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

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package shard
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"
)
// GetPrm groups the parameters of Get operation.
type GetPrm struct {
ln int64 // negative value for full range
off uint64
addr *objectSDK.Address
}
// GetRes groups resulting values of Get operation.
type GetRes struct {
obj *object.Object
}
// ErrObjectNotFound is returns on read operations requested on a missing object.
var ErrObjectNotFound = errors.New("object not found")
// 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
}
// WithFullRange is a Get option to receive full object payload.
func (p *GetPrm) WithFullRange() *GetPrm {
if p != nil {
p.ln = -1
}
return p
}
// WithRange is a Get option to set range of requested payload data.
//
// Calling with negative length is equivalent
// to getting the full payload range.
//
// Calling with zero length is equivalent
// to getting the object header.
func (p *GetPrm) WithRange(off uint64, ln int64) *GetPrm {
if p != nil {
p.off, p.ln = off, ln
}
return p
}
// Object returns the requested object part.
//
// Instance payload contains the requested range of the original object.
func (r *GetRes) Object() *object.Object {
return r.obj
}
// Get reads part of an object from shard.
//
// Returns any error encountered that
// did not allow to completely read the object part.
//
// Returns ErrObjectNotFound if requested object is missing in shard.
func (s *Shard) Get(prm *GetPrm) (*GetRes, error) {
if prm.ln < 0 {
// try to read from WriteCache
// TODO: implement
// form GetBig parameters
getBigPrm := new(blobstor.GetBigPrm)
getBigPrm.SetAddress(prm.addr)
res, err := s.blobStor.GetBig(getBigPrm)
if err != nil {
if errors.Is(err, blobstor.ErrObjectNotFound) {
err = ErrObjectNotFound
}
return nil, err
}
return &GetRes{
obj: res.Object(),
}, nil
} else if prm.ln == 0 {
head, err := s.metaBase.Get(prm.addr)
if err != nil {
return nil, err
}
return &GetRes{
obj: head,
}, nil
}
// try to read from WriteCache
// TODO: implement
// form GetRangeBig parameters
getRngBigPrm := new(blobstor.GetRangeBigPrm)
getRngBigPrm.SetAddress(prm.addr)
rng := objectSDK.NewRange()
rng.SetOffset(prm.off)
rng.SetLength(uint64(prm.ln))
getRngBigPrm.SetRange(rng)
res, err := s.blobStor.GetRangeBig(getRngBigPrm)
if err != nil {
if errors.Is(err, blobstor.ErrObjectNotFound) {
err = ErrObjectNotFound
}
return nil, err
}
obj := object.NewRaw()
obj.SetPayload(res.RangeData())
return &GetRes{
obj: obj.Object(),
}, nil
}