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

3 files changed, 208 insertions, 0 deletions

diff --git a/utils/fs/fs.go b/utils/fs/fs.go
new file mode 100644
index 0000000..df771dd
--- /dev/null
+++ b/utils/fs/fs.go
@@ -0,0 +1,21 @@
+package fs
+
+import (
+	"io"
+	"os"
+)
+
+// FS interface represent an abstracted filesystem, so you can
+// use NewRepositoryFromFS from any medium.
+type FS interface {
+	Stat(path string) (os.FileInfo, error)
+	Open(path string) (ReadSeekCloser, error)
+	ReadDir(path string) ([]os.FileInfo, error)
+	Join(elem ...string) string
+}
+
+// ReadSeekCloser is a Reader, Seeker and Closer.
+type ReadSeekCloser interface {
+	io.ReadCloser
+	io.Seeker
+}
diff --git a/utils/fs/os.go b/utils/fs/os.go
new file mode 100644
index 0000000..37ad75a
--- /dev/null
+++ b/utils/fs/os.go
@@ -0,0 +1,36 @@
+package fs
+
+import (
+	"io/ioutil"
+	"os"
+	"path/filepath"
+)
+
+// OS is a simple FS implementation for the current host filesystem.
+type OS struct{}
+
+// NewOS returns a new OS.
+func NewOS() FS {
+	return &OS{}
+}
+
+// Stat returns the filesystem info for a path.
+func (o *OS) Stat(path string) (os.FileInfo, error) {
+	return os.Stat(path)
+}
+
+// Open returns a ReadSeekCloser for the specified path.
+func (o *OS) Open(path string) (ReadSeekCloser, error) {
+	return os.Open(path)
+}
+
+// ReadDir returns the filesystem info for all the archives under the
+// specified path.
+func (o *OS) ReadDir(path string) ([]os.FileInfo, error) {
+	return ioutil.ReadDir(path)
+}
+
+// Join joins the specified elements using the filesystem separator.
+func (o *OS) Join(elem ...string) string {
+	return filepath.Join(elem...)
+}
diff --git a/utils/fs/os_test.go b/utils/fs/os_test.go
new file mode 100644
index 0000000..84fe895
--- /dev/null
+++ b/utils/fs/os_test.go
@@ -0,0 +1,151 @@
+package fs
+
+import (
+	"io/ioutil"
+	"os"
+	"testing"
+
+	"github.com/alcortesm/tgz"
+	. "gopkg.in/check.v1"
+)
+
+func Test(t *testing.T) { TestingT(t) }
+
+type FSImplSuite struct {
+	dir string
+}
+
+var _ = Suite(&FSImplSuite{})
+
+func (s *FSImplSuite) SetUpSuite(c *C) {
+	dir, err := tgz.Extract("../../storage/seekable/internal/gitdir/fixtures/spinnaker-gc.tgz")
+	c.Assert(err, IsNil)
+	s.dir = dir
+}
+
+func (s *FSImplSuite) TearDownSuite(c *C) {
+	err := os.RemoveAll(s.dir)
+	c.Assert(err, IsNil)
+}
+
+func (s *FSImplSuite) TestJoin(c *C) {
+	fs := NewOS()
+	for i, test := range [...]struct {
+		input    []string
+		expected string
+	}{
+		{
+			input:    []string{},
+			expected: "",
+		}, {
+			input:    []string{"a"},
+			expected: "a",
+		}, {
+			input:    []string{"a", "b"},
+			expected: "a/b",
+		}, {
+			input:    []string{"a", "b", "c"},
+			expected: "a/b/c",
+		},
+	} {
+		obtained := fs.Join(test.input...)
+		com := Commentf("test %d:\n\tinput = %v", i, test.input)
+		c.Assert(obtained, Equals, test.expected, com)
+	}
+}
+
+func (s *FSImplSuite) TestStat(c *C) {
+	fs := NewOS()
+	for i, path := range [...]string{
+		".git/index",
+		".git/info/refs",
+		".git/objects/pack/pack-584416f86235cac0d54bfabbdc399fb2b09a5269.pack",
+	} {
+		path := fs.Join(s.dir, path)
+		com := Commentf("test %d", i)
+
+		real, err := os.Open(path)
+		c.Assert(err, IsNil, com)
+
+		expected, err := real.Stat()
+		c.Assert(err, IsNil, com)
+
+		obtained, err := fs.Stat(path)
+		c.Assert(err, IsNil, com)
+
+		c.Assert(obtained, DeepEquals, expected, com)
+
+		err = real.Close()
+		c.Assert(err, IsNil, com)
+	}
+}
+
+func (s *FSImplSuite) TestStatErrors(c *C) {
+	fs := NewOS()
+	for i, test := range [...]struct {
+		input     string
+		errRegExp string
+	}{
+		{
+			input:     "bla",
+			errRegExp: ".*bla: no such file or directory",
+		}, {
+			input:     "bla/foo",
+			errRegExp: ".*bla/foo: no such file or directory",
+		},
+	} {
+		com := Commentf("test %d", i)
+		_, err := fs.Stat(test.input)
+		c.Assert(err, ErrorMatches, test.errRegExp, com)
+	}
+}
+
+func (s *FSImplSuite) TestOpen(c *C) {
+	fs := NewOS()
+	for i, test := range [...]string{
+		".git/index",
+		".git/info/refs",
+		".git/objects/pack/pack-584416f86235cac0d54bfabbdc399fb2b09a5269.pack",
+	} {
+		com := Commentf("test %d", i)
+		path := fs.Join(s.dir, test)
+
+		real, err := os.Open(path)
+		c.Assert(err, IsNil, com)
+		realData, err := ioutil.ReadAll(real)
+		c.Assert(err, IsNil, com)
+		err = real.Close()
+		c.Assert(err, IsNil, com)
+
+		obtained, err := fs.Open(path)
+		c.Assert(err, IsNil, com)
+		obtainedData, err := ioutil.ReadAll(obtained)
+		c.Assert(err, IsNil, com)
+		err = obtained.Close()
+		c.Assert(err, IsNil, com)
+
+		c.Assert(obtainedData, DeepEquals, realData, com)
+	}
+}
+
+func (s *FSImplSuite) TestReadDir(c *C) {
+	fs := NewOS()
+	for i, test := range [...]string{
+		".git/info",
+		".",
+		"",
+		".git/objects",
+		".git/objects/pack",
+	} {
+		com := Commentf("test %d", i)
+		path := fs.Join(s.dir, test)
+
+		expected, err := ioutil.ReadDir(path)
+		c.Assert(err, IsNil, com)
+
+		obtained, err := fs.ReadDir(path)
+		c.Assert(err, IsNil, com)
+
+		c.Assert(obtained, DeepEquals, expected, com)
+	}
+}