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package seekable
import (
"fmt"
"os"
"strings"
"gopkg.in/src-d/go-git.v4/core"
"gopkg.in/src-d/go-git.v4/formats/packfile"
"gopkg.in/src-d/go-git.v4/storage/seekable/internal/gitdir"
"gopkg.in/src-d/go-git.v4/storage/seekable/internal/index"
"gopkg.in/src-d/go-git.v4/utils/fs"
)
// ObjectStorage is an implementation of core.ObjectStorage that stores
// data on disk in the standard git format (this is, the .git directory).
//
// Zero values of this type are not safe to use, see the New function below.
//
// Currently only reads are supported, no writting.
//
// Also values from this type are not yet able to track changes on disk, this is,
// Gitdir values will get outdated as soon as repositories change on disk.
type ObjectStorage struct {
dir *gitdir.GitDir
index index.Index
}
// New returns a new ObjectStorage for the git directory at the specified path.
func New(fs fs.FS, path string) (*ObjectStorage, error) {
s := &ObjectStorage{}
var err error
s.dir, err = gitdir.New(fs, path)
if err != nil {
return nil, err
}
s.index, err = buildIndex(s.dir)
return s, err
}
func buildIndex(dir *gitdir.GitDir) (index.Index, error) {
fs, idxfile, err := dir.Idxfile()
if err != nil {
if err == gitdir.ErrIdxNotFound {
return buildIndexFromPackfile(dir)
}
return nil, err
}
return buildIndexFromIdxfile(fs, idxfile)
}
func buildIndexFromPackfile(dir *gitdir.GitDir) (index.Index, error) {
fs, packfile, err := dir.Packfile()
if err != nil {
return nil, err
}
f, err := fs.Open(packfile)
if err != nil {
return nil, err
}
defer func() {
errClose := f.Close()
if err == nil {
err = errClose
}
}()
return index.NewFromPackfile(f)
}
func buildIndexFromIdxfile(fs fs.FS, path string) (index.Index, error) {
f, err := fs.Open(path)
if err != nil {
return nil, err
}
defer func() {
errClose := f.Close()
if err == nil {
err = errClose
}
}()
return index.NewFromIdx(f)
}
// Set adds a new object to the storage. As this functionality is not
// yet supported, this method always returns a "not implemented yet"
// error an zero hash.
func (s *ObjectStorage) Set(core.Object) (core.Hash, error) {
return core.ZeroHash, fmt.Errorf("not implemented yet")
}
// Get returns the object with the given hash, by searching for it in
// the packfile.
func (s *ObjectStorage) Get(h core.Hash) (core.Object, error) {
offset, err := s.index.Get(h)
if err != nil {
return nil, err
}
fs, path, err := s.dir.Packfile()
if err != nil {
return nil, err
}
f, err := fs.Open(path)
if err != nil {
return nil, err
}
defer func() {
errClose := f.Close()
if err == nil {
err = errClose
}
}()
_, err = f.Seek(offset, os.SEEK_SET)
if err != nil {
return nil, err
}
r := packfile.NewSeekable(f)
r.HashToOffset = map[core.Hash]int64(s.index)
p := packfile.NewParser(r)
return p.ReadObject()
}
// Iter returns an iterator for all the objects in the packfile with the
// given type.
func (s *ObjectStorage) Iter(t core.ObjectType) (core.ObjectIter, error) {
var objects []core.Object
for hash := range s.index {
object, err := s.Get(hash)
if err != nil {
return nil, err
}
if object.Type() == t {
objects = append(objects, object)
}
}
return core.NewObjectSliceIter(objects), nil
}
const (
headErrPrefix = "cannot get HEAD reference:"
symrefCapability = "symref"
headRefPrefix = "HEAD:"
)
// Head returns the hash of the HEAD reference
func (s *ObjectStorage) Head() (core.Hash, error) {
cap, err := s.dir.Capabilities()
if err != nil {
return core.ZeroHash, fmt.Errorf("%s %s", headErrPrefix, err)
}
ok := cap.Supports(symrefCapability)
if !ok {
return core.ZeroHash,
fmt.Errorf("%s symref capability not supported", headErrPrefix)
}
symrefs := cap.Get(symrefCapability)
var headRef string
for _, ref := range symrefs.Values {
if strings.HasPrefix(ref, headRefPrefix) {
headRef = strings.TrimPrefix(ref, headRefPrefix)
}
}
if headRef == "" {
return core.ZeroHash, fmt.Errorf("%s HEAD reference not found",
headErrPrefix)
}
refs, err := s.dir.Refs()
if err != nil {
return core.ZeroHash, fmt.Errorf("%s %s", headErrPrefix, err)
}
head, ok := refs[headRef]
if !ok {
return core.ZeroHash, fmt.Errorf("%s reference %q not found",
headErrPrefix, headRef)
}
return head, nil
}
|
