ethdb: add ValueSize to Batch

ethdb/database.go

@@ -280,12 +280,14 @@ func (db *LDBDatabase) NewBatch() Batch {
 }
 
 type ldbBatch struct {
-	db *leveldb.DB
-	b  *leveldb.Batch
+	db   *leveldb.DB
+	b    *leveldb.Batch
+	size int
 }
 
 func (b *ldbBatch) Put(key, value []byte) error {
 	b.b.Put(key, value)
+	b.size += len(value)
 	return nil
 }
 
@@ -293,6 +295,10 @@ func (b *ldbBatch) Write() error {
 	return b.db.Write(b.b, nil)
 }
 
+func (b *ldbBatch) ValueSize() int {
+	return b.size
+}
+
 type table struct {
 	db     Database
 	prefix string
@@ -348,3 +354,7 @@ func (tb *tableBatch) Put(key, value []byte) error {
 func (tb *tableBatch) Write() error {
 	return tb.batch.Write()
 }
+
+func (tb *tableBatch) ValueSize() int {
+	return tb.batch.ValueSize()
+}

ethdb/interface.go

@@ -39,5 +39,6 @@ type Database interface {
 // when Write is called. Batch cannot be used concurrently.
 type Batch interface {
 	Putter
+	ValueSize() int // amount of data in the batch
 	Write() error
 }

ethdb/memory_database.go

@@ -101,10 +101,12 @@ type kv struct{ k, v []byte }
 type memBatch struct {
 	db     *MemDatabase
 	writes []kv
+	size   int
 }
 
 func (b *memBatch) Put(key, value []byte) error {
 	b.writes = append(b.writes, kv{common.CopyBytes(key), common.CopyBytes(value)})
+	b.size += len(value)
 	return nil
 }
 
@@ -117,3 +119,7 @@ func (b *memBatch) Write() error {
 	}
 	return nil
 }
+
+func (b *memBatch) ValueSize() int {
+	return b.size
+}