frostfs-node/pkg/local_object_storage/shard/get.go
Leonard Lyubich 383c483be7 [#176] localstore: Draft storage engine shard structure and ops
Implement the primary structure and operation of the local object
storage shard.

Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
2020-12-11 17:19:37 +03:00

79 lines
1.7 KiB
Go

package shard
import (
"errors"
objectSDK "github.com/nspcc-dev/neofs-api-go/pkg/object"
"github.com/nspcc-dev/neofs-node/pkg/core/object"
)
// 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.
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) {
s.mtx.RLock()
defer s.mtx.RUnlock()
// FIXME: implement me
return nil, nil
}