🎇 webdav unfinished

model/file.go

@@ -1,6 +1,7 @@
 package model
 
 import (
+	"github.com/Xhofe/alist/conf"
 	"sort"
 	"strings"
 	"time"
@@ -47,3 +48,19 @@ func SortFiles(files []File, account *Account) {
 		return false
 	})
 }
+
+func (f File) GetSize() uint64 {
+	return uint64(f.Size)
+}
+
+func (f File) GetName() string {
+	return f.Name
+}
+
+func (f File) ModTime() time.Time {
+	return *f.UpdatedAt
+}
+
+func (f File) IsDir() bool {
+	return f.Type == conf.FOLDER
+}

server/router.go

@@ -40,6 +40,7 @@ func InitApiRouter(r *gin.Engine) {
 		admin.DELETE("/meta", DeleteMeta)
 	}
 	Static(r)
+	WebDav(r)
 }
 
 func Cors(r *gin.Engine) {

server/webdav.go

@@ -0,0 +1,34 @@
+package server
+
+import (
+	"github.com/Xhofe/alist/server/webdav"
+	"github.com/gin-gonic/gin"
+)
+
+var handler *webdav.Handler
+
+func init() {
+	handler = &webdav.Handler{
+		Prefix:     "/dav",
+		LockSystem: webdav.NewMemLS(),
+	}
+}
+
+func WebDav(r *gin.Engine) {
+	dav := r.Group("/dav")
+	dav.Any("/*path", ServeWebDAV)
+	dav.Any("", ServeWebDAV)
+	dav.Handle("PROPFIND", "/*path", ServeWebDAV)
+	dav.Handle("PROPFIND", "", ServeWebDAV)
+	dav.Handle("MKCOL", "/*path", ServeWebDAV)
+	dav.Handle("LOCK", "/*path", ServeWebDAV)
+	dav.Handle("UNLOCK", "/*path", ServeWebDAV)
+	dav.Handle("PROPPATCH", "/*path", ServeWebDAV)
+	dav.Handle("COPY", "/*path", ServeWebDAV)
+	dav.Handle("MOVE", "/*path", ServeWebDAV)
+}
+
+func ServeWebDAV(c *gin.Context) {
+	fs := webdav.FileSystem{}
+	handler.ServeHTTP(c.Writer,c.Request,&fs)
+}

server/webdav/file.go

@@ -0,0 +1,162 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package webdav
+
+import (
+	"context"
+	"fmt"
+	"github.com/Xhofe/alist/conf"
+	"github.com/Xhofe/alist/drivers"
+	"github.com/Xhofe/alist/model"
+	"github.com/Xhofe/alist/utils"
+	"net/http"
+	"path"
+	"path/filepath"
+	"strings"
+)
+
+type FileSystem struct {}
+
+func ParsePath(rawPath string) (*model.Account, string, drivers.Driver, error) {
+	var path, name string
+	switch model.AccountsCount() {
+	case 0:
+		return nil, "", nil, fmt.Errorf("no accounts,please add one first")
+	case 1:
+		path = rawPath
+		break
+	default:
+		paths := strings.Split(rawPath, "/")
+		path = "/" + strings.Join(paths[2:], "/")
+		name = paths[1]
+	}
+	account, ok := model.GetAccount(name)
+	if !ok {
+		return nil, "", nil, fmt.Errorf("no [%s] account", name)
+	}
+	driver, ok := drivers.GetDriver(account.Type)
+	if !ok {
+		return nil, "", nil, fmt.Errorf("no [%s] driver", account.Type)
+	}
+	return &account, path, driver, nil
+}
+
+func (fs *FileSystem) File(rawPath string) (*model.File,error) {
+	rawPath = utils.ParsePath(rawPath)
+	if model.AccountsCount() > 1 && rawPath == "/" {
+		return &model.File{
+			Name:      "root",
+			Size:      0,
+			Type:      conf.FOLDER,
+			Driver:    "root",
+			UpdatedAt: nil,
+		},nil
+	}
+	account, path_, driver, err := ParsePath(rawPath)
+	if err != nil {
+		return nil, err
+	}
+	return driver.File(path_,account)
+}
+
+func (fs *FileSystem) Files(rawPath string) ([]model.File,error) {
+	rawPath = utils.ParsePath(rawPath)
+	if model.AccountsCount() > 1 && rawPath == "/" {
+		files, err := model.GetAccountFiles()
+		if err != nil {
+			return nil, err
+		}
+		return files,nil
+	}
+	account, path_, driver, err := ParsePath(rawPath)
+	if err != nil {
+		return nil, err
+	}
+	return driver.Files(path_,account)
+}
+
+func (fs *FileSystem) Link(rawPath string) (string, error) {
+	rawPath = utils.ParsePath(rawPath)
+	if model.AccountsCount() > 1 && rawPath == "/" {
+		// error
+	}
+	account, path_, driver, err := ParsePath(rawPath)
+	if err != nil {
+		return "", err
+	}
+	return driver.Link(path_,account)
+}
+
+func (fs *FileSystem) CreateDirectory(ctx context.Context, reqPath string) (interface{}, error) {
+	return nil, nil
+}
+
+// slashClean is equivalent to but slightly more efficient than
+// path.Clean("/" + name).
+func slashClean(name string) string {
+	if name == "" || name[0] != '/' {
+		name = "/" + name
+	}
+	return path.Clean(name)
+}
+
+// moveFiles moves files and/or directories from src to dst.
+//
+// See section 9.9.4 for when various HTTP status codes apply.
+func moveFiles(ctx context.Context, fs *FileSystem, src FileInfo, dst string, overwrite bool) (status int, err error) {
+
+	return http.StatusNoContent, nil
+}
+
+// copyFiles copies files and/or directories from src to dst.
+//
+// See section 9.8.5 for when various HTTP status codes apply.
+func copyFiles(ctx context.Context, fs *FileSystem, src FileInfo, dst string, overwrite bool, depth int, recursion int) (status int, err error) {
+
+	return http.StatusNoContent, nil
+}
+
+// walkFS traverses filesystem fs starting at name up to depth levels.
+//
+// Allowed values for depth are 0, 1 or infiniteDepth. For each visited node,
+// walkFS calls walkFn. If a visited file system node is a directory and
+// walkFn returns filepath.SkipDir, walkFS will skip traversal of this node.
+func walkFS(
+	ctx context.Context,
+	fs *FileSystem,
+	depth int,
+	name string,
+	info FileInfo,
+	walkFn func(reqPath string, info FileInfo, err error) error) error {
+	// This implementation is based on Walk's code in the standard path/filepath package.
+	err := walkFn(name, info, nil)
+	if err != nil {
+		if info.IsDir() && err == filepath.SkipDir {
+			return nil
+		}
+		return err
+	}
+	if !info.IsDir() || depth == 0 {
+		return nil
+	}
+	if depth == 1 {
+		depth = 0
+	}
+
+	files, err := fs.Files(name)
+	if err != nil {
+		return err
+	}
+	for _, fileInfo := range files {
+		filename := path.Join(name, fileInfo.Name)
+		err = walkFS(ctx, fs, depth, filename, &fileInfo, walkFn)
+		if err != nil {
+			if !fileInfo.IsDir() || err != filepath.SkipDir {
+				return err
+			}
+		}
+	}
+	return nil
+}

server/webdav/if.go

@@ -0,0 +1,173 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package webdav
+
+// The If header is covered by Section 10.4.
+// http://www.webdav.org/specs/rfc4918.html#HEADER_If
+
+import (
+	"strings"
+)
+
+// ifHeader is a disjunction (OR) of ifLists.
+type ifHeader struct {
+	lists []ifList
+}
+
+// ifList is a conjunction (AND) of Conditions, and an optional resource tag.
+type ifList struct {
+	resourceTag string
+	conditions  []Condition
+}
+
+// parseIfHeader parses the "If: foo bar" HTTP header. The httpHeader string
+// should omit the "If:" prefix and have any "\r\n"s collapsed to a " ", as is
+// returned by req.Header.Get("If") for a http.Request req.
+func parseIfHeader(httpHeader string) (h ifHeader, ok bool) {
+	s := strings.TrimSpace(httpHeader)
+	switch tokenType, _, _ := lex(s); tokenType {
+	case '(':
+		return parseNoTagLists(s)
+	case angleTokenType:
+		return parseTaggedLists(s)
+	default:
+		return ifHeader{}, false
+	}
+}
+
+func parseNoTagLists(s string) (h ifHeader, ok bool) {
+	for {
+		l, remaining, ok := parseList(s)
+		if !ok {
+			return ifHeader{}, false
+		}
+		h.lists = append(h.lists, l)
+		if remaining == "" {
+			return h, true
+		}
+		s = remaining
+	}
+}
+
+func parseTaggedLists(s string) (h ifHeader, ok bool) {
+	resourceTag, n := "", 0
+	for first := true; ; first = false {
+		tokenType, tokenStr, remaining := lex(s)
+		switch tokenType {
+		case angleTokenType:
+			if !first && n == 0 {
+				return ifHeader{}, false
+			}
+			resourceTag, n = tokenStr, 0
+			s = remaining
+		case '(':
+			n++
+			l, remaining, ok := parseList(s)
+			if !ok {
+				return ifHeader{}, false
+			}
+			l.resourceTag = resourceTag
+			h.lists = append(h.lists, l)
+			if remaining == "" {
+				return h, true
+			}
+			s = remaining
+		default:
+			return ifHeader{}, false
+		}
+	}
+}
+
+func parseList(s string) (l ifList, remaining string, ok bool) {
+	tokenType, _, s := lex(s)
+	if tokenType != '(' {
+		return ifList{}, "", false
+	}
+	for {
+		tokenType, _, remaining = lex(s)
+		if tokenType == ')' {
+			if len(l.conditions) == 0 {
+				return ifList{}, "", false
+			}
+			return l, remaining, true
+		}
+		c, remaining, ok := parseCondition(s)
+		if !ok {
+			return ifList{}, "", false
+		}
+		l.conditions = append(l.conditions, c)
+		s = remaining
+	}
+}
+
+func parseCondition(s string) (c Condition, remaining string, ok bool) {
+	tokenType, tokenStr, s := lex(s)
+	if tokenType == notTokenType {
+		c.Not = true
+		tokenType, tokenStr, s = lex(s)
+	}
+	switch tokenType {
+	case strTokenType, angleTokenType:
+		c.Token = tokenStr
+	case squareTokenType:
+		c.ETag = tokenStr
+	default:
+		return Condition{}, "", false
+	}
+	return c, s, true
+}
+
+// Single-rune tokens like '(' or ')' have a token type equal to their rune.
+// All other tokens have a negative token type.
+const (
+	errTokenType    = rune(-1)
+	eofTokenType    = rune(-2)
+	strTokenType    = rune(-3)
+	notTokenType    = rune(-4)
+	angleTokenType  = rune(-5)
+	squareTokenType = rune(-6)
+)
+
+func lex(s string) (tokenType rune, tokenStr string, remaining string) {
+	// The net/textproto Data that parses the HTTP header will collapse
+	// Linear White Space that spans multiple "\r\n" lines to a single " ",
+	// so we don't need to look for '\r' or '\n'.
+	for len(s) > 0 && (s[0] == '\t' || s[0] == ' ') {
+		s = s[1:]
+	}
+	if len(s) == 0 {
+		return eofTokenType, "", ""
+	}
+	i := 0
+loop:
+	for ; i < len(s); i++ {
+		switch s[i] {
+		case '\t', ' ', '(', ')', '<', '>', '[', ']':
+			break loop
+		}
+	}
+
+	if i != 0 {
+		tokenStr, remaining = s[:i], s[i:]
+		if tokenStr == "Not" {
+			return notTokenType, "", remaining
+		}
+		return strTokenType, tokenStr, remaining
+	}
+
+	j := 0
+	switch s[0] {
+	case '<':
+		j, tokenType = strings.IndexByte(s, '>'), angleTokenType
+	case '[':
+		j, tokenType = strings.IndexByte(s, ']'), squareTokenType
+	default:
+		return rune(s[0]), "", s[1:]
+	}
+	if j < 0 {
+		return errTokenType, "", ""
+	}
+	return tokenType, s[1:j], s[j+1:]
+}

server/webdav/internal/xml/README

@@ -0,0 +1,11 @@
+This is a fork of the encoding/xml package at ca1d6c4, the last commit before
+https://go.googlesource.com/go/+/c0d6d33 "encoding/xml: restore Go 1.4 name
+space behavior" made late in the lead-up to the Go 1.5 release.
+
+The list of encoding/xml changes is at
+https://go.googlesource.com/go/+log/master/src/encoding/xml
+
+This fork is temporary, and I (nigeltao) expect to revert it after Go 1.6 is
+released.
+
+See http://golang.org/issue/11841

server/webdav/internal/xml/read.go

@@ -0,0 +1,692 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package xml
+
+import (
+	"bytes"
+	"encoding"
+	"errors"
+	"fmt"
+	"reflect"
+	"strconv"
+	"strings"
+)
+
+// BUG(rsc): Mapping between XML elements and data structures is inherently flawed:
+// an XML element is an order-dependent collection of anonymous
+// values, while a data structure is an order-independent collection
+// of named values.
+// See package json for a textual representation more suitable
+// to data structures.
+
+// Unmarshal parses the XML-encoded data and stores the result in
+// the value pointed to by v, which must be an arbitrary struct,
+// slice, or string. Well-formed data that does not fit into v is
+// discarded.
+//
+// Because Unmarshal uses the reflect package, it can only assign
+// to exported (upper case) fields. Unmarshal uses a case-sensitive
+// comparison to match XML element names to tag values and struct
+// field names.
+//
+// Unmarshal maps an XML element to a struct using the following rules.
+// In the rules, the tag of a field refers to the value associated with the
+// key 'xml' in the struct field's tag (see the example above).
+//
+//   * If the struct has a field of type []byte or string with tag
+//      ",innerxml", Unmarshal accumulates the raw XML nested inside the
+//      element in that field. The rest of the rules still apply.
+//
+//   * If the struct has a field named XMLName of type xml.Name,
+//      Unmarshal records the element name in that field.
+//
+//   * If the XMLName field has an associated tag of the form
+//      "name" or "namespace-URL name", the XML element must have
+//      the given name (and, optionally, name space) or else Unmarshal
+//      returns an error.
+//
+//   * If the XML element has an attribute whose name matches a
+//      struct field name with an associated tag containing ",attr" or
+//      the explicit name in a struct field tag of the form "name,attr",
+//      Unmarshal records the attribute value in that field.
+//
+//   * If the XML element contains character data, that data is
+//      accumulated in the first struct field that has tag ",chardata".
+//      The struct field may have type []byte or string.
+//      If there is no such field, the character data is discarded.
+//
+//   * If the XML element contains comments, they are accumulated in
+//      the first struct field that has tag ",comment".  The struct
+//      field may have type []byte or string. If there is no such
+//      field, the comments are discarded.
+//
+//   * If the XML element contains a sub-element whose name matches
+//      the prefix of a tag formatted as "a" or "a>b>c", unmarshal
+//      will descend into the XML structure looking for elements with the
+//      given names, and will map the innermost elements to that struct
+//      field. A tag starting with ">" is equivalent to one starting
+//      with the field name followed by ">".
+//
+//   * If the XML element contains a sub-element whose name matches
+//      a struct field's XMLName tag and the struct field has no
+//      explicit name tag as per the previous rule, unmarshal maps
+//      the sub-element to that struct field.
+//
+//   * If the XML element contains a sub-element whose name matches a
+//      field without any mode flags (",attr", ",chardata", etc), Unmarshal
+//      maps the sub-element to that struct field.
+//
+//   * If the XML element contains a sub-element that hasn't matched any
+//      of the above rules and the struct has a field with tag ",any",
+//      unmarshal maps the sub-element to that struct field.
+//
+//   * An anonymous struct field is handled as if the fields of its
+//      value were part of the outer struct.
+//
+//   * A struct field with tag "-" is never unmarshalled into.
+//
+// Unmarshal maps an XML element to a string or []byte by saving the
+// concatenation of that element's character data in the string or
+// []byte. The saved []byte is never nil.
+//
+// Unmarshal maps an attribute value to a string or []byte by saving
+// the value in the string or slice.
+//
+// Unmarshal maps an XML element to a slice by extending the length of
+// the slice and mapping the element to the newly created value.
+//
+// Unmarshal maps an XML element or attribute value to a bool by
+// setting it to the boolean value represented by the string.
+//
+// Unmarshal maps an XML element or attribute value to an integer or
+// floating-point field by setting the field to the result of
+// interpreting the string value in decimal. There is no check for
+// overflow.
+//
+// Unmarshal maps an XML element to an xml.Name by recording the
+// element name.
+//
+// Unmarshal maps an XML element to a pointer by setting the pointer
+// to a freshly allocated value and then mapping the element to that value.
+//
+func Unmarshal(data []byte, v interface{}) error {
+	return NewDecoder(bytes.NewReader(data)).Decode(v)
+}
+
+// Decode works like xml.Unmarshal, except it reads the decoder
+// stream to find the start element.
+func (d *Decoder) Decode(v interface{}) error {
+	return d.DecodeElement(v, nil)
+}
+
+// DecodeElement works like xml.Unmarshal except that it takes
+// a pointer to the start XML element to decode into v.
+// It is useful when a client reads some raw XML tokens itself
+// but also wants to defer to Unmarshal for some elements.
+func (d *Decoder) DecodeElement(v interface{}, start *StartElement) error {
+	val := reflect.ValueOf(v)
+	if val.Kind() != reflect.Ptr {
+		return errors.New("non-pointer passed to Unmarshal")
+	}
+	return d.unmarshal(val.Elem(), start)
+}
+
+// An UnmarshalError represents an error in the unmarshalling process.
+type UnmarshalError string
+
+func (e UnmarshalError) Error() string { return string(e) }
+
+// Unmarshaler is the interface implemented by objects that can unmarshal
+// an XML element description of themselves.
+//
+// UnmarshalXML decodes a single XML element
+// beginning with the given start element.
+// If it returns an error, the outer call to Unmarshal stops and
+// returns that error.
+// UnmarshalXML must consume exactly one XML element.
+// One common implementation strategy is to unmarshal into
+// a separate value with a layout matching the expected XML
+// using d.DecodeElement,  and then to copy the data from
+// that value into the receiver.
+// Another common strategy is to use d.Token to process the
+// XML object one token at a time.
+// UnmarshalXML may not use d.RawToken.
+type Unmarshaler interface {
+	UnmarshalXML(d *Decoder, start StartElement) error
+}
+
+// UnmarshalerAttr is the interface implemented by objects that can unmarshal
+// an XML attribute description of themselves.
+//
+// UnmarshalXMLAttr decodes a single XML attribute.
+// If it returns an error, the outer call to Unmarshal stops and
+// returns that error.
+// UnmarshalXMLAttr is used only for struct fields with the
+// "attr" option in the field tag.
+type UnmarshalerAttr interface {
+	UnmarshalXMLAttr(attr Attr) error
+}
+
+// receiverType returns the receiver type to use in an expression like "%s.MethodName".
+func receiverType(val interface{}) string {
+	t := reflect.TypeOf(val)
+	if t.Name() != "" {
+		return t.String()
+	}
+	return "(" + t.String() + ")"
+}
+
+// unmarshalInterface unmarshals a single XML element into val.
+// start is the opening tag of the element.
+func (p *Decoder) unmarshalInterface(val Unmarshaler, start *StartElement) error {
+	// Record that decoder must stop at end tag corresponding to start.
+	p.pushEOF()
+
+	p.unmarshalDepth++
+	err := val.UnmarshalXML(p, *start)
+	p.unmarshalDepth--
+	if err != nil {
+		p.popEOF()
+		return err
+	}
+
+	if !p.popEOF() {
+		return fmt.Errorf("xml: %s.UnmarshalXML did not consume entire <%s> element", receiverType(val), start.Name.Local)
+	}
+
+	return nil
+}
+
+// unmarshalTextInterface unmarshals a single XML element into val.
+// The chardata contained in the element (but not its children)
+// is passed to the text unmarshaler.
+func (p *Decoder) unmarshalTextInterface(val encoding.TextUnmarshaler, start *StartElement) error {
+	var buf []byte
+	depth := 1
+	for depth > 0 {
+		t, err := p.Token()
+		if err != nil {
+			return err
+		}
+		switch t := t.(type) {
+		case CharData:
+			if depth == 1 {
+				buf = append(buf, t...)
+			}
+		case StartElement:
+			depth++
+		case EndElement:
+			depth--
+		}
+	}
+	return val.UnmarshalText(buf)
+}
+
+// unmarshalAttr unmarshals a single XML attribute into val.
+func (p *Decoder) unmarshalAttr(val reflect.Value, attr Attr) error {
+	if val.Kind() == reflect.Ptr {
+		if val.IsNil() {
+			val.Set(reflect.New(val.Type().Elem()))
+		}
+		val = val.Elem()
+	}
+
+	if val.CanInterface() && val.Type().Implements(unmarshalerAttrType) {
+		// This is an unmarshaler with a non-pointer receiver,
+		// so it's likely to be incorrect, but we do what we're told.
+		return val.Interface().(UnmarshalerAttr).UnmarshalXMLAttr(attr)
+	}
+	if val.CanAddr() {
+		pv := val.Addr()
+		if pv.CanInterface() && pv.Type().Implements(unmarshalerAttrType) {
+			return pv.Interface().(UnmarshalerAttr).UnmarshalXMLAttr(attr)
+		}
+	}
+
+	// Not an UnmarshalerAttr; try encoding.TextUnmarshaler.
+	if val.CanInterface() && val.Type().Implements(textUnmarshalerType) {
+		// This is an unmarshaler with a non-pointer receiver,
+		// so it's likely to be incorrect, but we do what we're told.
+		return val.Interface().(encoding.TextUnmarshaler).UnmarshalText([]byte(attr.Value))
+	}
+	if val.CanAddr() {
+		pv := val.Addr()
+		if pv.CanInterface() && pv.Type().Implements(textUnmarshalerType) {
+			return pv.Interface().(encoding.TextUnmarshaler).UnmarshalText([]byte(attr.Value))
+		}
+	}
+
+	copyValue(val, []byte(attr.Value))
+	return nil
+}
+
+var (
+	unmarshalerType     = reflect.TypeOf((*Unmarshaler)(nil)).Elem()
+	unmarshalerAttrType = reflect.TypeOf((*UnmarshalerAttr)(nil)).Elem()
+	textUnmarshalerType = reflect.TypeOf((*encoding.TextUnmarshaler)(nil)).Elem()
+)
+
+// Unmarshal a single XML element into val.
+func (p *Decoder) unmarshal(val reflect.Value, start *StartElement) error {
+	// Find start element if we need it.
+	if start == nil {
+		for {
+			tok, err := p.Token()
+			if err != nil {
+				return err
+			}
+			if t, ok := tok.(StartElement); ok {
+				start = &t
+				break
+			}
+		}
+	}
+
+	// Load value from interface, but only if the result will be
+	// usefully addressable.
+	if val.Kind() == reflect.Interface && !val.IsNil() {
+		e := val.Elem()
+		if e.Kind() == reflect.Ptr && !e.IsNil() {
+			val = e
+		}
+	}
+
+	if val.Kind() == reflect.Ptr {
+		if val.IsNil() {
+			val.Set(reflect.New(val.Type().Elem()))
+		}
+		val = val.Elem()
+	}
+
+	if val.CanInterface() && val.Type().Implements(unmarshalerType) {
+		// This is an unmarshaler with a non-pointer receiver,
+		// so it's likely to be incorrect, but we do what we're told.
+		return p.unmarshalInterface(val.Interface().(Unmarshaler), start)
+	}
+
+	if val.CanAddr() {
+		pv := val.Addr()
+		if pv.CanInterface() && pv.Type().Implements(unmarshalerType) {
+			return p.unmarshalInterface(pv.Interface().(Unmarshaler), start)
+		}
+	}
+
+	if val.CanInterface() && val.Type().Implements(textUnmarshalerType) {
+		return p.unmarshalTextInterface(val.Interface().(encoding.TextUnmarshaler), start)
+	}
+
+	if val.CanAddr() {
+		pv := val.Addr()
+		if pv.CanInterface() && pv.Type().Implements(textUnmarshalerType) {
+			return p.unmarshalTextInterface(pv.Interface().(encoding.TextUnmarshaler), start)
+		}
+	}
+
+	var (
+		data         []byte
+		saveData     reflect.Value
+		comment      []byte
+		saveComment  reflect.Value
+		saveXML      reflect.Value
+		saveXMLIndex int
+		saveXMLData  []byte
+		saveAny      reflect.Value
+		sv           reflect.Value
+		tinfo        *typeInfo
+		err          error
+	)
+
+	switch v := val; v.Kind() {
+	default:
+		return errors.New("unknown type " + v.Type().String())
+
+	case reflect.Interface:
+		// TODO: For now, simply ignore the field. In the near
+		//       future we may choose to unmarshal the start
+		//       element on it, if not nil.
+		return p.Skip()
+
+	case reflect.Slice:
+		typ := v.Type()
+		if typ.Elem().Kind() == reflect.Uint8 {
+			// []byte
+			saveData = v
+			break
+		}
+
+		// Slice of element values.
+		// Grow slice.
+		n := v.Len()
+		if n >= v.Cap() {
+			ncap := 2 * n
+			if ncap < 4 {
+				ncap = 4
+			}
+			new := reflect.MakeSlice(typ, n, ncap)
+			reflect.Copy(new, v)
+			v.Set(new)
+		}
+		v.SetLen(n + 1)
+
+		// Recur to read element into slice.
+		if err := p.unmarshal(v.Index(n), start); err != nil {
+			v.SetLen(n)
+			return err
+		}
+		return nil
+
+	case reflect.Bool, reflect.Float32, reflect.Float64, reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64, reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr, reflect.String:
+		saveData = v
+
+	case reflect.Struct:
+		typ := v.Type()
+		if typ == nameType {
+			v.Set(reflect.ValueOf(start.Name))
+			break
+		}
+
+		sv = v
+		tinfo, err = getTypeInfo(typ)
+		if err != nil {
+			return err
+		}
+
+		// Validate and assign element name.
+		if tinfo.xmlname != nil {
+			finfo := tinfo.xmlname
+			if finfo.name != "" && finfo.name != start.Name.Local {
+				return UnmarshalError("expected element type <" + finfo.name + "> but have <" + start.Name.Local + ">")
+			}
+			if finfo.xmlns != "" && finfo.xmlns != start.Name.Space {
+				e := "expected element <" + finfo.name + "> in name space " + finfo.xmlns + " but have "
+				if start.Name.Space == "" {
+					e += "no name space"
+				} else {
+					e += start.Name.Space
+				}
+				return UnmarshalError(e)
+			}
+			fv := finfo.value(sv)
+			if _, ok := fv.Interface().(Name); ok {
+				fv.Set(reflect.ValueOf(start.Name))
+			}
+		}
+
+		// Assign attributes.
+		// Also, determine whether we need to save character data or comments.
+		for i := range tinfo.fields {
+			finfo := &tinfo.fields[i]
+			switch finfo.flags & fMode {
+			case fAttr:
+				strv := finfo.value(sv)
+				// Look for attribute.
+				for _, a := range start.Attr {
+					if a.Name.Local == finfo.name && (finfo.xmlns == "" || finfo.xmlns == a.Name.Space) {
+						if err := p.unmarshalAttr(strv, a); err != nil {
+							return err
+						}
+						break
+					}
+				}
+
+			case fCharData:
+				if !saveData.IsValid() {
+					saveData = finfo.value(sv)
+				}
+
+			case fComment:
+				if !saveComment.IsValid() {
+					saveComment = finfo.value(sv)
+				}
+
+			case fAny, fAny | fElement:
+				if !saveAny.IsValid() {
+					saveAny = finfo.value(sv)
+				}
+
+			case fInnerXml:
+				if !saveXML.IsValid() {
+					saveXML = finfo.value(sv)
+					if p.saved == nil {
+						saveXMLIndex = 0
+						p.saved = new(bytes.Buffer)
+					} else {
+						saveXMLIndex = p.savedOffset()
+					}
+				}
+			}
+		}
+	}
+
+	// Find end element.
+	// Process sub-elements along the way.
+Loop:
+	for {
+		var savedOffset int
+		if saveXML.IsValid() {
+			savedOffset = p.savedOffset()
+		}
+		tok, err := p.Token()
+		if err != nil {
+			return err
+		}
+		switch t := tok.(type) {
+		case StartElement:
+			consumed := false
+			if sv.IsValid() {
+				consumed, err = p.unmarshalPath(tinfo, sv, nil, &t)
+				if err != nil {
+					return err
+				}
+				if !consumed && saveAny.IsValid() {
+					consumed = true
+					if err := p.unmarshal(saveAny, &t); err != nil {
+						return err
+					}
+				}
+			}
+			if !consumed {
+				if err := p.Skip(); err != nil {
+					return err
+				}
+			}
+
+		case EndElement:
+			if saveXML.IsValid() {
+				saveXMLData = p.saved.Bytes()[saveXMLIndex:savedOffset]
+				if saveXMLIndex == 0 {
+					p.saved = nil
+				}
+			}
+			break Loop
+
+		case CharData:
+			if saveData.IsValid() {
+				data = append(data, t...)
+			}
+
+		case Comment:
+			if saveComment.IsValid() {
+				comment = append(comment, t...)
+			}
+		}
+	}
+
+	if saveData.IsValid() && saveData.CanInterface() && saveData.Type().Implements(textUnmarshalerType) {
+		if err := saveData.Interface().(encoding.TextUnmarshaler).UnmarshalText(data); err != nil {
+			return err
+		}
+		saveData = reflect.Value{}
+	}
+
+	if saveData.IsValid() && saveData.CanAddr() {
+		pv := saveData.Addr()
+		if pv.CanInterface() && pv.Type().Implements(textUnmarshalerType) {
+			if err := pv.Interface().(encoding.TextUnmarshaler).UnmarshalText(data); err != nil {
+				return err
+			}
+			saveData = reflect.Value{}
+		}
+	}
+
+	if err := copyValue(saveData, data); err != nil {
+		return err
+	}
+
+	switch t := saveComment; t.Kind() {
+	case reflect.String:
+		t.SetString(string(comment))
+	case reflect.Slice:
+		t.Set(reflect.ValueOf(comment))
+	}
+
+	switch t := saveXML; t.Kind() {
+	case reflect.String:
+		t.SetString(string(saveXMLData))
+	case reflect.Slice:
+		t.Set(reflect.ValueOf(saveXMLData))
+	}
+
+	return nil
+}
+
+func copyValue(dst reflect.Value, src []byte) (err error) {
+	dst0 := dst
+
+	if dst.Kind() == reflect.Ptr {
+		if dst.IsNil() {
+			dst.Set(reflect.New(dst.Type().Elem()))
+		}
+		dst = dst.Elem()
+	}
+
+	// Save accumulated data.
+	switch dst.Kind() {
+	case reflect.Invalid:
+		// Probably a comment.
+	default:
+		return errors.New("cannot unmarshal into " + dst0.Type().String())
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		itmp, err := strconv.ParseInt(string(src), 10, dst.Type().Bits())
+		if err != nil {
+			return err
+		}
+		dst.SetInt(itmp)
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		utmp, err := strconv.ParseUint(string(src), 10, dst.Type().Bits())
+		if err != nil {
+			return err
+		}
+		dst.SetUint(utmp)
+	case reflect.Float32, reflect.Float64:
+		ftmp, err := strconv.ParseFloat(string(src), dst.Type().Bits())
+		if err != nil {
+			return err
+		}
+		dst.SetFloat(ftmp)
+	case reflect.Bool:
+		value, err := strconv.ParseBool(strings.TrimSpace(string(src)))
+		if err != nil {
+			return err
+		}
+		dst.SetBool(value)
+	case reflect.String:
+		dst.SetString(string(src))
+	case reflect.Slice:
+		if len(src) == 0 {
+			// non-nil to flag presence
+			src = []byte{}
+		}
+		dst.SetBytes(src)
+	}
+	return nil
+}
+
+// unmarshalPath walks down an XML structure looking for wanted
+// paths, and calls unmarshal on them.
+// The consumed result tells whether XML elements have been consumed
+// from the Decoder until start's matching end element, or if it's
+// still untouched because start is uninteresting for sv's fields.
+func (p *Decoder) unmarshalPath(tinfo *typeInfo, sv reflect.Value, parents []string, start *StartElement) (consumed bool, err error) {
+	recurse := false
+Loop:
+	for i := range tinfo.fields {
+		finfo := &tinfo.fields[i]
+		if finfo.flags&fElement == 0 || len(finfo.parents) < len(parents) || finfo.xmlns != "" && finfo.xmlns != start.Name.Space {
+			continue
+		}
+		for j := range parents {
+			if parents[j] != finfo.parents[j] {
+				continue Loop
+			}
+		}
+		if len(finfo.parents) == len(parents) && finfo.name == start.Name.Local {
+			// It's a perfect match, unmarshal the field.
+			return true, p.unmarshal(finfo.value(sv), start)
+		}
+		if len(finfo.parents) > len(parents) && finfo.parents[len(parents)] == start.Name.Local {
+			// It's a prefix for the field. Break and recurse
+			// since it's not ok for one field path to be itself
+			// the prefix for another field path.
+			recurse = true
+
+			// We can reuse the same slice as long as we
+			// don't try to append to it.
+			parents = finfo.parents[:len(parents)+1]
+			break
+		}
+	}
+	if !recurse {
+		// We have no business with this element.
+		return false, nil
+	}
+	// The element is not a perfect match for any field, but one
+	// or more fields have the path to this element as a parent
+	// prefix. Recurse and attempt to match these.
+	for {
+		var tok Token
+		tok, err = p.Token()
+		if err != nil {
+			return true, err
+		}
+		switch t := tok.(type) {
+		case StartElement:
+			consumed2, err := p.unmarshalPath(tinfo, sv, parents, &t)
+			if err != nil {
+				return true, err
+			}
+			if !consumed2 {
+				if err := p.Skip(); err != nil {
+					return true, err
+				}
+			}
+		case EndElement:
+			return true, nil
+		}
+	}
+}
+
+// Skip reads tokens until it has consumed the end element
+// matching the most recent start element already consumed.
+// It recurs if it encounters a start element, so it can be used to
+// skip nested structures.
+// It returns nil if it finds an end element matching the start
+// element; otherwise it returns an error describing the problem.
+func (d *Decoder) Skip() error {
+	for {
+		tok, err := d.Token()
+		if err != nil {
+			return err
+		}
+		switch tok.(type) {
+		case StartElement:
+			if err := d.Skip(); err != nil {
+				return err
+			}
+		case EndElement:
+			return nil
+		}
+	}
+}

server/webdav/internal/xml/typeinfo.go

@@ -0,0 +1,371 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package xml
+
+import (
+	"fmt"
+	"reflect"
+	"strings"
+	"sync"
+)
+
+// typeInfo holds details for the xml representation of a type.
+type typeInfo struct {
+	xmlname *fieldInfo
+	fields  []fieldInfo
+}
+
+// fieldInfo holds details for the xml representation of a single field.
+type fieldInfo struct {
+	idx     []int
+	name    string
+	xmlns   string
+	flags   fieldFlags
+	parents []string
+}
+
+type fieldFlags int
+
+const (
+	fElement fieldFlags = 1 << iota
+	fAttr
+	fCharData
+	fInnerXml
+	fComment
+	fAny
+
+	fOmitEmpty
+
+	fMode = fElement | fAttr | fCharData | fInnerXml | fComment | fAny
+)
+
+var tinfoMap = make(map[reflect.Type]*typeInfo)
+var tinfoLock sync.RWMutex
+
+var nameType = reflect.TypeOf(Name{})
+
+// getTypeInfo returns the typeInfo structure with details necessary
+// for marshalling and unmarshalling typ.
+func getTypeInfo(typ reflect.Type) (*typeInfo, error) {
+	tinfoLock.RLock()
+	tinfo, ok := tinfoMap[typ]
+	tinfoLock.RUnlock()
+	if ok {
+		return tinfo, nil
+	}
+	tinfo = &typeInfo{}
+	if typ.Kind() == reflect.Struct && typ != nameType {
+		n := typ.NumField()
+		for i := 0; i < n; i++ {
+			f := typ.Field(i)
+			if f.PkgPath != "" || f.Tag.Get("xml") == "-" {
+				continue // Private field
+			}
+
+			// For embedded structs, embed its fields.
+			if f.Anonymous {
+				t := f.Type
+				if t.Kind() == reflect.Ptr {
+					t = t.Elem()
+				}
+				if t.Kind() == reflect.Struct {
+					inner, err := getTypeInfo(t)
+					if err != nil {
+						return nil, err
+					}
+					if tinfo.xmlname == nil {
+						tinfo.xmlname = inner.xmlname
+					}
+					for _, finfo := range inner.fields {
+						finfo.idx = append([]int{i}, finfo.idx...)
+						if err := addFieldInfo(typ, tinfo, &finfo); err != nil {
+							return nil, err
+						}
+					}
+					continue
+				}
+			}
+
+			finfo, err := structFieldInfo(typ, &f)
+			if err != nil {
+				return nil, err
+			}
+
+			if f.Name == "XMLName" {
+				tinfo.xmlname = finfo
+				continue
+			}
+
+			// Add the field if it doesn't conflict with other fields.
+			if err := addFieldInfo(typ, tinfo, finfo); err != nil {
+				return nil, err
+			}
+		}
+	}
+	tinfoLock.Lock()
+	tinfoMap[typ] = tinfo
+	tinfoLock.Unlock()
+	return tinfo, nil
+}
+
+// structFieldInfo builds and returns a fieldInfo for f.
+func structFieldInfo(typ reflect.Type, f *reflect.StructField) (*fieldInfo, error) {
+	finfo := &fieldInfo{idx: f.Index}
+
+	// Split the tag from the xml namespace if necessary.
+	tag := f.Tag.Get("xml")
+	if i := strings.Index(tag, " "); i >= 0 {
+		finfo.xmlns, tag = tag[:i], tag[i+1:]
+	}
+
+	// Parse flags.
+	tokens := strings.Split(tag, ",")
+	if len(tokens) == 1 {
+		finfo.flags = fElement
+	} else {
+		tag = tokens[0]
+		for _, flag := range tokens[1:] {
+			switch flag {
+			case "attr":
+				finfo.flags |= fAttr
+			case "chardata":
+				finfo.flags |= fCharData
+			case "innerxml":
+				finfo.flags |= fInnerXml
+			case "comment":
+				finfo.flags |= fComment
+			case "any":
+				finfo.flags |= fAny
+			case "omitempty":
+				finfo.flags |= fOmitEmpty
+			}
+		}
+
+		// Validate the flags used.
+		valid := true
+		switch mode := finfo.flags & fMode; mode {
+		case 0:
+			finfo.flags |= fElement
+		case fAttr, fCharData, fInnerXml, fComment, fAny:
+			if f.Name == "XMLName" || tag != "" && mode != fAttr {
+				valid = false
+			}
+		default:
+			// This will also catch multiple modes in a single field.
+			valid = false
+		}
+		if finfo.flags&fMode == fAny {
+			finfo.flags |= fElement
+		}
+		if finfo.flags&fOmitEmpty != 0 && finfo.flags&(fElement|fAttr) == 0 {
+			valid = false
+		}
+		if !valid {
+			return nil, fmt.Errorf("xml: invalid tag in field %s of type %s: %q",
+				f.Name, typ, f.Tag.Get("xml"))
+		}
+	}
+
+	// Use of xmlns without a name is not allowed.
+	if finfo.xmlns != "" && tag == "" {
+		return nil, fmt.Errorf("xml: namespace without name in field %s of type %s: %q",
+			f.Name, typ, f.Tag.Get("xml"))
+	}
+
+	if f.Name == "XMLName" {
+		// The XMLName field records the XML element name. Don't
+		// process it as usual because its name should default to
+		// empty rather than to the field name.
+		finfo.name = tag
+		return finfo, nil
+	}
+
+	if tag == "" {
+		// If the name part of the tag is completely empty, get
+		// default from XMLName of underlying struct if feasible,
+		// or field name otherwise.
+		if xmlname := lookupXMLName(f.Type); xmlname != nil {
+			finfo.xmlns, finfo.name = xmlname.xmlns, xmlname.name
+		} else {
+			finfo.name = f.Name
+		}
+		return finfo, nil
+	}
+
+	if finfo.xmlns == "" && finfo.flags&fAttr == 0 {
+		// If it's an element no namespace specified, get the default
+		// from the XMLName of enclosing struct if possible.
+		if xmlname := lookupXMLName(typ); xmlname != nil {
+			finfo.xmlns = xmlname.xmlns
+		}
+	}
+
+	// Prepare field name and parents.
+	parents := strings.Split(tag, ">")
+	if parents[0] == "" {
+		parents[0] = f.Name
+	}
+	if parents[len(parents)-1] == "" {
+		return nil, fmt.Errorf("xml: trailing '>' in field %s of type %s", f.Name, typ)
+	}
+	finfo.name = parents[len(parents)-1]
+	if len(parents) > 1 {
+		if (finfo.flags & fElement) == 0 {
+			return nil, fmt.Errorf("xml: %s chain not valid with %s flag", tag, strings.Join(tokens[1:], ","))
+		}
+		finfo.parents = parents[:len(parents)-1]
+	}
+
+	// If the field type has an XMLName field, the names must match
+	// so that the behavior of both marshalling and unmarshalling
+	// is straightforward and unambiguous.
+	if finfo.flags&fElement != 0 {
+		ftyp := f.Type
+		xmlname := lookupXMLName(ftyp)
+		if xmlname != nil && xmlname.name != finfo.name {
+			return nil, fmt.Errorf("xml: name %q in tag of %s.%s conflicts with name %q in %s.XMLName",
+				finfo.name, typ, f.Name, xmlname.name, ftyp)
+		}
+	}
+	return finfo, nil
+}
+
+// lookupXMLName returns the fieldInfo for typ's XMLName field
+// in case it exists and has a valid xml field tag, otherwise
+// it returns nil.
+func lookupXMLName(typ reflect.Type) (xmlname *fieldInfo) {
+	for typ.Kind() == reflect.Ptr {
+		typ = typ.Elem()
+	}
+	if typ.Kind() != reflect.Struct {
+		return nil
+	}
+	for i, n := 0, typ.NumField(); i < n; i++ {
+		f := typ.Field(i)
+		if f.Name != "XMLName" {
+			continue
+		}
+		finfo, err := structFieldInfo(typ, &f)
+		if finfo.name != "" && err == nil {
+			return finfo
+		}
+		// Also consider errors as a non-existent field tag
+		// and let getTypeInfo itself report the error.
+		break
+	}
+	return nil
+}
+
+func min(a, b int) int {
+	if a <= b {
+		return a
+	}
+	return b
+}
+
+// addFieldInfo adds finfo to tinfo.fields if there are no
+// conflicts, or if conflicts arise from previous fields that were
+// obtained from deeper embedded structures than finfo. In the latter
+// case, the conflicting entries are dropped.
+// A conflict occurs when the path (parent + name) to a field is
+// itself a prefix of another path, or when two paths match exactly.
+// It is okay for field paths to share a common, shorter prefix.
+func addFieldInfo(typ reflect.Type, tinfo *typeInfo, newf *fieldInfo) error {
+	var conflicts []int
+Loop:
+	// First, figure all conflicts. Most working code will have none.
+	for i := range tinfo.fields {
+		oldf := &tinfo.fields[i]
+		if oldf.flags&fMode != newf.flags&fMode {
+			continue
+		}
+		if oldf.xmlns != "" && newf.xmlns != "" && oldf.xmlns != newf.xmlns {
+			continue
+		}
+		minl := min(len(newf.parents), len(oldf.parents))
+		for p := 0; p < minl; p++ {
+			if oldf.parents[p] != newf.parents[p] {
+				continue Loop
+			}
+		}
+		if len(oldf.parents) > len(newf.parents) {
+			if oldf.parents[len(newf.parents)] == newf.name {
+				conflicts = append(conflicts, i)
+			}
+		} else if len(oldf.parents) < len(newf.parents) {
+			if newf.parents[len(oldf.parents)] == oldf.name {
+				conflicts = append(conflicts, i)
+			}
+		} else {
+			if newf.name == oldf.name {
+				conflicts = append(conflicts, i)
+			}
+		}
+	}
+	// Without conflicts, add the new field and return.
+	if conflicts == nil {
+		tinfo.fields = append(tinfo.fields, *newf)
+		return nil
+	}
+
+	// If any conflict is shallower, ignore the new field.
+	// This matches the Go field resolution on embedding.
+	for _, i := range conflicts {
+		if len(tinfo.fields[i].idx) < len(newf.idx) {
+			return nil
+		}
+	}
+
+	// Otherwise, if any of them is at the same depth level, it's an error.
+	for _, i := range conflicts {
+		oldf := &tinfo.fields[i]
+		if len(oldf.idx) == len(newf.idx) {
+			f1 := typ.FieldByIndex(oldf.idx)
+			f2 := typ.FieldByIndex(newf.idx)
+			return &TagPathError{typ, f1.Name, f1.Tag.Get("xml"), f2.Name, f2.Tag.Get("xml")}
+		}
+	}
+
+	// Otherwise, the new field is shallower, and thus takes precedence,
+	// so drop the conflicting fields from tinfo and append the new one.
+	for c := len(conflicts) - 1; c >= 0; c-- {
+		i := conflicts[c]
+		copy(tinfo.fields[i:], tinfo.fields[i+1:])
+		tinfo.fields = tinfo.fields[:len(tinfo.fields)-1]
+	}
+	tinfo.fields = append(tinfo.fields, *newf)
+	return nil
+}
+
+// A TagPathError represents an error in the unmarshalling process
+// caused by the use of field tags with conflicting paths.
+type TagPathError struct {
+	Struct       reflect.Type
+	Field1, Tag1 string
+	Field2, Tag2 string
+}
+
+func (e *TagPathError) Error() string {
+	return fmt.Sprintf("%s field %q with tag %q conflicts with field %q with tag %q", e.Struct, e.Field1, e.Tag1, e.Field2, e.Tag2)
+}
+
+// value returns v's field value corresponding to finfo.
+// It's equivalent to v.FieldByIndex(finfo.idx), but initializes
+// and dereferences pointers as necessary.
+func (finfo *fieldInfo) value(v reflect.Value) reflect.Value {
+	for i, x := range finfo.idx {
+		if i > 0 {
+			t := v.Type()
+			if t.Kind() == reflect.Ptr && t.Elem().Kind() == reflect.Struct {
+				if v.IsNil() {
+					v.Set(reflect.New(v.Type().Elem()))
+				}
+				v = v.Elem()
+			}
+		}
+		v = v.Field(x)
+	}
+	return v
+}

server/webdav/lock.go

@@ -0,0 +1,445 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package webdav
+
+import (
+	"container/heap"
+	"errors"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+)
+
+var (
+	// ErrConfirmationFailed is returned by a LockSystem's Confirm method.
+	ErrConfirmationFailed = errors.New("webdav: confirmation failed")
+	// ErrForbidden is returned by a LockSystem's Unlock method.
+	ErrForbidden = errors.New("webdav: forbidden")
+	// ErrLocked is returned by a LockSystem's Create, Refresh and Unlock methods.
+	ErrLocked = errors.New("webdav: locked")
+	// ErrNoSuchLock is returned by a LockSystem's Refresh and Unlock methods.
+	ErrNoSuchLock = errors.New("webdav: no such lock")
+)
+
+// Condition can match a WebDAV resource, based on a token or ETag.
+// Exactly one of Token and ETag should be non-empty.
+type Condition struct {
+	Not   bool
+	Token string
+	ETag  string
+}
+
+// LockSystem manages access to a collection of named resources. The elements
+// in a lock name are separated by slash ('/', U+002F) characters, regardless
+// of host operating system convention.
+type LockSystem interface {
+	// Confirm confirms that the caller can claim all of the locks specified by
+	// the given conditions, and that holding the union of all of those locks
+	// gives exclusive access to all of the named resources. Up to two resources
+	// can be named. Empty names are ignored.
+	//
+	// Exactly one of release and err will be non-nil. If release is non-nil,
+	// all of the requested locks are held until release is called. Calling
+	// release does not unlock the lock, in the WebDAV UNLOCK sense, but once
+	// Confirm has confirmed that a lock claim is valid, that lock cannot be
+	// Confirmed again until it has been released.
+	//
+	// If Confirm returns ErrConfirmationFailed then the Handler will continue
+	// to try any other set of locks presented (a WebDAV HTTP request can
+	// present more than one set of locks). If it returns any other non-nil
+	// error, the Handler will write a "500 Internal Server Error" HTTP status.
+	Confirm(now time.Time, name0, name1 string, conditions ...Condition) (release func(), err error)
+
+	// Create creates a lock with the given depth, duration, owner and root
+	// (name). The depth will either be negative (meaning infinite) or zero.
+	//
+	// If Create returns ErrLocked then the Handler will write a "423 Locked"
+	// HTTP status. If it returns any other non-nil error, the Handler will
+	// write a "500 Internal Server Error" HTTP status.
+	//
+	// See http://www.webdav.org/specs/rfc4918.html#rfc.section.9.10.6 for
+	// when to use each error.
+	//
+	// The token returned identifies the created lock. It should be an absolute
+	// URI as defined by RFC 3986, Section 4.3. In particular, it should not
+	// contain whitespace.
+	Create(now time.Time, details LockDetails) (token string, err error)
+
+	// Refresh refreshes the lock with the given token.
+	//
+	// If Refresh returns ErrLocked then the Handler will write a "423 Locked"
+	// HTTP Status. If Refresh returns ErrNoSuchLock then the Handler will write
+	// a "412 Precondition Failed" HTTP Status. If it returns any other non-nil
+	// error, the Handler will write a "500 Internal Server Error" HTTP status.
+	//
+	// See http://www.webdav.org/specs/rfc4918.html#rfc.section.9.10.6 for
+	// when to use each error.
+	Refresh(now time.Time, token string, duration time.Duration) (LockDetails, error)
+
+	// Unlock unlocks the lock with the given token.
+	//
+	// If Unlock returns ErrForbidden then the Handler will write a "403
+	// Forbidden" HTTP Status. If Unlock returns ErrLocked then the Handler
+	// will write a "423 Locked" HTTP status. If Unlock returns ErrNoSuchLock
+	// then the Handler will write a "409 Conflict" HTTP Status. If it returns
+	// any other non-nil error, the Handler will write a "500 Internal Server
+	// Error" HTTP status.
+	//
+	// See http://www.webdav.org/specs/rfc4918.html#rfc.section.9.11.1 for
+	// when to use each error.
+	Unlock(now time.Time, token string) error
+}
+
+// LockDetails are a lock's metadata.
+type LockDetails struct {
+	// Root is the root resource name being locked. For a zero-depth lock, the
+	// root is the only resource being locked.
+	Root string
+	// Duration is the lock timeout. A negative duration means infinite.
+	Duration time.Duration
+	// OwnerXML is the verbatim <owner> XML given in a LOCK HTTP request.
+	//
+	// TODO: does the "verbatim" nature play well with XML namespaces?
+	// Does the OwnerXML field need to have more structure? See
+	// https://codereview.appspot.com/175140043/#msg2
+	OwnerXML string
+	// ZeroDepth is whether the lock has zero depth. If it does not have zero
+	// depth, it has infinite depth.
+	ZeroDepth bool
+}
+
+// NewMemLS returns a new in-memory LockSystem.
+func NewMemLS() LockSystem {
+	return &memLS{
+		byName:  make(map[string]*memLSNode),
+		byToken: make(map[string]*memLSNode),
+		gen:     uint64(time.Now().Unix()),
+	}
+}
+
+type memLS struct {
+	mu      sync.Mutex
+	byName  map[string]*memLSNode
+	byToken map[string]*memLSNode
+	gen     uint64
+	// byExpiry only contains those nodes whose LockDetails have a finite
+	// Duration and are yet to expire.
+	byExpiry byExpiry
+}
+
+func (m *memLS) nextToken() string {
+	m.gen++
+	return strconv.FormatUint(m.gen, 10)
+}
+
+func (m *memLS) collectExpiredNodes(now time.Time) {
+	for len(m.byExpiry) > 0 {
+		if now.Before(m.byExpiry[0].expiry) {
+			break
+		}
+		m.remove(m.byExpiry[0])
+	}
+}
+
+func (m *memLS) Confirm(now time.Time, name0, name1 string, conditions ...Condition) (func(), error) {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	m.collectExpiredNodes(now)
+
+	var n0, n1 *memLSNode
+	if name0 != "" {
+		if n0 = m.lookup(slashClean(name0), conditions...); n0 == nil {
+			return nil, ErrConfirmationFailed
+		}
+	}
+	if name1 != "" {
+		if n1 = m.lookup(slashClean(name1), conditions...); n1 == nil {
+			return nil, ErrConfirmationFailed
+		}
+	}
+
+	// Don't hold the same node twice.
+	if n1 == n0 {
+		n1 = nil
+	}
+
+	if n0 != nil {
+		m.hold(n0)
+	}
+	if n1 != nil {
+		m.hold(n1)
+	}
+	return func() {
+		m.mu.Lock()
+		defer m.mu.Unlock()
+		if n1 != nil {
+			m.unhold(n1)
+		}
+		if n0 != nil {
+			m.unhold(n0)
+		}
+	}, nil
+}
+
+// lookup returns the node n that locks the named resource, provided that n
+// matches at least one of the given conditions and that lock isn't held by
+// another party. Otherwise, it returns nil.
+//
+// n may be a parent of the named resource, if n is an infinite depth lock.
+func (m *memLS) lookup(name string, conditions ...Condition) (n *memLSNode) {
+	// TODO: support Condition.Not and Condition.ETag.
+	for _, c := range conditions {
+		n = m.byToken[c.Token]
+		if n == nil || n.held {
+			continue
+		}
+		if name == n.details.Root {
+			return n
+		}
+		if n.details.ZeroDepth {
+			continue
+		}
+		if n.details.Root == "/" || strings.HasPrefix(name, n.details.Root+"/") {
+			return n
+		}
+	}
+	return nil
+}
+
+func (m *memLS) hold(n *memLSNode) {
+	if n.held {
+		panic("webdav: memLS inconsistent held state")
+	}
+	n.held = true
+	if n.details.Duration >= 0 && n.byExpiryIndex >= 0 {
+		heap.Remove(&m.byExpiry, n.byExpiryIndex)
+	}
+}
+
+func (m *memLS) unhold(n *memLSNode) {
+	if !n.held {
+		panic("webdav: memLS inconsistent held state")
+	}
+	n.held = false
+	if n.details.Duration >= 0 {
+		heap.Push(&m.byExpiry, n)
+	}
+}
+
+func (m *memLS) Create(now time.Time, details LockDetails) (string, error) {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	m.collectExpiredNodes(now)
+	details.Root = slashClean(details.Root)
+
+	if !m.canCreate(details.Root, details.ZeroDepth) {
+		return "", ErrLocked
+	}
+	n := m.create(details.Root)
+	n.token = m.nextToken()
+	m.byToken[n.token] = n
+	n.details = details
+	if n.details.Duration >= 0 {
+		n.expiry = now.Add(n.details.Duration)
+		heap.Push(&m.byExpiry, n)
+	}
+	return n.token, nil
+}
+
+func (m *memLS) Refresh(now time.Time, token string, duration time.Duration) (LockDetails, error) {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	m.collectExpiredNodes(now)
+
+	n := m.byToken[token]
+	if n == nil {
+		return LockDetails{}, ErrNoSuchLock
+	}
+	if n.held {
+		return LockDetails{}, ErrLocked
+	}
+	if n.byExpiryIndex >= 0 {
+		heap.Remove(&m.byExpiry, n.byExpiryIndex)
+	}
+	n.details.Duration = duration
+	if n.details.Duration >= 0 {
+		n.expiry = now.Add(n.details.Duration)
+		heap.Push(&m.byExpiry, n)
+	}
+	return n.details, nil
+}
+
+func (m *memLS) Unlock(now time.Time, token string) error {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	m.collectExpiredNodes(now)
+
+	n := m.byToken[token]
+	if n == nil {
+		return ErrNoSuchLock
+	}
+	if n.held {
+		return ErrLocked
+	}
+	m.remove(n)
+	return nil
+}
+
+func (m *memLS) canCreate(name string, zeroDepth bool) bool {
+	return walkToRoot(name, func(name0 string, first bool) bool {
+		n := m.byName[name0]
+		if n == nil {
+			return true
+		}
+		if first {
+			if n.token != "" {
+				// The target node is already locked.
+				return false
+			}
+			if !zeroDepth {
+				// The requested lock depth is infinite, and the fact that n exists
+				// (n != nil) means that a descendent of the target node is locked.
+				return false
+			}
+		} else if n.token != "" && !n.details.ZeroDepth {
+			// An ancestor of the target node is locked with infinite depth.
+			return false
+		}
+		return true
+	})
+}
+
+func (m *memLS) create(name string) (ret *memLSNode) {
+	walkToRoot(name, func(name0 string, first bool) bool {
+		n := m.byName[name0]
+		if n == nil {
+			n = &memLSNode{
+				details: LockDetails{
+					Root: name0,
+				},
+				byExpiryIndex: -1,
+			}
+			m.byName[name0] = n
+		}
+		n.refCount++
+		if first {
+			ret = n
+		}
+		return true
+	})
+	return ret
+}
+
+func (m *memLS) remove(n *memLSNode) {
+	delete(m.byToken, n.token)
+	n.token = ""
+	walkToRoot(n.details.Root, func(name0 string, first bool) bool {
+		x := m.byName[name0]
+		x.refCount--
+		if x.refCount == 0 {
+			delete(m.byName, name0)
+		}
+		return true
+	})
+	if n.byExpiryIndex >= 0 {
+		heap.Remove(&m.byExpiry, n.byExpiryIndex)
+	}
+}
+
+func walkToRoot(name string, f func(name0 string, first bool) bool) bool {
+	for first := true; ; first = false {
+		if !f(name, first) {
+			return false
+		}
+		if name == "/" {
+			break
+		}
+		name = name[:strings.LastIndex(name, "/")]
+		if name == "" {
+			name = "/"
+		}
+	}
+	return true
+}
+
+type memLSNode struct {
+	// details are the lock metadata. Even if this node's name is not explicitly locked,
+	// details.Root will still equal the node's name.
+	details LockDetails
+	// token is the unique identifier for this node's lock. An empty token means that
+	// this node is not explicitly locked.
+	token string
+	// refCount is the number of self-or-descendent nodes that are explicitly locked.
+	refCount int
+	// expiry is when this node's lock expires.
+	expiry time.Time
+	// byExpiryIndex is the index of this node in memLS.byExpiry. It is -1
+	// if this node does not expire, or has expired.
+	byExpiryIndex int
+	// held is whether this node's lock is actively held by a Confirm call.
+	held bool
+}
+
+type byExpiry []*memLSNode
+
+func (b *byExpiry) Len() int {
+	return len(*b)
+}
+
+func (b *byExpiry) Less(i, j int) bool {
+	return (*b)[i].expiry.Before((*b)[j].expiry)
+}
+
+func (b *byExpiry) Swap(i, j int) {
+	(*b)[i], (*b)[j] = (*b)[j], (*b)[i]
+	(*b)[i].byExpiryIndex = i
+	(*b)[j].byExpiryIndex = j
+}
+
+func (b *byExpiry) Push(x interface{}) {
+	n := x.(*memLSNode)
+	n.byExpiryIndex = len(*b)
+	*b = append(*b, n)
+}
+
+func (b *byExpiry) Pop() interface{} {
+	i := len(*b) - 1
+	n := (*b)[i]
+	(*b)[i] = nil
+	n.byExpiryIndex = -1
+	*b = (*b)[:i]
+	return n
+}
+
+const infiniteTimeout = -1
+
+// parseTimeout parses the Timeout HTTP header, as per section 10.7. If s is
+// empty, an infiniteTimeout is returned.
+func parseTimeout(s string) (time.Duration, error) {
+	if s == "" {
+		return infiniteTimeout, nil
+	}
+	if i := strings.IndexByte(s, ','); i >= 0 {
+		s = s[:i]
+	}
+	s = strings.TrimSpace(s)
+	if s == "Infinite" {
+		return infiniteTimeout, nil
+	}
+	const pre = "Second-"
+	if !strings.HasPrefix(s, pre) {
+		return 0, errInvalidTimeout
+	}
+	s = s[len(pre):]
+	if s == "" || s[0] < '0' || '9' < s[0] {
+		return 0, errInvalidTimeout
+	}
+	n, err := strconv.ParseInt(s, 10, 64)
+	if err != nil || 1<<32-1 < n {
+		return 0, errInvalidTimeout
+	}
+	return time.Duration(n) * time.Second, nil
+}

server/webdav/prop.go

@@ -0,0 +1,413 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package webdav
+
+import (
+	"bytes"
+	"context"
+	"encoding/xml"
+	"errors"
+	"fmt"
+	"net/http"
+	"strconv"
+	"time"
+)
+
+type FileInfo interface {
+	GetSize() uint64
+	GetName() string
+	ModTime() time.Time
+	IsDir() bool
+	//GetPosition() string
+}
+
+// Proppatch describes a property update instruction as defined in RFC 4918.
+// See http://www.webdav.org/specs/rfc4918.html#METHOD_PROPPATCH
+type Proppatch struct {
+	// Remove specifies whether this patch removes properties. If it does not
+	// remove them, it sets them.
+	Remove bool
+	// Props contains the properties to be set or removed.
+	Props []Property
+}
+
+// Propstat describes a XML propstat element as defined in RFC 4918.
+// See http://www.webdav.org/specs/rfc4918.html#ELEMENT_propstat
+type Propstat struct {
+	// Props contains the properties for which Status applies.
+	Props []Property
+
+	// Status defines the HTTP status code of the properties in Prop.
+	// Allowed values include, but are not limited to the WebDAV status
+	// code extensions for HTTP/1.1.
+	// http://www.webdav.org/specs/rfc4918.html#status.code.extensions.to.http11
+	Status int
+
+	// XMLError contains the XML representation of the optional error element.
+	// XML content within this field must not rely on any predefined
+	// namespace declarations or prefixes. If empty, the XML error element
+	// is omitted.
+	XMLError string
+
+	// ResponseDescription contains the contents of the optional
+	// responsedescription field. If empty, the XML element is omitted.
+	ResponseDescription string
+}
+
+// makePropstats returns a slice containing those of x and y whose Props slice
+// is non-empty. If both are empty, it returns a slice containing an otherwise
+// zero Propstat whose HTTP status code is 200 OK.
+func makePropstats(x, y Propstat) []Propstat {
+	pstats := make([]Propstat, 0, 2)
+	if len(x.Props) != 0 {
+		pstats = append(pstats, x)
+	}
+	if len(y.Props) != 0 {
+		pstats = append(pstats, y)
+	}
+	if len(pstats) == 0 {
+		pstats = append(pstats, Propstat{
+			Status: http.StatusOK,
+		})
+	}
+	return pstats
+}
+
+// DeadPropsHolder holds the dead properties of a resource.
+//
+// Dead properties are those properties that are explicitly defined. In
+// comparison, live properties, such as DAV:getcontentlength, are implicitly
+// defined by the underlying resource, and cannot be explicitly overridden or
+// removed. See the Terminology section of
+// http://www.webdav.org/specs/rfc4918.html#rfc.section.3
+//
+// There is a whitelist of the names of live properties. This package handles
+// all live properties, and will only pass non-whitelisted names to the Patch
+// method of DeadPropsHolder implementations.
+type DeadPropsHolder interface {
+	// DeadProps returns a copy of the dead properties held.
+	DeadProps() (map[xml.Name]Property, error)
+
+	// Patch patches the dead properties held.
+	//
+	// Patching is atomic; either all or no patches succeed. It returns (nil,
+	// non-nil) if an internal server error occurred, otherwise the Propstats
+	// collectively contain one Property for each proposed patch Property. If
+	// all patches succeed, Patch returns a slice of length one and a Propstat
+	// element with a 200 OK HTTP status code. If none succeed, for reasons
+	// other than an internal server error, no Propstat has status 200 OK.
+	//
+	// For more details on when various HTTP status codes apply, see
+	// http://www.webdav.org/specs/rfc4918.html#PROPPATCH-status
+	Patch([]Proppatch) ([]Propstat, error)
+}
+
+// liveProps contains all supported, protected DAV: properties.
+var liveProps = map[xml.Name]struct {
+	// findFn implements the propfind function of this property. If nil,
+	// it indicates a hidden property.
+	findFn func(context.Context, *FileSystem, LockSystem, string, FileInfo) (string, error)
+	// dir is true if the property applies to directories.
+	dir bool
+}{
+	{Space: "DAV:", Local: "resourcetype"}: {
+		findFn: findResourceType,
+		dir:    true,
+	},
+	{Space: "DAV:", Local: "displayname"}: {
+		findFn: findDisplayName,
+		dir:    true,
+	},
+	{Space: "DAV:", Local: "getcontentlength"}: {
+		findFn: findContentLength,
+		dir:    false,
+	},
+	{Space: "DAV:", Local: "getlastmodified"}: {
+		findFn: findLastModified,
+		// http://webdav.org/specs/rfc4918.html#PROPERTY_getlastmodified
+		// suggests that getlastmodified should only apply to GETable
+		// resources, and this package does not support GET on directories.
+		//
+		// Nonetheless, some WebDAV clients expect child directories to be
+		// sortable by getlastmodified date, so this value is true, not false.
+		// See golang.org/issue/15334.
+		dir: true,
+	},
+	{Space: "DAV:", Local: "creationdate"}: {
+		findFn: nil,
+		dir:    false,
+	},
+	{Space: "DAV:", Local: "getcontentlanguage"}: {
+		findFn: nil,
+		dir:    false,
+	},
+	{Space: "DAV:", Local: "getcontenttype"}: {
+		findFn: findContentType,
+		dir:    false,
+	},
+	{Space: "DAV:", Local: "getetag"}: {
+		findFn: findETag,
+		// findETag implements ETag as the concatenated hex values of a file's
+		// modification time and size. This is not a reliable synchronization
+		// mechanism for directories, so we do not advertise getetag for DAV
+		// collections.
+		dir: false,
+	},
+
+	// TODO: The lockdiscovery property requires LockSystem to list the
+	// active locks on a resource.
+	{Space: "DAV:", Local: "lockdiscovery"}: {},
+	{Space: "DAV:", Local: "supportedlock"}: {
+		findFn: findSupportedLock,
+		dir:    true,
+	},
+}
+
+// TODO(nigeltao) merge props and allprop?
+
+// Props returns the status of the properties named pnames for resource name.
+//
+// Each Propstat has a unique status and each property name will only be part
+// of one Propstat element.
+func props(ctx context.Context, fs *FileSystem, ls LockSystem, fi FileInfo, pnames []xml.Name) ([]Propstat, error) {
+	isDir := fi.IsDir()
+
+	var deadProps map[xml.Name]Property
+
+	pstatOK := Propstat{Status: http.StatusOK}
+	pstatNotFound := Propstat{Status: http.StatusNotFound}
+	for _, pn := range pnames {
+		// If this file has dead properties, check if they contain pn.
+		if dp, ok := deadProps[pn]; ok {
+			pstatOK.Props = append(pstatOK.Props, dp)
+			continue
+		}
+		// Otherwise, it must either be a live property or we don't know it.
+		if prop := liveProps[pn]; prop.findFn != nil && (prop.dir || !isDir) {
+			innerXML, err := prop.findFn(ctx, fs, ls, fi.GetName(), fi)
+			if err != nil {
+				return nil, err
+			}
+			pstatOK.Props = append(pstatOK.Props, Property{
+				XMLName:  pn,
+				InnerXML: []byte(innerXML),
+			})
+		} else {
+			pstatNotFound.Props = append(pstatNotFound.Props, Property{
+				XMLName: pn,
+			})
+		}
+	}
+	return makePropstats(pstatOK, pstatNotFound), nil
+}
+
+// Propnames returns the property names defined for resource name.
+func propnames(ctx context.Context, fs *FileSystem, ls LockSystem, fi FileInfo) ([]xml.Name, error) {
+	isDir := fi.IsDir()
+
+	var deadProps map[xml.Name]Property
+
+	pnames := make([]xml.Name, 0, len(liveProps)+len(deadProps))
+	for pn, prop := range liveProps {
+		if prop.findFn != nil && (prop.dir || !isDir) {
+			pnames = append(pnames, pn)
+		}
+	}
+	return pnames, nil
+}
+
+// Allprop returns the properties defined for resource name and the properties
+// named in include.
+//
+// Note that RFC 4918 defines 'allprop' to return the DAV: properties defined
+// within the RFC plus dead properties. Other live properties should only be
+// returned if they are named in 'include'.
+//
+// See http://www.webdav.org/specs/rfc4918.html#METHOD_PROPFIND
+func allprop(ctx context.Context, fs *FileSystem, ls LockSystem, info FileInfo, include []xml.Name) ([]Propstat, error) {
+	pnames, err := propnames(ctx, fs, ls, info)
+	if err != nil {
+		return nil, err
+	}
+	// Add names from include if they are not already covered in pnames.
+	nameset := make(map[xml.Name]bool)
+	for _, pn := range pnames {
+		nameset[pn] = true
+	}
+	for _, pn := range include {
+		if !nameset[pn] {
+			pnames = append(pnames, pn)
+		}
+	}
+	return props(ctx, fs, ls, info, pnames)
+}
+
+// Patch patches the properties of resource name. The return values are
+// constrained in the same manner as DeadPropsHolder.Patch.
+func patch(ctx context.Context, fs *FileSystem, ls LockSystem, name string, patches []Proppatch) ([]Propstat, error) {
+	conflict := false
+loop:
+	for _, patch := range patches {
+		for _, p := range patch.Props {
+			if _, ok := liveProps[p.XMLName]; ok {
+				conflict = true
+				break loop
+			}
+		}
+	}
+	if conflict {
+		pstatForbidden := Propstat{
+			Status:   http.StatusForbidden,
+			XMLError: `<D:cannot-modify-protected-property xmlns:D="DAV:"/>`,
+		}
+		pstatFailedDep := Propstat{
+			Status: StatusFailedDependency,
+		}
+		for _, patch := range patches {
+			for _, p := range patch.Props {
+				if _, ok := liveProps[p.XMLName]; ok {
+					pstatForbidden.Props = append(pstatForbidden.Props, Property{XMLName: p.XMLName})
+				} else {
+					pstatFailedDep.Props = append(pstatFailedDep.Props, Property{XMLName: p.XMLName})
+				}
+			}
+		}
+		return makePropstats(pstatForbidden, pstatFailedDep), nil
+	}
+
+	// The file doesn't implement the optional DeadPropsHolder interface, so
+	// all patches are forbidden.
+	pstat := Propstat{Status: http.StatusOK}
+	for _, patch := range patches {
+		for _, p := range patch.Props {
+			pstat.Props = append(pstat.Props, Property{XMLName: p.XMLName})
+		}
+	}
+	return []Propstat{pstat}, nil
+}
+
+func escapeXML(s string) string {
+	for i := 0; i < len(s); i++ {
+		// As an optimization, if s contains only ASCII letters, digits or a
+		// few special characters, the escaped value is s itself and we don't
+		// need to allocate a buffer and convert between string and []byte.
+		switch c := s[i]; {
+		case c == ' ' || c == '_' ||
+			('+' <= c && c <= '9') || // Digits as well as + , - . and /
+			('A' <= c && c <= 'Z') ||
+			('a' <= c && c <= 'z'):
+			continue
+		}
+		// Otherwise, go through the full escaping process.
+		var buf bytes.Buffer
+		xml.EscapeText(&buf, []byte(s))
+		return buf.String()
+	}
+	return s
+}
+
+func findResourceType(ctx context.Context, fs *FileSystem, ls LockSystem, name string, fi FileInfo) (string, error) {
+	if fi.IsDir() {
+		return `<D:collection xmlns:D="DAV:"/>`, nil
+	}
+	return "", nil
+}
+
+func findDisplayName(ctx context.Context, fs *FileSystem, ls LockSystem, name string, fi FileInfo) (string, error) {
+	if slashClean(name) == "/" {
+		// Hide the real name of a possibly prefixed root directory.
+		return "", nil
+	}
+	return escapeXML(fi.GetName()), nil
+}
+
+func findContentLength(ctx context.Context, fs *FileSystem, ls LockSystem, name string, fi FileInfo) (string, error) {
+	return strconv.FormatUint(fi.GetSize(), 10), nil
+}
+
+func findLastModified(ctx context.Context, fs *FileSystem, ls LockSystem, name string, fi FileInfo) (string, error) {
+	return fi.ModTime().UTC().Format(http.TimeFormat), nil
+}
+
+// ErrNotImplemented should be returned by optional interfaces if they
+// want the original implementation to be used.
+var ErrNotImplemented = errors.New("not implemented")
+
+// ContentTyper is an optional interface for the os.FileInfo
+// objects returned by the FileSystem.
+//
+// If this interface is defined then it will be used to read the
+// content type from the object.
+//
+// If this interface is not defined the file will be opened and the
+// content type will be guessed from the initial contents of the file.
+type ContentTyper interface {
+	// ContentType returns the content type for the file.
+	//
+	// If this returns error ErrNotImplemented then the error will
+	// be ignored and the base implementation will be used
+	// instead.
+	ContentType(ctx context.Context) (string, error)
+}
+
+func findContentType(ctx context.Context, fs *FileSystem, ls LockSystem, name string, fi FileInfo) (string, error) {
+	//if do, ok := fi.(ContentTyper); ok {
+	//	ctype, err := do.ContentType(ctx)
+	//	if err != ErrNotImplemented {
+	//		return ctype, err
+	//	}
+	//}
+	//f, err := fs.OpenFile(ctx, name, os.O_RDONLY, 0)
+	//if err != nil {
+	//	return "", err
+	//}
+	//defer f.Close()
+	//// This implementation is based on serveContent's code in the standard net/http package.
+	//ctype := mime.TypeByExtension(filepath.Ext(name))
+	//if ctype != "" {
+	//	return ctype, nil
+	//}
+	//// Read a chunk to decide between utf-8 text and binary.
+	//var buf [512]byte
+	//n, err := io.ReadFull(f, buf[:])
+	//if err != nil && err != io.EOF && err != io.ErrUnexpectedEOF {
+	//	return "", err
+	//}
+	//ctype = http.DetectContentType(buf[:n])
+	//// Rewind file.
+	//_, err = f.Seek(0, os.SEEK_SET)
+	//return ctype, err
+	return "", nil
+}
+
+// ETager is an optional interface for the os.FileInfo objects
+// returned by the FileSystem.
+//
+// If this interface is defined then it will be used to read the ETag
+// for the object.
+//
+// If this interface is not defined an ETag will be computed using the
+// ModTime() and the Size() methods of the os.FileInfo object.
+type ETager interface {
+	// ETag returns an ETag for the file.  This should be of the
+	// form "value" or W/"value"
+	//
+	// If this returns error ErrNotImplemented then the error will
+	// be ignored and the base implementation will be used
+	// instead.
+	ETag(ctx context.Context) (string, error)
+}
+
+func findETag(ctx context.Context, fs *FileSystem, ls LockSystem, reqPath string, fi FileInfo) (string, error) {
+	return fmt.Sprintf(`"%x%x"`, fi.ModTime().UnixNano(), fi.GetSize()), nil
+}
+
+func findSupportedLock(ctx context.Context, fs *FileSystem, ls LockSystem, name string, fi FileInfo) (string, error) {
+	return `` +
+		`<D:lockentry xmlns:D="DAV:">` +
+		`<D:lockscope><D:exclusive/></D:lockscope>` +
+		`<D:locktype><D:write/></D:locktype>` +
+		`</D:lockentry>`, nil
+}

server/webdav/webdav.go

@@ -0,0 +1,728 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package webdav provides a WebDAV server implementation.
+package webdav // import "golang.org/x/net/webdav"
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"github.com/Xhofe/alist/utils"
+	log "github.com/sirupsen/logrus"
+	"net/http"
+	"net/url"
+	"path"
+	"strings"
+	"time"
+)
+
+type Handler struct {
+	// Prefix is the URL path prefix to strip from WebDAV resource paths.
+	Prefix string
+	// LockSystem is the lock management system.
+	LockSystem LockSystem
+	// Logger is an optional error logger. If non-nil, it will be called
+	// for all HTTP requests.
+	Logger func(*http.Request, error)
+}
+
+func (h *Handler) stripPrefix(p string) (string, int, error) {
+	if h.Prefix == "" {
+		return p, http.StatusOK, nil
+	}
+	prefix := h.Prefix
+	if r := strings.TrimPrefix(p, prefix); len(r) < len(p) {
+		if len(r) == 0 {
+			r = "/"
+		}
+		return utils.RemoveLastSlash(r), http.StatusOK, nil
+	}
+	return p, http.StatusNotFound, errPrefixMismatch
+}
+
+// isPathExist 路径是否存在
+func isPathExist(ctx context.Context, fs *FileSystem, path string) (bool, FileInfo) {
+	file, err := fs.File(path)
+	if err != nil {
+		return false, nil
+	}
+	return true, file
+}
+
+func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request, fs *FileSystem) {
+	status, err := http.StatusBadRequest, errUnsupportedMethod
+	if h.LockSystem == nil {
+		status, err = http.StatusInternalServerError, errNoLockSystem
+	} else {
+		switch r.Method {
+		case "OPTIONS":
+			status, err = h.handleOptions(w, r, fs)
+		case "GET", "HEAD", "POST":
+			status, err = h.handleGetHeadPost(w, r, fs)
+		case "DELETE":
+			status, err = h.handleDelete(w, r, fs)
+		case "PUT":
+			status, err = h.handlePut(w, r, fs)
+		case "MKCOL":
+			status, err = h.handleMkcol(w, r, fs)
+		case "COPY", "MOVE":
+			status, err = h.handleCopyMove(w, r, fs)
+		case "LOCK":
+			status, err = h.handleLock(w, r, fs)
+		case "UNLOCK":
+			status, err = h.handleUnlock(w, r, fs)
+		case "PROPFIND":
+			status, err = h.handlePropfind(w, r, fs)
+		case "PROPPATCH":
+			status, err = h.handleProppatch(w, r, fs)
+		}
+	}
+	if err != nil {
+		log.Error(err)
+	}
+	if status != 0 {
+		w.WriteHeader(status)
+		if status != http.StatusNoContent {
+			w.Write([]byte(StatusText(status)))
+		}
+	}
+	if h.Logger != nil {
+		h.Logger(r, err)
+	}
+}
+
+// OK
+func (h *Handler) lock(now time.Time, root string, fs *FileSystem) (token string, status int, err error) {
+	token, err = h.LockSystem.Create(now, LockDetails{
+		Root:      root,
+		Duration:  infiniteTimeout,
+		ZeroDepth: true,
+	})
+	if err != nil {
+		if err == ErrLocked {
+			return "", StatusLocked, err
+		}
+		return "", http.StatusInternalServerError, err
+	}
+	return token, 0, nil
+}
+
+// ok
+func (h *Handler) confirmLocks(r *http.Request, src, dst string, fs *FileSystem) (release func(), status int, err error) {
+	hdr := r.Header.Get("If")
+	if hdr == "" {
+		// An empty If header means that the client hasn't previously created locks.
+		// Even if this client doesn't care about locks, we still need to check that
+		// the resources aren't locked by another client, so we create temporary
+		// locks that would conflict with another client's locks. These temporary
+		// locks are unlocked at the end of the HTTP request.
+		now, srcToken, dstToken := time.Now(), "", ""
+		if src != "" {
+			srcToken, status, err = h.lock(now, src, fs)
+			if err != nil {
+				return nil, status, err
+			}
+		}
+		if dst != "" {
+			dstToken, status, err = h.lock(now, dst, fs)
+			if err != nil {
+				if srcToken != "" {
+					h.LockSystem.Unlock(now, srcToken)
+				}
+				return nil, status, err
+			}
+		}
+
+		return func() {
+			if dstToken != "" {
+				h.LockSystem.Unlock(now, dstToken)
+			}
+			if srcToken != "" {
+				h.LockSystem.Unlock(now, srcToken)
+			}
+		}, 0, nil
+	}
+
+	ih, ok := parseIfHeader(hdr)
+	if !ok {
+		return nil, http.StatusBadRequest, errInvalidIfHeader
+	}
+	// ih is a disjunction (OR) of ifLists, so any ifList will do.
+	for _, l := range ih.lists {
+		lsrc := l.resourceTag
+		if lsrc == "" {
+			lsrc = src
+		} else {
+			u, err := url.Parse(lsrc)
+			if err != nil {
+				continue
+			}
+			//if u.Host != r.Host {
+			//	continue
+			//}
+			lsrc, status, err = h.stripPrefix(u.Path)
+			if err != nil {
+				return nil, status, err
+			}
+		}
+		release, err = h.LockSystem.Confirm(
+			time.Now(),
+			lsrc,
+			dst,
+			l.conditions...,
+		)
+		if err == ErrConfirmationFailed {
+			continue
+		}
+		if err != nil {
+			return nil, http.StatusInternalServerError, err
+		}
+		return release, 0, nil
+	}
+	// Section 10.4.1 says that "If this header is evaluated and all state lists
+	// fail, then the request must fail with a 412 (Precondition Failed) status."
+	// We follow the spec even though the cond_put_corrupt_token test case from
+	// the litmus test warns on seeing a 412 instead of a 423 (Locked).
+	return nil, http.StatusPreconditionFailed, ErrLocked
+}
+
+//OK
+func (h *Handler) handleOptions(w http.ResponseWriter, r *http.Request, fs *FileSystem) (status int, err error) {
+	reqPath, status, err := h.stripPrefix(r.URL.Path)
+	if err != nil {
+		return status, err
+	}
+	ctx := r.Context()
+	allow := "OPTIONS, LOCK, PUT, MKCOL"
+	if exist, fi := isPathExist(ctx, fs, reqPath); exist {
+		if fi.IsDir() {
+			allow = "OPTIONS, LOCK, DELETE, PROPPATCH, COPY, MOVE, UNLOCK, PROPFIND"
+		} else {
+			allow = "OPTIONS, LOCK, GET, HEAD, POST, DELETE, PROPPATCH, COPY, MOVE, UNLOCK, PROPFIND, PUT"
+		}
+	}
+	w.Header().Set("Allow", allow)
+	// http://www.webdav.org/specs/rfc4918.html#dav.compliance.classes
+	w.Header().Set("DAV", "1, 2")
+	// http://msdn.microsoft.com/en-au/library/cc250217.aspx
+	w.Header().Set("MS-Author-Via", "DAV")
+	return 0, nil
+}
+
+// OK
+func (h *Handler) handleGetHeadPost(w http.ResponseWriter, r *http.Request, fs *FileSystem) (status int, err error) {
+
+	reqPath, status, err := h.stripPrefix(r.URL.Path)
+	if err != nil {
+		return status, err
+	}
+
+	ctx := r.Context()
+
+	exist, file := isPathExist(ctx, fs, reqPath)
+	if !exist {
+		return http.StatusNotFound, nil
+	}
+
+	etag, err := findETag(ctx, fs, h.LockSystem, reqPath, file)
+	if err != nil {
+		return http.StatusInternalServerError, err
+	}
+	w.Header().Set("ETag", etag)
+	link, err := fs.Link(reqPath)
+	if err != nil {
+		return http.StatusInternalServerError, err
+	}
+	http.Redirect(w, r, link, 302)
+	return 0, nil
+}
+
+// OK
+func (h *Handler) handleDelete(w http.ResponseWriter, r *http.Request, fs *FileSystem) (status int, err error) {
+
+	reqPath, status, err := h.stripPrefix(r.URL.Path)
+	if err != nil {
+		return status, err
+	}
+	release, status, err := h.confirmLocks(r, reqPath, "", fs)
+	if err != nil {
+		return status, err
+	}
+	defer release()
+
+	//ctx := r.Context()
+
+	//// 尝试作为文件删除
+	//if ok, file := fs.IsFileExist(reqPath); ok {
+	//	if err := fs.Delete(ctx, []uint{}, []uint{file.ID}, false); err != nil {
+	//		return http.StatusMethodNotAllowed, err
+	//	}
+	//	return http.StatusNoContent, nil
+	//}
+	//
+	//// 尝试作为目录删除
+	//if ok, folder := fs.IsPathExist(reqPath); ok {
+	//	if err := fs.Delete(ctx, []uint{folder.ID}, []uint{}, false); err != nil {
+	//		return http.StatusMethodNotAllowed, err
+	//	}
+	//	return http.StatusNoContent, nil
+	//}
+
+	return http.StatusNotFound, nil
+}
+
+// OK
+func (h *Handler) handlePut(w http.ResponseWriter, r *http.Request, fs *FileSystem) (status int, err error) {
+	reqPath, status, err := h.stripPrefix(r.URL.Path)
+	if err != nil {
+		return status, err
+	}
+	release, status, err := h.confirmLocks(r, reqPath, "", fs)
+	if err != nil {
+		return status, err
+	}
+	defer release()
+	// TODO(rost): Support the If-Match, If-None-Match headers? See bradfitz'
+	// comments in http.checkEtag.
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	etag, err := findETag(ctx, fs, h.LockSystem, reqPath, nil)
+	if err != nil {
+		return http.StatusInternalServerError, err
+	}
+	w.Header().Set("ETag", etag)
+	return http.StatusCreated, nil
+}
+
+// OK
+func (h *Handler) handleMkcol(w http.ResponseWriter, r *http.Request, fs *FileSystem) (status int, err error) {
+	reqPath, status, err := h.stripPrefix(r.URL.Path)
+	if err != nil {
+		return status, err
+	}
+	release, status, err := h.confirmLocks(r, reqPath, "", fs)
+	if err != nil {
+		return status, err
+	}
+	defer release()
+
+	ctx := r.Context()
+
+	if r.ContentLength > 0 {
+		return http.StatusUnsupportedMediaType, nil
+	}
+	if strings.Contains(r.UserAgent(), "rclone") {
+		//if _, ok := ctx.Value(fsctx.IgnoreDirectoryConflictCtx).(bool); !ok {
+		//	ctx = context.WithValue(ctx, fsctx.IgnoreDirectoryConflictCtx, true)
+		//}
+	}
+	if _, err := fs.CreateDirectory(ctx, reqPath); err != nil {
+		return http.StatusConflict, err
+	}
+	return http.StatusCreated, nil
+}
+
+// OK
+func (h *Handler) handleCopyMove(w http.ResponseWriter, r *http.Request, fs *FileSystem) (status int, err error) {
+
+	hdr := r.Header.Get("Destination")
+	if hdr == "" {
+		return http.StatusBadRequest, errInvalidDestination
+	}
+	u, err := url.Parse(hdr)
+	if err != nil {
+		return http.StatusBadRequest, errInvalidDestination
+	}
+	//if u.Host != "" && u.Host != r.Host {
+	//	return http.StatusBadGateway, errInvalidDestination
+	//}
+
+	src, status, err := h.stripPrefix(r.URL.Path)
+	if err != nil {
+		return status, err
+	}
+
+	dst, status, err := h.stripPrefix(u.Path)
+	if err != nil {
+		return status, err
+	}
+
+	if dst == "" {
+		return http.StatusBadGateway, errInvalidDestination
+	}
+	if dst == src {
+		return http.StatusForbidden, errDestinationEqualsSource
+	}
+
+	ctx := r.Context()
+
+	isExist, target := isPathExist(ctx, fs, src)
+
+	if !isExist {
+		return http.StatusNotFound, nil
+	}
+
+	if r.Method == "COPY" {
+		// Section 7.5.1 says that a COPY only needs to lock the destination,
+		// not both destination and source. Strictly speaking, this is racy,
+		// even though a COPY doesn't modify the source, if a concurrent
+		// operation modifies the source. However, the litmus test explicitly
+		// checks that COPYing a locked-by-another source is OK.
+		release, status, err := h.confirmLocks(r, "", dst, fs)
+		if err != nil {
+			return status, err
+		}
+		defer release()
+
+		// Section 9.8.3 says that "The COPY method on a collection without a Depth
+		// header must act as if a Depth header with value "infinity" was included".
+		depth := infiniteDepth
+		if hdr := r.Header.Get("Depth"); hdr != "" {
+			depth = parseDepth(hdr)
+			if depth != 0 && depth != infiniteDepth {
+				// Section 9.8.3 says that "A client may submit a Depth header on a
+				// COPY on a collection with a value of "0" or "infinity"."
+				return http.StatusBadRequest, errInvalidDepth
+			}
+		}
+		return copyFiles(ctx, fs, target, dst, r.Header.Get("Overwrite") != "F", depth, 0)
+	}
+
+	// windows下，某些情况下（网盘根目录下）Office保存文件时附带的锁token只包含源文件，
+	// 此处暂时去除了对dst锁的检查
+	release, status, err := h.confirmLocks(r, src, "", fs)
+	if err != nil {
+		return status, err
+	}
+	defer release()
+
+	// Section 9.9.2 says that "The MOVE method on a collection must act as if
+	// a "Depth: infinity" header was used on it. A client must not submit a
+	// Depth header on a MOVE on a collection with any value but "infinity"."
+	if hdr := r.Header.Get("Depth"); hdr != "" {
+		if parseDepth(hdr) != infiniteDepth {
+			return http.StatusBadRequest, errInvalidDepth
+		}
+	}
+	return moveFiles(ctx, fs, target, dst, r.Header.Get("Overwrite") == "T")
+}
+
+// OK
+func (h *Handler) handleLock(w http.ResponseWriter, r *http.Request, fs *FileSystem) (retStatus int, retErr error) {
+
+	duration, err := parseTimeout(r.Header.Get("Timeout"))
+	if err != nil {
+		return http.StatusBadRequest, err
+	}
+	li, status, err := readLockInfo(r.Body)
+	if err != nil {
+		return status, err
+	}
+
+	//ctx := r.Context()
+	token, ld, now, created := "", LockDetails{}, time.Now(), false
+	if li == (lockInfo{}) {
+		// An empty lockInfo means to refresh the lock.
+		ih, ok := parseIfHeader(r.Header.Get("If"))
+		if !ok {
+			return http.StatusBadRequest, errInvalidIfHeader
+		}
+		if len(ih.lists) == 1 && len(ih.lists[0].conditions) == 1 {
+			token = ih.lists[0].conditions[0].Token
+		}
+		if token == "" {
+			return http.StatusBadRequest, errInvalidLockToken
+		}
+		ld, err = h.LockSystem.Refresh(now, token, duration)
+		if err != nil {
+			if err == ErrNoSuchLock {
+				return http.StatusPreconditionFailed, err
+			}
+			return http.StatusInternalServerError, err
+		}
+
+	} else {
+		// Section 9.10.3 says that "If no Depth header is submitted on a LOCK request,
+		// then the request MUST act as if a "Depth:infinity" had been submitted."
+		depth := infiniteDepth
+		if hdr := r.Header.Get("Depth"); hdr != "" {
+			depth = parseDepth(hdr)
+			if depth != 0 && depth != infiniteDepth {
+				// Section 9.10.3 says that "Values other than 0 or infinity must not be
+				// used with the Depth header on a LOCK method".
+				return http.StatusBadRequest, errInvalidDepth
+			}
+		}
+		reqPath, status, err := h.stripPrefix(r.URL.Path)
+		if err != nil {
+			return status, err
+		}
+		ld = LockDetails{
+			Root:      reqPath,
+			Duration:  duration,
+			OwnerXML:  li.Owner.InnerXML,
+			ZeroDepth: depth == 0,
+		}
+		token, err = h.LockSystem.Create(now, ld)
+		if err != nil {
+			if err == ErrLocked {
+				return StatusLocked, err
+			}
+			return http.StatusInternalServerError, err
+		}
+		defer func() {
+			if retErr != nil {
+				h.LockSystem.Unlock(now, token)
+			}
+		}()
+
+		// Create the resource if it didn't previously exist.
+		//if _, err := h.FileSystem.Stat(ctx, reqPath); err != nil {
+		//	f, err := h.FileSystem.OpenFile(ctx, reqPath, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0666)
+		//	if err != nil {
+		//		// TODO: detect missing intermediate dirs and return http.StatusConflict?
+		//		return http.StatusInternalServerError, err
+		//	}
+		//	f.Close()
+		//	created = true
+		//}
+
+		// http://www.webdav.org/specs/rfc4918.html#HEADER_Lock-Token says that the
+		// Lock-Token value is a Coded-URL. We add angle brackets.
+		w.Header().Set("Lock-Token", "<"+token+">")
+	}
+
+	w.Header().Set("Content-Type", "application/xml; charset=utf-8")
+	if created {
+		// This is "w.WriteHeader(http.StatusCreated)" and not "return
+		// http.StatusCreated, nil" because we write our own (XML) response to w
+		// and Handler.ServeHTTP would otherwise write "Created".
+		w.WriteHeader(http.StatusCreated)
+	}
+	writeLockInfo(w, token, ld)
+	return 0, nil
+}
+
+// OK
+func (h *Handler) handleUnlock(w http.ResponseWriter, r *http.Request, fs *FileSystem) (status int, err error) {
+
+	// http://www.webdav.org/specs/rfc4918.html#HEADER_Lock-Token says that the
+	// Lock-Token value is a Coded-URL. We strip its angle brackets.
+	t := r.Header.Get("Lock-Token")
+	if len(t) < 2 || t[0] != '<' || t[len(t)-1] != '>' {
+		return http.StatusBadRequest, errInvalidLockToken
+	}
+	t = t[1 : len(t)-1]
+
+	switch err = h.LockSystem.Unlock(time.Now(), t); err {
+	case nil:
+		return http.StatusNoContent, err
+	case ErrForbidden:
+		return http.StatusForbidden, err
+	case ErrLocked:
+		return StatusLocked, err
+	case ErrNoSuchLock:
+		return http.StatusConflict, err
+	default:
+		return http.StatusInternalServerError, err
+	}
+}
+
+// OK
+func (h *Handler) handlePropfind(w http.ResponseWriter, r *http.Request, fs *FileSystem) (status int, err error) {
+	reqPath, status, err := h.stripPrefix(r.URL.Path)
+	if err != nil {
+		return status, err
+	}
+	ctx := r.Context()
+	ok, fi := isPathExist(ctx, fs, reqPath)
+	if !ok {
+		return http.StatusNotFound, err
+	}
+
+	depth := infiniteDepth
+	if hdr := r.Header.Get("Depth"); hdr != "" {
+		depth = parseDepth(hdr)
+		if depth == invalidDepth {
+			return http.StatusBadRequest, errInvalidDepth
+		}
+	}
+	pf, status, err := readPropfind(r.Body)
+	if err != nil {
+		return status, err
+	}
+
+	mw := multistatusWriter{w: w}
+
+	walkFn := func(reqPath string, info FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+		var pstats []Propstat
+		if pf.Propname != nil {
+			pnames, err := propnames(ctx, fs, h.LockSystem, info)
+			if err != nil {
+				return err
+			}
+			pstat := Propstat{Status: http.StatusOK}
+			for _, xmlname := range pnames {
+				pstat.Props = append(pstat.Props, Property{XMLName: xmlname})
+			}
+			pstats = append(pstats, pstat)
+		} else if pf.Allprop != nil {
+			pstats, err = allprop(ctx, fs, h.LockSystem, info, pf.Prop)
+		} else {
+			pstats, err = props(ctx, fs, h.LockSystem, info, pf.Prop)
+		}
+		if err != nil {
+			return err
+		}
+		href := path.Join(h.Prefix, reqPath)
+		if href != "/" && info.IsDir() {
+			href += "/"
+		}
+		return mw.write(makePropstatResponse(href, pstats))
+	}
+
+	walkErr := walkFS(ctx, fs, depth, reqPath, fi, walkFn)
+	closeErr := mw.close()
+	if walkErr != nil {
+		return http.StatusInternalServerError, walkErr
+	}
+	if closeErr != nil {
+		return http.StatusInternalServerError, closeErr
+	}
+	return 0, nil
+}
+
+func (h *Handler) handleProppatch(w http.ResponseWriter, r *http.Request, fs *FileSystem) (status int, err error) {
+
+	reqPath, status, err := h.stripPrefix(r.URL.Path)
+	if err != nil {
+		return status, err
+	}
+	release, status, err := h.confirmLocks(r, reqPath, "", fs)
+	if err != nil {
+		return status, err
+	}
+	defer release()
+
+	ctx := r.Context()
+
+	if exist, _ := isPathExist(ctx, fs, reqPath); !exist {
+		return http.StatusNotFound, nil
+	}
+	patches, status, err := readProppatch(r.Body)
+	if err != nil {
+		return status, err
+	}
+	pstats, err := patch(ctx, fs, h.LockSystem, reqPath, patches)
+	if err != nil {
+		return http.StatusInternalServerError, err
+	}
+	mw := multistatusWriter{w: w}
+	writeErr := mw.write(makePropstatResponse(r.URL.Path, pstats))
+	closeErr := mw.close()
+	if writeErr != nil {
+		return http.StatusInternalServerError, writeErr
+	}
+	if closeErr != nil {
+		return http.StatusInternalServerError, closeErr
+	}
+	return 0, nil
+}
+
+func makePropstatResponse(href string, pstats []Propstat) *response {
+	resp := response{
+		Href:     []string{(&url.URL{Path: href}).EscapedPath()},
+		Propstat: make([]propstat, 0, len(pstats)),
+	}
+	for _, p := range pstats {
+		var xmlErr *xmlError
+		if p.XMLError != "" {
+			xmlErr = &xmlError{InnerXML: []byte(p.XMLError)}
+		}
+		resp.Propstat = append(resp.Propstat, propstat{
+			Status:              fmt.Sprintf("HTTP/1.1 %d %s", p.Status, StatusText(p.Status)),
+			Prop:                p.Props,
+			ResponseDescription: p.ResponseDescription,
+			Error:               xmlErr,
+		})
+	}
+	return &resp
+}
+
+const (
+	infiniteDepth = -1
+	invalidDepth  = -2
+)
+
+// parseDepth maps the strings "0", "1" and "infinity" to 0, 1 and
+// infiniteDepth. Parsing any other string returns invalidDepth.
+//
+// Different WebDAV methods have further constraints on valid depths:
+//	- PROPFIND has no further restrictions, as per section 9.1.
+//	- COPY accepts only "0" or "infinity", as per section 9.8.3.
+//	- MOVE accepts only "infinity", as per section 9.9.2.
+//	- LOCK accepts only "0" or "infinity", as per section 9.10.3.
+// These constraints are enforced by the handleXxx methods.
+func parseDepth(s string) int {
+	switch s {
+	case "0":
+		return 0
+	case "1":
+		return 1
+	case "infinity":
+		return infiniteDepth
+	}
+	return invalidDepth
+}
+
+// http://www.webdav.org/specs/rfc4918.html#status.code.extensions.to.http11
+const (
+	StatusMulti               = 207
+	StatusUnprocessableEntity = 422
+	StatusLocked              = 423
+	StatusFailedDependency    = 424
+	StatusInsufficientStorage = 507
+)
+
+func StatusText(code int) string {
+	switch code {
+	case StatusMulti:
+		return "Multi-Status"
+	case StatusUnprocessableEntity:
+		return "Unprocessable Entity"
+	case StatusLocked:
+		return "Locked"
+	case StatusFailedDependency:
+		return "Failed Dependency"
+	case StatusInsufficientStorage:
+		return "Insufficient Storage"
+	}
+	return http.StatusText(code)
+}
+
+var (
+	errDestinationEqualsSource = errors.New("webdav: destination equals source")
+	errDirectoryNotEmpty       = errors.New("webdav: directory not empty")
+	errInvalidDepth            = errors.New("webdav: invalid depth")
+	errInvalidDestination      = errors.New("webdav: invalid destination")
+	errInvalidIfHeader         = errors.New("webdav: invalid If header")
+	errInvalidLockInfo         = errors.New("webdav: invalid lock info")
+	errInvalidLockToken        = errors.New("webdav: invalid lock token")
+	errInvalidPropfind         = errors.New("webdav: invalid propfind")
+	errInvalidProppatch        = errors.New("webdav: invalid proppatch")
+	errInvalidResponse         = errors.New("webdav: invalid response")
+	errInvalidTimeout          = errors.New("webdav: invalid timeout")
+	errNoFileSystem            = errors.New("webdav: no file system")
+	errNoLockSystem            = errors.New("webdav: no lock system")
+	errNotADirectory           = errors.New("webdav: not a directory")
+	errPrefixMismatch          = errors.New("webdav: prefix mismatch")
+	errRecursionTooDeep        = errors.New("webdav: recursion too deep")
+	errUnsupportedLockInfo     = errors.New("webdav: unsupported lock info")
+	errUnsupportedMethod       = errors.New("webdav: unsupported method")
+)

server/webdav/xml.go

@@ -0,0 +1,519 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package webdav
+
+// The XML encoding is covered by Section 14.
+// http://www.webdav.org/specs/rfc4918.html#xml.element.definitions
+
+import (
+	"bytes"
+	"encoding/xml"
+	"fmt"
+	"io"
+	"net/http"
+	"time"
+
+	// As of https://go-review.googlesource.com/#/c/12772/ which was submitted
+	// in July 2015, this package uses an internal fork of the standard
+	// library's encoding/xml package, due to changes in the way namespaces
+	// were encoded. Such changes were introduced in the Go 1.5 cycle, but were
+	// rolled back in response to https://github.com/golang/go/issues/11841
+	//
+	// However, this package's exported API, specifically the Property and
+	// DeadPropsHolder types, need to refer to the standard library's version
+	// of the xml.Name type, as code that imports this package cannot refer to
+	// the internal version.
+	//
+	// This file therefore imports both the internal and external versions, as
+	// ixml and xml, and converts between them.
+	//
+	// In the long term, this package should use the standard library's version
+	// only, and the internal fork deleted, once
+	// https://github.com/golang/go/issues/13400 is resolved.
+	ixml "github.com/Xhofe/alist/server/webdav/internal/xml"
+)
+
+// http://www.webdav.org/specs/rfc4918.html#ELEMENT_lockinfo
+type lockInfo struct {
+	XMLName   ixml.Name `xml:"lockinfo"`
+	Exclusive *struct{} `xml:"lockscope>exclusive"`
+	Shared    *struct{} `xml:"lockscope>shared"`
+	Write     *struct{} `xml:"locktype>write"`
+	Owner     owner     `xml:"owner"`
+}
+
+// http://www.webdav.org/specs/rfc4918.html#ELEMENT_owner
+type owner struct {
+	InnerXML string `xml:",innerxml"`
+}
+
+func readLockInfo(r io.Reader) (li lockInfo, status int, err error) {
+	c := &countingReader{r: r}
+	if err = ixml.NewDecoder(c).Decode(&li); err != nil {
+		if err == io.EOF {
+			if c.n == 0 {
+				// An empty body means to refresh the lock.
+				// http://www.webdav.org/specs/rfc4918.html#refreshing-locks
+				return lockInfo{}, 0, nil
+			}
+			err = errInvalidLockInfo
+		}
+		return lockInfo{}, http.StatusBadRequest, err
+	}
+	// We only support exclusive (non-shared) write locks. In practice, these are
+	// the only types of locks that seem to matter.
+	if li.Exclusive == nil || li.Shared != nil || li.Write == nil {
+		return lockInfo{}, http.StatusNotImplemented, errUnsupportedLockInfo
+	}
+	return li, 0, nil
+}
+
+type countingReader struct {
+	n int
+	r io.Reader
+}
+
+func (c *countingReader) Read(p []byte) (int, error) {
+	n, err := c.r.Read(p)
+	c.n += n
+	return n, err
+}
+
+func writeLockInfo(w io.Writer, token string, ld LockDetails) (int, error) {
+	depth := "infinity"
+	if ld.ZeroDepth {
+		depth = "0"
+	}
+	timeout := ld.Duration / time.Second
+	return fmt.Fprintf(w, "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n"+
+		"<D:prop xmlns:D=\"DAV:\"><D:lockdiscovery><D:activelock>\n"+
+		"	<D:locktype><D:write/></D:locktype>\n"+
+		"	<D:lockscope><D:exclusive/></D:lockscope>\n"+
+		"	<D:depth>%s</D:depth>\n"+
+		"	<D:owner>%s</D:owner>\n"+
+		"	<D:timeout>Second-%d</D:timeout>\n"+
+		"	<D:locktoken><D:href>%s</D:href></D:locktoken>\n"+
+		"	<D:lockroot><D:href>%s</D:href></D:lockroot>\n"+
+		"</D:activelock></D:lockdiscovery></D:prop>",
+		depth, ld.OwnerXML, timeout, escape(token), escape(ld.Root),
+	)
+}
+
+func escape(s string) string {
+	for i := 0; i < len(s); i++ {
+		switch s[i] {
+		case '"', '&', '\'', '<', '>':
+			b := bytes.NewBuffer(nil)
+			ixml.EscapeText(b, []byte(s))
+			return b.String()
+		}
+	}
+	return s
+}
+
+// Next returns the next token, if any, in the XML stream of d.
+// RFC 4918 requires to ignore comments, processing instructions
+// and directives.
+// http://www.webdav.org/specs/rfc4918.html#property_values
+// http://www.webdav.org/specs/rfc4918.html#xml-extensibility
+func next(d *ixml.Decoder) (ixml.Token, error) {
+	for {
+		t, err := d.Token()
+		if err != nil {
+			return t, err
+		}
+		switch t.(type) {
+		case ixml.Comment, ixml.Directive, ixml.ProcInst:
+			continue
+		default:
+			return t, nil
+		}
+	}
+}
+
+// http://www.webdav.org/specs/rfc4918.html#ELEMENT_prop (for propfind)
+type propfindProps []xml.Name
+
+// UnmarshalXML appends the property names enclosed within start to pn.
+//
+// It returns an error if start does not contain any properties or if
+// properties contain values. Character data between properties is ignored.
+func (pn *propfindProps) UnmarshalXML(d *ixml.Decoder, start ixml.StartElement) error {
+	for {
+		t, err := next(d)
+		if err != nil {
+			return err
+		}
+		switch t.(type) {
+		case ixml.EndElement:
+			if len(*pn) == 0 {
+				return fmt.Errorf("%s must not be empty", start.Name.Local)
+			}
+			return nil
+		case ixml.StartElement:
+			name := t.(ixml.StartElement).Name
+			t, err = next(d)
+			if err != nil {
+				return err
+			}
+			if _, ok := t.(ixml.EndElement); !ok {
+				return fmt.Errorf("unexpected token %T", t)
+			}
+			*pn = append(*pn, xml.Name(name))
+		}
+	}
+}
+
+// http://www.webdav.org/specs/rfc4918.html#ELEMENT_propfind
+type propfind struct {
+	XMLName  ixml.Name     `xml:"DAV: propfind"`
+	Allprop  *struct{}     `xml:"DAV: allprop"`
+	Propname *struct{}     `xml:"DAV: propname"`
+	Prop     propfindProps `xml:"DAV: prop"`
+	Include  propfindProps `xml:"DAV: include"`
+}
+
+func readPropfind(r io.Reader) (pf propfind, status int, err error) {
+	c := countingReader{r: r}
+	if err = ixml.NewDecoder(&c).Decode(&pf); err != nil {
+		if err == io.EOF {
+			if c.n == 0 {
+				// An empty body means to propfind allprop.
+				// http://www.webdav.org/specs/rfc4918.html#METHOD_PROPFIND
+				return propfind{Allprop: new(struct{})}, 0, nil
+			}
+			err = errInvalidPropfind
+		}
+		return propfind{}, http.StatusBadRequest, err
+	}
+
+	if pf.Allprop == nil && pf.Include != nil {
+		return propfind{}, http.StatusBadRequest, errInvalidPropfind
+	}
+	if pf.Allprop != nil && (pf.Prop != nil || pf.Propname != nil) {
+		return propfind{}, http.StatusBadRequest, errInvalidPropfind
+	}
+	if pf.Prop != nil && pf.Propname != nil {
+		return propfind{}, http.StatusBadRequest, errInvalidPropfind
+	}
+	if pf.Propname == nil && pf.Allprop == nil && pf.Prop == nil {
+		return propfind{}, http.StatusBadRequest, errInvalidPropfind
+	}
+	return pf, 0, nil
+}
+
+// Property represents a single DAV resource property as defined in RFC 4918.
+// See http://www.webdav.org/specs/rfc4918.html#data.model.for.resource.properties
+type Property struct {
+	// XMLName is the fully qualified name that identifies this property.
+	XMLName xml.Name
+
+	// Lang is an optional xml:lang attribute.
+	Lang string `xml:"xml:lang,attr,omitempty"`
+
+	// InnerXML contains the XML representation of the property value.
+	// See http://www.webdav.org/specs/rfc4918.html#property_values
+	//
+	// Property values of complex type or mixed-content must have fully
+	// expanded XML namespaces or be self-contained with according
+	// XML namespace declarations. They must not rely on any XML
+	// namespace declarations within the scope of the XML document,
+	// even including the DAV: namespace.
+	InnerXML []byte `xml:",innerxml"`
+}
+
+// ixmlProperty is the same as the Property type except it holds an ixml.Name
+// instead of an xml.Name.
+type ixmlProperty struct {
+	XMLName  ixml.Name
+	Lang     string `xml:"xml:lang,attr,omitempty"`
+	InnerXML []byte `xml:",innerxml"`
+}
+
+// http://www.webdav.org/specs/rfc4918.html#ELEMENT_error
+// See multistatusWriter for the "D:" namespace prefix.
+type xmlError struct {
+	XMLName  ixml.Name `xml:"D:error"`
+	InnerXML []byte    `xml:",innerxml"`
+}
+
+// http://www.webdav.org/specs/rfc4918.html#ELEMENT_propstat
+// See multistatusWriter for the "D:" namespace prefix.
+type propstat struct {
+	Prop                []Property `xml:"D:prop>_ignored_"`
+	Status              string     `xml:"D:status"`
+	Error               *xmlError  `xml:"D:error"`
+	ResponseDescription string     `xml:"D:responsedescription,omitempty"`
+}
+
+// ixmlPropstat is the same as the propstat type except it holds an ixml.Name
+// instead of an xml.Name.
+type ixmlPropstat struct {
+	Prop                []ixmlProperty `xml:"D:prop>_ignored_"`
+	Status              string         `xml:"D:status"`
+	Error               *xmlError      `xml:"D:error"`
+	ResponseDescription string         `xml:"D:responsedescription,omitempty"`
+}
+
+// MarshalXML prepends the "D:" namespace prefix on properties in the DAV: namespace
+// before encoding. See multistatusWriter.
+func (ps propstat) MarshalXML(e *ixml.Encoder, start ixml.StartElement) error {
+	// Convert from a propstat to an ixmlPropstat.
+	ixmlPs := ixmlPropstat{
+		Prop:                make([]ixmlProperty, len(ps.Prop)),
+		Status:              ps.Status,
+		Error:               ps.Error,
+		ResponseDescription: ps.ResponseDescription,
+	}
+	for k, prop := range ps.Prop {
+		ixmlPs.Prop[k] = ixmlProperty{
+			XMLName:  ixml.Name(prop.XMLName),
+			Lang:     prop.Lang,
+			InnerXML: prop.InnerXML,
+		}
+	}
+
+	for k, prop := range ixmlPs.Prop {
+		if prop.XMLName.Space == "DAV:" {
+			prop.XMLName = ixml.Name{Space: "", Local: "D:" + prop.XMLName.Local}
+			ixmlPs.Prop[k] = prop
+		}
+	}
+	// Distinct type to avoid infinite recursion of MarshalXML.
+	type newpropstat ixmlPropstat
+	return e.EncodeElement(newpropstat(ixmlPs), start)
+}
+
+// http://www.webdav.org/specs/rfc4918.html#ELEMENT_response
+// See multistatusWriter for the "D:" namespace prefix.
+type response struct {
+	XMLName             ixml.Name  `xml:"D:response"`
+	Href                []string   `xml:"D:href"`
+	Propstat            []propstat `xml:"D:propstat"`
+	Status              string     `xml:"D:status,omitempty"`
+	Error               *xmlError  `xml:"D:error"`
+	ResponseDescription string     `xml:"D:responsedescription,omitempty"`
+}
+
+// MultistatusWriter marshals one or more Responses into a XML
+// multistatus response.
+// See http://www.webdav.org/specs/rfc4918.html#ELEMENT_multistatus
+// TODO(rsto, mpl): As a workaround, the "D:" namespace prefix, defined as
+// "DAV:" on this element, is prepended on the nested response, as well as on all
+// its nested elements. All property names in the DAV: namespace are prefixed as
+// well. This is because some versions of Mini-Redirector (on windows 7) ignore
+// elements with a default namespace (no prefixed namespace). A less intrusive fix
+// should be possible after golang.org/cl/11074. See https://golang.org/issue/11177
+type multistatusWriter struct {
+	// ResponseDescription contains the optional responsedescription
+	// of the multistatus XML element. Only the latest content before
+	// close will be emitted. Empty response descriptions are not
+	// written.
+	responseDescription string
+
+	w   http.ResponseWriter
+	enc *ixml.Encoder
+}
+
+// Write validates and emits a DAV response as part of a multistatus response
+// element.
+//
+// It sets the HTTP status code of its underlying http.ResponseWriter to 207
+// (Multi-Status) and populates the Content-Type header. If r is the
+// first, valid response to be written, Write prepends the XML representation
+// of r with a multistatus tag. Callers must call close after the last response
+// has been written.
+func (w *multistatusWriter) write(r *response) error {
+	switch len(r.Href) {
+	case 0:
+		return errInvalidResponse
+	case 1:
+		if len(r.Propstat) > 0 != (r.Status == "") {
+			return errInvalidResponse
+		}
+	default:
+		if len(r.Propstat) > 0 || r.Status == "" {
+			return errInvalidResponse
+		}
+	}
+	err := w.writeHeader()
+	if err != nil {
+		return err
+	}
+	return w.enc.Encode(r)
+}
+
+// writeHeader writes a XML multistatus start element on w's underlying
+// http.ResponseWriter and returns the result of the write operation.
+// After the first write attempt, writeHeader becomes a no-op.
+func (w *multistatusWriter) writeHeader() error {
+	if w.enc != nil {
+		return nil
+	}
+	w.w.Header().Add("Content-Type", "text/xml; charset=utf-8")
+	w.w.WriteHeader(StatusMulti)
+	_, err := fmt.Fprintf(w.w, `<?xml version="1.0" encoding="UTF-8"?>`)
+	if err != nil {
+		return err
+	}
+	w.enc = ixml.NewEncoder(w.w)
+	return w.enc.EncodeToken(ixml.StartElement{
+		Name: ixml.Name{
+			Space: "DAV:",
+			Local: "multistatus",
+		},
+		Attr: []ixml.Attr{{
+			Name:  ixml.Name{Space: "xmlns", Local: "D"},
+			Value: "DAV:",
+		}},
+	})
+}
+
+// Close completes the marshalling of the multistatus response. It returns
+// an error if the multistatus response could not be completed. If both the
+// return value and field enc of w are nil, then no multistatus response has
+// been written.
+func (w *multistatusWriter) close() error {
+	if w.enc == nil {
+		return nil
+	}
+	var end []ixml.Token
+	if w.responseDescription != "" {
+		name := ixml.Name{Space: "DAV:", Local: "responsedescription"}
+		end = append(end,
+			ixml.StartElement{Name: name},
+			ixml.CharData(w.responseDescription),
+			ixml.EndElement{Name: name},
+		)
+	}
+	end = append(end, ixml.EndElement{
+		Name: ixml.Name{Space: "DAV:", Local: "multistatus"},
+	})
+	for _, t := range end {
+		err := w.enc.EncodeToken(t)
+		if err != nil {
+			return err
+		}
+	}
+	return w.enc.Flush()
+}
+
+var xmlLangName = ixml.Name{Space: "http://www.w3.org/XML/1998/namespace", Local: "lang"}
+
+func xmlLang(s ixml.StartElement, d string) string {
+	for _, attr := range s.Attr {
+		if attr.Name == xmlLangName {
+			return attr.Value
+		}
+	}
+	return d
+}
+
+type xmlValue []byte
+
+func (v *xmlValue) UnmarshalXML(d *ixml.Decoder, start ixml.StartElement) error {
+	// The XML value of a property can be arbitrary, mixed-content XML.
+	// To make sure that the unmarshalled value contains all required
+	// namespaces, we encode all the property value XML tokens into a
+	// buffer. This forces the encoder to redeclare any used namespaces.
+	var b bytes.Buffer
+	e := ixml.NewEncoder(&b)
+	for {
+		t, err := next(d)
+		if err != nil {
+			return err
+		}
+		if e, ok := t.(ixml.EndElement); ok && e.Name == start.Name {
+			break
+		}
+		if err = e.EncodeToken(t); err != nil {
+			return err
+		}
+	}
+	err := e.Flush()
+	if err != nil {
+		return err
+	}
+	*v = b.Bytes()
+	return nil
+}
+
+// http://www.webdav.org/specs/rfc4918.html#ELEMENT_prop (for proppatch)
+type proppatchProps []Property
+
+// UnmarshalXML appends the property names and values enclosed within start
+// to ps.
+//
+// An xml:lang attribute that is defined either on the DAV:prop or property
+// name XML element is propagated to the property's Lang field.
+//
+// UnmarshalXML returns an error if start does not contain any properties or if
+// property values contain syntactically incorrect XML.
+func (ps *proppatchProps) UnmarshalXML(d *ixml.Decoder, start ixml.StartElement) error {
+	lang := xmlLang(start, "")
+	for {
+		t, err := next(d)
+		if err != nil {
+			return err
+		}
+		switch elem := t.(type) {
+		case ixml.EndElement:
+			if len(*ps) == 0 {
+				return fmt.Errorf("%s must not be empty", start.Name.Local)
+			}
+			return nil
+		case ixml.StartElement:
+			p := Property{
+				XMLName: xml.Name(t.(ixml.StartElement).Name),
+				Lang:    xmlLang(t.(ixml.StartElement), lang),
+			}
+			err = d.DecodeElement(((*xmlValue)(&p.InnerXML)), &elem)
+			if err != nil {
+				return err
+			}
+			*ps = append(*ps, p)
+		}
+	}
+}
+
+// http://www.webdav.org/specs/rfc4918.html#ELEMENT_set
+// http://www.webdav.org/specs/rfc4918.html#ELEMENT_remove
+type setRemove struct {
+	XMLName ixml.Name
+	Lang    string         `xml:"xml:lang,attr,omitempty"`
+	Prop    proppatchProps `xml:"DAV: prop"`
+}
+
+// http://www.webdav.org/specs/rfc4918.html#ELEMENT_propertyupdate
+type propertyupdate struct {
+	XMLName   ixml.Name   `xml:"DAV: propertyupdate"`
+	Lang      string      `xml:"xml:lang,attr,omitempty"`
+	SetRemove []setRemove `xml:",any"`
+}
+
+func readProppatch(r io.Reader) (patches []Proppatch, status int, err error) {
+	var pu propertyupdate
+	if err = ixml.NewDecoder(r).Decode(&pu); err != nil {
+		return nil, http.StatusBadRequest, err
+	}
+	for _, op := range pu.SetRemove {
+		remove := false
+		switch op.XMLName {
+		case ixml.Name{Space: "DAV:", Local: "set"}:
+			// No-op.
+		case ixml.Name{Space: "DAV:", Local: "remove"}:
+			for _, p := range op.Prop {
+				if len(p.InnerXML) > 0 {
+					return nil, http.StatusBadRequest, errInvalidProppatch
+				}
+			}
+			remove = true
+		default:
+			return nil, http.StatusBadRequest, errInvalidProppatch
+		}
+		patches = append(patches, Proppatch{Remove: remove, Props: op.Prop})
+	}
+	return patches, 0, nil
+}

utils/file.go

@@ -89,3 +89,9 @@ func ParsePath(path string) string {
 	return path
 }
 
+func RemoveLastSlash(path string) string {
+	if len(path) > 1 {
+		return strings.TrimSuffix(path, "/")
+	}
+	return path
+}