forgejo/modules/lfs/pointer.go
Gusted 0d8478cff8
[GITEA] Drop sha256-simd in favor of stdlib
- In Go 1.21 the crypto/sha256 [got a massive
improvement](https://go.dev/doc/go1.21#crypto/sha256) by utilizing the
SHA instructions for AMD64 CPUs, which sha256-simd already was doing.
The performance is now on par and I think it's preferable to use the
standard library rather than a package when possible.

```
cpu: AMD Ryzen 5 3600X 6-Core Processor
                │  simd.txt   │               go.txt                │
                │   sec/op    │    sec/op     vs base               │
Hash/8Bytes-12    63.25n ± 1%    73.38n ± 1%  +16.02% (p=0.002 n=6)
Hash/64Bytes-12   98.73n ± 1%   105.30n ± 1%   +6.65% (p=0.002 n=6)
Hash/1K-12        567.2n ± 1%    572.8n ± 1%   +0.99% (p=0.002 n=6)
Hash/8K-12        4.062µ ± 1%    4.062µ ± 1%        ~ (p=0.396 n=6)
Hash/1M-12        512.1µ ± 0%    510.6µ ± 1%        ~ (p=0.485 n=6)
Hash/5M-12        2.556m ± 1%    2.564m ± 0%        ~ (p=0.093 n=6)
Hash/10M-12       5.112m ± 0%    5.127m ± 0%        ~ (p=0.093 n=6)
geomean           13.82µ         14.27µ        +3.28%

                │   simd.txt   │               go.txt                │
                │     B/s      │     B/s       vs base               │
Hash/8Bytes-12    120.6Mi ± 1%   104.0Mi ± 1%  -13.81% (p=0.002 n=6)
Hash/64Bytes-12   618.2Mi ± 1%   579.8Mi ± 1%   -6.22% (p=0.002 n=6)
Hash/1K-12        1.682Gi ± 1%   1.665Gi ± 1%   -0.98% (p=0.002 n=6)
Hash/8K-12        1.878Gi ± 1%   1.878Gi ± 1%        ~ (p=0.310 n=6)
Hash/1M-12        1.907Gi ± 0%   1.913Gi ± 1%        ~ (p=0.485 n=6)
Hash/5M-12        1.911Gi ± 1%   1.904Gi ± 0%        ~ (p=0.093 n=6)
Hash/10M-12       1.910Gi ± 0%   1.905Gi ± 0%        ~ (p=0.093 n=6)
geomean           1.066Gi        1.032Gi        -3.18%
```

(cherry picked from commit abd94ff5b5)
(cherry picked from commit 15e81637ab)

Conflicts:
	go.mod
	https://codeberg.org/forgejo/forgejo/pulls/1581
(cherry picked from commit 5caea2d75aeac78fb306f58a3cf7809d5b70c7f2)
(cherry picked from commit 08da542cce)
(cherry picked from commit d71a8cc9fb)
(cherry picked from commit 63c9fc2bee)
(cherry picked from commit e1db85d48a)
(cherry picked from commit 5e86a5d2d1)
2023-11-13 14:06:31 +01:00

129 lines
3.2 KiB
Go

// Copyright 2021 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
package lfs
import (
"crypto/sha256"
"encoding/hex"
"errors"
"fmt"
"io"
"path"
"regexp"
"strconv"
"strings"
)
const (
blobSizeCutoff = 1024
// MetaFileIdentifier is the string appearing at the first line of LFS pointer files.
// https://github.com/git-lfs/git-lfs/blob/master/docs/spec.md
MetaFileIdentifier = "version https://git-lfs.github.com/spec/v1"
// MetaFileOidPrefix appears in LFS pointer files on a line before the sha256 hash.
MetaFileOidPrefix = "oid sha256:"
)
var (
// ErrMissingPrefix occurs if the content lacks the LFS prefix
ErrMissingPrefix = errors.New("content lacks the LFS prefix")
// ErrInvalidStructure occurs if the content has an invalid structure
ErrInvalidStructure = errors.New("content has an invalid structure")
// ErrInvalidOIDFormat occurs if the oid has an invalid format
ErrInvalidOIDFormat = errors.New("OID has an invalid format")
)
// ReadPointer tries to read LFS pointer data from the reader
func ReadPointer(reader io.Reader) (Pointer, error) {
buf := make([]byte, blobSizeCutoff)
n, err := io.ReadFull(reader, buf)
if err != nil && err != io.ErrUnexpectedEOF {
return Pointer{}, err
}
buf = buf[:n]
return ReadPointerFromBuffer(buf)
}
var oidPattern = regexp.MustCompile(`^[a-f\d]{64}$`)
// ReadPointerFromBuffer will return a pointer if the provided byte slice is a pointer file or an error otherwise.
func ReadPointerFromBuffer(buf []byte) (Pointer, error) {
var p Pointer
headString := string(buf)
if !strings.HasPrefix(headString, MetaFileIdentifier) {
return p, ErrMissingPrefix
}
splitLines := strings.Split(headString, "\n")
if len(splitLines) < 3 {
return p, ErrInvalidStructure
}
oid := strings.TrimPrefix(splitLines[1], MetaFileOidPrefix)
if len(oid) != 64 || !oidPattern.MatchString(oid) {
return p, ErrInvalidOIDFormat
}
size, err := strconv.ParseInt(strings.TrimPrefix(splitLines[2], "size "), 10, 64)
if err != nil {
return p, err
}
p.Oid = oid
p.Size = size
return p, nil
}
// IsValid checks if the pointer has a valid structure.
// It doesn't check if the pointed-to-content exists.
func (p Pointer) IsValid() bool {
if len(p.Oid) != 64 {
return false
}
if !oidPattern.MatchString(p.Oid) {
return false
}
if p.Size < 0 {
return false
}
return true
}
// StringContent returns the string representation of the pointer
// https://github.com/git-lfs/git-lfs/blob/main/docs/spec.md#the-pointer
func (p Pointer) StringContent() string {
return fmt.Sprintf("%s\n%s%s\nsize %d\n", MetaFileIdentifier, MetaFileOidPrefix, p.Oid, p.Size)
}
// RelativePath returns the relative storage path of the pointer
func (p Pointer) RelativePath() string {
if len(p.Oid) < 5 {
return p.Oid
}
return path.Join(p.Oid[0:2], p.Oid[2:4], p.Oid[4:])
}
func (p Pointer) LogString() string {
if p.Oid == "" && p.Size == 0 {
return "<LFSPointer empty>"
}
return fmt.Sprintf("<LFSPointer %s:%d>", p.Oid, p.Size)
}
// GeneratePointer generates a pointer for arbitrary content
func GeneratePointer(content io.Reader) (Pointer, error) {
h := sha256.New()
c, err := io.Copy(h, content)
if err != nil {
return Pointer{}, err
}
sum := h.Sum(nil)
return Pointer{Oid: hex.EncodeToString(sum), Size: c}, nil
}