forked from TrueCloudLab/restic
dde8e9e296
This skips an allocation. internal/archiver benchmarks, Linux/amd64: name old time/op new time/op delta ArchiverSaveFileSmall-8 3.94ms ± 6% 3.91ms ± 6% ~ (p=0.947 n=20+20) ArchiverSaveFileLarge-8 304ms ± 3% 301ms ± 4% ~ (p=0.265 n=18+18) name old speed new speed delta ArchiverSaveFileSmall-8 1.04MB/s ± 6% 1.05MB/s ± 6% ~ (p=0.803 n=20+20) ArchiverSaveFileLarge-8 142MB/s ± 3% 143MB/s ± 4% ~ (p=0.421 n=18+19) name old alloc/op new alloc/op delta ArchiverSaveFileSmall-8 17.9MB ± 0% 17.9MB ± 0% -0.01% (p=0.000 n=19+19) ArchiverSaveFileLarge-8 382MB ± 2% 382MB ± 1% ~ (p=0.687 n=20+19) name old allocs/op new allocs/op delta ArchiverSaveFileSmall-8 540 ± 1% 528 ± 0% -2.19% (p=0.000 n=19+19) ArchiverSaveFileLarge-8 1.93k ± 3% 1.79k ± 4% -7.06% (p=0.000 n=20+20)
153 lines
2.9 KiB
Go
153 lines
2.9 KiB
Go
package restic
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import (
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"crypto/rand"
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"encoding/hex"
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"fmt"
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"io"
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"github.com/restic/restic/internal/errors"
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"github.com/minio/sha256-simd"
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)
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// Hash returns the ID for data.
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func Hash(data []byte) ID {
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return sha256.Sum256(data)
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}
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// idSize contains the size of an ID, in bytes.
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const idSize = sha256.Size
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// ID references content within a repository.
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type ID [idSize]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 ID{}, errors.Wrap(err, "hex.DecodeString")
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}
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if len(b) != idSize {
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return ID{}, errors.New("invalid length for hash")
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}
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id := ID{}
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copy(id[:], b)
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return id, 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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// NewRandomID returns a randomly generated ID. When reading from rand fails,
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// the function panics.
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func NewRandomID() ID {
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id := ID{}
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_, err := io.ReadFull(rand.Reader, id[:])
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if err != nil {
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panic(err)
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}
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return id
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}
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const shortStr = 4
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// Str returns the shortened string version of id.
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func (id *ID) Str() string {
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if id == nil {
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return "[nil]"
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}
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if id.IsNull() {
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return "[null]"
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}
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return hex.EncodeToString(id[:shortStr])
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}
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// IsNull returns true iff id only consists of null bytes.
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func (id ID) IsNull() bool {
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var nullID ID
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return id == nullID
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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 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, errors.Wrap(err, "hex.DecodeString")
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}
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id2 := ID{}
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copy(id2[:], s)
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return id == id2, nil
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}
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// MarshalJSON returns the JSON encoding of id.
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func (id ID) MarshalJSON() ([]byte, error) {
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buf := make([]byte, 2+hex.EncodedLen(len(id)))
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buf[0] = '"'
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hex.Encode(buf[1:], id[:])
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buf[len(buf)-1] = '"'
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return buf, nil
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}
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// UnmarshalJSON parses the JSON-encoded data and stores the result in id.
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func (id *ID) UnmarshalJSON(b []byte) error {
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// check string length
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if len(b) < 2 {
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return fmt.Errorf("invalid ID: %q", b)
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}
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if len(b)%2 != 0 {
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return fmt.Errorf("invalid ID length: %q", b)
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}
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// check string delimiters
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if b[0] != '"' && b[0] != '\'' {
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return fmt.Errorf("invalid start of string: %q", b[0])
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}
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last := len(b) - 1
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if b[0] != b[last] {
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return fmt.Errorf("starting string delimiter (%q) does not match end (%q)", b[0], b[last])
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}
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// strip JSON string delimiters
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b = b[1:last]
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if len(b) != 2*len(id) {
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return fmt.Errorf("invalid length for ID")
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}
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_, err := hex.Decode(id[:], b)
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if err != nil {
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return errors.Wrap(err, "hex.Decode")
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}
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return nil
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}
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// IDFromHash returns the ID for the hash.
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func IDFromHash(hash []byte) (id ID) {
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if len(hash) != idSize {
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panic("invalid hash type, not enough/too many bytes")
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}
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copy(id[:], hash)
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return id
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}
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