Fix memory leak in CallbackInput

[JJIngram]

Issue

I noticed there was a large buildup of memory when repeatedly calling parse on a Parser. After digging into the issue it turns out that input, and therefore inputString, was being retained by CallbackInput

node-tree-sitter/index.js

Line 355 in 419da7d

input = (offset, _position) => inputString.slice(offset)

Fix

This PR simply resets the resources in the destructor of CallbackInput to allow input and inputString to be garbage collected.

[amaanq]

thanks!

[maxbrunsfeld]

@JJIngram Just curious - do you know why we'd need to reset those handles in the destructor, when the handles are about to have their destructors called anyway?

[amaanq]

My guess is, and correct me if I'm wrong, if you call parse a ton of times within a short timespan, not all the strings have had their destructor(s) called yet, leading to the buildup if done so within a short time frame? At least that's how I interpreted it, I probably should have tried to reproduce first

[PandelisZ]

I can confirm the above was discovered through many many many many calls to this api happening in very short time spans yes.