More WIP.

Workaround for !Send SQLite causing problems as each get_txn creates a new transaction

sync-server/src/storage/sqlite.rs

@@ -1,9 +1,9 @@
 use super::{Client, Storage, StorageTxn, Uuid, Version};
+use anyhow::Context;
 use rusqlite::types::{FromSql, ToSql};
 use rusqlite::{params, Connection, OptionalExtension};
 use std::path::Path;
 use std::sync::{Arc, Mutex};
-use anyhow::Context;
 
 #[derive(Debug, thiserror::Error)]
 enum SqliteError {
@@ -11,7 +11,6 @@ enum SqliteError {
     TransactionAlreadyCommitted,
 }
 
-
 /// Newtype to allow implementing `FromSql` for foreign `uuid::Uuid`
 struct StoredUuid(Uuid);
 
@@ -50,8 +49,6 @@ impl ToSql for Client {
     }
 }
 
-
-
 /// DB Key for versions: concatenation of client_key and parent_version_id
 type VersionDbKey = [u8; 32];
 
@@ -89,7 +86,8 @@ impl SqliteStorage {
             let txn = con.transaction()?;
 
             let queries = vec![
-                "CREATE TABLE IF NOT EXISTS clients (id INTEGER PRIMARY KEY AUTOINCREMENT, data STRING);",
+                "CREATE TABLE IF NOT EXISTS clients (client_key STRING PRIMARY KEY, latest_version_id STRING);",
+                "CREATE TABLE IF NOT EXISTS versions (id STRING PRIMARY KEY, client_key STRING, parent STRING, history_segment STRING);",
             ];
             for q in queries {
                 txn.execute(q, []).context("Creating table")?;
@@ -104,7 +102,7 @@ impl SqliteStorage {
 impl Storage for SqliteStorage {
     fn txn<'a>(&'a self) -> anyhow::Result<Box<dyn StorageTxn + 'a>> {
         let con = self.new_connection()?;
-        let t = Txn{con, txn: None};
+        let t = Txn { con, txn: None };
         Ok(Box::new(t))
     }
 }
@@ -114,23 +112,28 @@ struct Txn<'t> {
     txn: Option<rusqlite::Transaction<'t>>,
 }
 
-impl <'t>Txn<'t> {
+impl<'t> Txn<'t> {
     fn get_txn(&mut self) -> Result<rusqlite::Transaction, SqliteError> {
         Ok(self.con.transaction().unwrap())
     }
 }
 
-
-impl <'t>StorageTxn for Txn<'t> {
+impl<'t> StorageTxn for Txn<'t> {
     fn get_client(&mut self, client_key: Uuid) -> anyhow::Result<Option<Client>> {
         let t = self.get_txn()?;
         let result: Option<Client> = t
             .query_row(
-                "SELECT data FROM clients WHERE client_key = ? LIMIT 1",
+                "SELECT latest_version_id FROM clients WHERE client_key = ? LIMIT 1",
                 [&StoredUuid(client_key)],
-                |r| r.get("data"),
+                |r| {
+                    let latest_version_id: StoredUuid = r.get(0)?;
+                    Ok(Client {
+                        latest_version_id: latest_version_id.0,
+                    })
+                },
             )
-            .optional()?;
+            .optional()
+            .context("Get client query")?;
 
         Ok(result)
     }
@@ -138,10 +141,9 @@ impl <'t>StorageTxn for Txn<'t> {
     fn new_client(&mut self, client_key: Uuid, latest_version_id: Uuid) -> anyhow::Result<()> {
         let t = self.get_txn()?;
 
-        let client = Client{ latest_version_id };
         t.execute(
             "INSERT OR REPLACE INTO clients (client_key, latest_version_id) VALUES (?, ?)",
-            params![&StoredUuid(latest_version_id), &client],
+            params![&StoredUuid(client_key), &StoredUuid(latest_version_id)],
         )
         .context("Create client query")?;
         Ok(())
@@ -173,16 +175,16 @@ impl <'t>StorageTxn for Txn<'t> {
     ) -> anyhow::Result<()> {
         let t = self.get_txn()?;
 
-        let version = Version {
-            version_id,
-            parent_version_id,
-            history_segment,
-        };
-
         t.execute(
-            "INSERT INTO versions (client_key, id, parent, history_segment)",
-            params![],
-            ).context("Add version query")?;
+            "INSERT INTO versions (id, client_key, parent, history_segment) VALUES(?, ?, ?, ?)",
+            params![
+                StoredUuid(version_id),
+                StoredUuid(client_key),
+                StoredUuid(parent_version_id),
+                history_segment
+            ],
+        )
+        .context("Add version query")?;
 
         Ok(())
     }
@@ -191,8 +193,7 @@ impl <'t>StorageTxn for Txn<'t> {
         let t: rusqlite::Transaction = self
             .txn
             .take()
-            .unwrap();
-            //.ok_or(SqliteError::TransactionAlreadyCommitted)?;
+            .ok_or(SqliteError::TransactionAlreadyCommitted)?;
         t.commit().context("Committing transaction")?;
         Ok(())
     }