Problem:
Treesitter injections are slow because all injected trees are invalidated on every change.
Solution:
Implement smarter invalidation to avoid reparsing injected regions.
- In on_bytes, try and update self._regions as best we can. This PR just offsets any regions after the change.
- Add valid flags for each region in self._regions.
- Call on_bytes recursively for all children.
- We still need to run the query every time for the top level tree. I don't know how to avoid this. However, if the new injection ranges don't change, then we re-use the old trees and avoid reparsing children.
This should result in roughly a 2-3x reduction in tree parsing when the comment injections are enabled.
