From a4a2343cdc1946e38da1aea1476642d1744c1354 Mon Sep 17 00:00:00 2001
From: gary rong <garyrong0905@gmail.com>
Date: Mon, 2 Jul 2018 16:16:30 +0800
Subject: ethdb, core: implement delete for db batch (#17101)

---
 ethdb/database.go        | 10 ++++++++++
 ethdb/interface.go       |  8 +++++++-
 ethdb/memory_database.go |  9 +++++++++
 3 files changed, 26 insertions(+), 1 deletion(-)

(limited to 'ethdb')

diff --git a/ethdb/database.go b/ethdb/database.go
index f4a5ce2c8..e32c912f9 100644
--- a/ethdb/database.go
+++ b/ethdb/database.go
@@ -388,6 +388,12 @@ func (b *ldbBatch) Put(key, value []byte) error {
 	return nil
 }
 
+func (b *ldbBatch) Delete(key []byte) error {
+	b.b.Delete(key)
+	b.size += 1
+	return nil
+}
+
 func (b *ldbBatch) Write() error {
 	return b.db.Write(b.b, nil)
 }
@@ -453,6 +459,10 @@ func (tb *tableBatch) Put(key, value []byte) error {
 	return tb.batch.Put(append([]byte(tb.prefix), key...), value)
 }
 
+func (tb *tableBatch) Delete(key []byte) error {
+	return tb.batch.Delete(append([]byte(tb.prefix), key...))
+}
+
 func (tb *tableBatch) Write() error {
 	return tb.batch.Write()
 }
diff --git a/ethdb/interface.go b/ethdb/interface.go
index 537312003..af1355779 100644
--- a/ethdb/interface.go
+++ b/ethdb/interface.go
@@ -25,12 +25,17 @@ type Putter interface {
 	Put(key []byte, value []byte) error
 }
 
+// Deleter wraps the database delete operation supported by both batches and regular databases.
+type Deleter interface {
+	Delete(key []byte) error
+}
+
 // Database wraps all database operations. All methods are safe for concurrent use.
 type Database interface {
 	Putter
+	Deleter
 	Get(key []byte) ([]byte, error)
 	Has(key []byte) (bool, error)
-	Delete(key []byte) error
 	Close()
 	NewBatch() Batch
 }
@@ -39,6 +44,7 @@ type Database interface {
 // when Write is called. Batch cannot be used concurrently.
 type Batch interface {
 	Putter
+	Deleter
 	ValueSize() int // amount of data in the batch
 	Write() error
 	// Reset resets the batch for reuse
diff --git a/ethdb/memory_database.go b/ethdb/memory_database.go
index c57042920..f28ff5481 100644
--- a/ethdb/memory_database.go
+++ b/ethdb/memory_database.go
@@ -110,11 +110,20 @@ func (b *memBatch) Put(key, value []byte) error {
 	return nil
 }
 
+func (b *memBatch) Delete(key []byte) error {
+	b.writes = append(b.writes, kv{common.CopyBytes(key), nil})
+	return nil
+}
+
 func (b *memBatch) Write() error {
 	b.db.lock.Lock()
 	defer b.db.lock.Unlock()
 
 	for _, kv := range b.writes {
+		if kv.v == nil {
+			delete(b.db.db, string(kv.k))
+			continue
+		}
 		b.db.db[string(kv.k)] = kv.v
 	}
 	return nil
-- 
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