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

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package shard
import (
"fmt"
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/blobovnicza"
"github.com/nspcc-dev/neofs-node/pkg/local_object_storage/blobstor"
)
// storFetcher is a type to unify object fetching mechanism in `fetchObjectData`
// method. It represents generalization of `getSmall` and `getBig` methods.
type storFetcher = func(stor *blobstor.BlobStor, id *blobovnicza.ID) (*object.Object, error)
// GetPrm groups the parameters of Get operation.
type GetPrm struct {
addr *objectSDK.Address
}
// GetRes groups resulting values of Get operation.
type GetRes struct {
obj *object.Object
}
// WithAddress is a Get option to set the address of the requested object.
//
// Option is required.
func (p *GetPrm) WithAddress(addr *objectSDK.Address) *GetPrm {
if p != nil {
p.addr = addr
}
return p
}
// Object returns the requested object.
func (r *GetRes) Object() *object.Object {
return r.obj
}
// Get reads an object from shard.
//
// Returns any error encountered that
// did not allow to completely read the object part.
//
// Returns object.ErrNotFound if requested object is missing in shard.
func (s *Shard) Get(prm *GetPrm) (*GetRes, error) {
var big, small storFetcher
big = func(stor *blobstor.BlobStor, _ *blobovnicza.ID) (*object.Object, error) {
getBigPrm := new(blobstor.GetBigPrm)
getBigPrm.SetAddress(prm.addr)
res, err := stor.GetBig(getBigPrm)
if err != nil {
return nil, err
}
return res.Object(), nil
}
small = func(stor *blobstor.BlobStor, id *blobovnicza.ID) (*object.Object, error) {
getSmallPrm := new(blobstor.GetSmallPrm)
getSmallPrm.SetAddress(prm.addr)
getSmallPrm.SetBlobovniczaID(id)
res, err := stor.GetSmall(getSmallPrm)
if err != nil {
return nil, err
}
return res.Object(), nil
}
obj, err := s.fetchObjectData(prm.addr, big, small)
return &GetRes{
obj: obj,
}, err
}
// fetchObjectData looks through writeCache and blobStor to find object.
func (s *Shard) fetchObjectData(addr *objectSDK.Address, big, small storFetcher) (*object.Object, error) {
var (
err error
res *object.Object
)
if s.hasWriteCache() {
res, err = small(s.writeCache, nil)
if err == nil {
return res, nil
}
s.log.Debug("miss in writeCache blobovnicza")
res, err = big(s.writeCache, nil)
if err == nil {
return res, nil
}
s.log.Debug("miss in writeCache shallow dir")
}
exists, err := s.metaBase.Exists(addr)
if err != nil {
return nil, err
}
if !exists {
return nil, object.ErrNotFound
}
blobovniczaID, err := s.metaBase.IsSmall(addr)
if err != nil {
return nil, fmt.Errorf("can't fetch blobovnicza id from metabase: %w", err)
}
if blobovniczaID != nil {
res, err = small(s.blobStor, blobovniczaID)
} else {
res, err = big(s.blobStor, nil)
}
return res, err
}