[#216] blobovnicza: Implement main methods and logic

Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>

pkg/local_object_storage/blobovnicza/sizes.go

@@ -0,0 +1,75 @@
+package blobovnicza
+
+import (
+	"encoding/binary"
+	"fmt"
+
+	"code.cloudfoundry.org/bytefmt"
+	"github.com/pkg/errors"
+	"go.etcd.io/bbolt"
+)
+
+const firstBucketBound = uint64(32 * 1 << 10) // 32KB
+
+func stringifyBounds(lower, upper uint64) string {
+	return fmt.Sprintf("[%s:%s]",
+		stringifyByteSize(lower),
+		stringifyByteSize(upper),
+	)
+}
+
+func stringifyByteSize(sz uint64) string {
+	return bytefmt.ByteSize(sz)
+}
+
+func bucketKeyFromBounds(upperBound uint64) []byte {
+	buf := make([]byte, binary.MaxVarintLen64)
+
+	ln := binary.PutUvarint(buf, upperBound)
+
+	return buf[:ln]
+}
+
+func bucketForSize(sz uint64) []byte {
+	var upperBound uint64
+
+	for upperBound = firstBucketBound; upperBound < sz; upperBound *= 2 {
+	}
+
+	return bucketKeyFromBounds(upperBound)
+}
+
+func (b *Blobovnicza) incSize(sz uint64) {
+	b.filled.Add(sz)
+}
+
+func (b *Blobovnicza) decSize(sz uint64) {
+	b.filled.Sub(sz)
+}
+
+func (b *Blobovnicza) full() bool {
+	return b.filled.Load() >= b.fullSizeLimit
+}
+
+func (b *Blobovnicza) syncFullnessCounter() error {
+	return errors.Wrap(b.boltDB.View(func(tx *bbolt.Tx) error {
+		sz := uint64(0)
+
+		if err := b.iterateBucketKeys(func(lower, upper uint64, key []byte) (bool, error) {
+			buck := tx.Bucket(key)
+			if buck == nil {
+				return false, errors.Errorf("bucket not found %s", stringifyBounds(lower, upper))
+			}
+
+			sz += uint64(buck.Stats().KeyN) * (upper - lower)
+
+			return false, nil
+		}); err != nil {
+			return err
+		}
+
+		b.filled.Store(sz)
+
+		return nil
+	}), "(%T) could not sync fullness counter")
+}