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5cdcc99eba
Since backend.ID is always a slice of constant length, use an array
instead of a slice. Mostly, arrays behave as slices, except that an
array cannot be nil, so use `*backend.ID` insteaf of `backend.ID` in
places where the absence of an ID is possible (e.g. for the Subtree of a
Node, which may not present when the node is a file node).
This change allows to directly use backend.ID as the the key for a map,
so that arbitrary data structures (e.g. a Set implemented as a
map[backend.ID]struct{}) can easily be formed.
87 lines
2 KiB
Go
87 lines
2 KiB
Go
package repository
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import (
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"crypto/rand"
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"crypto/sha256"
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"encoding/hex"
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"errors"
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"io"
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"github.com/restic/chunker"
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"github.com/restic/restic/backend"
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"github.com/restic/restic/debug"
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)
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// Config contains the configuration for a repository.
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type Config struct {
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Version uint `json:"version"`
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ID string `json:"id"`
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ChunkerPolynomial chunker.Pol `json:"chunker_polynomial"`
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}
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// repositoryIDSize is the length of the ID chosen at random for a new repository.
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const repositoryIDSize = sha256.Size
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// RepoVersion is the version that is written to the config when a repository
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// is newly created with Init().
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const RepoVersion = 1
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// JSONUnpackedSaver saves unpacked JSON.
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type JSONUnpackedSaver interface {
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SaveJSONUnpacked(backend.Type, interface{}) (backend.ID, error)
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}
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// JSONUnpackedLoader loads unpacked JSON.
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type JSONUnpackedLoader interface {
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LoadJSONUnpacked(backend.Type, backend.ID, interface{}) error
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}
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// CreateConfig creates a config file with a randomly selected polynomial and
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// ID and saves the config in the repository.
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func CreateConfig(r JSONUnpackedSaver) (Config, error) {
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var (
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err error
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cfg Config
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)
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cfg.ChunkerPolynomial, err = chunker.RandomPolynomial()
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if err != nil {
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return Config{}, err
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}
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newID := make([]byte, repositoryIDSize)
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_, err = io.ReadFull(rand.Reader, newID)
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if err != nil {
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return Config{}, err
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}
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cfg.ID = hex.EncodeToString(newID)
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cfg.Version = RepoVersion
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debug.Log("Repo.CreateConfig", "New config: %#v", cfg)
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_, err = r.SaveJSONUnpacked(backend.Config, cfg)
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return cfg, err
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}
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// LoadConfig returns loads, checks and returns the config for a repository.
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func LoadConfig(r JSONUnpackedLoader) (Config, error) {
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var (
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cfg Config
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)
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err := r.LoadJSONUnpacked(backend.Config, backend.ID{}, &cfg)
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if err != nil {
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return Config{}, err
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}
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if cfg.Version != RepoVersion {
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return Config{}, errors.New("unsupported repository version")
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}
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if !cfg.ChunkerPolynomial.Irreducible() {
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return Config{}, errors.New("invalid chunker polynomial")
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}
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return cfg, nil
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}
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