restic/cache.go

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2015-02-21 23:09:57 +00:00
package restic
import (
"fmt"
"io"
"os"
"path/filepath"
"github.com/restic/restic/backend"
)
type Cache struct {
base string
}
func NewCache() (*Cache, error) {
dir, err := GetCacheDir()
if err != nil {
return nil, err
}
return &Cache{base: dir}, nil
}
func (c *Cache) Has(t backend.Type, id backend.ID) (bool, error) {
// try to open file
filename, err := c.filename(t, id)
if err != nil {
return false, err
}
fd, err := os.Open(filename)
defer fd.Close()
if err != nil {
if os.IsNotExist(err) {
return false, nil
}
return false, err
}
return true, nil
}
func (c *Cache) Store(t backend.Type, id backend.ID, rd io.Reader) error {
filename, err := c.filename(t, id)
if err != nil {
return err
}
dirname := filepath.Dir(filename)
err = os.MkdirAll(dirname, 0700)
if err != nil {
return err
}
file, err := os.Create(filename)
defer file.Close()
if err != nil {
return err
}
_, err = io.Copy(file, rd)
return err
}
func (c *Cache) Load(t backend.Type, id backend.ID) (io.ReadCloser, error) {
// try to open file
filename, err := c.filename(t, id)
if err != nil {
return nil, err
}
return os.Open(filename)
}
// Construct file name for given Type.
func (c *Cache) filename(t backend.Type, id backend.ID) (string, error) {
cachedir, err := GetCacheDir()
if err != nil {
return "", err
}
switch t {
case backend.Snapshot:
return filepath.Join(cachedir, "snapshots", id.String()), nil
case backend.Tree:
return filepath.Join(cachedir, "trees", id.String()), nil
}
return "", fmt.Errorf("cache not supported for type %v", t)
}