minio/pkg/donut/encoder.go
Harshavardhana 45b59b8456 Probe revamped to provide for a new WrappedError struct to wrap probes as error interface
This convenience was necessary to be used for golang library functions like io.Copy and io.Pipe
where we shouldn't be writing proxies and alternatives returning *probe.Error

This change also brings more changes across code base for clear separation regarding where an error
interface should be passed encapsulating *probe.Error and where it should be used as is.
2015-08-08 00:16:38 -07:00

102 lines
2.8 KiB
Go

/*
* Minio Cloud Storage, (C) 2015 Minio, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package donut
import (
"io"
encoding "github.com/minio/minio/pkg/erasure"
"github.com/minio/minio/pkg/probe"
)
// encoder internal struct
type encoder struct {
encoder *encoding.Erasure
k, m uint8
technique encoding.Technique
}
// getErasureTechnique - convert technique string into Technique type
func getErasureTechnique(technique string) (encoding.Technique, *probe.Error) {
switch true {
case technique == "Cauchy":
return encoding.Cauchy, nil
case technique == "Vandermonde":
return encoding.Cauchy, nil
default:
return encoding.None, probe.NewError(InvalidErasureTechnique{Technique: technique})
}
}
// newEncoder - instantiate a new encoder
func newEncoder(k, m uint8, technique string) (encoder, *probe.Error) {
e := encoder{}
t, err := getErasureTechnique(technique)
if err != nil {
return encoder{}, err.Trace()
}
{
params, err := encoding.ValidateParams(k, m, t)
if err != nil {
return encoder{}, probe.NewError(err)
}
e.encoder = encoding.NewErasure(params)
e.k = k
e.m = m
e.technique = t
return e, nil
}
}
// TODO - think again if this is needed
// GetEncodedBlockLen - wrapper around erasure function with the same name
func (e encoder) GetEncodedBlockLen(dataLength int) (int, *probe.Error) {
if dataLength <= 0 {
return 0, probe.NewError(InvalidArgument{})
}
return encoding.GetEncodedBlockLen(dataLength, e.k), nil
}
// Encode - erasure code input bytes
func (e encoder) Encode(data []byte) ([][]byte, *probe.Error) {
if data == nil {
return nil, probe.NewError(InvalidArgument{})
}
encodedData, err := e.encoder.Encode(data)
if err != nil {
return nil, probe.NewError(err)
}
return encodedData, nil
}
func (e encoder) EncodeStream(data io.Reader, size int64) ([][]byte, []byte, *probe.Error) {
encodedData, inputData, err := e.encoder.EncodeStream(data, size)
if err != nil {
return nil, nil, probe.NewError(err)
}
return encodedData, inputData, nil
}
// Decode - erasure decode input encoded bytes
func (e encoder) Decode(encodedData [][]byte, dataLength int) ([]byte, *probe.Error) {
decodedData, err := e.encoder.Decode(encodedData, dataLength)
if err != nil {
return nil, probe.NewError(err)
}
return decodedData, nil
}