// https://github.com/git/git/blob/master/Documentation/gitrepository-layout.txt
package dotgit
import (
"bufio"
"errors"
"fmt"
"io/ioutil"
"os"
"strings"
"gopkg.in/src-d/go-git.v4/core"
"gopkg.in/src-d/go-git.v4/utils/fs"
)
const (
suffix = ".git"
packedRefsPath = "packed-refs"
configPath = "config"
objectsPath = "objects"
packPath = "pack"
refsPath = "refs"
packExt = ".pack"
idxExt = ".idx"
)
var (
// ErrNotFound is returned by New when the path is not found.
ErrNotFound = errors.New("path not found")
// ErrIdxNotFound is returned by Idxfile when the idx file is not found
ErrIdxNotFound = errors.New("idx file not found")
// ErrPackfileNotFound is returned by Packfile when the packfile is not found
ErrPackfileNotFound = errors.New("packfile not found")
// ErrConfigNotFound is returned by Config when the config is not found
ErrConfigNotFound = errors.New("config file not found")
// ErrPackedRefsDuplicatedRef is returned when a duplicated reference is
// found in the packed-ref file. This is usually the case for corrupted git
// repositories.
ErrPackedRefsDuplicatedRef = errors.New("duplicated ref found in packed-ref file")
// ErrPackedRefsBadFormat is returned when the packed-ref file corrupt.
ErrPackedRefsBadFormat = errors.New("malformed packed-ref")
// ErrSymRefTargetNotFound is returned when a symbolic reference is
// targeting a non-existing object. This usually means the repository
// is corrupt.
ErrSymRefTargetNotFound = errors.New("symbolic reference target not found")
)
// The DotGit type represents a local git repository on disk. This
// type is not zero-value-safe, use the New function to initialize it.
type DotGit struct {
fs fs.Filesystem
}
// New returns a DotGit value ready to be used. The path argument must
// be the absolute path of a git repository directory (e.g.
// "/foo/bar/.git").
func New(fs fs.Filesystem) *DotGit {
return &DotGit{fs: fs}
}
func (d *DotGit) ConfigWriter() (fs.File, error) {
return d.fs.Create(configPath)
}
// Config returns the path of the config file
func (d *DotGit) Config() (fs.File, error) {
return d.fs.Open(configPath)
}
// NewObjectPack return a writer for a new packfile, it saves the packfile to
// disk and also generates and save the index for the given packfile.
func (d *DotGit) NewObjectPack() (*PackWriter, error) {
return newPackWrite(d.fs)
}
// ObjectPacks returns the list of availables packfiles
func (d *DotGit) ObjectPacks() ([]core.Hash, error) {
packDir := d.fs.Join(objectsPath, packPath)
files, err := d.fs.ReadDir(packDir)
if err != nil {
if os.IsNotExist(err) {
return nil, nil
}
return nil, err
}
var packs []core.Hash
for _, f := range files {
if !strings.HasSuffix(f.Name(), packExt) {
continue
}
n := f.Name()
h := core.NewHash(n[5 : len(n)-5]) //pack-(hash).pack
packs = append(packs, h)
}
return packs, nil
}
// ObjectPack returns a fs.File of the given packfile
func (d *DotGit) ObjectPack(hash core.Hash) (fs.File, error) {
file := d.fs.Join(objectsPath, packPath, fmt.Sprintf("pack-%s.pack", hash.String()))
pack, err := d.fs.Open(file)
if err != nil {
if os.IsNotExist(err) {
return nil, ErrPackfileNotFound
}
return nil, err
}
return pack, nil
}
// ObjectPackIdx returns a fs.File of the index file for a given packfile
func (d *DotGit) ObjectPackIdx(hash core.Hash) (fs.File, error) {
file := d.fs.Join(objectsPath, packPath, fmt.Sprintf("pack-%s.idx", hash.String()))
idx, err := d.fs.Open(file)
if err != nil {
if os.IsNotExist(err) {
return nil, ErrPackfileNotFound
}
return nil, err
}
return idx, nil
}
// NewObject return a writer for a new object file.
func (d *DotGit) NewObject() (*ObjectWriter, error) {
return newObjectWriter(d.fs)
}
// Objects returns a slice with the hashes of objects found under the
// .git/objects/ directory.
func (d *DotGit) Objects() ([]core.Hash, error) {
files, err := d.fs.ReadDir(objectsPath)
if err != nil {
if os.IsNotExist(err) {
return nil, nil
}
return nil, err
}
var objects []core.Hash
for _, f := range files {
if f.IsDir() && len(f.Name()) == 2 && isHex(f.Name()) {
base := f.Name()
d, err := d.fs.ReadDir(d.fs.Join(objectsPath, base))
if err != nil {
return nil, err
}
for _, o := range d {
objects = append(objects, core.NewHash(base+o.Name()))
}
}
}
return objects, nil
}
// Object return a fs.File poiting the object file, if exists
func (d *DotGit) Object(h core.Hash) (fs.File, error) {
hash := h.String()
file := d.fs.Join(objectsPath, hash[0:2], hash[2:40])
return d.fs.Open(file)
}
func (d *DotGit) SetRef(r *core.Reference) error {
var content string
switch r.Type() {
case core.SymbolicReference:
content = fmt.Sprintf("ref: %s\n", r.Target())
case core.HashReference:
content = fmt.Sprintln(r.Hash().String())
}
f, err := d.fs.Create(r.Name().String())
if err != nil {
return err
}
if _, err := f.Write([]byte(content)); err != nil {
return err
}
return f.Close()
}
// Refs scans the git directory collecting references, which it returns.
// Symbolic references are resolved and included in the output.
func (d *DotGit) Refs() ([]*core.Reference, error) {
var refs []*core.Reference
if err := d.addRefsFromPackedRefs(&refs); err != nil {
return nil, err
}
if err := d.addRefsFromRefDir(&refs); err != nil {
return nil, err
}
if err := d.addRefFromHEAD(&refs); err != nil {
return nil, err
}
return refs, nil
}
func (d *DotGit) addRefsFromPackedRefs(refs *[]*core.Reference) (err error) {
f, err := d.fs.Open(packedRefsPath)
if err != nil {
if os.IsNotExist(err) {
return nil
}
return err
}
defer func() {
if errClose := f.Close(); err == nil {
err = errClose
}
}()
s := bufio.NewScanner(f)
for s.Scan() {
ref, err := d.processLine(s.Text())
if err != nil {
return err
}
if ref != nil {
*refs = append(*refs, ref)
}
}
return s.Err()
}
// process lines from a packed-refs file
func (d *DotGit) processLine(line string) (*core.Reference, error) {
switch line[0] {
case '#': // comment - ignore
return nil, nil
case '^': // annotated tag commit of the previous line - ignore
return nil, nil
default:
ws := strings.Split(line, " ") // hash then ref
if len(ws) != 2 {
return nil, ErrPackedRefsBadFormat
}
return core.NewReferenceFromStrings(ws[1], ws[0]), nil
}
}
func (d *DotGit) addRefsFromRefDir(refs *[]*core.Reference) error {
return d.walkReferencesTree(refs, refsPath)
}
func (d *DotGit) walkReferencesTree(refs *[]*core.Reference, relPath string) error {
files, err := d.fs.ReadDir(relPath)
if err != nil {
if os.IsNotExist(err) {
return nil
}
return err
}
for _, f := range files {
newRelPath := d.fs.Join(relPath, f.Name())
if f.IsDir() {
if err = d.walkReferencesTree(refs, newRelPath); err != nil {
return err
}
continue
}
ref, err := d.readReferenceFile(".", newRelPath)
if err != nil {
return err
}
if ref != nil {
*refs = append(*refs, ref)
}
}
return nil
}
func (d *DotGit) addRefFromHEAD(refs *[]*core.Reference) error {
ref, err := d.readReferenceFile(".", "HEAD")
if err != nil {
if os.IsNotExist(err) {
return nil
}
return err
}
*refs = append(*refs, ref)
return nil
}
func (d *DotGit) readReferenceFile(refsPath, refFile string) (ref *core.Reference, err error) {
path := d.fs.Join(refsPath, refFile)
f, err := d.fs.Open(path)
if err != nil {
return nil, err
}
defer func() {
if errClose := f.Close(); err == nil {
err = errClose
}
}()
b, err := ioutil.ReadAll(f)
if err != nil {
return nil, err
}
line := strings.TrimSpace(string(b))
return core.NewReferenceFromStrings(refFile, line), nil
}
func isHex(s string) bool {
for _, b := range []byte(s) {
if isNum(b) {
continue
}
if isHexAlpha(b) {
continue
}
return false
}
return true
}
func isNum(b byte) bool {
return b >= '0' && b <= '9'
}
func isHexAlpha(b byte) bool {
return b >= 'a' && b <= 'f' || b >= 'A' && b <= 'F'
}
