frostfs-node/pkg/local_object_storage/writecache/get.go

package writecache

import (
	"github.com/nspcc-dev/neofs-node/pkg/local_object_storage/blobstor/common"
	apistatus "github.com/nspcc-dev/neofs-sdk-go/client/status"
	objectSDK "github.com/nspcc-dev/neofs-sdk-go/object"
	oid "github.com/nspcc-dev/neofs-sdk-go/object/id"
	"go.etcd.io/bbolt"
)

// Get returns object from write-cache.
//
// Returns an error of type apistatus.ObjectNotFound if the requested object is missing in write-cache.
func (c *cache) Get(addr oid.Address) (*objectSDK.Object, error) {
	saddr := addr.EncodeToString()

	value, err := Get(c.db, []byte(saddr))
	if err == nil {
		obj := objectSDK.New()
		c.flushed.Get(saddr)
		return obj, obj.Unmarshal(value)
	}

	data, err := c.fsTree.Get(common.GetPrm{Address: addr})
	if err != nil {
		var errNotFound apistatus.ObjectNotFound

		return nil, errNotFound
	}

	obj := objectSDK.New()
	if err := obj.Unmarshal(data); err != nil {
		return nil, err
	}

	c.flushed.Get(saddr)
	return obj, nil
}

// Head returns object header from write-cache.
//
// Returns an error of type apistatus.ObjectNotFound if the requested object is missing in write-cache.
func (c *cache) Head(addr oid.Address) (*objectSDK.Object, error) {
	obj, err := c.Get(addr)
	if err != nil {
		return nil, err
	}

	return obj.CutPayload(), nil
}

// Get fetches object from the underlying database.
// Key should be a stringified address.
//
// Returns an error of type apistatus.ObjectNotFound if the requested object is missing in db.
func Get(db *bbolt.DB, key []byte) ([]byte, error) {
	var value []byte
	err := db.View(func(tx *bbolt.Tx) error {
		b := tx.Bucket(defaultBucket)
		if b == nil {
			return ErrNoDefaultBucket
		}
		value = b.Get(key)
		if value == nil {
			var errNotFound apistatus.ObjectNotFound

			return errNotFound
		}
		value = cloneBytes(value)
		return nil
	})
	return value, err
}