package object
import (
"context"
"errors"
"fmt"
"io"
"path"
"path/filepath"
"strings"
"github.com/go-git/go-git/v5/plumbing"
"github.com/go-git/go-git/v5/plumbing/filemode"
"github.com/go-git/go-git/v5/plumbing/storer"
"github.com/go-git/go-git/v5/utils/ioutil"
"github.com/go-git/go-git/v5/utils/sync"
)
const (
maxTreeDepth = 1024
startingStackSize = 8
)
// New errors defined by this package.
var (
ErrMaxTreeDepth = errors.New("maximum tree depth exceeded")
ErrFileNotFound = errors.New("file not found")
ErrDirectoryNotFound = errors.New("directory not found")
ErrEntryNotFound = errors.New("entry not found")
)
// Tree is basically like a directory - it references a bunch of other trees
// and/or blobs (i.e. files and sub-directories)
type Tree struct {
Entries []TreeEntry
Hash plumbing.Hash
s storer.EncodedObjectStorer
m map[string]*TreeEntry
t map[string]*Tree // tree path cache
}
// GetTree gets a tree from an object storer and decodes it.
func GetTree(s storer.EncodedObjectStorer, h plumbing.Hash) (*Tree, error) {
o, err := s.EncodedObject(plumbing.TreeObject, h)
if err != nil {
return nil, err
}
return DecodeTree(s, o)
}
// DecodeTree decodes an encoded object into a *Tree and associates it to the
// given object storer.
func DecodeTree(s storer.EncodedObjectStorer, o plumbing.EncodedObject) (*Tree, error) {
t := &Tree{s: s}
if err := t.Decode(o); err != nil {
return nil, err
}
return t, nil
}
// TreeEntry represents a file
type TreeEntry struct {
Name string
Mode filemode.FileMode
Hash plumbing.Hash
}
// File returns the hash of the file identified by the `path` argument.
// The path is interpreted as relative to the tree receiver.
func (t *Tree) File(path string) (*File, error) {
e, err := t.FindEntry(path)
if err != nil {
return nil, ErrFileNotFound
}
blob, err := GetBlob(t.s, e.Hash)
if err != nil {
if err == plumbing.ErrObjectNotFound {
return nil, ErrFileNotFound
}
return nil, err
}
return NewFile(path, e.Mode, blob), nil
}
// Size returns the plaintext size of an object, without reading it
// into memory.
func (t *Tree) Size(path string) (int64, error) {
e, err := t.FindEntry(path)
if err != nil {
return 0, ErrEntryNotFound
}
return t.s.EncodedObjectSize(e.Hash)
}
// Tree returns the tree identified by the `path` argument.
// The path is interpreted as relative to the tree receiver.
func (t *Tree) Tree(path string) (*Tree, error) {
e, err := t.FindEntry(path)
if err != nil {
return nil, ErrDirectoryNotFound
}
tree, err := GetTree(t.s, e.Hash)
if err == plumbing.ErrObjectNotFound {
return nil, ErrDirectoryNotFound
}
return tree, err
}
// TreeEntryFile returns the *File for a given *TreeEntry.
func (t *Tree) TreeEntryFile(e *TreeEntry) (*File, error) {
blob, err := GetBlob(t.s, e.Hash)
if err != nil {
return nil, err
}
return NewFile(e.Name, e.Mode, blob), nil
}
// FindEntry search a TreeEntry in this tree or any subtree.
func (t *Tree) FindEntry(path string) (*TreeEntry, error) {
if t.t == nil {
t.t = make(map[string]*Tree)
}
pathParts := strings.Split(path, "/")
startingTree := t
pathCurrent := ""
// search for the longest path in the tree path cache
for i := len(pathParts) - 1; i > 1; i-- {
path := filepath.Join(pathParts[:i]...)
tree, ok := t.t[path]
if ok {
startingTree = tree
pathParts = pathParts[i:]
pathCurrent = path
break
}
}
var tree *Tree
var err error
for tree = startingTree; len(pathParts) > 1; pathParts = pathParts[1:] {
if tree, err = tree.dir(pathParts[0]); err != nil {
return nil, err
}
pathCurrent = filepath.Join(pathCurrent, pathParts[0])
t.t[pathCurrent] = tree
}
return tree.entry(pathParts[0])
}
func (t *Tree) dir(baseName string) (*Tree, error) {
entry, err := t.entry(baseName)
if err != nil {
return nil, ErrDirectoryNotFound
}
obj, err := t.s.EncodedObject(plumbing.TreeObject, entry.Hash)
if err != nil {
return nil, err
}
tree := &Tree{s: t.s}
err = tree.Decode(obj)
return tree, err
}
func (t *Tree) entry(baseName string) (*TreeEntry, error) {
if t.m == nil {
t.buildMap()
}
entry, ok := t.m[baseName]
if !ok {
return nil, ErrEntryNotFound
}
return entry, nil
}
// Files returns a FileIter allowing to iterate over the Tree
func (t *Tree) Files() *FileIter {
return NewFileIter(t.s, t)
}
// ID returns the object ID of the tree. The returned value will always match
// the current value of Tree.Hash.
//
// ID is present to fulfill the Object interface.
func (t *Tree) ID() plumbing.Hash {
return t.Hash
}
// Type returns the type of object. It always returns plumbing.TreeObject.
func (t *Tree) Type() plumbing.ObjectType {
return plumbing.TreeObject
}
// Decode transform an plumbing.EncodedObject into a Tree struct
func (t *Tree) Decode(o plumbing.EncodedObject) (err error) {
if o.Type() != plumbing.TreeObject {
return ErrUnsupportedObject
}
t.Hash = o.Hash()
if o.Size() == 0 {
return nil
}
t.Entries = nil
t.m = nil
reader, err := o.Reader()
if err != nil {
return err
}
defer ioutil.CheckClose(reader, &err)
r := sync.GetBufioReader(reader)
defer sync.PutBufioReader(r)
for {
str, err := r.ReadString(' ')
if err != nil {
if err == io.EOF {
break
}
return err
}
str = str[:len(str)-1] // strip last byte (' ')
mode, err := filemode.New(str)
if err != nil {
return err
}
name, err := r.ReadString(0)
if err != nil && err != io.EOF {
return err
}
var hash plumbing.Hash
if _, err = io.ReadFull(r, hash[:]); err != nil {
return err
}
baseName := name[:len(name)-1]
t.Entries = append(t.Entries, TreeEntry{
Hash: hash,
Mode: mode,
Name: baseName,
})
}
return nil
}
// Encode transforms a Tree into a plumbing.EncodedObject.
func (t *Tree) Encode(o plumbing.EncodedObject) (err error) {
o.SetType(plumbing.TreeObject)
w, err := o.Writer()
if err != nil {
return err
}
defer ioutil.CheckClose(w, &err)
for _, entry := range t.Entries {
if _, err = fmt.Fprintf(w, "%o %s", entry.Mode, entry.Name); err != nil {
return err
}
if _, err = w.Write([]byte{0x00}); err != nil {
return err
}
if _, err = w.Write(entry.Hash[:]); err != nil {
return err
}
}
return err
}
func (t *Tree) buildMap() {
t.m = make(map[string]*TreeEntry)
for i := 0; i < len(t.Entries); i++ {
t.m[t.Entries[i].Name] = &t.Entries[i]
}
}
// Diff returns a list of changes between this tree and the provided one
func (t *Tree) Diff(to *Tree) (Changes, error) {
return t.DiffContext(context.Background(), to)
}
// DiffContext returns a list of changes between this tree and the provided one
// Error will be returned if context expires. Provided context must be non nil.
//
// NOTE: Since version 5.1.0 the renames are correctly handled, the settings
// used are the recommended options DefaultDiffTreeOptions.
func (t *Tree) DiffContext(ctx context.Context, to *Tree) (Changes, error) {
return DiffTreeWithOptions(ctx, t, to, DefaultDiffTreeOptions)
}
// Patch returns a slice of Patch objects with all the changes between trees
// in chunks. This representation can be used to create several diff outputs.
func (t *Tree) Patch(to *Tree) (*Patch, error) {
return t.PatchContext(context.Background(), to)
}
// PatchContext returns a slice of Patch objects with all the changes between
// trees in chunks. This representation can be used to create several diff
// outputs. If context expires, an error will be returned. Provided context must
// be non-nil.
//
// NOTE: Since version 5.1.0 the renames are correctly handled, the settings
// used are the recommended options DefaultDiffTreeOptions.
func (t *Tree) PatchContext(ctx context.Context, to *Tree) (*Patch, error) {
changes, err := t.DiffContext(ctx, to)
if err != nil {
return nil, err
}
return changes.PatchContext(ctx)
}
// treeEntryIter facilitates iterating through the TreeEntry objects in a Tree.
type treeEntryIter struct {
t *Tree
pos int
}
func (iter *treeEntryIter) Next() (TreeEntry, error) {
if iter.pos >= len(iter.t.Entries) {
return TreeEntry{}, io.EOF
}
iter.pos++
return iter.t.Entries[iter.pos-1], nil
}
// TreeWalker provides a means of walking through all of the entries in a Tree.
type TreeWalker struct {
stack []*treeEntryIter
base string
recursive bool
seen map[plumbing.Hash]bool
s storer.EncodedObjectStorer
t *Tree
}
// NewTreeWalker returns a new TreeWalker for the given tree.
//
// It is the caller's responsibility to call Close() when finished with the
// tree walker.
func NewTreeWalker(t *Tree, recursive bool, seen map[plumbing.Hash]bool) *TreeWalker {
stack := make([]*treeEntryIter, 0, startingStackSize)
stack = append(stack, &treeEntryIter{t, 0})
return &TreeWalker{
stack: stack,
recursive: recursive,
seen: seen,
s: t.s,
t: t,
}
}
// Next returns the next object from the tree. Objects are returned in order
// and subtrees are included. After the last object has been returned further
// calls to Next() will return io.EOF.
//
// In the current implementation any objects which cannot be found in the
// underlying repository will be skipped automatically. It is possible that this
// may change in future versions.
func (w *TreeWalker) Next() (name string, entry TreeEntry, err error) {
var obj *Tree
for {
current := len(w.stack) - 1
if current < 0 {
// Nothing left on the stack so we're finished
err = io.EOF
return
}
if current > maxTreeDepth {
// We're probably following bad data or some self-referencing tree
err = ErrMaxTreeDepth
return
}
entry, err = w.stack[current].Next()
if err == io.EOF {
// Finished with the current tree, move back up to the parent
w.stack = w.stack[:current]
w.base, _ = path.Split(w.base)
w.base = strings.TrimSuffix(w.base, "/")
continue
}
if err != nil {
return
}
if w.seen[entry.Hash] {
continue
}
if entry.Mode == filemode.Dir {
obj, err = GetTree(w.s, entry.Hash)
}
name = simpleJoin(w.base, entry.Name)
if err != nil {
err = io.EOF
return
}
break
}
if !w.recursive {
return
}
if obj != nil {
w.stack = append(w.stack, &treeEntryIter{obj, 0})
w.base = simpleJoin(w.base, entry.Name)
}
return
}
// Tree returns the tree that the tree walker most recently operated on.
func (w *TreeWalker) Tree() *Tree {
current := len(w.stack) - 1
if w.stack[current].pos == 0 {
current--
}
if current < 0 {
return nil
}
return w.stack[current].t
}
// Close releases any resources used by the TreeWalker.
func (w *TreeWalker) Close() {
w.stack = nil
}
// TreeIter provides an iterator for a set of trees.
type TreeIter struct {
storer.EncodedObjectIter
s storer.EncodedObjectStorer
}
// NewTreeIter takes a storer.EncodedObjectStorer and a
// storer.EncodedObjectIter and returns a *TreeIter that iterates over all
// tree contained in the storer.EncodedObjectIter.
//
// Any non-tree object returned by the storer.EncodedObjectIter is skipped.
func NewTreeIter(s storer.EncodedObjectStorer, iter storer.EncodedObjectIter) *TreeIter {
return &TreeIter{iter, s}
}
// Next moves the iterator to the next tree and returns a pointer to it. If
// there are no more trees, it returns io.EOF.
func (iter *TreeIter) Next() (*Tree, error) {
for {
obj, err := iter.EncodedObjectIter.Next()
if err != nil {
return nil, err
}
if obj.Type() != plumbing.TreeObject {
continue
}
return DecodeTree(iter.s, obj)
}
}
// ForEach call the cb function for each tree contained on this iter until
// an error happens or the end of the iter is reached. If ErrStop is sent
// the iteration is stop but no error is returned. The iterator is closed.
func (iter *TreeIter) ForEach(cb func(*Tree) error) error {
return iter.EncodedObjectIter.ForEach(func(obj plumbing.EncodedObject) error {
if obj.Type() != plumbing.TreeObject {
return nil
}
t, err := DecodeTree(iter.s, obj)
if err != nil {
return err
}
return cb(t)
})
}
func simpleJoin(parent, child string) string {
if len(parent) > 0 {
return parent + "/" + child
}
return child
}
