tailscale: update tailfs file and package names (#11590)

This change updates the tailfs file and package names to their new
naming convention.

Updates #tailscale/corp#16827

Signed-off-by: Charlotte Brandhorst-Satzkorn <charlotte@tailscale.com>

drive/driveimpl/compositedav/propfind.go

@@ -0,0 +1,84 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+package compositedav
+
+import (
+	"bytes"
+	"fmt"
+	"math"
+	"net/http"
+	"regexp"
+
+	"tailscale.com/drive/driveimpl/shared"
+)
+
+var (
+	hrefRegex = regexp.MustCompile(`(?s)<D:href>/?([^<]*)/?</D:href>`)
+)
+
+func (h *Handler) handlePROPFIND(w http.ResponseWriter, r *http.Request) {
+	pathComponents := shared.CleanAndSplit(r.URL.Path)
+	mpl := h.maxPathLength(r)
+	if !shared.IsRoot(r.URL.Path) && len(pathComponents)+getDepth(r) > mpl {
+		// Delegate to a Child.
+		depth := getDepth(r)
+
+		cached := h.StatCache.get(r.URL.Path, depth)
+		if cached != nil {
+			w.Header().Del("Content-Length")
+			w.WriteHeader(http.StatusMultiStatus)
+			w.Write(cached)
+			return
+		}
+
+		// Use a buffering ResponseWriter so that we can manipulate the result.
+		// The only thing we use from the original ResponseWriter is Header().
+		bw := &bufferingResponseWriter{ResponseWriter: w}
+
+		mpl := h.maxPathLength(r)
+		h.delegate(pathComponents[mpl-1:], bw, r)
+
+		// Fixup paths to add the requested path as a prefix.
+		pathPrefix := shared.Join(pathComponents[0:mpl]...)
+		b := hrefRegex.ReplaceAll(bw.buf.Bytes(), []byte(fmt.Sprintf("<D:href>%s/$1</D:href>", pathPrefix)))
+
+		if h.StatCache != nil && bw.status == http.StatusMultiStatus && b != nil {
+			h.StatCache.set(r.URL.Path, depth, b)
+		}
+
+		w.Header().Del("Content-Length")
+		w.WriteHeader(bw.status)
+		w.Write(b)
+
+		return
+	}
+
+	h.handle(w, r)
+}
+
+func getDepth(r *http.Request) int {
+	switch r.Header.Get("Depth") {
+	case "0":
+		return 0
+	case "1":
+		return 1
+	case "infinity":
+		return math.MaxInt
+	}
+	return 0
+}
+
+type bufferingResponseWriter struct {
+	http.ResponseWriter
+	status int
+	buf    bytes.Buffer
+}
+
+func (bw *bufferingResponseWriter) WriteHeader(statusCode int) {
+	bw.status = statusCode
+}
+
+func (bw *bufferingResponseWriter) Write(p []byte) (int, error) {
+	return bw.buf.Write(p)
+}