feat(ui): Add function to toggle reactions from timeline

[jonnyandrew]

Changes

• Add function to toggle reactions from the timeline
• Add local echo for reactions in the timeline
• Support local echo changing during previous request to add or redact a reaction

Current limitations

Does not include

• Allow adding a reaction to a local echo of a message #2127

Context

• Resolves Add reactions toggle to timeline with "simple debounce" using mutex #2125
• Resolves Add “advanced debounce” that allows immediate removal of reactions. #2126

Tasks

• Add toggle_reaction function to timeline
  • Integration test
  • Unit tests

Signed-off-by:

[codecov]

Codecov Report

Patch coverage: 86.25% and project coverage change: +0.19 🎉

Comparison is base (4c24007) 76.12% compared to head (291612c) 76.32%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2118      +/-   ##
==========================================
+ Coverage   76.12%   76.32%   +0.19%     
==========================================
  Files         163      163              
  Lines       17303    17513     +210     
==========================================
+ Hits        13172    13366     +194     
- Misses       4131     4147      +16     

Impacted Files	Coverage Δ
crates/matrix-sdk-ui/src/timeline/event_handler.rs	73.09% <68.00%> (-0.35%)	⬇️
crates/matrix-sdk-ui/src/timeline/inner.rs	74.56% <88.51%> (+4.82%)	⬆️
crates/matrix-sdk-ui/src/timeline/mod.rs	82.72% <88.57%> (+1.74%)	⬆️
...s/matrix-sdk-ui/src/timeline/event_item/content.rs	60.64% <100.00%> (+4.06%)	⬆️

... and 4 files with indirect coverage changes

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[jplatte]

Very rough first review. Thanks for adding a bunch of tests!

[jonnyandrew]

Thanks for the review @jplatte - I have addressed the issues

[bnjbvr]

Small code comments here and there, but with the main locking issue resolved, that looks good to me! Will let @jplatte handle the final approval.

[bnjbvr]

nit: This match could be avoided if we duplicated line 277 in the two places in the above match. I would prefer this slightly better, but it's personal taste, so feel free to dismiss :)

[jonnyandrew]

I added two matches to make it a bit clearer what is being done (i.e. first calculate the result, then update the state) and avoid the side effect getting lost amongst the other logic.

Given the function is already pretty long I'd probably err on the side of clarity if that makes sense to you also?

[jplatte]

One last thing, I think then we can merge.

[jonnyandrew]

Thanks @jplatte and @bnjbvr for the reviews! I don't have permissions to merge - are you able to take care of that?

[bnjbvr]

Great work @jonnyandrew!