Settings Ring: Lazily load available setting values the first time they're needed

[LeonarddeR]

Link to issue number:

None

Summary of the issue:

A settings ring entry for a String setting caches its possible values when creating the StringSynthSetting object. This can be costly if it takes some time for the possible values to return, for example when they're coming from a remote system in my remote desktop add-on.

Description of user facing changes

None.

Description of development approach

Load and cache the available settings values the first time they're fetched. This shouldn't have any noticeable impact for most synths.that

Testing strategy:

Tested with NVDA Remote Desktop add-on that initial setup of the remote synth is quicker, whereas the first selection of a settings ring entry is somewhat slower.

Known issues with pull request:

None

Change log entries:

For Developers

• The NVDA Synth Settings Ring now caches available setting values the first time they're needed, rather than when loading the synthesizer.

Code Review Checklist:

• Pull Request description:
  • description is up to date
  • change log entries
• Testing:
  • Unit tests
  • System (end to end) tests
  • Manual testing
• API is compatible with existing add-ons.
• Documentation:
  • User Documentation
  • Developer / Technical Documentation
  • Context sensitive help for GUI changes
• UX of all users considered:
  • Speech
  • Braille
  • Low Vision
  • Different web browsers
  • Localization in other languages / culture than English
• Security precautions taken.