Bug 341772 - Re-read metadata when image file timestamp has changed [patch]
Summary: Re-read metadata when image file timestamp has changed [patch]
Status: RESOLVED FIXED
Alias: None
Product: digikam
Classification: Applications
Component: Setup-Metadata (show other bugs)
Version: 4.5.0
Platform: Other Linux
: NOR wishlist
Target Milestone: ---
Assignee: Digikam Developers
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2014-12-11 14:12 UTC by Kristian Karl
Modified: 2017-08-12 06:35 UTC (History)
4 users (show)

See Also:
Latest Commit:
Version Fixed In: 4.9.0
Sentry Crash Report:


Attachments
Patch with proposed fix and unit test (92.04 KB, patch)
2015-03-29 10:53 UTC, Kristian Karl
Details
Improved patch with UI setting (100.49 KB, patch)
2015-03-29 16:41 UTC, Kristian Karl
Details
New UI setting (143.39 KB, image/png)
2015-03-29 16:43 UTC, Kristian Karl
Details

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Description Kristian Karl 2014-12-11 14:12:04 UTC
I would like to have a feature that automatically makes digikam re-read all image files that has a different time stamp.

If this feature already exists, I apologize that I have not yet found it, and would gladly take any pointer in how to do this. Otherwise, I'm prepare to write a path that implements such feature. 

This is my use case for this feature.
1) I have a Desktop with all my 88K+ images stored on SSD disks locally. All metadata are saved to the images.
2) I have a fast home wired/wifi network, and I use sshfs to share and mount those pics on my laptops.
3) I use a laptop to browse and occasionally update an image here and there using a local Digikam. I add new face tags, and normal tags.
4) Now, if I start Digikam on the Desktop, these changes will not appear in Digikam (on the Desktop machine), unless I do a complete re-read of metadata of all 88K+ images.

My suggestion is to save the time stamps of each image file into the digikam database. When Digikam starts, it will notice which files has changed (if they have gotten a changed file time stamp), and initiate a re-read of those specific image files. 

Does this sound like a feature that somebody else than me would like to have?
Comment 1 Alan Pater 2015-03-25 11:21:33 UTC
In theory, applications should update the Xmp.xmp.MetadataDate key. That way other apps would know to re-read metadata.
Comment 2 Kristian Karl 2015-03-25 11:35:03 UTC
Interesting. I guess though, that the performance penalty might be much higher, reading the  Xmp.xmp.MetadataDate key for the image, than reading the image files time stamp from the operating systems file system. Would do you think?
Comment 3 caulier.gilles 2015-03-25 11:39:50 UTC
1/ I don't know this XMP tag. Interesting.
2/ I'm not sure that all application will update this tag automatically. In digiKam case, this must be delegate to Exiv2, as finally library do the background job.
3/ about time latency to read XMP tag : yes, file system time stamp is a less time consuming operation. For XMP, file must be open, XMP container found, tag read, file closed, etc. This will take more time if a XMPS sidecar is present or not because a check must be operate before to see if original file or sidecar must be used.

Gilles Caulier
Comment 4 Kristian Karl 2015-03-25 11:43:22 UTC
I would be willing to try to implement this feature.
Comment 5 Kristian Karl 2015-03-29 10:53:32 UTC
Created attachment 91802 [details]
Patch with proposed fix and unit test

I realized that Digikam already detectes a change in an image file, using either file size and/or date time modification.

However, in CollectionScanner, scanModifiedFile(fi, scanInfo) is used to re-scan the file. That does not re-read metadata changes.
I tested using rescanFile(fi, scanInfo) instead, and that worked much better.

See: https://projects.kde.org/projects/extragear/graphics/digikam/repository/revisions/master/entry/libs/database/collectionscanner.cpp#L1202

The patch contains the proposed change, and a unit test to verify that metadata changes 'outside' digikam is detected and re-read into the database.
Comment 6 caulier.gilles 2015-03-29 12:54:28 UTC
Kristian,

Thanks a lots for your patch.

Marcel, do you want this patch included in Qt4 or Qt5 version of digiKam (or both) ?

Gilles
Comment 7 Kristian Karl 2015-03-29 13:06:26 UTC
I'm using KDE 4, so definitely Qt4. But why not both.
Comment 8 caulier.gilles 2015-03-29 13:09:52 UTC
yes Kristian, this can be applied to both, but i would to see Marcel viewpoint.

As i see, your patch is not intrusive. So for me both is fine. But Marcel know better than me this implementation, so we will wait feedback from him.

Gilles
Comment 9 caulier.gilles 2015-03-29 13:11:52 UTC
Kristian,

For the moment, digiKam core is ported to Qt5, but it still some task to achieve.

About scan image and FS detection changes, there is a port to pure Qt5 to do. 

See my wiki page for all technical details :

https://techbase.kde.org/Projects/Digikam/CodingSprint2014

Gilles Caulier
Comment 10 Marcel Wiesweg 2015-03-29 15:00:19 UTC
This is a very sensitive area. The current behavior has been conservative all these years:
You are not forced to have your db in sync with your metadata. You can update the metadata in the database and not write the change to the image. You can switch off writing to RAW images. There may be image formats which contain metadata but for which writing is not supported or experimental. Plus constellations that we did not think of. 
Against this background the full re-scan has been a manual operation.

If now any change in the file's modification date, which is done so easily, will cause a full re-scan, we change behavior which was constant over many years. I see many bugs reports and annoyed users.

The change is completely valid for your setup, but for me it must come with a setup option to enable it, and must be disabled by default.
Comment 11 Kristian Karl 2015-03-29 15:05:34 UTC
Ah, I agree. 
I'll rewrite the patch with a suggestion for setup option, which is disabled by default.
Comment 12 Kristian Karl 2015-03-29 16:41:38 UTC
Created attachment 91806 [details]
Improved patch with UI setting

An improved patch with UI setting and an additional unit test.
Comment 13 Kristian Karl 2015-03-29 16:43:10 UTC
Created attachment 91807 [details]
New UI setting

The UI setting shown in the Configure dialog.
Comment 14 Maik Qualmann 2015-04-01 17:07:13 UTC
Git commit 937109fb0f32192308258437ccad7f8dac536acd by Maik Qualmann.
Committed on 01/04/2015 at 16:40.
Pushed by mqualmann into branch 'master'.

apply patch #91806 from Kristian Karl to make an optional rescan of files when files are modified
FIXED-IN: 4.9.0
GUI:

M  +2    -1    NEWS
M  +9    -1    libs/database/collectionscanner.cpp
M  +3    -0    libs/dmetadata/metadatasettingscontainer.cpp
M  +1    -0    libs/dmetadata/metadatasettingscontainer.h
M  +17   -0    tests/CMakeLists.txt
A  +232  -0    tests/timestampupdatetest.cpp     [License: GPL (v2+)]
A  +48   -0    tests/timestampupdatetest.h     [License: GPL (v2+)]
A  +-    --    tests/timestampupdatetestimages/1.jpg
M  +19   -7    utilities/setup/setupmetadata.cpp

http://commits.kde.org/digikam/937109fb0f32192308258437ccad7f8dac536acd
Comment 15 caulier.gilles 2015-04-02 06:54:40 UTC
Git commit ca46de929504d17f57c45d8d4e5ff01dcbcef838 by Gilles Caulier.
Committed on 02/04/2015 at 06:53.
Pushed by cgilles into branch 'master'.

use Qt macro
use moc file
fix coding style
code polish

M  +18   -25   tests/timestampupdatetest.cpp
M  +6    -2    tests/timestampupdatetest.h

http://commits.kde.org/digikam/ca46de929504d17f57c45d8d4e5ff01dcbcef838
Comment 16 caulier.gilles 2015-04-02 07:22:58 UTC
Git commit b29881591ec06bb1574941686c40f1492ef82b57 by Gilles Caulier.
Committed on 27/03/2015 at 12:51.
Pushed by cgilles into branch 'frameworks'.

backport commit #937109fb0f32192308258437ccad7f8dac536acd from git/master to frameworks branch

M  +12   -4    libs/database/collection/collectionscanner.cpp
M  +3    -0    libs/dmetadata/metadatasettingscontainer.cpp
M  +1    -0    libs/dmetadata/metadatasettingscontainer.h
M  +34   -14   tests/CMakeLists.txt
A  +225  -0    tests/timestampupdatetest.cpp     [License: GPL (v2+)]
A  +52   -0    tests/timestampupdatetest.h     [License: GPL (v2+)]
A  +-    --    tests/timestampupdatetestimages/1.jpg
M  +19   -7    utilities/setup/setupmetadata.cpp

http://commits.kde.org/digikam/b29881591ec06bb1574941686c40f1492ef82b57
Comment 17 caulier.gilles 2015-04-02 07:27:31 UTC
Kristian,

Your patch is applied to next 4.9.0 and backported to future 5.0.0 (Qt5)

did you have another entries in bugzilla where you want to propose another patch ?

Note : git/master where KDE4 version of digiKam will only accept bugfixes or not too intrusive patches, because KDE and Qt5 implementation start to be seriously different. Backporting must still a simple task to do.

There are also few serious tasks to do on Qt5 port, as for ex the migration of code from KDirWatch to QFileSystemWatcher, to reduce KDE dependencies.

https://techbase.kde.org/Projects/Digikam/CodingSprint2014#digiKam_Core

Best

Gilles Caulier
Comment 18 Kristian Karl 2015-04-02 07:48:51 UTC
I have this one: https://bugs.kde.org/show_bug.cgi?id=329433