rclone/fs/fs.go

216 lines
5 KiB
Go

// File system interface
package fs
import (
"fmt"
"io"
"log"
"regexp"
"time"
)
// Globals
var (
// Filesystem registry
fsRegistry []*FsInfo
)
// Filesystem info
type FsInfo struct {
Name string // name of this fs
NewFs func(string, string) (Fs, error) // create a new file system
Config func(string) // function to call to help with config
Options []Option
}
// An options for a Fs
type Option struct {
Name string
Help string
Optional bool
Examples []OptionExample
}
// An example for an option
type OptionExample struct {
Value string
Help string
}
// Register a filesystem
//
// Fs modules should use this in an init() function
func Register(info *FsInfo) {
fsRegistry = append(fsRegistry, info)
}
// A Filesystem, describes the local filesystem and the remote object store
type Fs interface {
// String returns a description of the FS
String() string
// List the Fs into a channel
List() ObjectsChan
// List the Fs directories/buckets/containers into a channel
ListDir() DirChan
// Find the Object at remote. Returns nil if can't be found
NewFsObject(remote string) Object
// Put in to the remote path with the modTime given of the given size
//
// May create the object even if it returns an error - if so
// will return the object and the error, otherwise will return
// nil and the error
Put(in io.Reader, remote string, modTime time.Time, size int64) (Object, error)
// Make the directory (container, bucket)
Mkdir() error
// Remove the directory (container, bucket) if empty
Rmdir() error
// Precision of the ModTimes in this Fs
Precision() time.Duration
}
// A filesystem like object which can either be a remote object or a
// local file/directory
type Object interface {
// String returns a description of the Object
String() string
// Fs returns the Fs that this object is part of
Fs() Fs
// Remote returns the remote path
Remote() string
// Md5sum returns the md5 checksum of the file
Md5sum() (string, error)
// ModTime returns the modification date of the file
ModTime() time.Time
// SetModTime sets the metadata on the object to set the modification date
SetModTime(time.Time)
// Size returns the size of the file
Size() int64
// Open opens the file for read. Call Close() on the returned io.ReadCloser
Open() (io.ReadCloser, error)
// Storable says whether this object can be stored
Storable() bool
// Removes this object
Remove() error
}
// Optional interfaces
type Purger interface {
// Purge all files in the root and the root directory
//
// Implement this if you have a way of deleting all the files
// quicker than just running Remove() on the result of List()
Purge() error
}
// A channel of Objects
type ObjectsChan chan Object
// A slice of Objects
type Objects []Object
// A pair of Objects
type ObjectPair struct {
src, dst Object
}
// A channel of ObjectPair
type ObjectPairChan chan ObjectPair
// A structure of directory/container/bucket lists
type Dir struct {
Name string // name of the directory
When time.Time // modification or creation time - IsZero for unknown
Bytes int64 // size of directory and contents -1 for unknown
Count int64 // number of objects -1 for unknown
}
// A channel of Dir objects
type DirChan chan *Dir
// Pattern to match a url
var matcher = regexp.MustCompile(`^([\w_-]+):(.*)$`)
// Finds a FsInfo object for the name passed in
//
// Services are looked up in the config file
func Find(name string) (*FsInfo, error) {
for _, item := range fsRegistry {
if item.Name == name {
return item, nil
}
}
return nil, fmt.Errorf("Didn't find filing system for %q", name)
}
// NewFs makes a new Fs object from the path
//
// The path is of the form service://path
//
// Services are looked up in the config file
func NewFs(path string) (Fs, error) {
parts := matcher.FindStringSubmatch(path)
fsName, configName, fsPath := "local", "local", path
if parts != nil {
configName, fsPath = parts[1], parts[2]
var err error
fsName, err = ConfigFile.GetValue(configName, "type")
if err != nil {
return nil, fmt.Errorf("Didn't find section in config file for %q", configName)
}
}
fs, err := Find(fsName)
if err != nil {
return nil, err
}
return fs.NewFs(configName, fsPath)
}
// Outputs log for object
func OutputLog(o interface{}, text string, args ...interface{}) {
description := ""
if x, ok := o.(fmt.Stringer); ok {
description = x.String() + ": "
}
out := fmt.Sprintf(text, args...)
log.Print(description + out)
}
// Write debuging output for this Object or Fs
func Debug(o interface{}, text string, args ...interface{}) {
if Config.Verbose {
OutputLog(o, text, args...)
}
}
// Write log output for this Object or Fs
func Log(o interface{}, text string, args ...interface{}) {
if !Config.Quiet {
OutputLog(o, text, args...)
}
}
// checkClose is a utility function used to check the return from
// Close in a defer statement.
func checkClose(c io.Closer, err *error) {
cerr := c.Close()
if *err == nil {
*err = cerr
}
}