move plumbing from top level package to plumbing (#183)

* plumbing: rename Object -> EncodedObject.

* plumbing/storer: rename ObjectStorer -> EncodedObjectStorer.

* move difftree to plumbing/difftree.

* move diff -> utils/diff

* make Object/Tag/Blob/Tree/Commit/File depend on storer.

* Object and its implementations now depend only on
  storer.EncodedObjectStorer, not git.Repository.
* Tests are decoupled accordingly.

* move Object/Commit/File/Tag/Tree to plumbing/object.

* move Object/Commit/File/Tag/Tree to plumbing/object.
* move checkClose to utils/ioutil.

* move RevListObjects to plumbing/revlist.Objects.

* move DiffTree to plumbing/difftree package.

* rename files with plural nouns to singular

* plumbing/object: add GetBlob/GetCommit/GetTag/GetTree.

1 files changed, 0 insertions, 389 deletions

diff --git a/tree_diff_test.go b/tree_diff_test.go
deleted file mode 100644
index e78fbf1..0000000
--- a/tree_diff_test.go
+++ /dev/null
@@ -1,389 +0,0 @@
-package git
-
-import (
-	"sort"
-
-	"gopkg.in/src-d/go-git.v4/fixtures"
-	"gopkg.in/src-d/go-git.v4/plumbing"
-
-	. "gopkg.in/check.v1"
-)
-
-type DiffTreeSuite struct {
-	BaseSuite
-}
-
-var _ = Suite(&DiffTreeSuite{})
-
-func (s *DiffTreeSuite) TestActionString(c *C) {
-	expected := "Insert"
-	action := Insert
-	obtained := action.String()
-	c.Assert(obtained, Equals, expected)
-
-	expected = "Delete"
-	action = Delete
-	obtained = action.String()
-	c.Assert(obtained, Equals, expected)
-
-	expected = "Modify"
-	action = Modify
-	obtained = action.String()
-	c.Assert(obtained, Equals, expected)
-
-	action = 37
-	c.Assert(func() { _ = action.String() },
-		PanicMatches, "unsupported action: 37")
-}
-
-func (s *DiffTreeSuite) TestChangeFilesInsert(c *C) {
-	tree, err := s.Repository.Tree(plumbing.NewHash("a8d315b2b1c615d43042c3a62402b8a54288cf5c"))
-	c.Assert(err, IsNil)
-
-	change := &Change{Action: Insert}
-	change.To.Name = "json/long.json"
-	change.To.Tree = tree
-	change.To.TreeEntry.Hash = plumbing.NewHash("49c6bb89b17060d7b4deacb7b338fcc6ea2352a9")
-
-	from, to, err := change.Files()
-	c.Assert(err, IsNil)
-	c.Assert(from, IsNil)
-	c.Assert(to.ID(), Equals, change.To.TreeEntry.Hash)
-}
-
-func (s *DiffTreeSuite) TestChangeFilesDelete(c *C) {
-	tree, err := s.Repository.Tree(plumbing.NewHash("a8d315b2b1c615d43042c3a62402b8a54288cf5c"))
-	c.Assert(err, IsNil)
-
-	change := &Change{Action: Delete}
-	change.From.Name = "json/long.json"
-	change.From.Tree = tree
-	change.From.TreeEntry.Hash = plumbing.NewHash("49c6bb89b17060d7b4deacb7b338fcc6ea2352a9")
-
-	from, to, err := change.Files()
-	c.Assert(err, IsNil)
-	c.Assert(to, IsNil)
-	c.Assert(from.ID(), Equals, change.From.TreeEntry.Hash)
-}
-
-func (s *DiffTreeSuite) TestChangeFilesModify(c *C) {
-	tree, err := s.Repository.Tree(plumbing.NewHash("a8d315b2b1c615d43042c3a62402b8a54288cf5c"))
-	c.Assert(err, IsNil)
-
-	change := &Change{Action: Modify}
-	change.To.Name = "json/long.json"
-	change.To.Tree = tree
-	change.To.TreeEntry.Hash = plumbing.NewHash("49c6bb89b17060d7b4deacb7b338fcc6ea2352a9")
-	change.From.Name = "json/long.json"
-	change.From.Tree = tree
-	change.From.TreeEntry.Hash = plumbing.NewHash("9a48f23120e880dfbe41f7c9b7b708e9ee62a492")
-
-	from, to, err := change.Files()
-	c.Assert(err, IsNil)
-	c.Assert(to.ID(), Equals, change.To.TreeEntry.Hash)
-	c.Assert(from.ID(), Equals, change.From.TreeEntry.Hash)
-}
-
-func (s *DiffTreeSuite) TestChangeString(c *C) {
-	expected := "<Action: Insert, Path: foo>"
-	change := &Change{Action: Insert}
-	change.From.Name = "foo"
-
-	obtained := change.String()
-	c.Assert(obtained, Equals, expected)
-}
-
-func (s *DiffTreeSuite) TestChangesString(c *C) {
-	expected := "[]"
-	changes := newEmpty()
-	obtained := changes.String()
-	c.Assert(obtained, Equals, expected)
-
-	expected = "[<Action: Modify, Path: bla>]"
-	changes = make([]*Change, 1)
-	changes[0] = &Change{Action: Modify}
-	changes[0].From.Name = "bla"
-
-	obtained = changes.String()
-	c.Assert(obtained, Equals, expected)
-
-	expected = "[<Action: Modify, Path: bla>, <Action: Insert, Path: foo/bar>]"
-	changes = make([]*Change, 2)
-	changes[0] = &Change{Action: Modify}
-	changes[0].From.Name = "bla"
-	changes[1] = &Change{Action: Insert}
-	changes[1].From.Name = "foo/bar"
-	obtained = changes.String()
-	c.Assert(obtained, Equals, expected)
-}
-
-type expectChange struct {
-	Action Action
-	Name   string
-}
-
-func (s *DiffTreeSuite) TestDiffTree(c *C) {
-	for i, t := range []struct {
-		repository string         // the repo name as in localRepos
-		commit1    string         // the commit of the first tree
-		commit2    string         // the commit of the second tree
-		expected   []expectChange // the expected list of []changeExpect
-	}{{
-		"https://github.com/dezfowler/LiteMock.git",
-		"",
-		"",
-		[]expectChange{},
-	}, {
-		"https://github.com/dezfowler/LiteMock.git",
-		"b7965eaa2c4f245d07191fe0bcfe86da032d672a",
-		"b7965eaa2c4f245d07191fe0bcfe86da032d672a",
-		[]expectChange{},
-	}, {
-		"https://github.com/dezfowler/LiteMock.git",
-		"",
-		"b7965eaa2c4f245d07191fe0bcfe86da032d672a",
-		[]expectChange{
-			{Action: Insert, Name: "README"},
-		},
-	}, {
-		"https://github.com/dezfowler/LiteMock.git",
-		"b7965eaa2c4f245d07191fe0bcfe86da032d672a",
-		"",
-		[]expectChange{
-			{Action: Delete, Name: "README"},
-		},
-	}, {
-		"https://github.com/githubtraining/example-branches.git",
-		"",
-		"f0eb272cc8f77803478c6748103a1450aa1abd37",
-		[]expectChange{
-			{Action: Insert, Name: "README.md"},
-		},
-	}, {
-		"https://github.com/githubtraining/example-branches.git",
-		"f0eb272cc8f77803478c6748103a1450aa1abd37",
-		"",
-		[]expectChange{
-			{Action: Delete, Name: "README.md"},
-		},
-	}, {
-		"https://github.com/githubtraining/example-branches.git",
-		"f0eb272cc8f77803478c6748103a1450aa1abd37",
-		"f0eb272cc8f77803478c6748103a1450aa1abd37",
-		[]expectChange{},
-	}, {
-		"https://github.com/github/gem-builder.git",
-		"",
-		"9608eed92b3839b06ebf72d5043da547de10ce85",
-		[]expectChange{
-			{Action: Insert, Name: "README"},
-			{Action: Insert, Name: "gem_builder.rb"},
-			{Action: Insert, Name: "gem_eval.rb"},
-		},
-	}, {
-		"https://github.com/github/gem-builder.git",
-		"9608eed92b3839b06ebf72d5043da547de10ce85",
-		"",
-		[]expectChange{
-			{Action: Delete, Name: "README"},
-			{Action: Delete, Name: "gem_builder.rb"},
-			{Action: Delete, Name: "gem_eval.rb"},
-		},
-	}, {
-		"https://github.com/github/gem-builder.git",
-		"9608eed92b3839b06ebf72d5043da547de10ce85",
-		"9608eed92b3839b06ebf72d5043da547de10ce85",
-		[]expectChange{},
-	}, {
-		"https://github.com/toqueteos/ts3.git",
-		"",
-		"764e914b75d6d6df1fc5d832aa9840f590abf1bb",
-		[]expectChange{
-			{Action: Insert, Name: "README.markdown"},
-			{Action: Insert, Name: "examples/bot.go"},
-			{Action: Insert, Name: "examples/raw_shell.go"},
-			{Action: Insert, Name: "helpers.go"},
-			{Action: Insert, Name: "ts3.go"},
-		},
-	}, {
-		"https://github.com/toqueteos/ts3.git",
-		"764e914b75d6d6df1fc5d832aa9840f590abf1bb",
-		"",
-		[]expectChange{
-			{Action: Delete, Name: "README.markdown"},
-			{Action: Delete, Name: "examples/bot.go"},
-			{Action: Delete, Name: "examples/raw_shell.go"},
-			{Action: Delete, Name: "helpers.go"},
-			{Action: Delete, Name: "ts3.go"},
-		},
-	}, {
-		"https://github.com/toqueteos/ts3.git",
-		"764e914b75d6d6df1fc5d832aa9840f590abf1bb",
-		"764e914b75d6d6df1fc5d832aa9840f590abf1bb",
-		[]expectChange{},
-	}, {
-		"https://github.com/github/gem-builder.git",
-		"9608eed92b3839b06ebf72d5043da547de10ce85",
-		"6c41e05a17e19805879689414026eb4e279f7de0",
-		[]expectChange{
-			{Action: Modify, Name: "gem_eval.rb"},
-		},
-	}, {
-		"https://github.com/github/gem-builder.git",
-		"6c41e05a17e19805879689414026eb4e279f7de0",
-		"89be3aac2f178719c12953cc9eaa23441f8d9371",
-		[]expectChange{
-			{Action: Modify, Name: "gem_eval.rb"},
-			{Action: Insert, Name: "gem_eval_test.rb"},
-			{Action: Insert, Name: "security.rb"},
-			{Action: Insert, Name: "security_test.rb"},
-		},
-	}, {
-		"https://github.com/github/gem-builder.git",
-		"89be3aac2f178719c12953cc9eaa23441f8d9371",
-		"597240b7da22d03ad555328f15abc480b820acc0",
-		[]expectChange{
-			{Action: Modify, Name: "gem_eval.rb"},
-		},
-	}, {
-		"https://github.com/github/gem-builder.git",
-		"597240b7da22d03ad555328f15abc480b820acc0",
-		"0260380e375d2dd0e1a8fcab15f91ce56dbe778e",
-		[]expectChange{
-			{Action: Modify, Name: "gem_eval.rb"},
-			{Action: Modify, Name: "gem_eval_test.rb"},
-			{Action: Insert, Name: "lazy_dir.rb"},
-			{Action: Insert, Name: "lazy_dir_test.rb"},
-			{Action: Modify, Name: "security.rb"},
-			{Action: Modify, Name: "security_test.rb"},
-		},
-	}, {
-		"https://github.com/github/gem-builder.git",
-		"0260380e375d2dd0e1a8fcab15f91ce56dbe778e",
-		"597240b7da22d03ad555328f15abc480b820acc0",
-		[]expectChange{
-			{Action: Modify, Name: "gem_eval.rb"},
-			{Action: Modify, Name: "gem_eval_test.rb"},
-			{Action: Delete, Name: "lazy_dir.rb"},
-			{Action: Delete, Name: "lazy_dir_test.rb"},
-			{Action: Modify, Name: "security.rb"},
-			{Action: Modify, Name: "security_test.rb"},
-		},
-	}, {
-		"https://github.com/github/gem-builder.git",
-		"0260380e375d2dd0e1a8fcab15f91ce56dbe778e",
-		"ca9fd470bacb6262eb4ca23ee48bb2f43711c1ff",
-		[]expectChange{
-			{Action: Modify, Name: "gem_eval.rb"},
-			{Action: Modify, Name: "security.rb"},
-			{Action: Modify, Name: "security_test.rb"},
-		},
-	}, {
-		"https://github.com/github/gem-builder.git",
-		"fe3c86745f887c23a0d38c85cfd87ca957312f86",
-		"b7e3f636febf7a0cd3ab473b6d30081786d2c5b6",
-		[]expectChange{
-			{Action: Modify, Name: "gem_eval.rb"},
-			{Action: Modify, Name: "gem_eval_test.rb"},
-			{Action: Insert, Name: "git_mock"},
-			{Action: Modify, Name: "lazy_dir.rb"},
-			{Action: Modify, Name: "lazy_dir_test.rb"},
-			{Action: Modify, Name: "security.rb"},
-		},
-	}, {
-		"https://github.com/rumpkernel/rumprun-xen.git",
-		"1831e47b0c6db750714cd0e4be97b5af17fb1eb0",
-		"51d8515578ea0c88cc8fc1a057903675cf1fc16c",
-		[]expectChange{
-			{Action: Modify, Name: "Makefile"},
-			{Action: Modify, Name: "netbsd_init.c"},
-			{Action: Modify, Name: "rumphyper_stubs.c"},
-			{Action: Delete, Name: "sysproxy.c"},
-		},
-	}, {
-		"https://github.com/rumpkernel/rumprun-xen.git",
-		"1831e47b0c6db750714cd0e4be97b5af17fb1eb0",
-		"e13e678f7ee9badd01b120889e0ec5fdc8ae3802",
-		[]expectChange{
-			{Action: Modify, Name: "app-tools/rumprun"},
-		},
-	}} {
-		r := s.NewRepositoryFromPackfile(fixtures.ByURL(t.repository).One())
-
-		tree1, err := tree(r, t.commit1)
-		c.Assert(err, IsNil,
-			Commentf("subtest %d: unable to retrieve tree from commit %s and repo %s: %s", i, t.commit1, t.repository, err))
-
-		var tree2 *Tree
-		if t.commit1 == t.commit2 {
-			tree2 = tree1
-		} else {
-			tree2, err = tree(r, t.commit2)
-			c.Assert(err, IsNil,
-				Commentf("subtest %d: unable to retrieve tree from commit %s and repo %s", i, t.commit2, t.repository, err))
-		}
-
-		obtained, err := DiffTree(tree1, tree2)
-		c.Assert(err, IsNil,
-			Commentf("subtest %d: unable to calculate difftree: %s", i, err))
-		c.Assert(equalChanges(obtained, t.expected), Equals, true,
-			Commentf("subtest:%d\nrepo=%s\ncommit1=%s\ncommit2=%s\nexpected=%s\nobtained=%s",
-				i, t.repository, t.commit1, t.commit2, t.expected, obtained))
-
-		assertChanges(obtained, c)
-	}
-}
-
-func assertChanges(a Changes, c *C) {
-	for _, changes := range a {
-		switch changes.Action {
-		case Insert:
-			c.Assert(changes.From.Tree, IsNil)
-			c.Assert(changes.To.Tree, NotNil)
-		case Delete:
-			c.Assert(changes.From.Tree, NotNil)
-			c.Assert(changes.To.Tree, IsNil)
-		case Modify:
-			c.Assert(changes.From.Tree, NotNil)
-			c.Assert(changes.To.Tree, NotNil)
-		}
-	}
-}
-
-func equalChanges(a Changes, b []expectChange) bool {
-	if a == nil && b == nil {
-		return true
-	}
-
-	if a == nil || b == nil {
-		return false
-	}
-
-	if len(a) != len(b) {
-		return false
-	}
-
-	sort.Sort(a)
-
-	for i, va := range a {
-		vb := b[i]
-		if va.Action != vb.Action || va.name() != vb.Name {
-			return false
-		}
-	}
-
-	return true
-}
-
-func tree(repo *Repository, commitHashStr string) (*Tree, error) {
-	if commitHashStr == "" {
-		return nil, nil
-	}
-
-	commit, err := repo.Commit(plumbing.NewHash(commitHashStr))
-	if err != nil {
-		return nil, err
-	}
-
-	return commit.Tree()
-}