DiffTree based on TreeWalker

Author: mcuadros

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()
-}
+}

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
 	}
 }
 

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) {

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 {