trie/secure_trie.go

@@ -35,14 +35,14 @@ func NewSecure(owner common.Hash, root common.Hash, db *Database) (*SecureTrie,
 	return NewStateTrie(owner, root, db)
 }
 
-// StateTrie wraps a trie with key hashing. In a secure trie, all
+// StateTrie wraps a trie with key hashing. In a stateTrie trie, all
 // access operations hash the key using keccak256. This prevents
 // calling code from creating long chains of nodes that
 // increase the access time.
 //
 // Contrary to a regular trie, a StateTrie can only be created with
 // New and must have an attached database. The database also stores
-// the preimage of each key.
+// the preimage of each key if preimage recording is enabled.
 //
 // StateTrie is not safe for concurrent use.
 type StateTrie struct {
@@ -53,17 +53,11 @@ type StateTrie struct {
 	secKeyCacheOwner *StateTrie // Pointer to self, replace the key cache on mismatch
 }
 
-// NewStateTrie creates a trie with an existing root node from a backing database
-// and optional intermediate in-memory node pool.
+// NewStateTrie creates a trie with an existing root node from a backing database.
 //
 // If root is the zero hash or the sha3 hash of an empty string, the
 // trie is initially empty. Otherwise, New will panic if db is nil
 // and returns MissingNodeError if the root node cannot be found.
-//
-// Accessing the trie loads nodes from the database or node pool on demand.
-// Loaded nodes are kept around until their 'cache generation' expires.
-// A new cache generation is created by each call to Commit.
-// cachelimit sets the number of past cache generations to keep.
 func NewStateTrie(owner common.Hash, root common.Hash, db *Database) (*StateTrie, error) {
 	if db == nil {
 		panic("trie.NewSecure called without a database")
@@ -87,63 +81,46 @@ func (t *StateTrie) Get(key []byte) []byte {
 
 // TryGet returns the value for key stored in the trie.
 // The value bytes must not be modified by the caller.
-// If a node was not found in the database, a MissingNodeError is returned.
+// If the specified node is not in the trie, nil will be returned.
+// If a trie node is not found in the database, a MissingNodeError is returned.
 func (t *StateTrie) TryGet(key []byte) ([]byte, error) {
 	return t.trie.TryGet(t.hashKey(key))
 }
 
+// TryGetAccount attempts to retrieve an account with provided trie path.
+// If the specified account is not in the trie, nil will be returned.
+// If a trie node is not found in the database, a MissingNodeError is returned.
 func (t *StateTrie) TryGetAccount(key []byte) (*types.StateAccount, error) {
-	var ret types.StateAccount
 	res, err := t.trie.TryGet(t.hashKey(key))
-	if err != nil {
-		log.Error(fmt.Sprintf("Unhandled trie error: %v", err))
-		return &ret, err
+	if res == nil || err != nil {
+		return nil, err
 	}
-	if res == nil {
-		return nil, nil
-	}
-	err = rlp.DecodeBytes(res, &ret)
-	return &ret, err
+	ret := new(types.StateAccount)
+	err = rlp.DecodeBytes(res, ret)
+	return ret, err
 }
 
 // TryGetAccountWithPreHashedKey does the same thing as TryGetAccount, however
 // it expects a key that is already hashed. This constitutes an abstraction leak,
 // since the client code needs to know the key format.
 func (t *StateTrie) TryGetAccountWithPreHashedKey(key []byte) (*types.StateAccount, error) {
-	var ret types.StateAccount
 	res, err := t.trie.TryGet(key)
-	if err != nil {
-		log.Error(fmt.Sprintf("Unhandled trie error: %v", err))
-		return &ret, err
+	if res == nil || err != nil {
+		return nil, err
 	}
-	if res == nil {
-		return nil, nil
-	}
-	err = rlp.DecodeBytes(res, &ret)
-	return &ret, err
+	ret := new(types.StateAccount)
+	err = rlp.DecodeBytes(res, ret)
+	return ret, err
 }
 
 // TryGetNode attempts to retrieve a trie node by compact-encoded path. It is not
 // possible to use keybyte-encoding as the path might contain odd nibbles.
+// If the specified trie node is not in the trie, nil will be returned.
+// If a trie node is not found in the database, a MissingNodeError is returned.
 func (t *StateTrie) TryGetNode(path []byte) ([]byte, int, error) {
 	return t.trie.TryGetNode(path)
 }
 
-// TryUpdateAccount account will abstract the write of an account to the
-// secure trie.
-func (t *StateTrie) TryUpdateAccount(key []byte, acc *types.StateAccount) error {
-	hk := t.hashKey(key)
-	data, err := rlp.EncodeToBytes(acc)
-	if err != nil {
-		return err
-	}
-	if err := t.trie.TryUpdate(hk, data); err != nil {
-		return err
-	}
-	t.getSecKeyCache()[string(hk)] = common.CopyBytes(key)
-	return nil
-}
-
 // Update associates key with value in the trie. Subsequent calls to
 // Get will return value. If value has length zero, any existing value
 // is deleted from the trie and calls to Get will return nil.
@@ -163,7 +140,7 @@ func (t *StateTrie) Update(key, value []byte) {
 // The value bytes must not be modified by the caller while they are
 // stored in the trie.
 //
-// If a node was not found in the database, a MissingNodeError is returned.
+// If a node is not found in the database, a MissingNodeError is returned.
 func (t *StateTrie) TryUpdate(key, value []byte) error {
 	hk := t.hashKey(key)
 	err := t.trie.TryUpdate(hk, value)
@@ -174,6 +151,21 @@ func (t *StateTrie) TryUpdate(key, value []byte) error {
 	return nil
 }
 
+// TryUpdateAccount account will abstract the write of an account to the
+// secure trie.
+func (t *StateTrie) TryUpdateAccount(key []byte, acc *types.StateAccount) error {
+	hk := t.hashKey(key)
+	data, err := rlp.EncodeToBytes(acc)
+	if err != nil {
+		return err
+	}
+	if err := t.trie.TryUpdate(hk, data); err != nil {
+		return err
+	}
+	t.getSecKeyCache()[string(hk)] = common.CopyBytes(key)
+	return nil
+}
+
 // Delete removes any existing value for key from the trie.
 func (t *StateTrie) Delete(key []byte) {
 	if err := t.TryDelete(key); err != nil {
@@ -182,14 +174,15 @@ func (t *StateTrie) Delete(key []byte) {
 }
 
 // TryDelete removes any existing value for key from the trie.
-// If a node was not found in the database, a MissingNodeError is returned.
+// If the specified trie node is not in the trie, nothing will be changed.
+// If a node is not found in the database, a MissingNodeError is returned.
 func (t *StateTrie) TryDelete(key []byte) error {
 	hk := t.hashKey(key)
 	delete(t.getSecKeyCache(), string(hk))
 	return t.trie.TryDelete(hk)
 }
 
-// TryDeleteACcount abstracts an account deletion from the trie.
+// TryDeleteAccount abstracts an account deletion from the trie.
 func (t *StateTrie) TryDeleteAccount(key []byte) error {
 	hk := t.hashKey(key)
 	delete(t.getSecKeyCache(), string(hk))