diff options
Diffstat (limited to 'utils/difftree/difftree.go')
-rw-r--r-- | utils/difftree/difftree.go | 194 |
1 files changed, 0 insertions, 194 deletions
diff --git a/utils/difftree/difftree.go b/utils/difftree/difftree.go deleted file mode 100644 index e2cb9a5..0000000 --- a/utils/difftree/difftree.go +++ /dev/null @@ -1,194 +0,0 @@ -package difftree - -import ( - "bytes" - "fmt" - "io" - "sort" - "strings" - - "gopkg.in/src-d/go-git.v4" - "gopkg.in/src-d/go-git.v4/core" -) - -type Action int - -func (a Action) String() string { - switch a { - case Insert: - return "Insert" - case Delete: - return "Delete" - case Modify: - return "Modify" - default: - panic(fmt.Sprintf("unsupported action: %d", a)) - } -} - -const ( - Insert Action = iota - Delete - Modify -) - -type Change struct { - Action - File *git.File -} - -func (c *Change) String() string { - return fmt.Sprintf("<Action: %s, Path: %s, Size: %d>", c.Action, c.File.Name, c.File.Size) -} - -type Changes []*Change - -func newEmpty() Changes { - return make([]*Change, 0, 0) -} - -func New(a, b *git.Tree) (Changes, error) { - if a == b { - return newEmpty(), nil - } - - if a == nil || b == nil { - return newWithEmpty(a, b) - } - - return newDiffTree(a, b) -} - -func (c Changes) Len() int { - return len(c) -} - -func (c Changes) Swap(i, j int) { - c[i], c[j] = c[j], c[i] -} - -func (c Changes) Less(i, j int) bool { - return strings.Compare(c[i].File.Name, c[j].File.Name) < 0 -} - -func (c Changes) String() string { - var buffer bytes.Buffer - buffer.WriteString("[") - comma := "" - for _, v := range c { - buffer.WriteString(comma) - buffer.WriteString(v.String()) - comma = ", " - } - buffer.WriteString("]") - - return buffer.String() -} - -func newWithEmpty(a, b *git.Tree) (Changes, error) { - changes := newEmpty() - - var action Action - var tree *git.Tree - if a == nil { - action = Insert - tree = b - } else { - action = Delete - tree = a - } - - iter := tree.Files() - defer iter.Close() - - for { - file, err := iter.Next() - if err == io.EOF { - break - } else if err != nil { - return nil, fmt.Errorf("cannot get next file: %s", err) - } - - insert := &Change{ - Action: action, - File: file, - } - changes = append(changes, insert) - } - - return changes, nil -} - -// FIXME: this is very inefficient, but correct. -// The proper way to do this is to implement a diff-tree algorithm, -// while taking advantage of the tree hashes to avoid traversing -// subtrees when the hash is equal in both inputs. -func newDiffTree(a, b *git.Tree) (Changes, error) { - result := newEmpty() - - aChanges, err := newWithEmpty(a, nil) - if err != nil { - return nil, fmt.Errorf("cannot create nil-diff of source tree: %s", err) - } - sort.Sort(aChanges) - - bChanges, err := newWithEmpty(nil, b) - if err != nil { - return nil, fmt.Errorf("cannot create nil-diff of destination tree: %s", err) - } - sort.Sort(bChanges) - - for len(aChanges) > 0 && len(bChanges) > 0 { - switch comp := strings.Compare(aChanges[0].File.Name, bChanges[0].File.Name); { - case comp == 0: // append as "Modify" or ignore if not changed - modified, err := hasChange(a, b, aChanges[0].File.Name) - if err != nil { - return nil, err - } - if modified { - bChanges[0].Action = Modify - result = append(result, bChanges[0]) - } else { - } - aChanges = aChanges[1:] - bChanges = bChanges[1:] - case comp < 0: // delete first a change - result = append(result, aChanges[0]) - aChanges = aChanges[1:] - case comp > 0: // insert first b change - result = append(result, bChanges[0]) - bChanges = bChanges[1:] - } - } - - // append all remaining changes in aChanges, if any, as deletes - // append all remaining changes in bChanges, if any, as inserts - result = append(result, aChanges...) - result = append(result, bChanges...) - - return result, nil -} - -func hasChange(a, b *git.Tree, path string) (bool, error) { - ha, err := hash(a, path) - if err != nil { - return false, err - } - - hb, err := hash(b, path) - if err != nil { - return false, err - } - - return ha != hb, nil -} - -func hash(tree *git.Tree, path string) (core.Hash, error) { - file, err := tree.File(path) - if err != nil { - var empty core.Hash - return empty, fmt.Errorf("cannot find file %s in tree: %s", path, err) - } - - return file.Hash, nil -} |