Exploratory work to statically link a SQLite extension written in Rust to a WASM build of SQLite.

Kicked off by this issue: asg017/sqlite-loadable-rs#5

• js/example/ contains an example app that uses the built wasm
• wa-sqlite/ is our wasm port of SQLite
• rs/ contains our rust lib

Building

cd wa-sqlite
make

This will build and link in the Rust code as well.

The interesting commit that updated wa-sqlite to include the rust code is this one:
vlcn-io/wa-sqlite@22985f9

Running Example App

cd js
pnpm install
pnpm start

Is it actually doing anything?

Yes. You can test that testext_commit_hook is being called by flipping the return value to 1.

In that case, the demo app fails because the transaction is aborted.

Flipping it back to 0 and recompiling and everything works as expected.

How is it done?

The Rust code is compiled to LLVM bitcode against a wasm-unknown-unknown target.

nit: probably doable by packaging into a single .a file targeting wasm32-unkown-unknown -- to test.

RUSTFLAGS="--emit=llvm-bc" cargo build --target wasm32-unknown-unknown

This bitcode is then able to be linked by emscripten to the broader SQLite WASM bundle.