From 28d6482e8224c37ab541fb718c31bd31ba52f961 Mon Sep 17 00:00:00 2001
From: Artem Vorotnikov <artem@vorotnikov.me>
Date: Sat, 3 Apr 2021 07:17:51 +0300
Subject: [PATCH] Stateless Tx interface

---
 ethdb/kv_abstract.go | 45 ++++++++++++++++++++++++++++----------------
 1 file changed, 29 insertions(+), 16 deletions(-)

diff --git a/ethdb/kv_abstract.go b/ethdb/kv_abstract.go
index 44960226224..cd46e4189a3 100644
--- a/ethdb/kv_abstract.go
+++ b/ethdb/kv_abstract.go
@@ -81,42 +81,55 @@ const (
 	RO TxFlags = 0x02
 )
 
-type Tx interface {
-	// Cursor - creates cursor object on top of given bucket. Type of cursor - depends on bucket configuration.
-	// If bucket was created with lmdb.DupSort flag, then cursor with interface CursorDupSort created
-	// Otherwise - object of interface Cursor created
-	//
-	// Cursor, also provides a grain of magic - it can use a declarative configuration - and automatically break
-	// long keys into DupSort key/values. See docs for `bucket.go:BucketConfigItem`
-	Cursor(bucket string) (Cursor, error)
-	CursorDupSort(bucket string) (CursorDupSort, error) // CursorDupSort - can be used if bucket has lmdb.DupSort flag
+type StatelessReadTx interface {
 	GetOne(bucket string, key []byte) (val []byte, err error)
 	HasOne(bucket string, key []byte) (bool, error)
 
 	Commit(ctx context.Context) error // Commit all the operations of a transaction into the database.
 	Rollback()                        // Rollback - abandon all the operations of the transaction instead of saving them.
 
-	Comparator(bucket string) dbutils.CmpFunc
-
 	// ReadSequence - allows to create a linear sequence of unique positive integers for each table.
 	// Can be called for a read transaction to retrieve the current sequence value, and the increment must be zero.
 	// Sequence changes become visible outside the current write transaction after it is committed, and discarded on abort.
 	// Starts from 0.
 	ReadSequence(bucket string) (uint64, error)
+}
+
+type StatelessWriteTx interface {
+	IncrementSequence(bucket string, amount uint64) (uint64, error)
+
+	Put(bucket string, k, v []byte) error
+	Delete(bucket string, k, v []byte) error
+}
+
+type StatelessRwTx interface {
+	StatelessReadTx
+	StatelessWriteTx
+}
+
+type Tx interface {
+	StatelessReadTx
+
+	// Cursor - creates cursor object on top of given bucket. Type of cursor - depends on bucket configuration.
+	// If bucket was created with lmdb.DupSort flag, then cursor with interface CursorDupSort created
+	// Otherwise - object of interface Cursor created
+	//
+	// Cursor, also provides a grain of magic - it can use a declarative configuration - and automatically break
+	// long keys into DupSort key/values. See docs for `bucket.go:BucketConfigItem`
+	Cursor(bucket string) (Cursor, error)
+	CursorDupSort(bucket string) (CursorDupSort, error) // CursorDupSort - can be used if bucket has lmdb.DupSort flag
+
+	Comparator(bucket string) dbutils.CmpFunc
 
 	CHandle() unsafe.Pointer // Pointer to the underlying C transaction handle (e.g. *C.MDB_txn)
 }
 
 type RwTx interface {
 	Tx
+	StatelessWriteTx
 
 	RwCursor(bucket string) (RwCursor, error)
 	RwCursorDupSort(bucket string) (RwCursorDupSort, error)
-
-	IncrementSequence(bucket string, amount uint64) (uint64, error)
-
-	Put(bucket string, k, v []byte) error
-	Delete(bucket string, k, v []byte) error
 }
 
 // BucketMigrator used for buckets migration, don't use it in usual app code