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forgejo/modules/lfs/pointer.go
zeripath 75eb6cc9c1
Improve SyncMirrors logging ()
Yet another issue has come up where the logging from SyncMirrors does not provide
enough context. This PR adds more context to these logging events.

Related 

Signed-off-by: Andrew Thornton <art27@cantab.net>
2022-03-10 10:09:48 +00:00

137 lines
3.4 KiB
Go

// Copyright 2021 The Gitea Authors. All rights reserved.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file.
package lfs
import (
"crypto/sha256"
"encoding/hex"
"errors"
"fmt"
"io"
"path"
"regexp"
"strconv"
"strings"
"code.gitea.io/gitea/modules/log"
)
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:])
}
// ColorFormat provides a basic color format for a Team
func (p Pointer) ColorFormat(s fmt.State) {
if p.Oid == "" && p.Size == 0 {
log.ColorFprintf(s, "<empty>")
return
}
log.ColorFprintf(s, "%s:%d",
log.NewColoredIDValue(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
}