task(storage/child-trie): implement store/load of child trie from DB (#2122)

Fixes #1490

Author: kishansagathiya

dot/state/storage_test.go

@@ -11,8 +11,11 @@ import (
 
 	"github.com/ChainSafe/gossamer/dot/state/pruner"
 	"github.com/ChainSafe/gossamer/dot/types"
+	"github.com/ChainSafe/gossamer/lib/common"
+	"github.com/ChainSafe/gossamer/lib/genesis"
 	runtime "github.com/ChainSafe/gossamer/lib/runtime/storage"
 	"github.com/ChainSafe/gossamer/lib/trie"
+	"github.com/ChainSafe/gossamer/lib/utils"
 
 	"github.com/stretchr/testify/require"
 )
@@ -183,3 +186,51 @@ func TestStorage_StoreTrie_NotSyncing(t *testing.T) {
 	require.NoError(t, err)
 	require.Equal(t, 2, syncMapLen(storage.tries))
 }
+
+func TestGetStorageChildAndGetStorageFromChild(t *testing.T) {
+	// initialise database using data directory
+	basepath := t.TempDir()
+	db, err := utils.SetupDatabase(basepath, false)
+	require.NoError(t, err)
+
+	_, genTrie, genHeader := genesis.NewTestGenesisWithTrieAndHeader(t)
+
+	blockState, err := NewBlockStateFromGenesis(db, genHeader)
+	require.NoError(t, err)
+
+	testChildTrie := trie.NewEmptyTrie()
+	testChildTrie.Put([]byte("keyInsidechild"), []byte("voila"))
+
+	err = genTrie.PutChild([]byte("keyToChild"), testChildTrie)
+	require.NoError(t, err)
+
+	storage, err := NewStorageState(db, blockState, genTrie, pruner.Config{})
+	require.NoError(t, err)
+
+	trieState, err := runtime.NewTrieState(genTrie)
+	require.NoError(t, err)
+
+	header, err := types.NewHeader(blockState.GenesisHash(), trieState.MustRoot(),
+		common.Hash{}, big.NewInt(1), types.NewDigest())
+	require.NoError(t, err)
+
+	err = storage.StoreTrie(trieState, header)
+	require.NoError(t, err)
+
+	rootHash, err := genTrie.Hash()
+	require.NoError(t, err)
+
+	_, err = storage.GetStorageChild(&rootHash, []byte("keyToChild"))
+	require.NoError(t, err)
+
+	// Clear trie from cache and fetch data from disk.
+	storage.tries.Delete(rootHash)
+
+	_, err = storage.GetStorageChild(&rootHash, []byte("keyToChild"))
+	require.NoError(t, err)
+
+	value, err := storage.GetStorageFromChild(&rootHash, []byte("keyToChild"), []byte("keyInsidechild"))
+	require.NoError(t, err)
+
+	require.Equal(t, []byte("voila"), value)
+}

lib/runtime/storage/trie_test.go

@@ -6,6 +6,7 @@ package storage
 import (
 	"bytes"
 	"encoding/binary"
+	"fmt"
 	"sort"
 	"testing"
 
@@ -221,7 +222,7 @@ func TestTrieState_DeleteChildLimit(t *testing.T) {
 			limit:           optLimit2,
 			expectedDeleted: 0,
 			expectedDelAll:  false,
-			errMsg:          "child trie does not exist at key :child_storage:default:fakekey",
+			errMsg:          fmt.Sprintf("child trie does not exist at key 0x%x", ":child_storage:default:fakekey"),
 		},
 		{key: []byte("keytochild"), limit: optLimit2, expectedDeleted: 2, expectedDelAll: false},
 		{key: []byte("keytochild"), limit: nil, expectedDeleted: 1, expectedDelAll: true},

lib/trie/child_storage.go

@@ -4,6 +4,7 @@
 package trie
 
 import (
+	"errors"
 	"fmt"
 
 	"github.com/ChainSafe/gossamer/lib/common"
@@ -12,6 +13,8 @@ import (
 // ChildStorageKeyPrefix is the prefix for all child storage keys
 var ChildStorageKeyPrefix = []byte(":child_storage:default:")
 
+var ErrChildTrieDoesNotExist = errors.New("child trie does not exist")
+
 // PutChild inserts a child trie into the main trie at key :child_storage:[keyToChild]
 func (t *Trie) PutChild(keyToChild []byte, child *Trie) error {
 	childHash, err := child.Hash()
@@ -32,7 +35,7 @@ func (t *Trie) GetChild(keyToChild []byte) (*Trie, error) {
 	key := append(ChildStorageKeyPrefix, keyToChild...)
 	childHash := t.Get(key)
 	if childHash == nil {
-		return nil, fmt.Errorf("child trie does not exist at key %s%s", ChildStorageKeyPrefix, keyToChild)
+		return nil, fmt.Errorf("%w at key 0x%x%x", ErrChildTrieDoesNotExist, ChildStorageKeyPrefix, keyToChild)
 	}
 
 	hash := [32]byte{}
@@ -58,7 +61,7 @@ func (t *Trie) PutIntoChild(keyToChild, key, value []byte) error {
 		return err
 	}
 
-	t.childTries[origChildHash] = nil
+	delete(t.childTries, origChildHash)
 	t.childTries[childHash] = child
 
 	return t.PutChild(keyToChild, child)
@@ -73,7 +76,7 @@ func (t *Trie) GetFromChild(keyToChild, key []byte) ([]byte, error) {
 	}
 
 	if child == nil {
-		return nil, fmt.Errorf("child trie does not exist at key %s%s", ChildStorageKeyPrefix, keyToChild)
+		return nil, fmt.Errorf("%w at key 0x%x%x", ErrChildTrieDoesNotExist, ChildStorageKeyPrefix, keyToChild)
 	}
 
 	val := child.Get(key)
@@ -93,7 +96,7 @@ func (t *Trie) ClearFromChild(keyToChild, key []byte) error {
 		return err
 	}
 	if child == nil {
-		return fmt.Errorf("child trie does not exist at key %s%s", ChildStorageKeyPrefix, keyToChild)
+		return fmt.Errorf("%w at key 0x%x%x", ErrChildTrieDoesNotExist, ChildStorageKeyPrefix, keyToChild)
 	}
 	child.Delete(key)
 	return nil

lib/trie/database.go

@@ -25,6 +25,12 @@ var (
 // and the value is the encoded node.
 // Generally, this will only be used for the genesis trie.
 func (t *Trie) Store(db chaindb.Database) error {
+	for _, v := range t.childTries {
+		if err := v.Store(db); err != nil {
+			return fmt.Errorf("failed to store child trie with root hash=0x%x in the db: %w", v.root.GetHash(), err)
+		}
+	}
+
 	batch := db.NewBatch()
 	err := t.store(batch, t.root)
 	if err != nil {
@@ -201,6 +207,21 @@ func (t *Trie) load(db chaindb.Database, n Node) error {
 		}
 	}
 
+	for _, key := range t.GetKeysWithPrefix(ChildStorageKeyPrefix) {
+		childTrie := NewEmptyTrie()
+		value := t.Get(key)
+		err := childTrie.Load(db, common.NewHash(value))
+		if err != nil {
+			return fmt.Errorf("failed to load child trie with root hash=0x%x: %w", value, err)
+		}
+
+		err = t.PutChild(value, childTrie)
+		if err != nil {
+			return fmt.Errorf("failed to insert child trie with root hash=0x%x into main trie: %w",
+				childTrie.root.GetHash(), err)
+		}
+	}
+
 	return nil
 }
 
@@ -395,6 +416,12 @@ func (t *Trie) writeDirty(db chaindb.Batch, n Node) error {
 		}
 	}
 
+	for _, childTrie := range t.childTries {
+		if err := childTrie.writeDirty(db, childTrie.root); err != nil {
+			return fmt.Errorf("failed to write dirty node=0x%x to database: %w", childTrie.root.GetHash(), err)
+		}
+	}
+
 	branch.SetDirty(false)
 
 	return nil