mirror of https://github.com/octoleo/restic.git
111 lines
1.8 KiB
Go
111 lines
1.8 KiB
Go
package backend
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import (
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"bytes"
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"crypto/sha256"
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"encoding/hex"
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"encoding/json"
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"errors"
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)
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const sha256_length = 32 // in bytes
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// References content within a repository.
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type ID []byte
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// ParseID converts the given string to an ID.
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func ParseID(s string) (ID, error) {
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b, err := hex.DecodeString(s)
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if err != nil {
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return nil, err
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}
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if len(b) != sha256_length {
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return nil, errors.New("invalid length for sha256 hash")
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}
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return ID(b), nil
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}
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func (id ID) String() string {
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return hex.EncodeToString(id)
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}
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// Equal compares an ID to another other.
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func (id ID) Equal(other ID) bool {
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return bytes.Equal(id, other)
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}
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// EqualString compares this ID to another one, given as a string.
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func (id ID) EqualString(other string) (bool, error) {
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s, err := hex.DecodeString(other)
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if err != nil {
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return false, err
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}
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return id.Equal(ID(s)), nil
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}
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// Compare compares this ID to another one, returning -1, 0, or 1.
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func (id ID) Compare(other ID) int {
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return bytes.Compare(other, id)
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}
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func (id ID) MarshalJSON() ([]byte, error) {
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return json.Marshal(id.String())
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}
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func (id *ID) UnmarshalJSON(b []byte) error {
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var s string
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err := json.Unmarshal(b, &s)
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if err != nil {
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return err
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}
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*id = make([]byte, len(s)/2)
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_, err = hex.Decode(*id, []byte(s))
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if err != nil {
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return err
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}
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return nil
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}
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func IDFromData(d []byte) ID {
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hash := sha256.Sum256(d)
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id := make([]byte, sha256_length)
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copy(id, hash[:])
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return id
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}
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type IDs []ID
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func (ids IDs) Len() int {
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return len(ids)
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}
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func (ids IDs) Less(i, j int) bool {
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if len(ids[i]) < len(ids[j]) {
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return true
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}
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for k, b := range ids[i] {
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if b == ids[j][k] {
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continue
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}
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if b < ids[j][k] {
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return true
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} else {
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return false
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}
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}
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return false
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}
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func (ids IDs) Swap(i, j int) {
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ids[i], ids[j] = ids[j], ids[i]
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}
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