In Calibre 0.9.16 books is see no books on my Sony reader

[kovidgoyal]

@PeterT: And the books did not match? Hmm, I've made a possible fix for the issue, though I don't really understand it nor can I reproduce it. I will upload a build with the fix in a little while, or if you are running from source you can update yourself. Let me know if it fixes it.

[kovidgoyal]

I think I know what is going on, the SONY T1/T2 and Kobo drivers use a different format for returning the books thumbnail, which causes the the new code to error out leading to failed matches. I've adjusted the code to take that into account, hopefully that will fix it.

[davidfor]

@Kovid: Peter beat me with the log. Mine was the same. I also realised I was wrong about the cause, which caused a few extra tests. Somewhere in there I also saw the error DrChiper reported when changing library while the device was connected.

Anyway, I've updated my source and run using that. Both Kobo devices are working correctly. The books are shown on the device correctly, I've sent a few books and I have changed the library a couple of times. I didn't see any errors.

I assume this means that I Kobo devices won't get the performance improvement you put in. I'll have a look at the thumbnails in the driver and see what is different.

Thanks for the quick fix.

[JSWolf]

Originally Posted by kovidgoyal

I think I know what is going on, the SONY T1/T2 and Kobo drivers use a different format for returning the books thumbnail, which causes the the new code to error out leading to failed matches. I've adjusted the code to take that into account, hopefully that will fix it.

Before I update to 0.9.16, is the version with the fix the current version or should I wait until 0.9.17?

[stewacide]

Not to pester but I'd also like to know if I should wait to download.

[kovidgoyal]

I'll post here when the upload of 0.9.16 with the fix finishes. My internet connection has very low upload speeds.

[kovidgoyal]

@davidfor: It wasn't my code, the credit, or blame, goes to chaley I'll leave it up to him to comment on how to handle thumbnails in the device drivers. Looking at the interface specification in devices.interface.BookList what the kobo driver is returning is correct.

[JSWolf]

Originally Posted by kovidgoyal

I'll post here when the upload of 0.9.16 with the fix finishes. My internet connection has very low upload speeds.

Thank you.

[kovidgoyal]

Fixed builds uploaded. Re-download and re-install and hopefully you will be fine.

[JSWolf]

Originally Posted by kovidgoyal

Fixed builds uploaded. Re-download and re-install and hopefully you will be fine.

I'll give it a try on Sunday night and see how it goes. I'kk be away from the computer and all I'll have access to is an iPad. Should I backup the contents of the T1 just in case?

[kovidgoyal]

This bug does not affect the contents of your reader, only the metadata.calibre file and by extension the on device column in calibre.

[chaley]

Originally Posted by davidfor

I assume this means that I Kobo devices won't get the performance improvement you put in. I'll have a look at the thumbnails in the driver and see what is different.

Devices that cannot ask for different thumbnail/cover sizes on different connections will see the performance improvement. Devices that can ask for different thumbnail sizes might or might not produce correct results.

The assumption made by my code was that a thumbnail in a device book dict was made by gui2.device.cover_to_thumbnail. This was true for all the devices I have and have looked at, so my testing didn't find the (apparently) two devices that do something else.

Details: cover_to_thumbnail returns a 3-element tuple (width, height, image_bytes). One part of the optimization, the part that won't be done for Sony Tx and Kobo devices, was to check that the existing thumb is the size requested by the device. If it is not, then the thumbnail is regenerated and the book dict updated. If it is the same size and if nothing else in the mi structure has changed since the book's metadata was sent to the device (the other part of the optimization), then that book is left alone, saving a substantial amount of computation. In my testing the time savings was approximately 0.01 second per book on the device that did not need updating. YMMV depending on processor speed and memory available.

If the device can change the size of the thumbnail either "by itself" (e.g., a smart device) or by the user changing some preference, then if the tuple is not used it is possible that the thumbnail will not be updated upon connect. This is the incorrect result mentioned above. Another possibility: if the device depends on receiving a tuple but does not return a tuple, then the device might be surprised by receiving something unexpected, the value it put into the book dict.

[davidfor]

@chaley: Thanks. it sounds like it is right for the Kobo devices. I'll still have a look as I haven't looked at the thumbnail stuff before.

[JSWolf]

So if the thumbnail does not exist for an ePub that loaded on a T1, will the thumbnail be created?

Also, if an ePub is deleted from a T1 using Calibre, will the thumbnail also be deleted.

Next questions are device independent.

The default Calibre settings for sending an eBook to the device is to create a subdirectory and put the eBook there. If Calibre is not used to delete the eBook, will Calibre delete these empty subdirectories? If Calibre is used to delete an eBook, does that subdirectory and all associated file(s) get deleted?

[JSWolf]

Has anyone used the updated 0.9.16 with a T1? If so, does the fix work?