[#472] blobstor: implement write-cache

Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>

pkg/local_object_storage/writecache/delete.go

@@ -0,0 +1,49 @@
+package writecache
+
+import (
+	"errors"
+
+	objectSDK "github.com/nspcc-dev/neofs-api-go/pkg/object"
+	"github.com/nspcc-dev/neofs-node/pkg/core/object"
+	"github.com/nspcc-dev/neofs-node/pkg/local_object_storage/blobstor/fstree"
+	"go.etcd.io/bbolt"
+)
+
+// Delete removes object from write-cache.
+func (c *cache) Delete(addr *objectSDK.Address) error {
+	saddr := addr.String()
+
+	// Check memory cache.
+	c.mtx.Lock()
+	for i := range c.mem {
+		if saddr == c.mem[i].addr {
+			copy(c.mem[i:], c.mem[i+1:])
+			c.mem = c.mem[:len(c.mem)-1]
+			c.mtx.Unlock()
+			return nil
+		}
+	}
+	c.mtx.Unlock()
+
+	// Check disk cache.
+	has := false
+	_ = c.db.View(func(tx *bbolt.Tx) error {
+		b := tx.Bucket(defaultBucket)
+		has = b.Get([]byte(saddr)) != nil
+		return nil
+	})
+
+	if has {
+		return c.db.Update(func(tx *bbolt.Tx) error {
+			b := tx.Bucket(defaultBucket)
+			return b.Delete([]byte(saddr))
+		})
+	}
+
+	err := c.fsTree.Delete(addr)
+	if errors.Is(err, fstree.ErrFileNotFound) {
+		err = object.ErrNotFound
+	}
+
+	return err
+}