restic/backend/interface.go
2016-01-23 12:46:20 +01:00

87 lines
2.1 KiB
Go

package backend
import (
"fmt"
"io"
)
// Type is the type of a Blob.
type Type string
// These are the different data types a backend can store.
const (
Data Type = "data"
Key = "key"
Lock = "lock"
Snapshot = "snapshot"
Index = "index"
Config = "config"
)
// Handle is used to store and access data in a backend.
type Handle struct {
Type Type
Name string
}
func (h Handle) String() string {
name := h.Name
if len(name) > 10 {
name = name[:10]
}
return fmt.Sprintf("<%s/%s>", h.Type, name)
}
// Backend is used to store and access data.
type Backend interface {
// Location returns a string that describes the type and location of the
// repository.
Location() string
// Create creates a new Blob. The data is available only after Finalize()
// has been called on the returned Blob.
Create() (Blob, error)
// Get returns an io.ReadCloser for the Blob with the given name of type t.
Get(t Type, name string) (io.ReadCloser, error)
// GetReader returns an io.ReadCloser for the Blob with the given name of
// type t at offset and length.
GetReader(t Type, name string, offset, length uint) (io.ReadCloser, error)
// Test a boolean value whether a Blob with the name and type exists.
Test(t Type, name string) (bool, error)
// Remove removes a Blob with type t and name.
Remove(t Type, name string) error
// Close the backend
Close() error
Lister
}
// Lister implements listing data items stored in a backend.
type Lister interface {
// List returns a channel that yields all names of blobs of type t in
// lexicographic order. A goroutine is started for this. If the channel
// done is closed, sending stops.
List(t Type, done <-chan struct{}) <-chan string
}
// Deleter are backends that allow to self-delete all content stored in them.
type Deleter interface {
// Delete the complete repository.
Delete() error
}
// Blob is old.
type Blob interface {
io.Writer
// Finalize moves the data blob to the final location for type and name.
Finalize(t Type, name string) error
// Size returns the number of bytes written to the backend so far.
Size() uint
}