Adds support to open local repositories and to use file-based object storage (#55)v3.1.0

* remove some comments

* idx writer/reader

* Shut up ssh tests, they are annoying

* Add file scheme test to clients

* Add dummy file client

* Add test fot file client

* Make tests use fixture endpoint

* add parser for packed-refs format

* add parser for packed-refs format

* WIP adding dir.Refs() tests

* Add test for fixture refs

* refs parser for the refs directory

* Documentation

* Add Capabilities to file client

* tgz.Exatract now accpets a path instead of a Reader

* fix bug in idxfile fanout calculation

* remove dead code

* packfile documentation

* clean packfile parser code

* add core.Object.Content() and returns errors for core.ObjectStorage.Iter()

* add seekable storage

* add dir repos to NewRepository

* clean prints

* Add dir client documentation to README

* Organize the README

* README

* Clean tgz package

* Clean temp dirs after tgz tests

* Gometalinter on gitdir

* Clean pattern function

* metalinter tgz

* metalinter gitdir

* gitdir coverage and remove seekable packfile filedescriptor leak

* gitdir Idxfile tests and remove file descriptor leak

* gitdir Idxfile tests when no idx is found

* clean storage/seekable/internal/index and some formats/idxfile API issues

* clean storage/seekable

* clean formats/idx

* turn packfile/doc.go into packfile/doc.txt

* move formats/packfile/reader to decoder

* fix packfile decoder error names

* improve documentation

* comment packfile decoder errors

* comment public API (format/packfile)

* remve duplicated code in packfile decoder test

* move tracking_reader into an internal package and clean it

* use iota for packfile format

* rename packfile parse.go to packfile object_at.go

* clean packfile deltas

* fix delta header size bug

* improve delta documentation

* clean packfile deltas

* clean packfiles deltas

* clean repository.go

* Remove go 1.5 from Travis CI

Because go 1.5 does not suport internal packages.

* change local repo scheme to local://

* change "local://" to "file://" as the local scheme

* fix broken indentation

* shortens names of variables in short scopes

* more shortening of variable names

* more shortening of variable names

* Rename git dir client to "file", as the scheme used for it

* Fix file format ctor name, now that the package name has change

* Sortcut local repo constructor to not use remotes

The object storage is build directly in the repository ctor, instead
of creating a remote and waiting for the user to pull it.

* update README and fix some errors in it

* remove file scheme client

* Local respositories has now a new ctor

This is, they are no longer identified by the scheme of the URL, but are
created different from inception.

* remove unused URL field form Repository

* move all git dir logic to seekable sotrage ctor

* fix documentation

* Make formats/file/dir an internal package to storage/seekable

* change package storage/seekable to storage/fs

* clean storage/fs

* overall storage/fs clean

* more cleaning

* some metalinter fixes

* upgrade cshared to last changes

* remove dead code

* fix test error info

* remove file scheme check from clients

* fix test error message

* fix test error message

* fix error messages

* style changes

* fix comments everywhere

* style changes

* style changes

* scaffolding and tests for local packfiles without ifx files

* outsource index building from packfile to the packfile decoder

* refactor packfile header reading into a new function

* move code to generate index from packfile back to index package

* add header parsing

* fix documentation errata

* add undeltified and OFS delta support for index building from the packfile

* add tests for packfile with ref-deltas

* support for packfiles with ref-deltas and no idx

* refactor packfile format parser to reuse code

* refactor packfile format parser to reuse code

* refactor packfile format parser to reuse code

* refactor packfile format parser to reuse code

* refactor packfile format parser to reuse code

* WIP refactor packfile format parser to reuse code

* refactor packfile format parser to reuse code

* remove prints from tests

* remove prints from tests

* refactor packfile.core into packfile.parser

* rename packfile reader to something that shows it is a recaller

* rename cannot recall error

* rename packfile.Reader to packfile.ReadRecaller and document

* speed up test by using StreamReader instead of SeekableReader when possible

* clean packfile StreamReader

* stream_reader tests

* refactor packfile.StreamReader into packfile.StreamReadRecaller

* refactor packfile.SeekableReader into packfile.SeekableReadRecaller and document it

* generalize packfile.StreamReadRecaller test to all packfile.ReadRecaller implementations

* speed up storage/fs tests

* speed up tests in . by loading packfiles in memory

* speed up repository tests by using and smaller fixture

* restore doc.go files

* rename packfile.ReadRecaller implementations to shorter names

* update comments to type changes

* packfile.Parser test (WIP)

* packfile.Parser tests and add ForgetAll() to packfile.ReadRecaller

* add test for packfile.ReadRecaller.ForgetAll()

* clarify seekable being able to recallByOffset forgetted objects

* use better names for internal maps

* metalinter packfile package

* speed up some tests

* documentation fixes

* change storage.fs package name to storage.proxy to avoid confusion with new filesystem support

* New fs package and os transparent implementation

Now NewRepositoryFromFS receives a fs and a path and tests are
modified accordingly, but it is still not using for anything.

* add fs to gitdir and proxy.store

* reduce fs interface for easier implementation

* remove garbage dirs from tgz tests

* change file name gitdir/dir.go to gitdir/gitdir.go

* fs.OS tests

* metalinter utils/fs

* add NewRepositoryFromFS documentation to README

* Readability fixes to README

* move tgz to an external dependency

* move filesystem impl. example to example dir

* rename proxy/store.go to proxy/storage.go for coherence with memory/storage.go

* rename proxy package to seekable

1 files changed, 145 insertions, 0 deletions

diff --git a/storage/seekable/internal/gitdir/gitdir.go b/storage/seekable/internal/gitdir/gitdir.go
new file mode 100644
index 0000000..bfdf030
--- /dev/null
+++ b/storage/seekable/internal/gitdir/gitdir.go
@@ -0,0 +1,145 @@
+package gitdir
+
+import (
+	"errors"
+	"io/ioutil"
+	"os"
+	"strings"
+
+	"gopkg.in/src-d/go-git.v3/clients/common"
+	"gopkg.in/src-d/go-git.v3/core"
+	"gopkg.in/src-d/go-git.v3/utils/fs"
+)
+
+const (
+	suffix         = ".git"
+	packedRefsPath = "packed-refs"
+)
+
+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 on the
+	// repository.
+	ErrIdxNotFound = errors.New("idx file not found")
+	// ErrPackfileNotFound is returned by Packfile when the packfile is not found
+	// on the repository.
+	ErrPackfileNotFound = errors.New("packfile not found")
+)
+
+// The GitDir type represents a local git repository on disk. This
+// type is not zero-value-safe, use the New function to initialize it.
+type GitDir struct {
+	fs      fs.FS
+	path    string
+	refs    map[string]core.Hash
+	packDir string
+}
+
+// New returns a GitDir 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.FS, path string) (*GitDir, error) {
+	d := &GitDir{}
+	d.fs = fs
+	d.path = path
+	d.packDir = d.fs.Join(d.path, "objects", "pack")
+
+	if _, err := fs.Stat(path); err != nil {
+		if os.IsNotExist(err) {
+			return nil, ErrNotFound
+		}
+		return nil, err
+	}
+
+	return d, nil
+}
+
+// Refs scans the git directory collecting references, which it returns.
+// Symbolic references are resolved and included in the output.
+func (d *GitDir) Refs() (map[string]core.Hash, error) {
+	var err error
+
+	d.refs = make(map[string]core.Hash)
+
+	if err = d.addRefsFromPackedRefs(); err != nil {
+		return nil, err
+	}
+
+	if err = d.addRefsFromRefDir(); err != nil {
+		return nil, err
+	}
+
+	return d.refs, err
+}
+
+// Capabilities scans the git directory collection capabilities, which it returns.
+func (d *GitDir) Capabilities() (*common.Capabilities, error) {
+	c := common.NewCapabilities()
+
+	err := d.addSymRefCapability(c)
+
+	return c, err
+}
+
+func (d *GitDir) addSymRefCapability(cap *common.Capabilities) (err error) {
+	f, err := d.fs.Open(d.fs.Join(d.path, "HEAD"))
+	if err != nil {
+		return err
+	}
+
+	defer func() {
+		errClose := f.Close()
+		if err == nil {
+			err = errClose
+		}
+	}()
+
+	b, err := ioutil.ReadAll(f)
+	if err != nil {
+		return err
+	}
+	data := strings.TrimSpace(string(b))
+
+	c := "symref"
+	ref := strings.TrimPrefix(data, symRefPrefix)
+	cap.Set(c, "HEAD:"+ref)
+
+	return nil
+}
+
+// Packfile returns the path of the packfile (really, it returns the
+// path of the first file in the "objects/pack/" directory with a
+// ".pack" extension.
+func (d *GitDir) Packfile() (fs.FS, string, error) {
+	files, err := d.fs.ReadDir(d.packDir)
+	if err != nil {
+		return nil, "", err
+	}
+
+	for _, f := range files {
+		if strings.HasSuffix(f.Name(), ".pack") {
+			return d.fs, d.fs.Join(d.packDir, f.Name()), nil
+		}
+	}
+
+	return nil, "", ErrPackfileNotFound
+}
+
+// Packfile returns the path of the idx file (really, it returns the
+// path of the first file in the "objects/pack/" directory with an
+// ".idx" extension.
+func (d *GitDir) Idxfile() (fs.FS, string, error) {
+	files, err := d.fs.ReadDir(d.packDir)
+	if err != nil {
+		return nil, "", err
+	}
+
+	for _, f := range files {
+		if strings.HasSuffix(f.Name(), ".idx") {
+			return d.fs, d.fs.Join(d.packDir, f.Name()), nil
+		}
+	}
+
+	return nil, "", ErrIdxNotFound
+}