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

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package writecache
import (
"github.com/nspcc-dev/neofs-node/pkg/core/object"
addressSDK "github.com/nspcc-dev/neofs-sdk-go/object/address"
"go.etcd.io/bbolt"
)
// Get returns object from write-cache.
func (c *cache) Get(addr *addressSDK.Address) (*object.Object, error) {
saddr := addr.String()
c.mtx.RLock()
for i := range c.mem {
if saddr == c.mem[i].addr {
obj := c.mem[i].obj
c.mtx.RUnlock()
return obj, nil
}
}
c.mtx.RUnlock()
value, err := Get(c.db, []byte(saddr))
if err == nil {
obj := object.New()
c.flushed.Get(saddr)
return obj, obj.Unmarshal(value)
}
data, err := c.fsTree.Get(addr)
if err != nil {
return nil, object.ErrNotFound
}
obj := object.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.
func (c *cache) Head(addr *addressSDK.Address) (*object.Object, error) {
// TODO: easiest to implement solution is presented here, consider more efficient way, e.g.:
// - provide header as common object.Object to Put, but marked to prevent correlation with full object
// (all write-cache logic will automatically spread to headers, except flushing)
// - cut header from in-memory objects directly and persist headers into particular bucket of DB
// (explicit sync with full objects is needed)
// - try to pull out binary header from binary full object (not sure if it is possible)
obj, err := c.Get(addr)
if err != nil {
return nil, err
}
// NOTE: resetting the payload via the setter can lead to data corruption of in-memory objects, but ok for others
return object.NewRawFromObject(obj).CutPayload().Object(), nil
}
// Get fetches object from the underlying database.
// Key should be a stringified address.
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 {
return object.ErrNotFound
}
value = cloneBytes(value)
return nil
})
return value, err
}