timeout)
def create_staging(self, library_path):
base_path = os.path.dirname(library_path)
base = os.path.basename(library_path)
try:
ans = tempfile.mkdtemp(prefix=base+' deleted ', dir=base_path)
except OSError:
ans = tempfile.mkdtemp(prefix=base+' deleted ')
atexit.register(remove_dir, ans)
return ans
def remove_dir_if_empty(self, path):
try:
os.rmdir(path)
except OSError as e:
if e.errno == errno.ENOTEMPTY or len(os.listdir(path)) > 0:
# Some linux systems appear to raise an EPERM instead of an
# ENOTEMPTY, see https://bugs.launchpad.net/bugs/1240797
return
raise
def delete_books(self, paths, library_path):
tdir = self.create_staging(library_path)
self.queue_paths(tdir, paths, delete_empty_parent=True)
def queue_paths(self, tdir, paths, delete_empty_parent=True):
try:
self._queue_paths(tdir, paths, delete_empty_parent=delete_empty_parent)
except:
if os.path.exists(tdir):
shutil.rmtree(tdir, ignore_errors=True)
raise
def _queue_paths(self, tdir, paths, delete_empty_parent=True):
requests = []
for path in paths:
if os.path.exists(path):
basename = os.path.basename(path)
c = 0
while True:
dest = os.path.join(tdir, basename)
if not os.path.exists(dest):
break
c += 1
basename = '%d - %s' % (c, os.path.basename(path))
try:
shutil.move(path, dest)
except OSError:
if os.path.isdir(path):
# shutil.move may have partially copied the directory,
# so the subsequent call to move() will fail as the
# destination directory already exists
raise
# Wait a little in case something has locked a file
time.sleep(1)
shutil.move(path, dest)
if delete_empty_parent:
remove_dir_if_empty(os.path.dirname(path), ignore_metadata_caches=True)
requests.append(dest)
if not requests:
remove_dir_if_empty(tdir)
else:
self.requests.put(tdir)
def delete_files(self, paths, library_path):
tdir = self.create_staging(library_path)
self.queue_paths(tdir, paths, delete_empty_parent=False)
def run(self):
while True:
x = self.requests.get()
try:
if x is None:
break
try:
self.do_delete(x)
except:
import traceback
traceback.print_exc()
finally:
self.requests.task_done()
def wait(self):
'Blocks until all pending deletes have completed'
self.requests.join()
def do_delete(self, tdir):
if os.path.exists(tdir):
try:
for x in os.listdir(tdir):
x = os.path.join(tdir, x)
if os.path.isdir(x):
delete_tree(x)
else:
delete_file(x)
finally:
shutil.rmtree(tdir)
__ds = None
def delete_service():
global __ds
if __ds is None:
__ds = DeleteService()
__ds.start()
return __ds
def shutdown(timeout=20):
global __ds
if __ds is not None:
__ds.shutdown(timeout)
__ds = None
def has_jobs():
global __ds
if __ds is not None:
return (not __ds.requests.empty()) or __ds.requests.unfinished_tasks
return False
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