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// Copyright 2012, 2013 Canonical Ltd.
// Licensed under the AGPLv3, see LICENCE file for details.
package filestorage
import (
"fmt"
"io"
"io/ioutil"
"os"
"path/filepath"
"sort"
"strings"
"launchpad.net/juju-core/environs/storage"
coreerrors "launchpad.net/juju-core/errors"
"launchpad.net/juju-core/utils"
)
// fileStorageReader implements StorageReader backed
// by the local filesystem.
type fileStorageReader struct {
path string
}
// NewFileStorageReader returns a new storage reader for
// a directory inside the local file system.
func NewFileStorageReader(path string) (reader storage.StorageReader, err error) {
var p string
if p, err = utils.NormalizePath(path); err != nil {
return nil, err
}
if p, err = filepath.Abs(p); err != nil {
return nil, err
}
fi, err := os.Stat(p)
if err != nil {
return nil, err
}
if !fi.Mode().IsDir() {
return nil, fmt.Errorf("specified source path is not a directory: %s", path)
}
return &fileStorageReader{p}, nil
}
func (f *fileStorageReader) fullPath(name string) string {
return filepath.Join(f.path, name)
}
// Get implements storage.StorageReader.Get.
func (f *fileStorageReader) Get(name string) (io.ReadCloser, error) {
filename := f.fullPath(name)
fi, err := os.Stat(filename)
if err != nil {
if os.IsNotExist(err) {
err = coreerrors.NewNotFoundError(err, "")
}
return nil, err
} else if fi.IsDir() {
return nil, coreerrors.NotFoundf("no such file with name %q", name)
}
file, err := os.Open(filename)
if err != nil {
return nil, err
}
return file, nil
}
// List implements storage.StorageReader.List.
func (f *fileStorageReader) List(prefix string) ([]string, error) {
prefix = filepath.Join(f.path, prefix)
dir := filepath.Dir(prefix)
var names []string
err := filepath.Walk(dir, func(path string, info os.FileInfo, err error) error {
if err != nil {
return err
}
if !info.IsDir() && strings.HasPrefix(path, prefix) {
names = append(names, path[len(f.path)+1:])
}
return nil
})
if err != nil && !os.IsNotExist(err) {
return nil, err
}
sort.Strings(names)
return names, nil
}
// URL implements storage.StorageReader.URL.
func (f *fileStorageReader) URL(name string) (string, error) {
return "file://" + filepath.Join(f.path, name), nil
}
// ConsistencyStrategy implements storage.StorageReader.ConsistencyStrategy.
func (f *fileStorageReader) DefaultConsistencyStrategy() utils.AttemptStrategy {
return utils.AttemptStrategy{}
}
// ShouldRetry is specified in the StorageReader interface.
func (f *fileStorageReader) ShouldRetry(err error) bool {
return false
}
type fileStorageWriter struct {
fileStorageReader
tmpdir string
}
// UseDefaultTmpDir may be passed into NewFileStorageWriter
// for the tmpdir argument, to signify that the default
// value should be used. See NewFileStorageWriter for more.
const UseDefaultTmpDir = ""
// NewFileStorageWriter returns a new read/write storag for
// a directory inside the local file system.
//
// A temporary directory may be specified, in which files will be written
// to before moving to the final destination. If specified, the temporary
// directory should be on the same filesystem as the storage directory
// to ensure atomicity. If tmpdir == UseDefaultTmpDir (""), then path+".tmp"
// will be used.
//
// If tmpdir == UseDefaultTmpDir, it will be created when Put is invoked,
// and will be removed afterwards. If tmpdir != UseDefaultTmpDir, it must
// already exist, and will never be removed.
func NewFileStorageWriter(path, tmpdir string) (storage.Storage, error) {
reader, err := NewFileStorageReader(path)
if err != nil {
return nil, err
}
return &fileStorageWriter{*reader.(*fileStorageReader), tmpdir}, nil
}
func (f *fileStorageWriter) Put(name string, r io.Reader, length int64) error {
fullpath := f.fullPath(name)
dir := filepath.Dir(fullpath)
tmpdir := f.tmpdir
if tmpdir == UseDefaultTmpDir {
tmpdir = f.path + ".tmp"
if err := os.MkdirAll(tmpdir, 0755); err != nil && !os.IsExist(err) {
return err
}
defer os.Remove(tmpdir)
}
if err := os.MkdirAll(dir, 0755); err != nil && !os.IsExist(err) {
return err
}
// Write to a temporary file first, and then move (atomically).
file, err := ioutil.TempFile(tmpdir, "juju-filestorage-")
if err != nil {
return err
}
_, err = io.CopyN(file, r, length)
file.Close()
if err != nil {
os.Remove(file.Name())
return err
}
return utils.ReplaceFile(file.Name(), fullpath)
}
func (f *fileStorageWriter) Remove(name string) error {
fullpath := f.fullPath(name)
err := os.Remove(fullpath)
if os.IsNotExist(err) {
err = nil
}
return err
}
func (f *fileStorageWriter) RemoveAll() error {
return storage.RemoveAll(f)
}
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