Vendoring with Glide and delete function handler

gateway/vendor/golang.org/x/net/webdav/prop.go

@@ -0,0 +1,418 @@
+// 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"
+	"encoding/xml"
+	"fmt"
+	"io"
+	"mime"
+	"net/http"
+	"os"
+	"path/filepath"
+	"strconv"
+
+	"golang.org/x/net/context"
+)
+
+// 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, os.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, name string, pnames []xml.Name) ([]Propstat, error) {
+	f, err := fs.OpenFile(ctx, name, os.O_RDONLY, 0)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+	fi, err := f.Stat()
+	if err != nil {
+		return nil, err
+	}
+	isDir := fi.IsDir()
+
+	var deadProps map[xml.Name]Property
+	if dph, ok := f.(DeadPropsHolder); ok {
+		deadProps, err = dph.DeadProps()
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	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, name, 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, name string) ([]xml.Name, error) {
+	f, err := fs.OpenFile(ctx, name, os.O_RDONLY, 0)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+	fi, err := f.Stat()
+	if err != nil {
+		return nil, err
+	}
+	isDir := fi.IsDir()
+
+	var deadProps map[xml.Name]Property
+	if dph, ok := f.(DeadPropsHolder); ok {
+		deadProps, err = dph.DeadProps()
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	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)
+		}
+	}
+	for pn := range deadProps {
+		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, name string, include []xml.Name) ([]Propstat, error) {
+	pnames, err := propnames(ctx, fs, ls, name)
+	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, name, 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
+	}
+
+	f, err := fs.OpenFile(ctx, name, os.O_RDWR, 0)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+	if dph, ok := f.(DeadPropsHolder); ok {
+		ret, err := dph.Patch(patches)
+		if err != nil {
+			return nil, err
+		}
+		// http://www.webdav.org/specs/rfc4918.html#ELEMENT_propstat says that
+		// "The contents of the prop XML element must only list the names of
+		// properties to which the result in the status element applies."
+		for _, pstat := range ret {
+			for i, p := range pstat.Props {
+				pstat.Props[i] = Property{XMLName: p.XMLName}
+			}
+		}
+		return ret, nil
+	}
+	// The file doesn't implement the optional DeadPropsHolder interface, so
+	// all patches are forbidden.
+	pstat := Propstat{Status: http.StatusForbidden}
+	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 os.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 os.FileInfo) (string, error) {
+	if slashClean(name) == "/" {
+		// Hide the real name of a possibly prefixed root directory.
+		return "", nil
+	}
+	return escapeXML(fi.Name()), nil
+}
+
+func findContentLength(ctx context.Context, fs FileSystem, ls LockSystem, name string, fi os.FileInfo) (string, error) {
+	return strconv.FormatInt(fi.Size(), 10), nil
+}
+
+func findLastModified(ctx context.Context, fs FileSystem, ls LockSystem, name string, fi os.FileInfo) (string, error) {
+	return fi.ModTime().Format(http.TimeFormat), nil
+}
+
+func findContentType(ctx context.Context, fs FileSystem, ls LockSystem, name string, fi os.FileInfo) (string, error) {
+	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
+}
+
+func findETag(ctx context.Context, fs FileSystem, ls LockSystem, name string, fi os.FileInfo) (string, error) {
+	// The Apache http 2.4 web server by default concatenates the
+	// modification time and size of a file. We replicate the heuristic
+	// with nanosecond granularity.
+	return fmt.Sprintf(`"%x%x"`, fi.ModTime().UnixNano(), fi.Size()), nil
+}
+
+func findSupportedLock(ctx context.Context, fs FileSystem, ls LockSystem, name string, fi os.FileInfo) (string, error) {
+	return `` +
+		`<D:lockentry xmlns:D="DAV:">` +
+		`<D:lockscope><D:exclusive/></D:lockscope>` +
+		`<D:locktype><D:write/></D:locktype>` +
+		`</D:lockentry>`, nil
+}