From bf165c22f71b02f613bfeab99e4c0eefc1894063 Mon Sep 17 00:00:00 2001
From: Ziyang Hu <hu.ziyang@cantab.net>
Date: Sat, 12 Nov 2022 00:44:48 +0800
Subject: [PATCH] read-write distinction in the tx API

---
 cozo-core/src/runtime/db.rs    | 6 +++---
 cozo-core/src/storage/mod.rs   | 2 +-
 cozo-core/src/storage/rocks.rs | 2 +-
 cozo-core/src/storage/sled.rs  | 2 +-
 4 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/cozo-core/src/runtime/db.rs b/cozo-core/src/runtime/db.rs
index 2e28d4ca..c520eed8 100644
--- a/cozo-core/src/runtime/db.rs
+++ b/cozo-core/src/runtime/db.rs
@@ -122,7 +122,7 @@ where
     }
     fn transact(&self) -> Result<SessionTx> {
         let ret = SessionTx {
-            tx: Box::new(self.db.transact()?),
+            tx: Box::new(self.db.transact(false)?),
             mem_store_id: Default::default(),
             relation_store_id: self.relation_store_id.clone(),
         };
@@ -130,7 +130,7 @@ where
     }
     fn transact_write(&self) -> Result<SessionTx> {
         let ret = SessionTx {
-            tx: Box::new(self.db.transact()?),
+            tx: Box::new(self.db.transact(true)?),
             mem_store_id: Default::default(),
             relation_store_id: self.relation_store_id.clone(),
         };
@@ -716,7 +716,7 @@ where
             LARGEST_UTF_CHAR,
         )))])
         .encode_as_key(RelationId::SYSTEM);
-        let tx = self.db.transact()?;
+        let tx = self.db.transact(false)?;
         let mut collected = vec![];
         for kv_res in tx.range_scan_raw(&lower, &upper) {
             let (k_slice, v_slice) = kv_res?;
diff --git a/cozo-core/src/storage/mod.rs b/cozo-core/src/storage/mod.rs
index 85f3088c..19ce36a5 100644
--- a/cozo-core/src/storage/mod.rs
+++ b/cozo-core/src/storage/mod.rs
@@ -13,7 +13,7 @@ pub(crate) mod tikv;
 pub trait Storage {
     type Tx: StoreTx;
 
-    fn transact(&self) -> Result<Self::Tx>;
+    fn transact(&self, write: bool) -> Result<Self::Tx>;
     fn del_range(&self, lower: &[u8], upper: &[u8]) -> Result<()>;
     fn range_compact(&self, lower: &[u8], upper: &[u8]) -> Result<()>;
 }
diff --git a/cozo-core/src/storage/rocks.rs b/cozo-core/src/storage/rocks.rs
index b5a0e08a..9dd3a13d 100644
--- a/cozo-core/src/storage/rocks.rs
+++ b/cozo-core/src/storage/rocks.rs
@@ -90,7 +90,7 @@ impl RocksDbStorage {
 impl Storage for RocksDbStorage {
     type Tx = RocksDbTx;
 
-    fn transact(&self) -> Result<Self::Tx> {
+    fn transact(&self, _write: bool) -> Result<Self::Tx> {
         let db_tx = self.db.transact().set_snapshot(true).start();
         Ok(RocksDbTx { db_tx })
     }
diff --git a/cozo-core/src/storage/sled.rs b/cozo-core/src/storage/sled.rs
index 2c27e09d..5a22bf4f 100644
--- a/cozo-core/src/storage/sled.rs
+++ b/cozo-core/src/storage/sled.rs
@@ -34,7 +34,7 @@ const DEL_MARKER: u8 = 0;
 impl Storage for SledStorage {
     type Tx = SledTx;
 
-    fn transact(&self) -> Result<Self::Tx> {
+    fn transact(&self, _write: bool) -> Result<Self::Tx> {
         Ok(SledTx {
             db: self.db.clone(),
             changes: Default::default(),