Avoid JSON deserialization in common trivial cases

[starypatyk]

This is a very simple approach to reduce time spent on JSON deserialization when reading file data from the local DB - much simpler than originally proposed in #11181.

I have noticed that in my tests, in more than 90% of the cases, the JSON data retrieved from the database is:

• sharees - "[]"
• metadataSize - "null"

The proposed changes handle these common trivial cases without invoking the JSON parser.

With this change and #11227 I have observed that the time spent inside FileDataStorageManager::createFileInstance method is less than 10% of the overall time of FileDataStorageManager::getFolderContent. Remaining 90% is in fileDao.getFolderContent - as expected.

[starypatyk]

I have looked at the failing tests:

• tests-stable/gplay - I do not see relationship to my changes.
• tests-master/gplay - Might be related, but I do not know how to diagnose it.

[AlvaroBrey]

I have looked at the failing tests:

• tests-stable/gplay - I do not see relationship to my changes.
• tests-master/gplay - Might be related, but I do not know how to diagnose it.

Let's rebase the branch to have the tests run again

[AlvaroBrey]

/rebase

[github-actions]

APK file: https://www.kaminsky.me/nc-dev/android-artifacts/11251.apk



To test this change/fix you can simply download above APK file and install and test it in parallel to your existing Nextcloud app.

[github-actions]

Codacy

Lint

Type	master	PR
Warnings	76	76
Errors	0	0

SpotBugs

Category	Base	New
Bad practice	27	27
Correctness	44	44
Dodgy code	335	335
Internationalization	9	9
Multithreaded correctness	9	9
Performance	58	58
Security	18	18
Total	500	500

[codecov]

Codecov Report

Merging #11251 (49cccd1) into master (20c22eb) will increase coverage by 0.08%.
The diff coverage is 50.00%.

Additional details and impacted files

@@             Coverage Diff              @@
##             master   #11251      +/-   ##
============================================
+ Coverage     31.30%   31.38%   +0.08%     
- Complexity     3351     3368      +17     
============================================
  Files           566      566              
  Lines         41584    41586       +2     
  Branches       5629     5631       +2     
============================================
+ Hits          13016    13052      +36     
+ Misses        26624    26587      -37     
- Partials       1944     1947       +3     

Impacted Files	Coverage Δ
...loud/android/datamodel/FileDataStorageManager.java	61.95% <50.00%> (-0.03%)	⬇️
...cloud/android/ui/activity/SyncedFoldersActivity.kt	20.53% <0.00%> (-0.45%)	⬇️
...wncloud/android/providers/FileContentProvider.java	73.45% <0.00%> (-0.31%)	⬇️
...cloud/android/ui/activity/FileDisplayActivity.java	27.08% <0.00%> (-0.09%)	⬇️
.../java/com/owncloud/android/utils/DisplayUtils.java	37.10% <0.00%> (+0.28%)	⬆️
...loud/android/datamodel/ThumbnailsCacheManager.java	40.89% <0.00%> (+0.47%)	⬆️
...d/android/operations/SynchronizeFileOperation.java	39.36% <0.00%> (+14.89%)	⬆️
.../java/com/nextcloud/client/jobs/OfflineSyncWork.kt	53.12% <0.00%> (+32.81%)	⬆️

[AlvaroBrey]

Great idea, @starypatyk ! Many thanks!