[#1621] pilorama: Batch related operations

Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
Signed-off-by: Evgenii Stratonikov <evgeniy@morphbits.ru>
Signed-off-by: Evgenii Stratonikov <e.stratonikov@yadro.com>

pkg/local_object_storage/pilorama/batch.go

@@ -0,0 +1,49 @@
+package pilorama
+
+import (
+	"sort"
+	"sync"
+	"time"
+
+	cidSDK "github.com/TrueCloudLab/frostfs-sdk-go/container/id"
+	"go.etcd.io/bbolt"
+)
+
+type batch struct {
+	forest     *boltForest
+	timer      *time.Timer
+	mtx        sync.Mutex
+	start      sync.Once
+	cid        cidSDK.ID
+	treeID     string
+	results    []chan<- error
+	operations []*Move
+}
+
+func (b *batch) trigger() {
+	b.mtx.Lock()
+	if b.timer != nil {
+		b.timer.Stop()
+		b.timer = nil
+	}
+	b.mtx.Unlock()
+	b.start.Do(b.run)
+}
+
+func (b *batch) run() {
+	sort.Slice(b.operations, func(i, j int) bool {
+		return b.operations[i].Time < b.operations[j].Time
+	})
+	err := b.forest.db.Update(func(tx *bbolt.Tx) error {
+		bLog, bTree, err := b.forest.getTreeBuckets(tx, b.cid, b.treeID)
+		if err != nil {
+			return err
+		}
+
+		var lm LogMove
+		return b.forest.applyOperation(bLog, bTree, b.operations, &lm)
+	})
+	for i := range b.operations {
+		b.results[i] <- err
+	}
+}