Move @tursodatabase/sync code to sync/javascript

sync/javascript/src/generator.rs

@@ -0,0 +1,45 @@
+use napi_derive::napi;
+use std::{future::Future, sync::Mutex};
+
+use turso_sync_engine::types::ProtocolCommand;
+
+pub const GENERATOR_RESUME_IO: u32 = 0;
+pub const GENERATOR_RESUME_DONE: u32 = 1;
+
+pub trait Generator {
+    fn resume(&mut self, result: Option<String>) -> napi::Result<u32>;
+}
+
+impl<F: Future<Output = turso_sync_engine::Result<()>>> Generator
+    for genawaiter::sync::Gen<ProtocolCommand, turso_sync_engine::Result<()>, F>
+{
+    fn resume(&mut self, error: Option<String>) -> napi::Result<u32> {
+        let result = match error {
+            Some(err) => Err(turso_sync_engine::errors::Error::DatabaseSyncEngineError(
+                format!("JsProtocolIo error: {err}"),
+            )),
+            None => Ok(()),
+        };
+        match self.resume_with(result) {
+            genawaiter::GeneratorState::Yielded(ProtocolCommand::IO) => Ok(GENERATOR_RESUME_IO),
+            genawaiter::GeneratorState::Complete(Ok(())) => Ok(GENERATOR_RESUME_DONE),
+            genawaiter::GeneratorState::Complete(Err(err)) => Err(napi::Error::new(
+                napi::Status::GenericFailure,
+                format!("sync engine operation failed: {err}"),
+            )),
+        }
+    }
+}
+
+#[napi]
+pub struct GeneratorHolder {
+    pub(crate) inner: Box<Mutex<dyn Generator>>,
+}
+
+#[napi]
+impl GeneratorHolder {
+    #[napi]
+    pub fn resume(&self, error: Option<String>) -> napi::Result<u32> {
+        self.inner.lock().unwrap().resume(error)
+    }
+}