restic/map.go

237 lines
4.3 KiB
Go

package restic
import (
"bytes"
"encoding/json"
"errors"
"sort"
"sync"
"github.com/restic/restic/backend"
"github.com/restic/restic/debug"
)
type Map struct {
list []Blob
m sync.Mutex
}
var ErrBlobNotFound = errors.New("Blob not found")
func NewMap() *Map {
return &Map{
list: []Blob{},
}
}
func (bl *Map) find(blob Blob, checkSize bool) (int, Blob, error) {
pos := sort.Search(len(bl.list), func(i int) bool {
return blob.ID.Compare(bl.list[i].ID) >= 0
})
if pos < len(bl.list) {
b := bl.list[pos]
if blob.ID.Compare(b.ID) == 0 && (!checkSize || blob.Size == b.Size) {
return pos, b, nil
}
}
return pos, Blob{}, ErrBlobNotFound
}
func (bl *Map) Find(blob Blob) (Blob, error) {
bl.m.Lock()
defer bl.m.Unlock()
_, blob, err := bl.find(blob, true)
return blob, err
}
func (bl *Map) FindID(id backend.ID) (Blob, error) {
bl.m.Lock()
defer bl.m.Unlock()
_, blob, err := bl.find(Blob{ID: id}, false)
return blob, err
}
func (bl *Map) Merge(other *Map) {
bl.m.Lock()
defer bl.m.Unlock()
other.m.Lock()
defer other.m.Unlock()
for _, blob := range other.list {
bl.insert(blob)
}
}
func (bl *Map) insert(blob Blob) Blob {
pos, b, err := bl.find(blob, true)
if err == nil {
// already present
return b
}
// insert blob
// https://code.google.com/p/go-wiki/wiki/SliceTricks
bl.list = append(bl.list, Blob{})
copy(bl.list[pos+1:], bl.list[pos:])
bl.list[pos] = blob
return blob
}
func (bl *Map) Insert(blob Blob) Blob {
bl.m.Lock()
defer bl.m.Unlock()
debug.Log("Map.Insert", " Map<%p> insert %v", bl, blob)
return bl.insert(blob)
}
func (bl *Map) MarshalJSON() ([]byte, error) {
return json.Marshal(bl.list)
}
func (bl *Map) UnmarshalJSON(data []byte) error {
return json.Unmarshal(data, &bl.list)
}
func (bl *Map) IDs() []backend.ID {
bl.m.Lock()
defer bl.m.Unlock()
ids := make([]backend.ID, 0, len(bl.list))
for _, b := range bl.list {
ids = append(ids, b.ID)
}
return ids
}
func (bl *Map) StorageIDs() []backend.ID {
bl.m.Lock()
defer bl.m.Unlock()
ids := make([]backend.ID, 0, len(bl.list))
for _, b := range bl.list {
ids = append(ids, b.Storage)
}
return ids
}
func (bl *Map) Equals(other *Map) bool {
if bl == nil && other == nil {
return true
}
if bl == nil || other == nil {
return false
}
bl.m.Lock()
defer bl.m.Unlock()
if len(bl.list) != len(other.list) {
debug.Log("Map.Equals", "length does not match: %d != %d", len(bl.list), len(other.list))
return false
}
for i := 0; i < len(bl.list); i++ {
if bl.list[i].Compare(other.list[i]) != 0 {
debug.Log("Map.Equals", "entry %d does not match: %v != %v", i, bl.list[i], other.list[i])
return false
}
}
return true
}
// Each calls f for each blob in the Map. While Each is running, no other
// operation is possible, since a mutex is held for the whole time.
func (bl *Map) Each(f func(blob Blob)) {
bl.m.Lock()
defer bl.m.Unlock()
for _, blob := range bl.list {
f(blob)
}
}
// Select returns a list of of blobs from the plaintext IDs given in list.
func (bl *Map) Select(list backend.IDs) (Blobs, error) {
bl.m.Lock()
defer bl.m.Unlock()
blobs := make(Blobs, 0, len(list))
for _, id := range list {
_, blob, err := bl.find(Blob{ID: id}, false)
if err != nil {
return nil, err
}
blobs = append(blobs, blob)
}
return blobs, nil
}
// Len returns the number of blobs in the map.
func (bl *Map) Len() int {
bl.m.Lock()
defer bl.m.Unlock()
return len(bl.list)
}
// Prune deletes all IDs from the map except the ones listed in ids.
func (m *Map) Prune(ids *backend.IDSet) {
m.m.Lock()
defer m.m.Unlock()
pos := 0
for pos < len(m.list) {
blob := m.list[pos]
if ids.Find(blob.ID) != nil {
// remove element
m.list = append(m.list[:pos], m.list[pos+1:]...)
continue
}
pos++
}
}
// DeleteID removes the plaintext ID id from the map.
func (m *Map) DeleteID(id backend.ID) {
m.m.Lock()
defer m.m.Unlock()
pos, _, err := m.find(Blob{ID: id}, false)
if err != nil {
return
}
m.list = append(m.list[:pos], m.list[pos+1:]...)
}
// Compare compares two blobs by comparing the ID and the size. It returns -1,
// 0, or 1.
func (blob Blob) Compare(other Blob) int {
if res := bytes.Compare(other.ID, blob.ID); res != 0 {
return res
}
if blob.Size < other.Size {
return -1
}
if blob.Size > other.Size {
return 1
}
return 0
}