DiffTree based on TreeWalker

5 files changed, 190 insertions, 77 deletions

diff --git a/cshared/tree_cshared.go b/cshared/tree_cshared.go
index 3884817..ddaf0f1 100644
--- a/cshared/tree_cshared.go
+++ b/cshared/tree_cshared.go
@@ -106,20 +106,18 @@ func c_NewTreeWalker(r uint64, t uint64) uint64 {
 }
 
 //export c_TreeWalker_Next
-func c_TreeWalker_Next(tw uint64) (*C.char, *C.char, uint32, *C.char,
-                                   uint64, int, *C.char) {
+func c_TreeWalker_Next(tw uint64) (*C.char, *C.char, uint32, *C.char, int, *C.char) {
 	obj, ok := GetObject(Handle(tw))
 	if !ok {
-		return nil, nil, 0, nil, IH, ErrorCodeNotFound, C.CString(MessageNotFound)
+		return nil, nil, 0, nil, ErrorCodeNotFound, C.CString(MessageNotFound)
 	}
 	walker := obj.(*git.TreeWalker)
-	name, entry, object, err := walker.Next()
+	name, entry, err := walker.Next()
 	if err != nil {
-		return nil, nil, 0, nil, IH, ErrorCodeInternal, C.CString(err.Error())
+		return nil, nil, 0, nil, ErrorCodeInternal, C.CString(err.Error())
 	}
 	return C.CString(name), C.CString(entry.Name), uint32(entry.Mode),
-	       CBytes(entry.Hash[:]), uint64(RegisterObject(&object)),
-	       ErrorCodeSuccess, nil
+		CBytes(entry.Hash[:]), ErrorCodeSuccess, nil
 }
 
 //export c_TreeWalker_Tree
@@ -140,4 +138,4 @@ func c_TreeWalker_Close(tw uint64) {
 	}
 	walker := obj.(*git.TreeWalker)
 	walker.Close()
-}
\ No newline at end of file
+}
diff --git a/file.go b/file.go
index e18caaf..9180528 100644
--- a/file.go
+++ b/file.go
@@ -16,7 +16,8 @@ type File struct {
 	Blob
 }
 
-func newFile(name string, m os.FileMode, b *Blob) *File {
+// NewFile returns a File based on the given blob object
+func NewFile(name string, m os.FileMode, b *Blob) *File {
 	return &File{Name: name, Mode: m, Blob: *b}
 }
 
@@ -77,7 +78,7 @@ func (iter *FileIter) Next() (*File, error) {
 			return nil, err
 		}
 
-		return newFile(name, entry.Mode, blob), nil
+		return NewFile(name, entry.Mode, blob), nil
 	}
 }
 
diff --git a/tree.go b/tree.go
index eaa0c15..462589d 100644
--- a/tree.go
+++ b/tree.go
@@ -62,7 +62,7 @@ func (t *Tree) File(path string) (*File, error) {
 	blob := &Blob{}
 	blob.Decode(obj)
 
-	return newFile(path, e.Mode, blob), nil
+	return NewFile(path, e.Mode, blob), nil
 }
 
 func (t *Tree) findEntry(path string) (*TreeEntry, error) {
diff --git a/tree_diff.go b/tree_diff.go
index bad2230..1c613bd 100644
--- a/tree_diff.go
+++ b/tree_diff.go
@@ -33,12 +33,54 @@ const (
 
 type Change struct {
 	Action
-	Name  string
-	Files [2]*File
+	From ChangeEntry
+	To   ChangeEntry
+}
+
+type ChangeEntry struct {
+	Name      string
+	Tree      *Tree
+	TreeEntry TreeEntry
+}
+
+func (c *Change) Files() (from *File, to *File, err error) {
+	if c.Action == Insert || c.Action == Modify {
+		to, err = newFileFromTreeEntry(c.To.Tree, &c.To.TreeEntry)
+		if err != nil {
+			return
+		}
+
+	}
+
+	if c.Action == Delete || c.Action == Modify {
+		from, err = newFileFromTreeEntry(c.From.Tree, &c.From.TreeEntry)
+		if err != nil {
+			return
+		}
+	}
+
+	return
+}
+
+func newFileFromTreeEntry(t *Tree, e *TreeEntry) (*File, error) {
+	blob, err := t.r.Blob(e.Hash)
+	if err != nil {
+		return nil, err
+	}
+
+	return NewFile(e.Name, e.Mode, blob), nil
 }
 
 func (c *Change) String() string {
-	return fmt.Sprintf("<Action: %s, Path: %s>", c.Action, c.Name)
+	return fmt.Sprintf("<Action: %s, Path: %s>", c.Action, c.name())
+}
+
+func (c *Change) name() string {
+	if c.From.Name != "" {
+		return c.From.Name
+	}
+
+	return c.To.Name
 }
 
 type Changes []*Change
@@ -68,7 +110,7 @@ func (c Changes) Swap(i, j int) {
 }
 
 func (c Changes) Less(i, j int) bool {
-	return strings.Compare(c[i].Name, c[j].Name) < 0
+	return strings.Compare(c[i].name(), c[j].name()) < 0
 }
 
 func (c Changes) String() string {
@@ -98,29 +140,34 @@ func newWithEmpty(a, b *Tree) (Changes, error) {
 		tree = a
 	}
 
-	iter := tree.Files()
-	defer iter.Close()
+	w := NewTreeWalker(tree.r, tree)
+	defer w.Close()
 
 	for {
-		file, err := iter.Next()
+		path, entry, err := w.Next()
 		if err == io.EOF {
 			break
 		} else if err != nil {
 			return nil, fmt.Errorf("cannot get next file: %s", err)
 		}
 
-		var files [2]*File
+		if entry.Mode.IsDir() {
+			continue
+		}
+
+		c := &Change{Action: action}
+
 		if action == Insert {
-			files[1] = file
+			c.To.Name = path
+			c.To.TreeEntry = entry
+			c.To.Tree = tree
 		} else {
-			files[0] = file
+			c.From.Name = path
+			c.From.TreeEntry = entry
+			c.From.Tree = tree
 		}
 
-		changes = append(changes, &Change{
-			Action: action,
-			Name:   file.Name,
-			Files:  files,
-		})
+		changes = append(changes, c)
 	}
 
 	return changes, nil
@@ -146,19 +193,16 @@ func newDiffTree(a, b *Tree) ([]*Change, error) {
 	sort.Sort(bChanges)
 
 	for len(aChanges) > 0 && len(bChanges) > 0 {
-		switch comp := strings.Compare(aChanges[0].Name, bChanges[0].Name); {
+		switch comp := strings.Compare(aChanges[0].name(), bChanges[0].name()); {
 		case comp == 0: // append as "Modify" or ignore if not changed
-			modified, err := hasChange(a, b, aChanges[0].Name)
+			modified, err := hasChange(a, b, aChanges[0].name())
 			if err != nil {
 				return nil, err
 			}
 
 			if modified {
-				result = append(result, &Change{
-					Action: Modify,
-					Name:   aChanges[0].Name,
-					Files:  [2]*File{aChanges[0].Files[0], bChanges[0].Files[1]},
-				})
+				c := mergeInsertAndDeleteIntoModify(aChanges[0], bChanges[0])
+				result = append(result, c)
 			}
 
 			aChanges = aChanges[1:]
@@ -180,6 +224,18 @@ func newDiffTree(a, b *Tree) ([]*Change, error) {
 	return result, nil
 }
 
+func mergeInsertAndDeleteIntoModify(a, b *Change) *Change {
+	c := &Change{Action: Modify}
+	c.From.Name = a.From.Name
+	c.From.Tree = a.From.Tree
+	c.From.TreeEntry = a.From.TreeEntry
+	c.To.Name = b.To.Name
+	c.To.Tree = b.To.Tree
+	c.To.TreeEntry = b.To.TreeEntry
+
+	return c
+}
+
 func hasChange(a, b *Tree, path string) (bool, error) {
 	ha, err := hash(a, path)
 	if err != nil {
diff --git a/tree_diff_test.go b/tree_diff_test.go
index 7733c90..b7efaa1 100644
--- a/tree_diff_test.go
+++ b/tree_diff_test.go
@@ -11,12 +11,16 @@ import (
 )
 
 type DiffTreeSuite struct {
+	BaseSuite
+
 	repos map[string]*Repository
 }
 
 var _ = Suite(&DiffTreeSuite{})
 
 func (s *DiffTreeSuite) SetUpSuite(c *C) {
+	s.BaseSuite.SetUpSuite(c)
+
 	fixtureRepos := [...]struct {
 		url      string
 		packfile string
@@ -74,12 +78,58 @@ func (s *DiffTreeSuite) TestActionString(c *C) {
 		PanicMatches, "unsupported action: 37")
 }
 
+func (s *DiffTreeSuite) TestChangeFilesInsert(c *C) {
+	tree, err := s.Repository.Tree(core.NewHash("a8d315b2b1c615d43042c3a62402b8a54288cf5c"))
+	c.Assert(err, IsNil)
+
+	change := &Change{Action: Insert}
+	change.To.Name = "json/long.json"
+	change.To.Tree = tree
+	change.To.TreeEntry.Hash = core.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(core.NewHash("a8d315b2b1c615d43042c3a62402b8a54288cf5c"))
+	c.Assert(err, IsNil)
+
+	change := &Change{Action: Delete}
+	change.From.Name = "json/long.json"
+	change.From.Tree = tree
+	change.From.TreeEntry.Hash = core.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(core.NewHash("a8d315b2b1c615d43042c3a62402b8a54288cf5c"))
+	c.Assert(err, IsNil)
+
+	change := &Change{Action: Modify}
+	change.To.Name = "json/long.json"
+	change.To.Tree = tree
+	change.To.TreeEntry.Hash = core.NewHash("49c6bb89b17060d7b4deacb7b338fcc6ea2352a9")
+	change.From.Name = "json/long.json"
+	change.From.Tree = tree
+	change.From.TreeEntry.Hash = core.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,
-		Name:   "foo",
-	}
+	change := &Change{Action: Insert}
+	change.From.Name = "foo"
 
 	obtained := change.String()
 	c.Assert(obtained, Equals, expected)
@@ -93,42 +143,51 @@ func (s *DiffTreeSuite) TestChangesString(c *C) {
 
 	expected = "[<Action: Modify, Path: bla>]"
 	changes = make([]*Change, 1)
-	changes[0] = &Change{Action: Modify, Name: "bla"}
+	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, Name: "bla"}
-	changes[1] = &Change{Action: Insert, Name: "foo/bar"}
+	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 {
-		repo     string  // the repo name as in localRepos
-		commit1  string  // the commit of the first tree
-		commit2  string  // the commit of the second tree
-		expected Changes // the expected list of changes
+		repo     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
 	}{
 		{
 			"git://github.com/dezfowler/LiteMock.git",
 			"",
 			"",
-			Changes{},
+			[]expectChange{},
 		},
 		{
 			"git://github.com/dezfowler/LiteMock.git",
 			"b7965eaa2c4f245d07191fe0bcfe86da032d672a",
 			"b7965eaa2c4f245d07191fe0bcfe86da032d672a",
-			Changes{},
+			[]expectChange{},
 		},
 		{
 			"git://github.com/dezfowler/LiteMock.git",
 			"",
 			"b7965eaa2c4f245d07191fe0bcfe86da032d672a",
-			Changes{
+			[]expectChange{
 				{Action: Insert, Name: "README"},
 			},
 		},
@@ -136,7 +195,7 @@ func (s *DiffTreeSuite) TestDiffTree(c *C) {
 			"git://github.com/dezfowler/LiteMock.git",
 			"b7965eaa2c4f245d07191fe0bcfe86da032d672a",
 			"",
-			Changes{
+			[]expectChange{
 				{Action: Delete, Name: "README"},
 			},
 		},
@@ -144,7 +203,7 @@ func (s *DiffTreeSuite) TestDiffTree(c *C) {
 			"git://github.com/githubtraining/example-branches.git",
 			"",
 			"f0eb272cc8f77803478c6748103a1450aa1abd37",
-			Changes{
+			[]expectChange{
 				{Action: Insert, Name: "README.md"},
 			},
 		},
@@ -152,7 +211,7 @@ func (s *DiffTreeSuite) TestDiffTree(c *C) {
 			"git://github.com/githubtraining/example-branches.git",
 			"f0eb272cc8f77803478c6748103a1450aa1abd37",
 			"",
-			Changes{
+			[]expectChange{
 				{Action: Delete, Name: "README.md"},
 			},
 		},
@@ -160,13 +219,13 @@ func (s *DiffTreeSuite) TestDiffTree(c *C) {
 			"git://github.com/githubtraining/example-branches.git",
 			"f0eb272cc8f77803478c6748103a1450aa1abd37",
 			"f0eb272cc8f77803478c6748103a1450aa1abd37",
-			Changes{},
+			[]expectChange{},
 		},
 		{
 			"git://github.com/github/gem-builder.git",
 			"",
 			"9608eed92b3839b06ebf72d5043da547de10ce85",
-			Changes{
+			[]expectChange{
 				{Action: Insert, Name: "README"},
 				{Action: Insert, Name: "gem_builder.rb"},
 				{Action: Insert, Name: "gem_eval.rb"},
@@ -176,7 +235,7 @@ func (s *DiffTreeSuite) TestDiffTree(c *C) {
 			"git://github.com/github/gem-builder.git",
 			"9608eed92b3839b06ebf72d5043da547de10ce85",
 			"",
-			Changes{
+			[]expectChange{
 				{Action: Delete, Name: "README"},
 				{Action: Delete, Name: "gem_builder.rb"},
 				{Action: Delete, Name: "gem_eval.rb"},
@@ -186,17 +245,17 @@ func (s *DiffTreeSuite) TestDiffTree(c *C) {
 			"git://github.com/github/gem-builder.git",
 			"9608eed92b3839b06ebf72d5043da547de10ce85",
 			"9608eed92b3839b06ebf72d5043da547de10ce85",
-			Changes{},
+			[]expectChange{},
 		},
 		{
 			"git://github.com/toqueteos/ts3.git",
 			"",
 			"764e914b75d6d6df1fc5d832aa9840f590abf1bb",
-			Changes{
+			[]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: "README.markdown"},
 				{Action: Insert, Name: "ts3.go"},
 			},
 		},
@@ -204,11 +263,11 @@ func (s *DiffTreeSuite) TestDiffTree(c *C) {
 			"git://github.com/toqueteos/ts3.git",
 			"764e914b75d6d6df1fc5d832aa9840f590abf1bb",
 			"",
-			Changes{
+			[]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: "README.markdown"},
 				{Action: Delete, Name: "ts3.go"},
 			},
 		},
@@ -216,13 +275,13 @@ func (s *DiffTreeSuite) TestDiffTree(c *C) {
 			"git://github.com/toqueteos/ts3.git",
 			"764e914b75d6d6df1fc5d832aa9840f590abf1bb",
 			"764e914b75d6d6df1fc5d832aa9840f590abf1bb",
-			Changes{},
+			[]expectChange{},
 		},
 		{
 			"git://github.com/github/gem-builder.git",
 			"9608eed92b3839b06ebf72d5043da547de10ce85",
 			"6c41e05a17e19805879689414026eb4e279f7de0",
-			Changes{
+			[]expectChange{
 				{Action: Modify, Name: "gem_eval.rb"},
 			},
 		},
@@ -230,7 +289,7 @@ func (s *DiffTreeSuite) TestDiffTree(c *C) {
 			"git://github.com/github/gem-builder.git",
 			"6c41e05a17e19805879689414026eb4e279f7de0",
 			"89be3aac2f178719c12953cc9eaa23441f8d9371",
-			Changes{
+			[]expectChange{
 				{Action: Modify, Name: "gem_eval.rb"},
 				{Action: Insert, Name: "gem_eval_test.rb"},
 				{Action: Insert, Name: "security.rb"},
@@ -241,7 +300,7 @@ func (s *DiffTreeSuite) TestDiffTree(c *C) {
 			"git://github.com/github/gem-builder.git",
 			"89be3aac2f178719c12953cc9eaa23441f8d9371",
 			"597240b7da22d03ad555328f15abc480b820acc0",
-			Changes{
+			[]expectChange{
 				{Action: Modify, Name: "gem_eval.rb"},
 			},
 		},
@@ -249,7 +308,7 @@ func (s *DiffTreeSuite) TestDiffTree(c *C) {
 			"git://github.com/github/gem-builder.git",
 			"597240b7da22d03ad555328f15abc480b820acc0",
 			"0260380e375d2dd0e1a8fcab15f91ce56dbe778e",
-			Changes{
+			[]expectChange{
 				{Action: Modify, Name: "gem_eval.rb"},
 				{Action: Modify, Name: "gem_eval_test.rb"},
 				{Action: Insert, Name: "lazy_dir.rb"},
@@ -262,7 +321,7 @@ func (s *DiffTreeSuite) TestDiffTree(c *C) {
 			"git://github.com/github/gem-builder.git",
 			"0260380e375d2dd0e1a8fcab15f91ce56dbe778e",
 			"597240b7da22d03ad555328f15abc480b820acc0",
-			Changes{
+			[]expectChange{
 				{Action: Modify, Name: "gem_eval.rb"},
 				{Action: Modify, Name: "gem_eval_test.rb"},
 				{Action: Delete, Name: "lazy_dir.rb"},
@@ -275,7 +334,7 @@ func (s *DiffTreeSuite) TestDiffTree(c *C) {
 			"git://github.com/github/gem-builder.git",
 			"0260380e375d2dd0e1a8fcab15f91ce56dbe778e",
 			"ca9fd470bacb6262eb4ca23ee48bb2f43711c1ff",
-			Changes{
+			[]expectChange{
 				{Action: Modify, Name: "gem_eval.rb"},
 				{Action: Modify, Name: "security.rb"},
 				{Action: Modify, Name: "security_test.rb"},
@@ -285,7 +344,7 @@ func (s *DiffTreeSuite) TestDiffTree(c *C) {
 			"git://github.com/github/gem-builder.git",
 			"fe3c86745f887c23a0d38c85cfd87ca957312f86",
 			"b7e3f636febf7a0cd3ab473b6d30081786d2c5b6",
-			Changes{
+			[]expectChange{
 				{Action: Modify, Name: "gem_eval.rb"},
 				{Action: Modify, Name: "gem_eval_test.rb"},
 				{Action: Insert, Name: "git_mock"},
@@ -298,7 +357,7 @@ func (s *DiffTreeSuite) TestDiffTree(c *C) {
 			"git://github.com/rumpkernel/rumprun-xen.git",
 			"1831e47b0c6db750714cd0e4be97b5af17fb1eb0",
 			"51d8515578ea0c88cc8fc1a057903675cf1fc16c",
-			Changes{
+			[]expectChange{
 				{Action: Modify, Name: "Makefile"},
 				{Action: Modify, Name: "netbsd_init.c"},
 				{Action: Modify, Name: "rumphyper_stubs.c"},
@@ -309,7 +368,7 @@ func (s *DiffTreeSuite) TestDiffTree(c *C) {
 			"git://github.com/rumpkernel/rumprun-xen.git",
 			"1831e47b0c6db750714cd0e4be97b5af17fb1eb0",
 			"e13e678f7ee9badd01b120889e0ec5fdc8ae3802",
-			Changes{
+			[]expectChange{
 				{Action: Modify, Name: "app-tools/rumprun"},
 			},
 		},
@@ -346,19 +405,19 @@ func assertChanges(a Changes, c *C) {
 	for _, changes := range a {
 		switch changes.Action {
 		case Insert:
-			c.Assert(changes.Files[0], IsNil)
-			c.Assert(changes.Files[1], NotNil)
+			c.Assert(changes.From.Tree, IsNil)
+			c.Assert(changes.To.Tree, NotNil)
 		case Delete:
-			c.Assert(changes.Files[0], NotNil)
-			c.Assert(changes.Files[1], IsNil)
+			c.Assert(changes.From.Tree, NotNil)
+			c.Assert(changes.To.Tree, IsNil)
 		case Modify:
-			c.Assert(changes.Files[0], NotNil)
-			c.Assert(changes.Files[1], NotNil)
+			c.Assert(changes.From.Tree, NotNil)
+			c.Assert(changes.To.Tree, NotNil)
 		}
 	}
 }
 
-func equalChanges(a, b Changes) bool {
+func equalChanges(a Changes, b []expectChange) bool {
 	if a == nil && b == nil {
 		return true
 	}
@@ -372,11 +431,10 @@ func equalChanges(a, b Changes) bool {
 	}
 
 	sort.Sort(a)
-	sort.Sort(b)
 
 	for i, va := range a {
 		vb := b[i]
-		if va.Action != vb.Action || va.Name != vb.Name {
+		if va.Action != vb.Action || va.name() != vb.Name {
 			return false
 		}
 	}