Detecting complete sync of books from device

[meme]

Is there a way to tell when a device is fully connected - in the sense that calibre knows the ids of the books on the device.

I occasionally get a condition where someone (ok, me mainly ) runs the plugin before all the books that are on the device are identified. This means when my plugin asks calibre for the data, it gets back 0 books on the device, until you run it a second time after the job is done.

[chaley]

No, there isn't. What would you do if you had something like this? Refuse to run?

We could add a signal that is fired when the ondevice calculations are done. I see two issues. 1) It would be best not to interact with the user in that signal handler, because the GUI would blocked at what appears to be a random time. 2) it would be signaled when books are added or deleted.

Kovid, I am thinking of emitting the signal after we call self.library_view.model().refresh_ondevice() at line 803 of device.py. Do you see any problem with this?

[kovidgoyal]

Why not do it at the end of metadata_downloaded? IIRC, that means the device is "fully connected"

[chaley]

Originally Posted by kovidgoyal

Why not do it at the end of metadata_downloaded? IIRC, that means the device is "fully connected"

The last thing metadata_downloaded does is call refresh_ondevice().

My thought was that if we are adding this signal, something that connects to the signal might want to know if the booklists have changed. There are other methods that change the booklist, for example books_uploaded and books_deleted, and both of these call refresh_ondevice at the right time.

[kovidgoyal]

Best to have two signals in that case, it's not like they are a scarce resource metadata_downloaded and book list changed are very different things.

[chaley]

Both of them result in the same thing -- telling the signal recipient that the ondevice information has (potentially) changed. But I don't care enough to argue. I will add the signal to the end of metadata_downloaded.

[chaley]

Code pushed.

The signal is device_metadata_available, and is raised after all the connection processing is complete. It should be visible to a plugin as gui.device_metadata_available.

The sequence: gui.device_manager.is_device_connected will become True, then sometime later gui.device_metadata_available will be signaled. This does not mean that there are no more jobs running. Automatic metadata management might have kicked off a sync_booklists to write new metadata onto the device, and that job might still be running when the signal is emitted.

[kovidgoyal]

merged .

[meme]

Step away for a minute and look what happens

Just to be clear - my plugin does not have to be running and looking for a signal? It just has to test if gui.device_metadata_available is True before continuing - otherwise I will issue an error dialog to tell the user to wait and try again. (Actually I currently test if gui.device_manager.is_device_connected is True, and then I test if gui.device_manager.connected_device._main_prefix has a value because I think I used to test for just main_prefix but found that wasn't reset between connections so I test both - and now I'll add a 3rd test).

I understand it won't be perfect as there could be books to send to/sync with the device - but it will prevent the majority of issues that might happen.

Many thanks.

[chaley]

Originally Posted by meme

Just to be clear - my plugin does not have to be running and looking for a signal? It just has to test if gui.device_metadata_available is True before continuing - otherwise I will issue an error dialog to tell the user to wait and try again.

No. It is a signal, not a flag. You can't test it at random times.

Thinking about it, I understand one of the difficulties you are facing. You don't track connections and disconnections, so this one signal isn't sufficient. You need to know when the device connects and disconnects so you can know what this signal means.

Assuming Kovid accepts the change, I have added a second signal, gui.device_connected_changed.emit(connected). This signal is emitted whenever a device is connected or disconnected. The argument to the signal, connected, is True if a device has been connected, False otherwise.

In your init method, connect to these two signals. If you get device_connected_changed(False), mark the fact that there is no device and clear the device valid indication. If you get device_connected_changed(True), mark that fact, and prepare to receive the device_metadata_available signal. When you receive the device_metadata_available, note that fact, which the rest of your plugin will use to determine whether the info is available or not.

The initial condition is that there is no device.

[kovidgoyal]

Merged.

[meme]

Got it. Of course the plugin is already live once calibre starts. Thanks.

[meme]

Ok, don't got it.

I'm running from the source with the signals, but I'm obviously missing something in the syntax/use as I'm getting an error.

I've put in my genesis routine in ui.py (testconnect1 just prints hello):

self.gui.device_metadata_available.connect(self.te stconnect1)

but I get this when I start calibre:

File "/home/meme/Calibre-Source/calibre/src/calibre/gui2/main.py", line 253, in initialize
self.initialize_db()
File "/home/meme/Calibre-Source/calibre/src/calibre/gui2/main.py", line 234, in initialize_db
self.initialize_db_stage2(db, None)
File "/home/meme/Calibre-Source/calibre/src/calibre/gui2/main.py", line 203, in initialize_db_stage2
self.start_gui(db)
File "/home/meme/Calibre-Source/calibre/src/calibre/gui2/main.py", line 159, in start_gui
main.initialize(self.library_path, db, self.listener, self.actions)
File "/home/meme/Calibre-Source/calibre/src/calibre/gui2/ui.py", line 195, in initialize
ac.do_genesis()
File "/home/meme/Calibre-Source/calibre/src/calibre/gui2/actions/__init__.py", line 97, in do_genesis
self.genesis()
File "calibre_plugins.kindle_collections.ui", line 55, in genesis

TypeError: connect() failed between [] and unislot()

[kiwidude]

@meme - try hooking in initialization_complete rather than genesis?

[kovidgoyal]

There was a bug with the way signals were implemented. Charles committed a fix a little while ago.

Use

self.gui.device_signals.signal_name.connect(...