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-rw-r--r--trie/trie.go204
1 files changed, 146 insertions, 58 deletions
diff --git a/trie/trie.go b/trie/trie.go
index a3a383fb5..717296e27 100644
--- a/trie/trie.go
+++ b/trie/trie.go
@@ -19,7 +19,6 @@ package trie
import (
"bytes"
- "errors"
"fmt"
"hash"
@@ -44,7 +43,10 @@ var (
emptyState = crypto.Sha3Hash(nil)
)
-var ErrMissingRoot = errors.New("missing root node")
+// ClearGlobalCache clears the global trie cache
+func ClearGlobalCache() {
+ globalCache.Clear()
+}
// Database must be implemented by backing stores for the trie.
type Database interface {
@@ -67,8 +69,9 @@ type DatabaseWriter interface {
//
// Trie is not safe for concurrent use.
type Trie struct {
- root node
- db Database
+ root node
+ db Database
+ originalRoot common.Hash
*hasher
}
@@ -76,16 +79,19 @@ type Trie struct {
//
// If root is the zero hash or the sha3 hash of an empty string, the
// trie is initially empty and does not require a database. Otherwise,
-// New will panics if db is nil or root does not exist in the
-// database. Accessing the trie loads nodes from db on demand.
+// New will panic if db is nil and returns a MissingNodeError if root does
+// not exist in the database. Accessing the trie loads nodes from db on demand.
func New(root common.Hash, db Database) (*Trie, error) {
- trie := &Trie{db: db}
+ trie := &Trie{db: db, originalRoot: root}
if (root != common.Hash{}) && root != emptyRoot {
if db == nil {
panic("trie.New: cannot use existing root without a database")
}
if v, _ := trie.db.Get(root[:]); len(v) == 0 {
- return nil, ErrMissingRoot
+ return nil, &MissingNodeError{
+ RootHash: root,
+ NodeHash: root,
+ }
}
trie.root = hashNode(root.Bytes())
}
@@ -100,28 +106,44 @@ func (t *Trie) Iterator() *Iterator {
// Get returns the value for key stored in the trie.
// The value bytes must not be modified by the caller.
func (t *Trie) Get(key []byte) []byte {
+ res, err := t.TryGet(key)
+ if err != nil && glog.V(logger.Error) {
+ glog.Errorf("Unhandled trie error: %v", err)
+ }
+ return res
+}
+
+// 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.
+func (t *Trie) TryGet(key []byte) ([]byte, error) {
key = compactHexDecode(key)
+ pos := 0
tn := t.root
- for len(key) > 0 {
+ for pos < len(key) {
switch n := tn.(type) {
case shortNode:
- if len(key) < len(n.Key) || !bytes.Equal(n.Key, key[:len(n.Key)]) {
- return nil
+ if len(key)-pos < len(n.Key) || !bytes.Equal(n.Key, key[pos:pos+len(n.Key)]) {
+ return nil, nil
}
tn = n.Val
- key = key[len(n.Key):]
+ pos += len(n.Key)
case fullNode:
- tn = n[key[0]]
- key = key[1:]
+ tn = n[key[pos]]
+ pos++
case nil:
- return nil
+ return nil, nil
case hashNode:
- tn = t.resolveHash(n)
+ var err error
+ tn, err = t.resolveHash(n, key[:pos], key[pos:])
+ if err != nil {
+ return nil, err
+ }
default:
panic(fmt.Sprintf("%T: invalid node: %v", tn, tn))
}
}
- return tn.(valueNode)
+ return tn.(valueNode), nil
}
// Update associates key with value in the trie. Subsequent calls to
@@ -131,17 +153,40 @@ func (t *Trie) Get(key []byte) []byte {
// The value bytes must not be modified by the caller while they are
// stored in the trie.
func (t *Trie) Update(key, value []byte) {
+ if err := t.TryUpdate(key, value); err != nil && glog.V(logger.Error) {
+ glog.Errorf("Unhandled trie error: %v", err)
+ }
+}
+
+// TryUpdate 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.
+//
+// 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.
+func (t *Trie) TryUpdate(key, value []byte) error {
k := compactHexDecode(key)
if len(value) != 0 {
- t.root = t.insert(t.root, k, valueNode(value))
+ n, err := t.insert(t.root, nil, k, valueNode(value))
+ if err != nil {
+ return err
+ }
+ t.root = n
} else {
- t.root = t.delete(t.root, k)
+ n, err := t.delete(t.root, nil, k)
+ if err != nil {
+ return err
+ }
+ t.root = n
}
+ return nil
}
-func (t *Trie) insert(n node, key []byte, value node) node {
+func (t *Trie) insert(n node, prefix, key []byte, value node) (node, error) {
if len(key) == 0 {
- return value
+ return value, nil
}
switch n := n.(type) {
case shortNode:
@@ -149,25 +194,40 @@ func (t *Trie) insert(n node, key []byte, value node) node {
// If the whole key matches, keep this short node as is
// and only update the value.
if matchlen == len(n.Key) {
- return shortNode{n.Key, t.insert(n.Val, key[matchlen:], value)}
+ nn, err := t.insert(n.Val, append(prefix, key[:matchlen]...), key[matchlen:], value)
+ if err != nil {
+ return nil, err
+ }
+ return shortNode{n.Key, nn}, nil
}
// Otherwise branch out at the index where they differ.
var branch fullNode
- branch[n.Key[matchlen]] = t.insert(nil, n.Key[matchlen+1:], n.Val)
- branch[key[matchlen]] = t.insert(nil, key[matchlen+1:], value)
+ var err error
+ branch[n.Key[matchlen]], err = t.insert(nil, append(prefix, n.Key[:matchlen+1]...), n.Key[matchlen+1:], n.Val)
+ if err != nil {
+ return nil, err
+ }
+ branch[key[matchlen]], err = t.insert(nil, append(prefix, key[:matchlen+1]...), key[matchlen+1:], value)
+ if err != nil {
+ return nil, err
+ }
// Replace this shortNode with the branch if it occurs at index 0.
if matchlen == 0 {
- return branch
+ return branch, nil
}
// Otherwise, replace it with a short node leading up to the branch.
- return shortNode{key[:matchlen], branch}
+ return shortNode{key[:matchlen], branch}, nil
case fullNode:
- n[key[0]] = t.insert(n[key[0]], key[1:], value)
- return n
+ nn, err := t.insert(n[key[0]], append(prefix, key[0]), key[1:], value)
+ if err != nil {
+ return nil, err
+ }
+ n[key[0]] = nn
+ return n, nil
case nil:
- return shortNode{key, value}
+ return shortNode{key, value}, nil
case hashNode:
// We've hit a part of the trie that isn't loaded yet. Load
@@ -176,7 +236,11 @@ func (t *Trie) insert(n node, key []byte, value node) node {
//
// TODO: track whether insertion changed the value and keep
// n as a hash node if it didn't.
- return t.insert(t.resolveHash(n), key, value)
+ rn, err := t.resolveHash(n, prefix, key)
+ if err != nil {
+ return nil, err
+ }
+ return t.insert(rn, prefix, key, value)
default:
panic(fmt.Sprintf("%T: invalid node: %v", n, n))
@@ -185,28 +249,44 @@ func (t *Trie) insert(n node, key []byte, value node) node {
// Delete removes any existing value for key from the trie.
func (t *Trie) Delete(key []byte) {
+ if err := t.TryDelete(key); err != nil && glog.V(logger.Error) {
+ glog.Errorf("Unhandled trie error: %v", err)
+ }
+}
+
+// TryDelete removes any existing value for key from the trie.
+// If a node was not found in the database, a MissingNodeError is returned.
+func (t *Trie) TryDelete(key []byte) error {
k := compactHexDecode(key)
- t.root = t.delete(t.root, k)
+ n, err := t.delete(t.root, nil, k)
+ if err != nil {
+ return err
+ }
+ t.root = n
+ return nil
}
// delete returns the new root of the trie with key deleted.
// It reduces the trie to minimal form by simplifying
// nodes on the way up after deleting recursively.
-func (t *Trie) delete(n node, key []byte) node {
+func (t *Trie) delete(n node, prefix, key []byte) (node, error) {
switch n := n.(type) {
case shortNode:
matchlen := prefixLen(key, n.Key)
if matchlen < len(n.Key) {
- return n // don't replace n on mismatch
+ return n, nil // don't replace n on mismatch
}
if matchlen == len(key) {
- return nil // remove n entirely for whole matches
+ return nil, nil // remove n entirely for whole matches
}
// The key is longer than n.Key. Remove the remaining suffix
// from the subtrie. Child can never be nil here since the
// subtrie must contain at least two other values with keys
// longer than n.Key.
- child := t.delete(n.Val, key[len(n.Key):])
+ child, err := t.delete(n.Val, append(prefix, key[:len(n.Key)]...), key[len(n.Key):])
+ if err != nil {
+ return nil, err
+ }
switch child := child.(type) {
case shortNode:
// Deleting from the subtrie reduced it to another
@@ -215,13 +295,17 @@ func (t *Trie) delete(n node, key []byte) node {
// always creates a new slice) instead of append to
// avoid modifying n.Key since it might be shared with
// other nodes.
- return shortNode{concat(n.Key, child.Key...), child.Val}
+ return shortNode{concat(n.Key, child.Key...), child.Val}, nil
default:
- return shortNode{n.Key, child}
+ return shortNode{n.Key, child}, nil
}
case fullNode:
- n[key[0]] = t.delete(n[key[0]], key[1:])
+ nn, err := t.delete(n[key[0]], append(prefix, key[0]), key[1:])
+ if err != nil {
+ return nil, err
+ }
+ n[key[0]] = nn
// Check how many non-nil entries are left after deleting and
// reduce the full node to a short node if only one entry is
// left. Since n must've contained at least two children
@@ -250,21 +334,24 @@ func (t *Trie) delete(n node, key []byte) node {
// shortNode{..., shortNode{...}}. Since the entry
// might not be loaded yet, resolve it just for this
// check.
- cnode := t.resolve(n[pos])
+ cnode, err := t.resolve(n[pos], prefix, []byte{byte(pos)})
+ if err != nil {
+ return nil, err
+ }
if cnode, ok := cnode.(shortNode); ok {
k := append([]byte{byte(pos)}, cnode.Key...)
- return shortNode{k, cnode.Val}
+ return shortNode{k, cnode.Val}, nil
}
}
// Otherwise, n is replaced by a one-nibble short node
// containing the child.
- return shortNode{[]byte{byte(pos)}, n[pos]}
+ return shortNode{[]byte{byte(pos)}, n[pos]}, nil
}
// n still contains at least two values and cannot be reduced.
- return n
+ return n, nil
case nil:
- return nil
+ return nil, nil
case hashNode:
// We've hit a part of the trie that isn't loaded yet. Load
@@ -273,7 +360,11 @@ func (t *Trie) delete(n node, key []byte) node {
//
// TODO: track whether deletion actually hit a key and keep
// n as a hash node if it didn't.
- return t.delete(t.resolveHash(n), key)
+ rn, err := t.resolveHash(n, prefix, key)
+ if err != nil {
+ return nil, err
+ }
+ return t.delete(rn, prefix, key)
default:
panic(fmt.Sprintf("%T: invalid node: %v (%v)", n, n, key))
@@ -287,34 +378,31 @@ func concat(s1 []byte, s2 ...byte) []byte {
return r
}
-func (t *Trie) resolve(n node) node {
+func (t *Trie) resolve(n node, prefix, suffix []byte) (node, error) {
if n, ok := n.(hashNode); ok {
- return t.resolveHash(n)
+ return t.resolveHash(n, prefix, suffix)
}
- return n
+ return n, nil
}
-func (t *Trie) resolveHash(n hashNode) node {
+func (t *Trie) resolveHash(n hashNode, prefix, suffix []byte) (node, error) {
if v, ok := globalCache.Get(n); ok {
- return v
+ return v, nil
}
enc, err := t.db.Get(n)
if err != nil || enc == nil {
- // TODO: This needs to be improved to properly distinguish errors.
- // Disk I/O errors shouldn't produce nil (and cause a
- // consensus failure or weird crash), but it is unclear how
- // they could be handled because the entire stack above the trie isn't
- // prepared to cope with missing state nodes.
- if glog.V(logger.Error) {
- glog.Errorf("Dangling hash node ref %x: %v", n, err)
+ return nil, &MissingNodeError{
+ RootHash: t.originalRoot,
+ NodeHash: common.BytesToHash(n),
+ KeyPrefix: prefix,
+ KeySuffix: suffix,
}
- return nil
}
dec := mustDecodeNode(n, enc)
if dec != nil {
globalCache.Put(n, dec)
}
- return dec
+ return dec, nil
}
// Root returns the root hash of the trie.
generated by cgit (git 2.34.1) at 2024-11-13 00:34:14 +0800