Small bug fixes and my own implementation of webdav.Dir

Former-commit-id: 7a3c55bea22252b404430c5fa5fff9272dde87fd [formerly a5fa2aedbc584606fc5c114689df1f993640ff2d] [formerly c9a062d45c7560bd71b9362ce02cbe7a95273399 [formerly a753247333f361566867ff885cb5baa1bf4b41c0]]
Former-commit-id: 920069815b8425641cf2c13f95f3d69b6980b901 [formerly 89b7604b2f2569bcd177b90972ef53738a6777b6]
Former-commit-id: 4230d8c5f7b18f0668b207ffe44a74882808cab8

dir/dir.go

@@ -0,0 +1,226 @@
+// Package dir implements a FileSystem interface using the native
+// file system restricted to a specific directory tree. Originally from
+// https://github.com/golang/net/blob/master/webdav/file.go#L68
+package dir
+
+import (
+	"errors"
+	"io"
+	"os"
+	"path"
+	"path/filepath"
+	"strings"
+)
+
+// A Dir uses the native file system restricted to a specific directory tree.
+//
+// While the FileSystem.OpenFile method takes '/'-separated paths, a Dir's
+// string value is a filename on the native file system, not a URL, so it is
+// separated by filepath.Separator, which isn't necessarily '/'.
+//
+// An empty Dir is treated as ".".
+type Dir string
+
+func (d Dir) resolve(name string) string {
+	// This implementation is based on Dir.Open's code in the standard net/http package.
+	if filepath.Separator != '/' && strings.IndexRune(name, filepath.Separator) >= 0 ||
+		strings.Contains(name, "\x00") {
+		return ""
+	}
+
+	dir := string(d)
+	if dir == "" {
+		dir = "."
+	}
+
+	return filepath.Join(dir, filepath.FromSlash(SlashClean(name)))
+}
+
+// Mkdir implements os.Mkdir in this directory context.
+func (d Dir) Mkdir(name string, perm os.FileMode) error {
+	if name = d.resolve(name); name == "" {
+		return os.ErrNotExist
+	}
+	return os.Mkdir(name, perm)
+}
+
+// OpenFile implements os.OpenFile in this directory context.
+func (d Dir) OpenFile(name string, flag int, perm os.FileMode) (*os.File, error) {
+	if name = d.resolve(name); name == "" {
+		return nil, os.ErrNotExist
+	}
+	f, err := os.OpenFile(name, flag, perm)
+	if err != nil {
+		return nil, err
+	}
+	return f, nil
+}
+
+// RemoveAll implements os.RemoveAll in this directory context.
+func (d Dir) RemoveAll(name string) error {
+	if name = d.resolve(name); name == "" {
+		return os.ErrNotExist
+	}
+
+	if name == filepath.Clean(string(d)) {
+		// Prohibit removing the virtual root directory.
+		return os.ErrInvalid
+	}
+	return os.RemoveAll(name)
+}
+
+// Rename implements os.Rename in this directory context.
+func (d Dir) Rename(oldName, newName string) error {
+	if oldName = d.resolve(oldName); oldName == "" {
+		return os.ErrNotExist
+	}
+	if newName = d.resolve(newName); newName == "" {
+		return os.ErrNotExist
+	}
+	if root := filepath.Clean(string(d)); root == oldName || root == newName {
+		// Prohibit renaming from or to the virtual root directory.
+		return os.ErrInvalid
+	}
+	return os.Rename(oldName, newName)
+}
+
+// Stat implements os.Stat in this directory context.
+func (d Dir) Stat(name string) (os.FileInfo, error) {
+	if name = d.resolve(name); name == "" {
+		return nil, os.ErrNotExist
+	}
+
+	return os.Stat(name)
+}
+
+// Copy copies a file or directory from src to dst. If it is
+// a directory, all of the files and sub-directories will be copied.
+func (d Dir) Copy(src, dst string) error {
+	if src = d.resolve(src); src == "" {
+		return os.ErrNotExist
+	}
+
+	if dst = d.resolve(dst); dst == "" {
+		return os.ErrNotExist
+	}
+
+	if root := filepath.Clean(string(d)); root == src || root == dst {
+		// Prohibit copying from or to the virtual root directory.
+		return os.ErrInvalid
+	}
+
+	info, err := d.Stat(src)
+	if err != nil {
+		return err
+	}
+
+	if info.IsDir() {
+		return CopyDir(src, dst)
+	}
+
+	return CopyFile(src, dst)
+}
+
+// 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)
+}
+
+// CopyFile copies a file from source to dest and returns
+// an error if any.
+func CopyFile(source string, dest string) error {
+	// Open the source file.
+	src, err := os.Open(source)
+	if err != nil {
+		return err
+	}
+	defer src.Close()
+
+	// Makes the directory needed to create the dst
+	// file.
+	err = os.MkdirAll(filepath.Dir(dest), 0666)
+	if err != nil {
+		return err
+	}
+
+	// Create the destination file.
+	dst, err := os.Create(dest)
+	if err != nil {
+		return err
+	}
+	defer dst.Close()
+
+	// Copy the contents of the file.
+	_, err = io.Copy(dst, src)
+	if err != nil {
+		return err
+	}
+
+	// Copy the mode if the user can't
+	// open the file.
+	info, err := os.Stat(source)
+	if err != nil {
+		err = os.Chmod(dest, info.Mode())
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+// CopyDir copies a directory from source to dest and all
+// of its sub-directories. It doesn't stop if it finds an error
+// during the copy. Returns an error if any.
+func CopyDir(source string, dest string) error {
+	// Get properties of source.
+	srcinfo, err := os.Stat(source)
+	if err != nil {
+		return err
+	}
+
+	// Create the destination directory.
+	err = os.MkdirAll(dest, srcinfo.Mode())
+	if err != nil {
+		return err
+	}
+
+	dir, _ := os.Open(source)
+	obs, err := dir.Readdir(-1)
+
+	var errs []error
+
+	for _, obj := range obs {
+		fsource := source + "/" + obj.Name()
+		fdest := dest + "/" + obj.Name()
+
+		if obj.IsDir() {
+			// Create sub-directories, recursively.
+			err = CopyDir(fsource, fdest)
+			if err != nil {
+				errs = append(errs, err)
+			}
+		} else {
+			// Perform the file copy.
+			err = CopyFile(fsource, fdest)
+			if err != nil {
+				errs = append(errs, err)
+			}
+		}
+	}
+
+	var errString string
+	for _, err := range errs {
+		errString += err.Error() + "\n"
+	}
+
+	if errString != "" {
+		return errors.New(errString)
+	}
+
+	return nil
+}