This is a reasonably significant upgrade, as it allows for
async functions to be Send, which could unlock more efficiencies
in our overall scheduling.
This commit is just the basic changes required to get the updated
mlua version compiling, it doesn't change anything else.
I've been holding off on this for a while, because I remember
this upgrade being a bit of a PITA for wezterm. Since then
there is a `derive(FromLua)` that makes the transition much
easier.
This upgrade makes it potentially a bit easier/nicer/cheaper for
memoize, because it is now possible to retrieve references to userdata
values (rather than always cloning them), but I haven't done anything
special to take advantage of that in this commit.
We were binding as blobs which we could read back as strings,
but which didn't match string inputs! Very confusing!
Always bind as strings.
For the empty rows case: don't return the affected row count
unless the query has 0 columns, as we otherwise cannot distinguish
between no matching results and a single column with 0.
A bit of a big commit because I wanted sqlite queries to run
async and there isn't a sane way to tell in mlua whether a
given context is safe to yield for an await, which meant making
every case where we call into lua be fully async.
This adds a simple but powerful binding to sqlite that performs
its IO in a blocking tokio thread pool, and returns the results
back to lua.
There is no implicit caching of queries, and no implicit connection
pooling.
Wez Furlong