restic/vendor/github.com/pkg/sftp/request-example.go

263 lines
5.7 KiB
Go

package sftp
// This serves as an example of how to implement the request server handler as
// well as a dummy backend for testing. It implements an in-memory backend that
// works as a very simple filesystem with simple flat key-value lookup system.
import (
"bytes"
"fmt"
"io"
"os"
"path/filepath"
"sort"
"sync"
"time"
)
// InMemHandler returns a Hanlders object with the test handlers.
func InMemHandler() Handlers {
root := &root{
files: make(map[string]*memFile),
}
root.memFile = newMemFile("/", true)
return Handlers{root, root, root, root}
}
// Example Handlers
func (fs *root) Fileread(r *Request) (io.ReaderAt, error) {
if fs.mockErr != nil {
return nil, fs.mockErr
}
fs.filesLock.Lock()
defer fs.filesLock.Unlock()
file, err := fs.fetch(r.Filepath)
if err != nil {
return nil, err
}
if file.symlink != "" {
file, err = fs.fetch(file.symlink)
if err != nil {
return nil, err
}
}
return file.ReaderAt()
}
func (fs *root) Filewrite(r *Request) (io.WriterAt, error) {
if fs.mockErr != nil {
return nil, fs.mockErr
}
fs.filesLock.Lock()
defer fs.filesLock.Unlock()
file, err := fs.fetch(r.Filepath)
if err == os.ErrNotExist {
dir, err := fs.fetch(filepath.Dir(r.Filepath))
if err != nil {
return nil, err
}
if !dir.isdir {
return nil, os.ErrInvalid
}
file = newMemFile(r.Filepath, false)
fs.files[r.Filepath] = file
}
return file.WriterAt()
}
func (fs *root) Filecmd(r *Request) error {
if fs.mockErr != nil {
return fs.mockErr
}
fs.filesLock.Lock()
defer fs.filesLock.Unlock()
switch r.Method {
case "Setstat":
return nil
case "Rename":
file, err := fs.fetch(r.Filepath)
if err != nil {
return err
}
if _, ok := fs.files[r.Target]; ok {
return &os.LinkError{Op: "rename", Old: r.Filepath, New: r.Target,
Err: fmt.Errorf("dest file exists")}
}
file.name = r.Target
fs.files[r.Target] = file
delete(fs.files, r.Filepath)
case "Rmdir", "Remove":
_, err := fs.fetch(filepath.Dir(r.Filepath))
if err != nil {
return err
}
delete(fs.files, r.Filepath)
case "Mkdir":
_, err := fs.fetch(filepath.Dir(r.Filepath))
if err != nil {
return err
}
fs.files[r.Filepath] = newMemFile(r.Filepath, true)
case "Symlink":
_, err := fs.fetch(r.Filepath)
if err != nil {
return err
}
link := newMemFile(r.Target, false)
link.symlink = r.Filepath
fs.files[r.Target] = link
}
return nil
}
type listerat []os.FileInfo
// Modeled after strings.Reader's ReadAt() implementation
func (f listerat) ListAt(ls []os.FileInfo, offset int64) (int, error) {
var n int
if offset >= int64(len(f)) {
return 0, io.EOF
}
n = copy(ls, f[offset:])
if n < len(ls) {
return n, io.EOF
}
return n, nil
}
func (fs *root) Filelist(r *Request) (ListerAt, error) {
if fs.mockErr != nil {
return nil, fs.mockErr
}
fs.filesLock.Lock()
defer fs.filesLock.Unlock()
switch r.Method {
case "List":
ordered_names := []string{}
for fn, _ := range fs.files {
if filepath.Dir(fn) == r.Filepath {
ordered_names = append(ordered_names, fn)
}
}
sort.Strings(ordered_names)
list := make([]os.FileInfo, len(ordered_names))
for i, fn := range ordered_names {
list[i] = fs.files[fn]
}
return listerat(list), nil
case "Stat":
file, err := fs.fetch(r.Filepath)
if err != nil {
return nil, err
}
return listerat([]os.FileInfo{file}), nil
case "Readlink":
file, err := fs.fetch(r.Filepath)
if err != nil {
return nil, err
}
if file.symlink != "" {
file, err = fs.fetch(file.symlink)
if err != nil {
return nil, err
}
}
return listerat([]os.FileInfo{file}), nil
}
return nil, nil
}
// In memory file-system-y thing that the Hanlders live on
type root struct {
*memFile
files map[string]*memFile
filesLock sync.Mutex
mockErr error
}
// Set a mocked error that the next handler call will return.
// Set to nil to reset for no error.
func (fs *root) returnErr(err error) {
fs.mockErr = err
}
func (fs *root) fetch(path string) (*memFile, error) {
if path == "/" {
return fs.memFile, nil
}
if file, ok := fs.files[path]; ok {
return file, nil
}
return nil, os.ErrNotExist
}
// Implements os.FileInfo, Reader and Writer interfaces.
// These are the 3 interfaces necessary for the Handlers.
type memFile struct {
name string
modtime time.Time
symlink string
isdir bool
content []byte
contentLock sync.RWMutex
}
// factory to make sure modtime is set
func newMemFile(name string, isdir bool) *memFile {
return &memFile{
name: name,
modtime: time.Now(),
isdir: isdir,
}
}
// Have memFile fulfill os.FileInfo interface
func (f *memFile) Name() string { return filepath.Base(f.name) }
func (f *memFile) Size() int64 { return int64(len(f.content)) }
func (f *memFile) Mode() os.FileMode {
ret := os.FileMode(0644)
if f.isdir {
ret = os.FileMode(0755) | os.ModeDir
}
if f.symlink != "" {
ret = os.FileMode(0777) | os.ModeSymlink
}
return ret
}
func (f *memFile) ModTime() time.Time { return f.modtime }
func (f *memFile) IsDir() bool { return f.isdir }
func (f *memFile) Sys() interface{} {
return fakeFileInfoSys()
}
// Read/Write
func (f *memFile) ReaderAt() (io.ReaderAt, error) {
if f.isdir {
return nil, os.ErrInvalid
}
return bytes.NewReader(f.content), nil
}
func (f *memFile) WriterAt() (io.WriterAt, error) {
if f.isdir {
return nil, os.ErrInvalid
}
return f, nil
}
func (f *memFile) WriteAt(p []byte, off int64) (int, error) {
// fmt.Println(string(p), off)
// mimic write delays, should be optional
time.Sleep(time.Microsecond * time.Duration(len(p)))
f.contentLock.Lock()
defer f.contentLock.Unlock()
plen := len(p) + int(off)
if plen >= len(f.content) {
nc := make([]byte, plen)
copy(nc, f.content)
f.content = nc
}
copy(f.content[off:], p)
return len(p), nil
}