plumbing/object: move difftree to object package

- To avoid ciclic dependency errors, we move all the difftree files to object package.
- Added Diff method to Tree object.

1 files changed, 381 insertions, 0 deletions

diff --git a/plumbing/object/difftree_test.go b/plumbing/object/difftree_test.go
new file mode 100644
index 0000000..594c49d
--- /dev/null
+++ b/plumbing/object/difftree_test.go
@@ -0,0 +1,381 @@
+package object
+
+import (
+	"os"
+	"sort"
+
+	"srcd.works/go-git.v4/plumbing"
+	"srcd.works/go-git.v4/plumbing/format/packfile"
+	"srcd.works/go-git.v4/plumbing/storer"
+	"srcd.works/go-git.v4/storage/filesystem"
+	"srcd.works/go-git.v4/storage/memory"
+	"srcd.works/go-git.v4/utils/merkletrie"
+
+	"github.com/src-d/go-git-fixtures"
+	. "gopkg.in/check.v1"
+)
+
+type DiffTreeSuite struct {
+	fixtures.Suite
+	Storer  storer.EncodedObjectStorer
+	Fixture *fixtures.Fixture
+	cache   map[string]storer.EncodedObjectStorer
+}
+
+func (s *DiffTreeSuite) SetUpSuite(c *C) {
+	s.Suite.SetUpSuite(c)
+	s.Fixture = fixtures.Basic().One()
+	sto, err := filesystem.NewStorage(s.Fixture.DotGit())
+	c.Assert(err, IsNil)
+	s.Storer = sto
+	s.cache = make(map[string]storer.EncodedObjectStorer)
+}
+
+func (s *DiffTreeSuite) commitFromStorer(c *C, sto storer.EncodedObjectStorer,
+	h plumbing.Hash) *Commit {
+
+	commit, err := GetCommit(sto, h)
+	c.Assert(err, IsNil)
+	return commit
+}
+
+func (s *DiffTreeSuite) storageFromPackfile(f *fixtures.Fixture) storer.EncodedObjectStorer {
+	sto, ok := s.cache[f.URL]
+	if ok {
+		return sto
+	}
+
+	sto = memory.NewStorage()
+
+	pf := f.Packfile()
+
+	defer pf.Close()
+
+	n := packfile.NewScanner(pf)
+	d, err := packfile.NewDecoder(n, sto)
+	if err != nil {
+		panic(err)
+	}
+
+	_, err = d.Decode()
+	if err != nil {
+		panic(err)
+	}
+
+	s.cache[f.URL] = sto
+	return sto
+}
+
+var _ = Suite(&DiffTreeSuite{})
+
+type expectChange struct {
+	Action merkletrie.Action
+	Name   string
+}
+
+func assertChanges(a Changes, c *C) {
+	for _, changes := range a {
+		action, err := changes.Action()
+		c.Assert(err, IsNil)
+		switch action {
+		case merkletrie.Insert:
+			c.Assert(changes.From.Tree, IsNil)
+			c.Assert(changes.To.Tree, NotNil)
+		case merkletrie.Delete:
+			c.Assert(changes.From.Tree, NotNil)
+			c.Assert(changes.To.Tree, IsNil)
+		case merkletrie.Modify:
+			c.Assert(changes.From.Tree, NotNil)
+			c.Assert(changes.To.Tree, NotNil)
+		default:
+			c.Fatalf("unknown action: %d", action)
+		}
+	}
+}
+
+func equalChanges(a Changes, b []expectChange, c *C) bool {
+	if len(a) != len(b) {
+		return false
+	}
+
+	sort.Sort(a)
+
+	for i, va := range a {
+		vb := b[i]
+		action, err := va.Action()
+		c.Assert(err, IsNil)
+		if action != vb.Action || va.name() != vb.Name {
+			return false
+		}
+	}
+
+	return true
+}
+
+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: merkletrie.Insert, Name: "README"},
+			},
+		},
+		{
+			"https://github.com/dezfowler/LiteMock.git",
+			"b7965eaa2c4f245d07191fe0bcfe86da032d672a",
+			"",
+			[]expectChange{
+				{Action: merkletrie.Delete, Name: "README"},
+			},
+		},
+		{
+			"https://github.com/githubtraining/example-branches.git",
+			"",
+			"f0eb272cc8f77803478c6748103a1450aa1abd37",
+			[]expectChange{
+				{Action: merkletrie.Insert, Name: "README.md"},
+			},
+		},
+		{
+			"https://github.com/githubtraining/example-branches.git",
+			"f0eb272cc8f77803478c6748103a1450aa1abd37",
+			"",
+			[]expectChange{
+				{Action: merkletrie.Delete, Name: "README.md"},
+			},
+		},
+		{
+			"https://github.com/githubtraining/example-branches.git",
+			"f0eb272cc8f77803478c6748103a1450aa1abd37",
+			"f0eb272cc8f77803478c6748103a1450aa1abd37",
+			[]expectChange{},
+		},
+		{
+			"https://github.com/github/gem-builder.git",
+			"",
+			"9608eed92b3839b06ebf72d5043da547de10ce85",
+			[]expectChange{
+				{Action: merkletrie.Insert, Name: "README"},
+				{Action: merkletrie.Insert, Name: "gem_builder.rb"},
+				{Action: merkletrie.Insert, Name: "gem_eval.rb"},
+			},
+		},
+		{
+			"https://github.com/github/gem-builder.git",
+			"9608eed92b3839b06ebf72d5043da547de10ce85",
+			"",
+			[]expectChange{
+				{Action: merkletrie.Delete, Name: "README"},
+				{Action: merkletrie.Delete, Name: "gem_builder.rb"},
+				{Action: merkletrie.Delete, Name: "gem_eval.rb"},
+			},
+		},
+		{
+			"https://github.com/github/gem-builder.git",
+			"9608eed92b3839b06ebf72d5043da547de10ce85",
+			"9608eed92b3839b06ebf72d5043da547de10ce85",
+			[]expectChange{},
+		},
+		{
+			"https://github.com/toqueteos/ts3.git",
+			"",
+			"764e914b75d6d6df1fc5d832aa9840f590abf1bb",
+			[]expectChange{
+				{Action: merkletrie.Insert, Name: "README.markdown"},
+				{Action: merkletrie.Insert, Name: "examples/bot.go"},
+				{Action: merkletrie.Insert, Name: "examples/raw_shell.go"},
+				{Action: merkletrie.Insert, Name: "helpers.go"},
+				{Action: merkletrie.Insert, Name: "ts3.go"},
+			},
+		},
+		{
+			"https://github.com/toqueteos/ts3.git",
+			"764e914b75d6d6df1fc5d832aa9840f590abf1bb",
+			"",
+			[]expectChange{
+				{Action: merkletrie.Delete, Name: "README.markdown"},
+				{Action: merkletrie.Delete, Name: "examples/bot.go"},
+				{Action: merkletrie.Delete, Name: "examples/raw_shell.go"},
+				{Action: merkletrie.Delete, Name: "helpers.go"},
+				{Action: merkletrie.Delete, Name: "ts3.go"},
+			},
+		},
+		{
+			"https://github.com/toqueteos/ts3.git",
+			"764e914b75d6d6df1fc5d832aa9840f590abf1bb",
+			"764e914b75d6d6df1fc5d832aa9840f590abf1bb",
+			[]expectChange{},
+		},
+		{
+			"https://github.com/github/gem-builder.git",
+			"9608eed92b3839b06ebf72d5043da547de10ce85",
+			"6c41e05a17e19805879689414026eb4e279f7de0",
+			[]expectChange{
+				{Action: merkletrie.Modify, Name: "gem_eval.rb"},
+			},
+		},
+		{
+			"https://github.com/github/gem-builder.git",
+			"6c41e05a17e19805879689414026eb4e279f7de0",
+			"89be3aac2f178719c12953cc9eaa23441f8d9371",
+			[]expectChange{
+				{Action: merkletrie.Modify, Name: "gem_eval.rb"},
+				{Action: merkletrie.Insert, Name: "gem_eval_test.rb"},
+				{Action: merkletrie.Insert, Name: "security.rb"},
+				{Action: merkletrie.Insert, Name: "security_test.rb"},
+			},
+		},
+		{
+			"https://github.com/github/gem-builder.git",
+			"89be3aac2f178719c12953cc9eaa23441f8d9371",
+			"597240b7da22d03ad555328f15abc480b820acc0",
+			[]expectChange{
+				{Action: merkletrie.Modify, Name: "gem_eval.rb"},
+			},
+		},
+		{
+			"https://github.com/github/gem-builder.git",
+			"597240b7da22d03ad555328f15abc480b820acc0",
+			"0260380e375d2dd0e1a8fcab15f91ce56dbe778e",
+			[]expectChange{
+				{Action: merkletrie.Modify, Name: "gem_eval.rb"},
+				{Action: merkletrie.Modify, Name: "gem_eval_test.rb"},
+				{Action: merkletrie.Insert, Name: "lazy_dir.rb"},
+				{Action: merkletrie.Insert, Name: "lazy_dir_test.rb"},
+				{Action: merkletrie.Modify, Name: "security.rb"},
+				{Action: merkletrie.Modify, Name: "security_test.rb"},
+			},
+		},
+		{
+			"https://github.com/github/gem-builder.git",
+			"0260380e375d2dd0e1a8fcab15f91ce56dbe778e",
+			"597240b7da22d03ad555328f15abc480b820acc0",
+			[]expectChange{
+				{Action: merkletrie.Modify, Name: "gem_eval.rb"},
+				{Action: merkletrie.Modify, Name: "gem_eval_test.rb"},
+				{Action: merkletrie.Delete, Name: "lazy_dir.rb"},
+				{Action: merkletrie.Delete, Name: "lazy_dir_test.rb"},
+				{Action: merkletrie.Modify, Name: "security.rb"},
+				{Action: merkletrie.Modify, Name: "security_test.rb"},
+			},
+		},
+		{
+			"https://github.com/github/gem-builder.git",
+			"0260380e375d2dd0e1a8fcab15f91ce56dbe778e",
+			"ca9fd470bacb6262eb4ca23ee48bb2f43711c1ff",
+			[]expectChange{
+				{Action: merkletrie.Modify, Name: "gem_eval.rb"},
+				{Action: merkletrie.Modify, Name: "security.rb"},
+				{Action: merkletrie.Modify, Name: "security_test.rb"},
+			},
+		},
+		{
+			"https://github.com/github/gem-builder.git",
+			"fe3c86745f887c23a0d38c85cfd87ca957312f86",
+			"b7e3f636febf7a0cd3ab473b6d30081786d2c5b6",
+			[]expectChange{
+				{Action: merkletrie.Modify, Name: "gem_eval.rb"},
+				{Action: merkletrie.Modify, Name: "gem_eval_test.rb"},
+				{Action: merkletrie.Insert, Name: "git_mock"},
+				{Action: merkletrie.Modify, Name: "lazy_dir.rb"},
+				{Action: merkletrie.Modify, Name: "lazy_dir_test.rb"},
+				{Action: merkletrie.Modify, Name: "security.rb"},
+			},
+		},
+		{
+			"https://github.com/rumpkernel/rumprun-xen.git",
+			"1831e47b0c6db750714cd0e4be97b5af17fb1eb0",
+			"51d8515578ea0c88cc8fc1a057903675cf1fc16c",
+			[]expectChange{
+				{Action: merkletrie.Modify, Name: "Makefile"},
+				{Action: merkletrie.Modify, Name: "netbsd_init.c"},
+				{Action: merkletrie.Modify, Name: "rumphyper_stubs.c"},
+				{Action: merkletrie.Delete, Name: "sysproxy.c"},
+			},
+		},
+		{
+			"https://github.com/rumpkernel/rumprun-xen.git",
+			"1831e47b0c6db750714cd0e4be97b5af17fb1eb0",
+			"e13e678f7ee9badd01b120889e0ec5fdc8ae3802",
+			[]expectChange{
+				{Action: merkletrie.Modify, Name: "app-tools/rumprun"},
+			},
+		},
+	} {
+		f := fixtures.ByURL(t.repository).One()
+		sto := s.storageFromPackfile(f)
+
+		var tree1, tree2 *Tree
+		var err error
+		if t.commit1 != "" {
+			tree1, err = s.commitFromStorer(c, sto,
+				plumbing.NewHash(t.commit1)).Tree()
+			c.Assert(err, IsNil,
+				Commentf("subtest %d: unable to retrieve tree from commit %s and repo %s: %s", i, t.commit1, t.repository, err))
+		}
+
+		if t.commit2 != "" {
+			tree2, err = s.commitFromStorer(c, sto,
+				plumbing.NewHash(t.commit2)).Tree()
+			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))
+		obtainedFromMethod, err := tree1.Diff(tree2)
+		c.Assert(err, IsNil,
+			Commentf("subtest %d: unable to calculate difftree: %s. Result calling Diff method from Tree object returns an error", i, err))
+
+		c.Assert(obtained, DeepEquals, obtainedFromMethod)
+
+		c.Assert(equalChanges(obtained, t.expected, c), 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 (s *DiffTreeSuite) TestIssue279(c *C) {
+	// HashEqual should ignore files if the only change is from a 100664
+	// mode to a 100644 or vice versa.
+	from := &treeNoder{
+		hash: plumbing.NewHash("d08e895238bac36d8220586fdc28c27e1a7a76d3"),
+		mode: os.FileMode(0100664),
+	}
+	to := &treeNoder{
+		hash: plumbing.NewHash("d08e895238bac36d8220586fdc28c27e1a7a76d3"),
+		mode: os.FileMode(0100644),
+	}
+	c.Assert(hashEqual(from, to), Equals, true)
+	c.Assert(hashEqual(to, from), Equals, true)
+
+	// but should detect if the contents of the file also changed.
+	to = &treeNoder{
+		hash: plumbing.NewHash("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"),
+		mode: os.FileMode(0100644),
+	}
+	c.Assert(hashEqual(from, to), Equals, false)
+	c.Assert(hashEqual(to, from), Equals, false)
+}