--- /dev/null
+// Copyright 2013 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 httpfs implements http.FileSystem using a godoc vfs.FileSystem.
+package httpfs // import "golang.org/x/tools/godoc/vfs/httpfs"
+
+import (
+ "fmt"
+ "io"
+ "net/http"
+ "os"
+
+ "golang.org/x/tools/godoc/vfs"
+)
+
+func New(fs vfs.FileSystem) http.FileSystem {
+ return &httpFS{fs}
+}
+
+type httpFS struct {
+ fs vfs.FileSystem
+}
+
+func (h *httpFS) Open(name string) (http.File, error) {
+ fi, err := h.fs.Stat(name)
+ if err != nil {
+ return nil, err
+ }
+ if fi.IsDir() {
+ return &httpDir{h.fs, name, nil}, nil
+ }
+ f, err := h.fs.Open(name)
+ if err != nil {
+ return nil, err
+ }
+ return &httpFile{h.fs, f, name}, nil
+}
+
+// httpDir implements http.File for a directory in a FileSystem.
+type httpDir struct {
+ fs vfs.FileSystem
+ name string
+ pending []os.FileInfo
+}
+
+func (h *httpDir) Close() error { return nil }
+func (h *httpDir) Stat() (os.FileInfo, error) { return h.fs.Stat(h.name) }
+func (h *httpDir) Read([]byte) (int, error) {
+ return 0, fmt.Errorf("cannot Read from directory %s", h.name)
+}
+
+func (h *httpDir) Seek(offset int64, whence int) (int64, error) {
+ if offset == 0 && whence == 0 {
+ h.pending = nil
+ return 0, nil
+ }
+ return 0, fmt.Errorf("unsupported Seek in directory %s", h.name)
+}
+
+func (h *httpDir) Readdir(count int) ([]os.FileInfo, error) {
+ if h.pending == nil {
+ d, err := h.fs.ReadDir(h.name)
+ if err != nil {
+ return nil, err
+ }
+ if d == nil {
+ d = []os.FileInfo{} // not nil
+ }
+ h.pending = d
+ }
+
+ if len(h.pending) == 0 && count > 0 {
+ return nil, io.EOF
+ }
+ if count <= 0 || count > len(h.pending) {
+ count = len(h.pending)
+ }
+ d := h.pending[:count]
+ h.pending = h.pending[count:]
+ return d, nil
+}
+
+// httpFile implements http.File for a file (not directory) in a FileSystem.
+type httpFile struct {
+ fs vfs.FileSystem
+ vfs.ReadSeekCloser
+ name string
+}
+
+func (h *httpFile) Stat() (os.FileInfo, error) { return h.fs.Stat(h.name) }
+func (h *httpFile) Readdir(int) ([]os.FileInfo, error) {
+ return nil, fmt.Errorf("cannot Readdir from file %s", h.name)
+}