From 70105477cf7b0de148c7909798ad39aa920beb4d Mon Sep 17 00:00:00 2001
From: Steve Yen <steve.yen@gmail.com>
Date: Thu, 7 Jan 2016 17:54:21 -0800
Subject: [PATCH] added Close() method to KVBatch interface

---
 index/store/batch.go           | 4 ++++
 index/store/goleveldb/batch.go | 7 +++++++
 index/store/kvstore.go         | 3 +++
 index/store/metrics/batch.go   | 6 ++++++
 index/store/null/null.go       | 1 +
 5 files changed, 21 insertions(+)

diff --git a/index/store/batch.go b/index/store/batch.go
index 07a22ddd..231dc0ba 100644
--- a/index/store/batch.go
+++ b/index/store/batch.go
@@ -51,3 +51,7 @@ func (b *EmulatedBatch) Merge(key, val []byte) {
 func (b *EmulatedBatch) Reset() {
 	b.Ops = b.Ops[:0]
 }
+
+func (b *EmulatedBatch) Close() error {
+	return nil
+}
diff --git a/index/store/goleveldb/batch.go b/index/store/goleveldb/batch.go
index 91b2598e..b909f822 100644
--- a/index/store/goleveldb/batch.go
+++ b/index/store/goleveldb/batch.go
@@ -36,3 +36,10 @@ func (b *Batch) Reset() {
 	b.batch.Reset()
 	b.merge = store.NewEmulatedMerge(b.store.mo)
 }
+
+func (b *Batch) Close() error {
+	b.batch.Reset()
+	b.batch = nil
+	b.merge = nil
+	return nil
+}
diff --git a/index/store/kvstore.go b/index/store/kvstore.go
index e1e04d73..d1ecea3e 100644
--- a/index/store/kvstore.go
+++ b/index/store/kvstore.go
@@ -118,4 +118,7 @@ type KVBatch interface {
 
 	// Reset frees resources for this batch and allows reuse
 	Reset()
+
+	// Close frees resources
+	Close() error
 }
diff --git a/index/store/metrics/batch.go b/index/store/metrics/batch.go
index 8c30448f..146cb4b3 100644
--- a/index/store/metrics/batch.go
+++ b/index/store/metrics/batch.go
@@ -24,3 +24,9 @@ func (b *Batch) Merge(key, val []byte) {
 func (b *Batch) Reset() {
 	b.o.Reset()
 }
+
+func (b *Batch) Close() error {
+	err := b.o.Close()
+	b.o = nil
+	return err
+}
diff --git a/index/store/null/null.go b/index/store/null/null.go
index 53ebbca8..92be3330 100644
--- a/index/store/null/null.go
+++ b/index/store/null/null.go
@@ -84,6 +84,7 @@ func (i *batch) Set(key, val []byte)   {}
 func (i *batch) Delete(key []byte)     {}
 func (i *batch) Merge(key, val []byte) {}
 func (i *batch) Reset()                {}
+func (i *batch) Close() error          { return nil }
 
 type writer struct{}