From 50f131e8fe44926afe8adbb97eefe9b1c74536bd Mon Sep 17 00:00:00 2001
From: Patrick O'Grady <prohb125@gmail.com>
Date: Thu, 12 Oct 2023 23:04:02 -0700
Subject: [PATCH] [x/merkledb] `Prefetcher` interface (#2167)

---
 x/merkledb/db.go      | 14 ++++++++++++++
 x/merkledb/mock_db.go | 28 ++++++++++++++++++++++++++++
 2 files changed, 42 insertions(+)

diff --git a/x/merkledb/db.go b/x/merkledb/db.go
index 320c5a524608..e5a5e1170dc8 100644
--- a/x/merkledb/db.go
+++ b/x/merkledb/db.go
@@ -114,6 +114,19 @@ type RangeProofer interface {
 	CommitRangeProof(ctx context.Context, start, end maybe.Maybe[[]byte], proof *RangeProof) error
 }
 
+type Prefetcher interface {
+	// PrefetchPath attempts to load all trie nodes on the path of [key]
+	// into the cache.
+	PrefetchPath(key []byte) error
+
+	// PrefetchPaths attempts to load all trie nodes on the paths of [keys]
+	// into the cache.
+	//
+	// Using PrefetchPaths can be more efficient than PrefetchPath because
+	// the underlying view used to compute each path can be reused.
+	PrefetchPaths(keys [][]byte) error
+}
+
 type MerkleDB interface {
 	database.Database
 	Trie
@@ -121,6 +134,7 @@ type MerkleDB interface {
 	ProofGetter
 	ChangeProofer
 	RangeProofer
+	Prefetcher
 }
 
 type Config struct {
diff --git a/x/merkledb/mock_db.go b/x/merkledb/mock_db.go
index 5256837a5244..f2d8eae8a69b 100644
--- a/x/merkledb/mock_db.go
+++ b/x/merkledb/mock_db.go
@@ -345,6 +345,34 @@ func (mr *MockMerkleDBMockRecorder) NewView(arg0, arg1 interface{}) *gomock.Call
 	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "NewView", reflect.TypeOf((*MockMerkleDB)(nil).NewView), arg0, arg1)
 }
 
+// PrefetchPath mocks base method.
+func (m *MockMerkleDB) PrefetchPath(arg0 []byte) error {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "PrefetchPath", arg0)
+	ret0, _ := ret[0].(error)
+	return ret0
+}
+
+// PrefetchPath indicates an expected call of PrefetchPath.
+func (mr *MockMerkleDBMockRecorder) PrefetchPath(arg0 interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "PrefetchPath", reflect.TypeOf((*MockMerkleDB)(nil).PrefetchPath), arg0)
+}
+
+// PrefetchPaths mocks base method.
+func (m *MockMerkleDB) PrefetchPaths(arg0 [][]byte) error {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "PrefetchPaths", arg0)
+	ret0, _ := ret[0].(error)
+	return ret0
+}
+
+// PrefetchPaths indicates an expected call of PrefetchPaths.
+func (mr *MockMerkleDBMockRecorder) PrefetchPaths(arg0 interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "PrefetchPaths", reflect.TypeOf((*MockMerkleDB)(nil).PrefetchPaths), arg0)
+}
+
 // Put mocks base method.
 func (m *MockMerkleDB) Put(arg0, arg1 []byte) error {
 	m.ctrl.T.Helper()