// ParseMultiaddr parses a multiaddr into an IPFSAddr
func ParseMultiaddr(m ma.Multiaddr) (a IPFSAddr, err error) {
	// never panic.
	defer func() {
		if r := recover(); r != nil {
			log.Debug("recovered from panic: ", r)
			a = nil
			err = ErrInvalidAddr
		}
	}()

	if m == nil {
		return nil, ErrInvalidAddr
	}

	// make sure it's an ipfs addr
	parts := ma.Split(m)
	if len(parts) < 1 {
		return nil, ErrInvalidAddr
	}
	ipfspart := parts[len(parts)-1] // last part
	if ipfspart.Protocols()[0].Code != ma.P_IPFS {
		return nil, ErrInvalidAddr
	}

	// make sure ipfs id parses as a peer.ID
	peerIdParts := path.SplitList(ipfspart.String())
	peerIdStr := peerIdParts[len(peerIdParts)-1]
	id, err := peer.IDB58Decode(peerIdStr)
	if err != nil {
		return nil, err
	}

	return ipfsAddr{ma: m, id: id}, nil
}

func mkdirP(t *testing.T, root *Directory, pth string) *Directory {
	dirs := path.SplitList(pth)
	cur := root
	for _, d := range dirs {
		n, err := cur.Mkdir(d)
		if err != nil && err != os.ErrExist {
			t.Fatal(err)
		}
		if err == os.ErrExist {
			fsn, err := cur.Child(d)
			if err != nil {
				t.Fatal(err)
			}
			switch fsn := fsn.(type) {
			case *Directory:
				n = fsn
			case *File:
				t.Fatal("tried to make a directory where a file already exists")
			}
		}

		cur = n
	}
	return cur
}

// adds a '-' to the beginning of each path element so we can use 'data' as a
// special link in the structure without having to worry about
func escapePath(pth string) string {
	elems := path.SplitList(strings.Trim(pth, "/"))
	for i, e := range elems {
		elems[i] = "-" + e
	}
	return path.Join(elems)
}

// Mkdir creates a directory at 'path' under the directory 'd', creating
// intermediary directories as needed if 'mkparents' is set to true
func Mkdir(r *Root, pth string, mkparents bool, flush bool) error {
	if pth == "" {
		return fmt.Errorf("no path given to Mkdir")
	}
	parts := path.SplitList(pth)
	if parts[0] == "" {
		parts = parts[1:]
	}

	// allow 'mkdir /a/b/c/' to create c
	if parts[len(parts)-1] == "" {
		parts = parts[:len(parts)-1]
	}

	if len(parts) == 0 {
		// this will only happen on 'mkdir /'
		if mkparents {
			return nil
		}
		return fmt.Errorf("cannot create directory '/': Already exists")
	}

	cur := r.GetValue().(*Directory)
	for i, d := range parts[:len(parts)-1] {
		fsn, err := cur.Child(d)
		if err == os.ErrNotExist && mkparents {
			mkd, err := cur.Mkdir(d)
			if err != nil {
				return err
			}
			fsn = mkd
		} else if err != nil {
			return err
		}

		next, ok := fsn.(*Directory)
		if !ok {
			return fmt.Errorf("%s was not a directory", path.Join(parts[:i]))
		}
		cur = next
	}

	final, err := cur.Mkdir(parts[len(parts)-1])
	if err != nil {
		if !mkparents || err != os.ErrExist || final == nil {
			return err
		}
	}

	if flush {
		err := final.Flush()
		if err != nil {
			return err
		}
	}

	return nil
}

func (e *Editor) RmLink(ctx context.Context, pth string) error {
	splpath := path.SplitList(pth)
	nd, err := e.rmLink(ctx, e.root, splpath)
	if err != nil {
		return err
	}
	e.root = nd
	return nil
}

func (e *Editor) InsertNodeAtPath(ctx context.Context, pth string, toinsert *dag.Node, create func() *dag.Node) error {
	splpath := path.SplitList(pth)
	nd, err := e.insertNodeAtPath(ctx, e.root, splpath, toinsert, create)
	if err != nil {
		return err
	}
	e.root = nd
	return nil
}

func escapeDhtKey(s string) (string, error) {
	parts := path.SplitList(s)
	switch len(parts) {
	case 1:
		return string(b58.Decode(s)), nil
	case 3:
		k := b58.Decode(parts[2])
		return path.Join(append(parts[:2], string(k))), nil
	default:
		return "", errors.New("invalid key")
	}
}

func escapeDhtKey(s string) (key.Key, error) {
	parts := path.SplitList(s)
	switch len(parts) {
	case 1:
		return key.B58KeyDecode(s), nil
	case 3:
		k := key.B58KeyDecode(parts[2])
		return key.Key(path.Join(append(parts[:2], k.String()))), nil
	default:
		return "", errors.New("invalid key")
	}
}

func assertFileAtPath(ds dag.DAGService, root *Directory, expn node.Node, pth string) error {
	exp, ok := expn.(*dag.ProtoNode)
	if !ok {
		return dag.ErrNotProtobuf
	}

	parts := path.SplitList(pth)
	cur := root
	for i, d := range parts[:len(parts)-1] {
		next, err := cur.Child(d)
		if err != nil {
			return fmt.Errorf("looking for %s failed: %s", pth, err)
		}

		nextDir, ok := next.(*Directory)
		if !ok {
			return fmt.Errorf("%s points to a non-directory", parts[:i+1])
		}

		cur = nextDir
	}

	last := parts[len(parts)-1]
	finaln, err := cur.Child(last)
	if err != nil {
		return err
	}

	file, ok := finaln.(*File)
	if !ok {
		return fmt.Errorf("%s was not a file!", pth)
	}

	rfd, err := file.Open(OpenReadOnly, false)
	if err != nil {
		return err
	}

	out, err := ioutil.ReadAll(rfd)
	if err != nil {
		return err
	}

	expbytes, err := catNode(ds, exp)
	if err != nil {
		return err
	}

	if !bytes.Equal(out, expbytes) {
		return fmt.Errorf("Incorrect data at path!")
	}
	return nil
}

func (v Validator) IsSigned(k key.Key) (bool, error) {
	// Now, check validity func
	parts := path.SplitList(string(k))
	if len(parts) < 3 {
		log.Infof("Record key does not have validator: %s", k)
		return false, nil
	}

	val, ok := v[parts[1]]
	if !ok {
		log.Infof("Unrecognized key prefix: %s", parts[1])
		return false, ErrInvalidRecordType
	}

	return val.Sign, nil
}

// VerifyRecord checks a record and ensures it is still valid.
// It runs needed validators
func (v Validator) VerifyRecord(r *pb.Record) error {
	// Now, check validity func
	parts := path.SplitList(r.GetKey())
	if len(parts) < 3 {
		log.Infof("Record key does not have validator: %s", key.Key(r.GetKey()))
		return nil
	}

	val, ok := v[parts[1]]
	if !ok {
		log.Infof("Unrecognized key prefix: %s", parts[1])
		return ErrInvalidRecordType
	}

	return val.Func(key.Key(r.GetKey()), r.GetValue())
}

func assertNodeAtPath(t *testing.T, ds dag.DAGService, root *dag.ProtoNode, pth string, exp *cid.Cid) {
	parts := path.SplitList(pth)
	cur := root
	for _, e := range parts {
		nxt, err := cur.GetLinkedProtoNode(context.Background(), ds, e)
		if err != nil {
			t.Fatal(err)
		}

		cur = nxt
	}

	curc := cur.Cid()
	if !curc.Equals(exp) {
		t.Fatal("node not as expected at end of path")
	}
}

func (s Selector) BestRecord(k key.Key, recs [][]byte) (int, error) {
	if len(recs) == 0 {
		return 0, errors.New("no records given!")
	}

	parts := path.SplitList(string(k))
	if len(parts) < 3 {
		log.Infof("Record key does not have selectorfunc: %s", k)
		return 0, errors.New("record key does not have selectorfunc")
	}

	sel, ok := s[parts[1]]
	if !ok {
		log.Infof("Unrecognized key prefix: %s", parts[1])
		return 0, ErrInvalidRecordType
	}

	return sel(k, recs)
}

func assertNodeAtPath(t *testing.T, ds dag.DAGService, root *dag.Node, pth string, exp key.Key) {
	parts := path.SplitList(pth)
	cur := root
	for _, e := range parts {
		nxt, err := cur.GetLinkedNode(context.Background(), ds, e)
		if err != nil {
			t.Fatal(err)
		}

		cur = nxt
	}

	curk, err := cur.Key()
	if err != nil {
		t.Fatal(err)
	}

	if curk != exp {
		t.Fatal("node not as expected at end of path")
	}
}

func TestIDMatches(t *testing.T) {
	for _, g := range good {
		a, err := ParseString(g)
		if err != nil {
			t.Error("failed to parse", g, err)
			continue
		}

		sp := path.SplitList(g)
		sid := sp[len(sp)-1]
		id, err := peer.IDB58Decode(sid)
		if err != nil {
			t.Error("failed to parse", sid, err)
			continue
		}

		if a.ID() != id {
			t.Error("not equal", a.ID(), id)
		}
	}
}

// DirLookup will look up a file or directory at the given path
// under the directory 'd'
func DirLookup(d *Directory, pth string) (FSNode, error) {
	pth = strings.Trim(pth, "/")
	parts := path.SplitList(pth)
	if len(parts) == 1 && parts[0] == "" {
		return d, nil
	}

	var cur FSNode
	cur = d
	for i, p := range parts {
		chdir, ok := cur.(*Directory)
		if !ok {
			return nil, fmt.Errorf("cannot access %s: Not a directory", path.Join(parts[:i+1]))
		}

		child, err := chdir.Child(p)
		if err != nil {
			return nil, err
		}

		cur = child
	}
	return cur, nil
}

//.........这里部分代码省略.........
		w.Header().Set("Cache-Control", "public, max-age=29030400")

		// set modtime to a really long time ago, since files are immutable and should stay cached
		modtime = time.Unix(1, 0)
	}

	if err == nil {
		defer dr.Close()
		name := gopath.Base(urlPath)
		http.ServeContent(w, r, name, modtime, dr)
		return
	}

	// storage for directory listing
	var dirListing []directoryItem
	// loop through files
	foundIndex := false
	for _, link := range nd.Links {
		if link.Name == "index.html" {
			log.Debugf("found index.html link for %s", urlPath)
			foundIndex = true

			if urlPath[len(urlPath)-1] != '/' {
				// See comment above where originalUrlPath is declared.
				http.Redirect(w, r, originalUrlPath+"/", 302)
				log.Debugf("redirect to %s", originalUrlPath+"/")
				return
			}

			// return index page instead.
			nd, err := core.Resolve(ctx, i.node, path.Path(urlPath+"/index.html"))
			if err != nil {
				internalWebError(w, err)
				return
			}
			dr, err := uio.NewDagReader(ctx, nd, i.node.DAG)
			if err != nil {
				internalWebError(w, err)
				return
			}
			defer dr.Close()

			// write to request
			http.ServeContent(w, r, "index.html", modtime, dr)
			break
		}

		// See comment above where originalUrlPath is declared.
		di := directoryItem{humanize.Bytes(link.Size), link.Name, gopath.Join(originalUrlPath, link.Name)}
		dirListing = append(dirListing, di)
	}

	if !foundIndex {
		if r.Method != "HEAD" {
			// construct the correct back link
			// https://github.com/ipfs/go-ipfs/issues/1365
			var backLink string = prefix + urlPath

			// don't go further up than /ipfs/$hash/
			pathSplit := path.SplitList(backLink)
			switch {
			// keep backlink
			case len(pathSplit) == 3: // url: /ipfs/$hash

			// keep backlink
			case len(pathSplit) == 4 && pathSplit[3] == "": // url: /ipfs/$hash/

			// add the correct link depending on wether the path ends with a slash
			default:
				if strings.HasSuffix(backLink, "/") {
					backLink += "./.."
				} else {
					backLink += "/.."
				}
			}

			// strip /ipfs/$hash from backlink if IPNSHostnameOption touched the path.
			if ipnsHostname {
				backLink = prefix + "/"
				if len(pathSplit) > 5 {
					// also strip the trailing segment, because it's a backlink
					backLinkParts := pathSplit[3 : len(pathSplit)-2]
					backLink += path.Join(backLinkParts) + "/"
				}
			}

			// See comment above where originalUrlPath is declared.
			tplData := listingTemplateData{
				Listing:  dirListing,
				Path:     originalUrlPath,
				BackLink: backLink,
			}
			err := listingTemplate.Execute(w, tplData)
			if err != nil {
				internalWebError(w, err)
				return
			}
		}
	}
}

//.........这里部分代码省略.........
	if !dir {
		name := gopath.Base(urlPath)
		http.ServeContent(w, r, name, modtime, dr)
		return
	}

	links, err := i.api.Ls(ctx, urlPath)
	if err != nil {
		internalWebError(w, err)
		return
	}

	// storage for directory listing
	var dirListing []directoryItem
	// loop through files
	foundIndex := false
	for _, link := range links {
		if link.Name == "index.html" {
			log.Debugf("found index.html link for %s", urlPath)
			foundIndex = true

			if urlPath[len(urlPath)-1] != '/' {
				// See comment above where originalUrlPath is declared.
				http.Redirect(w, r, originalUrlPath+"/", 302)
				log.Debugf("redirect to %s", originalUrlPath+"/")
				return
			}

			p, err := path.ParsePath(urlPath + "/index.html")
			if err != nil {
				internalWebError(w, err)
				return
			}

			// return index page instead.
			dr, err := i.api.Cat(ctx, p.String())
			if err != nil {
				internalWebError(w, err)
				return
			}
			defer dr.Close()

			// write to request
			http.ServeContent(w, r, "index.html", modtime, dr)
			break
		}

		// See comment above where originalUrlPath is declared.
		di := directoryItem{humanize.Bytes(link.Size), link.Name, gopath.Join(originalUrlPath, link.Name)}
		dirListing = append(dirListing, di)
	}

	if !foundIndex {
		if r.Method != "HEAD" {
			// construct the correct back link
			// https://github.com/ipfs/go-ipfs/issues/1365
			var backLink string = prefix + urlPath

			// don't go further up than /ipfs/$hash/
			pathSplit := path.SplitList(backLink)
			switch {
			// keep backlink
			case len(pathSplit) == 3: // url: /ipfs/$hash

			// keep backlink
			case len(pathSplit) == 4 && pathSplit[3] == "": // url: /ipfs/$hash/

			// add the correct link depending on wether the path ends with a slash
			default:
				if strings.HasSuffix(backLink, "/") {
					backLink += "./.."
				} else {
					backLink += "/.."
				}
			}

			// strip /ipfs/$hash from backlink if IPNSHostnameOption touched the path.
			if ipnsHostname {
				backLink = prefix + "/"
				if len(pathSplit) > 5 {
					// also strip the trailing segment, because it's a backlink
					backLinkParts := pathSplit[3 : len(pathSplit)-2]
					backLink += path.Join(backLinkParts) + "/"
				}
			}

			// See comment above where originalUrlPath is declared.
			tplData := listingTemplateData{
				Listing:  dirListing,
				Path:     originalUrlPath,
				BackLink: backLink,
			}
			err := listingTemplate.Execute(w, tplData)
			if err != nil {
				internalWebError(w, err)
				return
			}
		}
	}
}

// Parse parses the data in a http.Request and returns a command Request object
func Parse(r *http.Request, root *cmds.Command) (cmds.Request, error) {
	if !strings.HasPrefix(r.URL.Path, ApiPath) {
		return nil, errors.New("Unexpected path prefix")
	}
	pth := path.SplitList(strings.TrimPrefix(r.URL.Path, ApiPath+"/"))

	stringArgs := make([]string, 0)

	if err := apiVersionMatches(r); err != nil {
		if pth[0] != "version" { // compatibility with previous version check
			return nil, err
		}
	}

	cmd, err := root.Get(pth[:len(pth)-1])
	if err != nil {
		// 404 if there is no command at that path
		return nil, ErrNotFound

	}

	if sub := cmd.Subcommand(pth[len(pth)-1]); sub == nil {
		if len(pth) <= 1 {
			return nil, ErrNotFound
		}

		// if the last string in the path isn't a subcommand, use it as an argument
		// e.g. /objects/Qabc12345 (we are passing "Qabc12345" to the "objects" command)
		stringArgs = append(stringArgs, pth[len(pth)-1])
		pth = pth[:len(pth)-1]

	} else {
		cmd = sub
	}

	opts, stringArgs2 := parseOptions(r)
	stringArgs = append(stringArgs, stringArgs2...)

	// count required argument definitions
	numRequired := 0
	for _, argDef := range cmd.Arguments {
		if argDef.Required {
			numRequired++
		}
	}

	// count the number of provided argument values
	valCount := len(stringArgs)

	args := make([]string, valCount)

	valIndex := 0
	requiredFile := ""
	for _, argDef := range cmd.Arguments {
		// skip optional argument definitions if there aren't sufficient remaining values
		if valCount-valIndex <= numRequired && !argDef.Required {
			continue
		} else if argDef.Required {
			numRequired--
		}

		if argDef.Type == cmds.ArgString {
			if argDef.Variadic {
				for _, s := range stringArgs {
					args[valIndex] = s
					valIndex++
				}
				valCount -= len(stringArgs)

			} else if len(stringArgs) > 0 {
				args[valIndex] = stringArgs[0]
				stringArgs = stringArgs[1:]
				valIndex++

			} else {
				break
			}
		} else if argDef.Type == cmds.ArgFile && argDef.Required && len(requiredFile) == 0 {
			requiredFile = argDef.Name
		}
	}

	optDefs, err := root.GetOptions(pth)
	if err != nil {
		return nil, err
	}

	// create cmds.File from multipart/form-data contents
	contentType := r.Header.Get(contentTypeHeader)
	mediatype, _, _ := mime.ParseMediaType(contentType)

	var f files.File
	if mediatype == "multipart/form-data" {
		reader, err := r.MultipartReader()
		if err != nil {
			return nil, err
		}

		f = &files.MultipartFile{
//.........这里部分代码省略.........