Extract billy (#173)

* Extract billy

Billy is a new library directly extracted from go-git. It abstract
several storages systems in a filesystem interface.

More in github.com/src-d/billy

* Fix grouping in imports block

* Update billy to v1

* Re-remove fs_implementation example

8 files changed, 34 insertions, 26 deletions

diff --git a/storage/filesystem/config_test.go b/storage/filesystem/config_test.go
index b86eaee..6fbf826 100644
--- a/storage/filesystem/config_test.go
+++ b/storage/filesystem/config_test.go
@@ -6,7 +6,8 @@ import (
 
 	"gopkg.in/src-d/go-git.v4/fixtures"
 	"gopkg.in/src-d/go-git.v4/storage/filesystem/internal/dotgit"
-	"gopkg.in/src-d/go-git.v4/utils/fs/os"
+
+	"srcd.works/go-billy.v1/os"
 
 	. "gopkg.in/check.v1"
 )
diff --git a/storage/filesystem/internal/dotgit/dotgit.go b/storage/filesystem/internal/dotgit/dotgit.go
index 3405908..f9763d1 100644
--- a/storage/filesystem/internal/dotgit/dotgit.go
+++ b/storage/filesystem/internal/dotgit/dotgit.go
@@ -10,7 +10,8 @@ import (
 	"strings"
 
 	"gopkg.in/src-d/go-git.v4/plumbing"
-	"gopkg.in/src-d/go-git.v4/utils/fs"
+
+	"srcd.works/go-billy.v1"
 )
 
 const (
@@ -51,33 +52,33 @@ var (
 // 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
+	fs billy.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 {
+func New(fs billy.Filesystem) *DotGit {
 	return &DotGit{fs: fs}
 }
 
 // ConfigWriter returns a file pointer for write to the config file
-func (d *DotGit) ConfigWriter() (fs.File, error) {
+func (d *DotGit) ConfigWriter() (billy.File, error) {
 	return d.fs.Create(configPath)
 }
 
 // Config returns a file pointer for read to the config file
-func (d *DotGit) Config() (fs.File, error) {
+func (d *DotGit) Config() (billy.File, error) {
 	return d.fs.Open(configPath)
 }
 
 // ShallowWriter returns a file pointer for write to the shallow file
-func (d *DotGit) ShallowWriter() (fs.File, error) {
+func (d *DotGit) ShallowWriter() (billy.File, error) {
 	return d.fs.Create(shallowPath)
 }
 
 // Shallow returns a file pointer for read to the shallow file
-func (d *DotGit) Shallow() (fs.File, error) {
+func (d *DotGit) Shallow() (billy.File, error) {
 	f, err := d.fs.Open(shallowPath)
 	if err != nil {
 		if os.IsNotExist(err) {
@@ -124,7 +125,7 @@ func (d *DotGit) ObjectPacks() ([]plumbing.Hash, error) {
 }
 
 // ObjectPack returns a fs.File of the given packfile
-func (d *DotGit) ObjectPack(hash plumbing.Hash) (fs.File, error) {
+func (d *DotGit) ObjectPack(hash plumbing.Hash) (billy.File, error) {
 	file := d.fs.Join(objectsPath, packPath, fmt.Sprintf("pack-%s.pack", hash.String()))
 
 	pack, err := d.fs.Open(file)
@@ -140,7 +141,7 @@ func (d *DotGit) ObjectPack(hash plumbing.Hash) (fs.File, error) {
 }
 
 // ObjectPackIdx returns a fs.File of the index file for a given packfile
-func (d *DotGit) ObjectPackIdx(hash plumbing.Hash) (fs.File, error) {
+func (d *DotGit) ObjectPackIdx(hash plumbing.Hash) (billy.File, error) {
 	file := d.fs.Join(objectsPath, packPath, fmt.Sprintf("pack-%s.idx", hash.String()))
 	idx, err := d.fs.Open(file)
 	if err != nil {
@@ -190,7 +191,7 @@ func (d *DotGit) Objects() ([]plumbing.Hash, error) {
 }
 
 // Object return a fs.File poiting the object file, if exists
-func (d *DotGit) Object(h plumbing.Hash) (fs.File, error) {
+func (d *DotGit) Object(h plumbing.Hash) (billy.File, error) {
 	hash := h.String()
 	file := d.fs.Join(objectsPath, hash[0:2], hash[2:40])
 
diff --git a/storage/filesystem/internal/dotgit/dotgit_test.go b/storage/filesystem/internal/dotgit/dotgit_test.go
index b645a85..48f02f0 100644
--- a/storage/filesystem/internal/dotgit/dotgit_test.go
+++ b/storage/filesystem/internal/dotgit/dotgit_test.go
@@ -9,7 +9,8 @@ import (
 
 	"gopkg.in/src-d/go-git.v4/fixtures"
 	"gopkg.in/src-d/go-git.v4/plumbing"
-	osfs "gopkg.in/src-d/go-git.v4/utils/fs/os"
+
+	osfs "srcd.works/go-billy.v1/os"
 
 	. "gopkg.in/check.v1"
 )
diff --git a/storage/filesystem/internal/dotgit/writers.go b/storage/filesystem/internal/dotgit/writers.go
index 8e22a39..1cd893d 100644
--- a/storage/filesystem/internal/dotgit/writers.go
+++ b/storage/filesystem/internal/dotgit/writers.go
@@ -9,7 +9,8 @@ import (
 	"gopkg.in/src-d/go-git.v4/plumbing/format/idxfile"
 	"gopkg.in/src-d/go-git.v4/plumbing/format/objfile"
 	"gopkg.in/src-d/go-git.v4/plumbing/format/packfile"
-	"gopkg.in/src-d/go-git.v4/utils/fs"
+
+	"srcd.works/go-billy.v1"
 )
 
 // PackWriter is a io.Writer that generates the packfile index simultaneously,
@@ -21,15 +22,15 @@ import (
 type PackWriter struct {
 	Notify func(h plumbing.Hash, i idxfile.Idxfile)
 
-	fs       fs.Filesystem
-	fr, fw   fs.File
+	fs       billy.Filesystem
+	fr, fw   billy.File
 	synced   *syncedReader
 	checksum plumbing.Hash
 	index    idxfile.Idxfile
 	result   chan error
 }
 
-func newPackWrite(fs fs.Filesystem) (*PackWriter, error) {
+func newPackWrite(fs billy.Filesystem) (*PackWriter, error) {
 	fw, err := fs.TempFile(fs.Join(objectsPath, packPath), "tmp_pack_")
 	if err != nil {
 		return nil, err
@@ -248,11 +249,11 @@ func (s *syncedReader) Close() error {
 
 type ObjectWriter struct {
 	objfile.Writer
-	fs fs.Filesystem
-	f  fs.File
+	fs billy.Filesystem
+	f  billy.File
 }
 
-func newObjectWriter(fs fs.Filesystem) (*ObjectWriter, error) {
+func newObjectWriter(fs billy.Filesystem) (*ObjectWriter, error) {
 	f, err := fs.TempFile(fs.Join(objectsPath, packPath), "tmp_obj_")
 	if err != nil {
 		return nil, err
diff --git a/storage/filesystem/internal/dotgit/writers_test.go b/storage/filesystem/internal/dotgit/writers_test.go
index c66613a..c546a3a 100644
--- a/storage/filesystem/internal/dotgit/writers_test.go
+++ b/storage/filesystem/internal/dotgit/writers_test.go
@@ -9,7 +9,8 @@ import (
 	"strconv"
 
 	"gopkg.in/src-d/go-git.v4/fixtures"
-	osfs "gopkg.in/src-d/go-git.v4/utils/fs/os"
+
+	osfs "srcd.works/go-billy.v1/os"
 
 	. "gopkg.in/check.v1"
 )
diff --git a/storage/filesystem/object.go b/storage/filesystem/object.go
index 836e7f3..e9b5bb7 100644
--- a/storage/filesystem/object.go
+++ b/storage/filesystem/object.go
@@ -11,7 +11,8 @@ import (
 	"gopkg.in/src-d/go-git.v4/plumbing/storer"
 	"gopkg.in/src-d/go-git.v4/storage/filesystem/internal/dotgit"
 	"gopkg.in/src-d/go-git.v4/storage/memory"
-	"gopkg.in/src-d/go-git.v4/utils/fs"
+
+	"srcd.works/go-billy.v1"
 )
 
 type ObjectStorage struct {
@@ -261,7 +262,7 @@ func (i index) Decode(r io.Reader) error {
 }
 
 type packfileIter struct {
-	f fs.File
+	f billy.File
 	d *packfile.Decoder
 	t plumbing.ObjectType
 
@@ -270,7 +271,7 @@ type packfileIter struct {
 	total    uint32
 }
 
-func newPackfileIter(f fs.File, t plumbing.ObjectType, seen map[plumbing.Hash]bool) (storer.EncodedObjectIter, error) {
+func newPackfileIter(f billy.File, t plumbing.ObjectType, seen map[plumbing.Hash]bool) (storer.EncodedObjectIter, error) {
 	s := packfile.NewScanner(f)
 	_, total, err := s.Header()
 	if err != nil {
diff --git a/storage/filesystem/storage.go b/storage/filesystem/storage.go
index e414428..a60d0f4 100644
--- a/storage/filesystem/storage.go
+++ b/storage/filesystem/storage.go
@@ -3,7 +3,8 @@ package filesystem
 
 import (
 	"gopkg.in/src-d/go-git.v4/storage/filesystem/internal/dotgit"
-	"gopkg.in/src-d/go-git.v4/utils/fs"
+
+	"srcd.works/go-billy.v1"
 )
 
 // Storage is an implementation of git.Storer that stores data on disk in the
@@ -17,7 +18,7 @@ type Storage struct {
 }
 
 // NewStorage returns a new Storage backed by a given `fs.Filesystem`
-func NewStorage(fs fs.Filesystem) (*Storage, error) {
+func NewStorage(fs billy.Filesystem) (*Storage, error) {
 	dir := dotgit.New(fs)
 	o, err := newObjectStorage(dir)
 	if err != nil {
diff --git a/storage/filesystem/storage_test.go b/storage/filesystem/storage_test.go
index c24d5d5..0e8ffb3 100644
--- a/storage/filesystem/storage_test.go
+++ b/storage/filesystem/storage_test.go
@@ -4,7 +4,8 @@ import (
 	"testing"
 
 	"gopkg.in/src-d/go-git.v4/storage/test"
-	"gopkg.in/src-d/go-git.v4/utils/fs/os"
+
+	"srcd.works/go-billy.v1/os"
 
 	. "gopkg.in/check.v1"
 )