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minio/cmd/storage-interface.go

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2.8 KiB

/*
* Minio Cloud Storage, (C) 2016 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 cmd
import (
"io"
"github.com/minio/minio/pkg/disk"
)
// StorageAPI interface.
type StorageAPI interface {
// Stringified version of disk.
String() string
// Storage operations.
Init() (err error)
Close() (err error)
DiskInfo() (info disk.Info, err error)
// Volume operations.
MakeVol(volume string) (err error)
ListVols() (vols []VolInfo, err error)
StatVol(volume string) (vol VolInfo, err error)
DeleteVol(volume string) (err error)
// File operations.
ListDir(volume, dirPath string) ([]string, error)
ReadFile(volume string, path string, offset int64, buf []byte) (n int64, err error)
ReadFileWithVerify(volume string, path string, offset int64, buf []byte, verifier *BitrotVerifier) (n int64, err error)
PrepareFile(volume string, path string, len int64) (err error)
AppendFile(volume string, path string, buf []byte) (err error)
RenameFile(srcVolume, srcPath, dstVolume, dstPath string) error
StatFile(volume string, path string) (file FileInfo, err error)
DeleteFile(volume string, path string) (err error)
// Read all.
ReadAll(volume string, path string) (buf []byte, err error)
}
// storageReader is an io.Reader view of a disk
type storageReader struct {
storage StorageAPI
volume, path string
offset int64
}
func (r *storageReader) Read(p []byte) (n int, err error) {
nn, err := r.storage.ReadFile(r.volume, r.path, r.offset, p)
r.offset += nn
n = int(nn)
if err == io.ErrUnexpectedEOF && nn > 0 {
err = io.EOF
}
return
}
// storageWriter is a io.Writer view of a disk.
type storageWriter struct {
storage StorageAPI
volume, path string
}
func (w *storageWriter) Write(p []byte) (n int, err error) {
err = w.storage.AppendFile(w.volume, w.path, p)
if err == nil {
n = len(p)
}
return
}
// StorageWriter returns a new io.Writer which appends data to the file
// at the given disk, volume and path.
func StorageWriter(storage StorageAPI, volume, path string) io.Writer {
return &storageWriter{storage, volume, path}
}
// StorageReader returns a new io.Reader which reads data to the file
// at the given disk, volume, path and offset.
func StorageReader(storage StorageAPI, volume, path string, offset int64) io.Reader {
return &storageReader{storage, volume, path, offset}
}