[GUI Plugin] Reading List

[PeterT]

@Kiwidude; still seeing occurrences of

calibre, version 0.8.62
ERROR: Unhandled exception: <b>RuntimeError</b>:wrapped C/C++ object of %S has been deleted

Traceback (most recent call last):
  File "calibre_plugins.reading_list.config", line 773, in on_device_connection_changed
  File "calibre_plugins.reading_list.config", line 862, in update_from_connection_status
  File "calibre_plugins.reading_list.config", line 376, in get_data
RuntimeError: wrapped C/C++ object of %S has been deleted

This seems to happen after I have gone into the configuration option of the plugin and made no changes.

Then when I attach my device and it is processing either the Auto Update list or the Send to Device list, that error happens.

Also just received an occurrence on Eject Device. Will see if I can get a calibre debug log and a repeatable failure.

[PeterT]

As far as I can tell these are the steps I did:

• Right clicked on book
• selected Reading List
• selected Customize Plugin
• went to devices tab, then other tab, and back to lists tab
• shows my "sync later" list
  • device to sync this list too Kobo Touch (main)
  • Add new list items to device
  • Sync to device when connected
  • Clear this list after sync
• selected my "On Kobo Touch" list
  • device to sync this list too Kobo Touch (main)
  • Auto populate from books on device
  • Update column for add or remove
  • Column name: #onKobo (On Kobo)
  • Value to add / remove Y
• selected OK
• Attached Kobo
• Error message
• Ejected Kobo
• Error message

Spoiler:

DeviceJob: 2 Get list of books on device done, calling callback
READING LIST: Metadata available: {'main': {u'device_store_uuid': u'abf9c02a-5a0b-4150-a227-9c625bdf9550', u'location_code': 'main', u'device_name': u'Kobo Reader', u'calibre_version': u'0.8.62', u'prefix': 'P:/', u'last_library_uuid': u'f5ff2231-fad2-4df4-98e7-41638249dd44', u'date_last_connected': u'2012-07-30T04:41:41.019000+00:00'}}
READING LIST: Sync Now - force_sync= False
READING LIST: Device found to sync to: Kobo Reader abf9c02a-5a0b-4150-a227-9c625bdf9550
READING LIST: No books on 'Sync Later' list need to be synced
READING LIST: Checking for automatic list(s)  [u'On Kobo Touch']
READING LIST: Auto-populating list:  On Kobo Touch
READING LIST: Removing 0 ids from automatic list: On Kobo Touch
READING LIST: Adding 0 ids to automatic list: On Kobo Touch
Traceback (most recent call last):
  File "calibre_plugins.reading_list.config", line 777, in on_device_metadata_available
  File "calibre_plugins.reading_list.config", line 862, in update_from_connection_status
  File "calibre_plugins.reading_list.config", line 376, in get_data
RuntimeError: wrapped C/C++ object of %S has been deleted

Job: 2 Get list of books on device finished
No details available.
DeviceJob: 2 Get list of books on device callback returned
Job: 2 Get list of books on device finished
No details available.
READING LIST: Device disconnected
Traceback (most recent call last):
  File "calibre_plugins.reading_list.config", line 773, in on_device_connection_changed
  File "calibre_plugins.reading_list.config", line 862, in update_from_connection_status
  File "calibre_plugins.reading_list.config", line 376, in get_data
RuntimeError: wrapped C/C++ object of %S has been deleted

[chaley]

@kiwidude: it is possible that you are being bit by something that got me while developing the new smartdevice driver. It turns out that any plugin can be allocated and its __init__ called more than once. For example, this happened to my driver when I added a book.

The lesson I learned after discussion with Kovid: __init__ must not allocate externally-visible resources or initialize class-level attributes (attributes declared explicitly in the class). In my case I was allocating the listen socket in __init__, an action that blew up in the second __init__. The problem with class-level attributes is that they are static; they exist in memory only once. The second __init__ is changing the value of the same memory used by the first.

[kiwidude]

@chaley - thx for the info and that makes sense, but why would __init__() be being called more than once on a GUI plugin? Surely only one instance of the Reading List plugin is ever being created?

What happens with this plugin is that the configuration widget subscribes to some signals from the plugin action, which it uses to updates its grid to shwo device status, in case a user plugs in a device while they have the config screen open. It looks to me like those signals are not being disconnected in PeterT's case (I can't replicate the error myself).

At the moment I disconnect those signals in an __exit__() function on my config widget, but that must be the wrong place for PeterT. The problem is that there are no guaranteed callbacks to my widget from calibre's do_user_config code() if the user does not click on "ok" so that save_settings gets called. So where should I put my signal disconnections?

I am guessing that the Qt object the config widget uses is being garbage collected before the Python ConfigWidget is, so my __exit__ has not yet been called or something. However since from a config widget you have no hooks to the parent dialog I can't think of a way out of this that doesn't involve calibre looking for an optional functional name on the config widget to call as a "cleanup" that I could disconnect in that gets invoked when the config dialog is closed?

[kovidgoyal]

@kiwidude: In the slot your are connecting to the signal, use

import sip
if sip.isdeleted(self): return

sip.isdeleted() returns True if the underlying C++ object has been deleted.

[chaley]

Originally Posted by kiwidude

@chaley - thx for the info and that makes sense, but why would __init__() be being called more than once on a GUI plugin? Surely only one instance of the Reading List plugin is ever being created?

To quote Kovid:

__init__ can be called at anytime or multiple times on a plugin class. There can be multiple plugin objects.

I haven't been able to find a spot outside of a worker process where this would happen, but that doesn't mean that there isn't one.

What happens with this plugin is that the configuration widget subscribes to some signals from the plugin action, which it uses to updates its grid to shwo device status, in case a user plugs in a device while they have the config screen open. It looks to me like those signals are not being disconnected in PeterT's case (I can't replicate the error myself).

At the moment I disconnect those signals in an __exit__() function on my config widget, but that must be the wrong place for PeterT. The problem is that there are no guaranteed callbacks to my widget from calibre's do_user_config code() if the user does not click on "ok" so that save_settings gets called. So where should I put my signal disconnections?

__exit__ is part of the "with x:" construct. Do you do something like "with configWidgetClass() as widget:"? Interesting idea. I haven't ever tried that.

Doesn't do_user_config open a Qt widget of some kind? If so, then override the accept and reject methods. One of the two of these will get called when the dialog is closed in some way.

Another possibility is to connect the signals to methods that will not go away. These methods verify the situation and pass the calls along only when it is correct to do so. This way you connect the signal once, never disconnecting it. Edit: Kovid has provided a method to check if it is correct to pass the call along.

[darkmiss]

Hi kiwidude,

most of the time I add a book to more than one reading list and it's a bit tedious to go "Reading List" -> Add to list -> List A several times per book.

I have no inkling about writing software so I don't know if this is even possible but it would be really cool to have a list of the lists (ha!) displayed with checkboxes. This way you wouldn't even need the "add to" and "remove from" menu items, because you could see if the book is on the list by looking at the checkboxes.

Just dreaming here ...

Take care, Ingrid

[kiwidude]

@Kovid/chaley, thx for the info. The __exit__ was just a brain fart on my part a long time ago. I figured out a solution (overriding do_user_config so that I can disconnect).

@PeterT - please give the attached version a whirl to see if it solves the issue for you.

@darkmiss - I've enhanced the "Move to list" option to allow you to select multiple lists on the RHS. So use that option instead of the Add menus. Can you also please give the attached version a whirl and verify it is working without issues for you.

I wiill release it officially when you have both replied.

[PeterT]

@Kiwidude; so far seems fine. I will try a few more times but it was reproducible at will last night and is not now.

OOPS.. Spoke to soonn.. Trying to go reinvoke the plugin after ejecting now gets the following

Spoiler:

calibre, version 0.8.62
ERROR: Unhandled exception: <b>TypeError</b>:'ConfigWidget' object is not callable

Traceback (most recent call last):
  File "calibre_plugins.reading_list.action", line 732, in show_configuration
  File "calibre_plugins.reading_list.__init__", line 48, in do_user_config
  File "site-packages\calibre\customize\__init__.py", line 150, in do_user_config
TypeError: 'ConfigWidget' object is not callable

[PeterT]

It does not even need the device to be attached; just try to launch Reading list | Customize twice in a row

Spoiler:

calibre Debug log
calibre 0.8.62
Windows-7-6.1.7601-SP1
Windows
('Windows', '7', '6.1.7601')
Python 2.7.3
Windows: ('7', '6.1.7601', 'SP1', 'Multiprocessor Free')
Starting up...
INFO:cherrypy.error:[30/Jul/2012:10:35:38] ENGINE Bus STARTING
INFO:cherrypy.error:[30/Jul/2012:10:35:38] ENGINE Started monitor thread '_TimeoutMonitor'.
self.current_prefs == None(True) or self.libraryid != libraryid(True)
get prefs from db
INFO:cherrypy.error:[30/Jul/2012:10:35:38] ENGINE Serving on 0.0.0.0:8080
INFO:cherrypy.error:[30/Jul/2012:10:35:40] ENGINE Bus STARTED
Started up in 13.69 seconds with 731 books
Traceback (most recent call last):
  File "calibre_plugins.reading_list.action", line 732, in show_configuration
  File "calibre_plugins.reading_list.__init__", line 48, in do_user_config
  File "site-packages\calibre\customize\__init__.py", line 150, in do_user_config
TypeError: 'ConfigWidget' object is not callable

INFO:cherrypy.error:[30/Jul/2012:10:36:25] ENGINE Bus STOPPING
INFO:cherrypy.error:[30/Jul/2012:10:36:26] ENGINE HTTP Server cherrypy._cpwsgi_server.CPWSGIServer(('0.0.0.0', 8080)) shut down
INFO:cherrypy.error:[30/Jul/2012:10:36:26] ENGINE Stopped thread '_TimeoutMonitor'.
INFO:cherrypy.error:[30/Jul/2012:10:36:26] ENGINE Bus STOPPED
INFO:cherrypy.error:[30/Jul/2012:10:36:26] ENGINE Bus EXITING
INFO:cherrypy.error:[30/Jul/2012:10:36:26] ENGINE Waiting for child threads to terminate...
INFO:cherrypy.error:[30/Jul/2012:10:36:26] ENGINE Bus EXITED
INFO:cherrypy.error:[30/Jul/2012:10:36:26] ENGINE Waiting for thread MainThread.

[darkmiss]

Thanks for the prompt reply, kiwidude. I tested the "move to list" -> perfect. It will be a great time saver!

Regards from Germany,
Ingrid

[kiwidude]

@darkmiss - thx for the feedback.

@PeterT - try the new version above. I am at work and USB is blocked so I wasn't able to test the attaching here, and did something stupid in the code...

[PeterT]

@Kiwidude; looks good

[magphil]

Will this plugin help create/manage kobo touch shelves in recent 2.0 firmware ?

[PeterT]

@Magphil: nope