package git
import (
"bufio"
"errors"
"fmt"
"io"
"os"
"path"
"strconv"
"strings"
"gopkg.in/src-d/go-git.v4/core"
)
const (
maxTreeDepth = 1024
startingStackSize = 8
submoduleMode = 0160000
directoryMode = 0040000
)
// New errors defined by this package.
var (
ErrMaxTreeDepth = errors.New("maximum tree depth exceeded")
ErrFileNotFound = errors.New("file 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 core.Hash
r *Repository
m map[string]*TreeEntry
}
// TreeEntry represents a file
type TreeEntry struct {
Name string
Mode os.FileMode
Hash core.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
}
obj, err := t.r.s.ObjectStorage().Get(core.BlobObject, e.Hash)
if err != nil {
return nil, err
}
blob := &Blob{}
blob.Decode(obj)
return NewFile(path, e.Mode, blob), nil
}
func (t *Tree) findEntry(path string) (*TreeEntry, error) {
pathParts := strings.Split(path, "/")
var tree *Tree
var err error
for tree = t; len(pathParts) > 1; pathParts = pathParts[1:] {
if tree, err = tree.dir(pathParts[0]); err != nil {
return nil, err
}
}
return tree.entry(pathParts[0])
}
var errDirNotFound = errors.New("directory not found")
func (t *Tree) dir(baseName string) (*Tree, error) {
entry, err := t.entry(baseName)
if err != nil {
return nil, errDirNotFound
}
obj, err := t.r.s.ObjectStorage().Get(core.TreeObject, entry.Hash)
if err != nil {
return nil, err
}
tree := &Tree{r: t.r}
tree.Decode(obj)
return tree, nil
}
var errEntryNotFound = errors.New("entry not found")
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.r, 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() core.Hash {
return t.Hash
}
// Type returns the type of object. It always returns core.TreeObject.
func (t *Tree) Type() core.ObjectType {
return core.TreeObject
}
// Decode transform an core.Object into a Tree struct
func (t *Tree) Decode(o core.Object) (err error) {
if o.Type() != core.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 checkClose(reader, &err)
r := bufio.NewReader(reader)
for {
mode, err := r.ReadString(' ')
if err != nil {
if err == io.EOF {
break
}
return err
}
fm, err := t.decodeFileMode(mode[:len(mode)-1])
if err != nil && err != io.EOF {
return err
}
name, err := r.ReadString(0)
if err != nil && err != io.EOF {
return err
}
var hash core.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: fm,
Name: baseName,
})
}
return nil
}
func (t *Tree) decodeFileMode(mode string) (os.FileMode, error) {
fm, err := strconv.ParseInt(mode, 8, 32)
if err != nil && err != io.EOF {
return 0, err
}
m := os.FileMode(fm)
switch fm {
case 0040000: //tree
m = m | os.ModeDir
case 0120000: //symlink
m = m | os.ModeSymlink
}
return m, nil
}
// Encode transforms a Tree into a core.Object.
func (t *Tree) Encode(o core.Object) error {
o.SetType(core.TreeObject)
w, err := o.Writer()
if err != nil {
return err
}
var size int
defer checkClose(w, &err)
for _, entry := range t.Entries {
n, err := fmt.Fprintf(w, "%o %s", entry.Mode, entry.Name)
if err != nil {
return err
}
size += n
n, err = w.Write([]byte{0x00})
if err != nil {
return err
}
size += n
n, err = w.Write([]byte(entry.Hash[:]))
if err != nil {
return err
}
size += n
}
o.SetSize(int64(size))
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]
}
}
// 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 TreeIter struct {
stack []treeEntryIter
base string
recursive bool
r *Repository
t *Tree
}
// NewTreeIter returns a new TreeIter for the given repository and tree.
//
// It is the caller's responsibility to call Close() when finished with the
// tree walker.
func NewTreeIter(r *Repository, t *Tree, recursive bool) *TreeIter {
stack := make([]treeEntryIter, 0, startingStackSize)
stack = append(stack, treeEntryIter{t, 0})
return &TreeIter{
stack: stack,
recursive: recursive,
r: r,
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 *TreeIter) Next() (name string, entry TreeEntry, err error) {
var obj Object
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 = path.Clean(w.base) // Remove trailing slash
continue
}
if err != nil {
return
}
if entry.Mode == submoduleMode {
err = nil
continue
}
if entry.Mode.IsDir() {
obj, err = w.r.Tree(entry.Hash)
}
name = path.Join(w.base, entry.Name)
if err != nil {
err = io.EOF
return
}
break
}
if !w.recursive {
return
}
if t, ok := obj.(*Tree); ok {
w.stack = append(w.stack, treeEntryIter{t, 0})
w.base = path.Join(w.base, entry.Name)
}
return
}
// Tree returns the tree that the tree walker most recently operated on.
func (w *TreeIter) 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 *TreeIter) Close() {
w.stack = nil
}
