core/state: add trie prefetcher tests (#23216)

* core/state: add trie prefetcher tests

* core/state: add missing license

core/state/trie_prefetcher_test.go

+// Copyright 2021 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package state
+
+import (
+	"math/big"
+	"testing"
+	"time"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/rawdb"
+)
+
+func filledStateDB() *StateDB {
+	state, _ := New(common.Hash{}, NewDatabase(rawdb.NewMemoryDatabase()), nil)
+
+	// Create an account and check if the retrieved balance is correct
+	addr := common.HexToAddress("0xaffeaffeaffeaffeaffeaffeaffeaffeaffeaffe")
+	skey := common.HexToHash("aaa")
+	sval := common.HexToHash("bbb")
+
+	state.SetBalance(addr, big.NewInt(42)) // Change the account trie
+	state.SetCode(addr, []byte("hello"))   // Change an external metadata
+	state.SetState(addr, skey, sval)       // Change the storage trie
+	for i := 0; i < 100; i++ {
+		sk := common.BigToHash(big.NewInt(int64(i)))
+		state.SetState(addr, sk, sk) // Change the storage trie
+	}
+	return state
+}
+
+func TestCopyAndClose(t *testing.T) {
+	db := filledStateDB()
+	prefetcher := newTriePrefetcher(db.db, db.originalRoot, "")
+	skey := common.HexToHash("aaa")
+	prefetcher.prefetch(db.originalRoot, [][]byte{skey.Bytes()})
+	prefetcher.prefetch(db.originalRoot, [][]byte{skey.Bytes()})
+	time.Sleep(1 * time.Second)
+	a := prefetcher.trie(db.originalRoot)
+	prefetcher.prefetch(db.originalRoot, [][]byte{skey.Bytes()})
+	b := prefetcher.trie(db.originalRoot)
+	cpy := prefetcher.copy()
+	cpy.prefetch(db.originalRoot, [][]byte{skey.Bytes()})
+	cpy.prefetch(db.originalRoot, [][]byte{skey.Bytes()})
+	c := cpy.trie(db.originalRoot)
+	prefetcher.close()
+	cpy2 := cpy.copy()
+	cpy2.prefetch(db.originalRoot, [][]byte{skey.Bytes()})
+	d := cpy2.trie(db.originalRoot)
+	cpy.close()
+	cpy2.close()
+	if a.Hash() != b.Hash() || a.Hash() != c.Hash() || a.Hash() != d.Hash() {
+		t.Fatalf("Invalid trie, hashes should be equal: %v %v %v %v", a.Hash(), b.Hash(), c.Hash(), d.Hash())
+	}
+}
+
+func TestUseAfterClose(t *testing.T) {
+	db := filledStateDB()
+	prefetcher := newTriePrefetcher(db.db, db.originalRoot, "")
+	skey := common.HexToHash("aaa")
+	prefetcher.prefetch(db.originalRoot, [][]byte{skey.Bytes()})
+	a := prefetcher.trie(db.originalRoot)
+	prefetcher.close()
+	b := prefetcher.trie(db.originalRoot)
+	if a == nil {
+		t.Fatal("Prefetching before close should not return nil")
+	}
+	if b != nil {
+		t.Fatal("Trie after close should return nil")
+	}
+}
+
+func TestCopyClose(t *testing.T) {
+	db := filledStateDB()
+	prefetcher := newTriePrefetcher(db.db, db.originalRoot, "")
+	skey := common.HexToHash("aaa")
+	prefetcher.prefetch(db.originalRoot, [][]byte{skey.Bytes()})
+	cpy := prefetcher.copy()
+	a := prefetcher.trie(db.originalRoot)
+	b := cpy.trie(db.originalRoot)
+	prefetcher.close()
+	c := prefetcher.trie(db.originalRoot)
+	d := cpy.trie(db.originalRoot)
+	if a == nil {
+		t.Fatal("Prefetching before close should not return nil")
+	}
+	if b == nil {
+		t.Fatal("Copy trie should return nil")
+	}
+	if c != nil {
+		t.Fatal("Trie after close should return nil")
+	}
+	if d == nil {
+		t.Fatal("Copy trie should not return nil")
+	}
+}