Update bootstrap_db to return True if we did bootstrap

Author: avinassh

libsql/src/sync.rs

@@ -687,25 +687,29 @@ async fn atomic_write<P: AsRef<Path>>(path: P, data: &[u8]) -> Result<()> {
 /// bootstrap_db brings the .db file from remote, if required. If the .db file already exists, then
 /// it does nothing. Calling this function multiple times is safe.
 /// However, make sure there are no existing active connections to the db file as this method can
-/// replace it
-pub async fn bootstrap_db(sync_ctx: &mut SyncContext) -> Result<()> {
+/// replace it.
+/// This method true if the db file was bootstrapped from remote, false otherwise.
+pub async fn bootstrap_db(sync_ctx: &mut SyncContext) -> Result<bool> {
     // todo: we are checking with the remote server only during initialisation. ideally,
     // we need to do this when we notice a large gap in generations, when bootstrapping is cheaper
     // than pulling each frame
-    if !sync_ctx.initial_server_sync {
-        // sync is being called first time. so we will call remote, get the generation information
-        // if we are lagging behind, then we will call the export API and get to the latest
-        // generation directly.
-        let info = sync_ctx.get_remote_info().await?;
-        sync_ctx
-            .sync_db_if_needed(info.current_generation)
-            .await?;
-        // when sync_ctx is initialised, we set durable_generation to 0. however, once
-        // sync_db is called, it should be > 0.
-        assert!(sync_ctx.durable_generation > 0, "generation should be > 0");
-        sync_ctx.initial_server_sync = true;
+    if sync_ctx.initial_server_sync {
+        // initial sync has been already attempted, nothing to do now
+        return Ok(false);
     }
-    Ok(())
+
+    // sync is being called first time. so we will call remote, get the generation information
+    // if we are lagging behind, then we will call the export API and get to the latest
+    // generation directly.
+    let info = sync_ctx.get_remote_info().await?;
+    sync_ctx
+        .sync_db_if_needed(info.current_generation)
+        .await?;
+    // when sync_ctx is initialised, we set durable_generation to 0. however, once
+    // sync_db is called, it should be > 0.
+    assert!(sync_ctx.durable_generation > 0, "generation should be > 0");
+    sync_ctx.initial_server_sync = true;
+    Ok(true)
 }
 
 /// Sync WAL frames to remote.