From 5bd95b3ce1a43b59559c8e705f862f2ad1a5179f Mon Sep 17 00:00:00 2001
From: Alexander Neumann <alexander@bumpern.de>
Date: Sat, 15 Apr 2017 10:53:12 +0200
Subject: [PATCH] Implement MkdirAll() for Windows

Closes #735
---
 src/restic/fs/file.go         | 38 ---------------
 src/restic/fs/file_unix.go    | 19 ++++++++
 src/restic/fs/file_windows.go | 87 +++++++++++++++++++++++++++++++++++
 3 files changed, 106 insertions(+), 38 deletions(-)
 create mode 100644 src/restic/fs/file_unix.go
 create mode 100644 src/restic/fs/file_windows.go

diff --git a/src/restic/fs/file.go b/src/restic/fs/file.go
index 2ba5d138e..e23da2bcb 100644
--- a/src/restic/fs/file.go
+++ b/src/restic/fs/file.go
@@ -4,8 +4,6 @@ import (
 	"io"
 	"os"
 	"path/filepath"
-	"runtime"
-	"strings"
 )
 
 // File is an open file on a file system.
@@ -21,31 +19,6 @@ type File interface {
 	Stat() (os.FileInfo, error)
 }
 
-// fixpath returns an absolute path on windows, so restic can open long file
-// names.
-func fixpath(name string) string {
-	if runtime.GOOS == "windows" {
-		abspath, err := filepath.Abs(name)
-		if err == nil {
-			// Check if \\?\UNC\ already exist
-			if strings.HasPrefix(abspath, `\\?\UNC\`) {
-				return abspath
-			}
-			// Check if \\?\ already exist
-			if strings.HasPrefix(abspath, `\\?\`) {
-				return abspath
-			}
-			// Check if path starts with \\
-			if strings.HasPrefix(abspath, `\\`) {
-				return strings.Replace(abspath, `\\`, `\\?\UNC\`, 1)
-			}
-			// Normal path
-			return `\\?\` + abspath
-		}
-	}
-	return name
-}
-
 // Chmod changes the mode of the named file to mode.
 func Chmod(name string, mode os.FileMode) error {
 	return os.Chmod(fixpath(name), mode)
@@ -57,17 +30,6 @@ func Mkdir(name string, perm os.FileMode) error {
 	return os.Mkdir(fixpath(name), perm)
 }
 
-// MkdirAll creates a directory named path,
-// along with any necessary parents, and returns nil,
-// or else returns an error.
-// The permission bits perm are used for all
-// directories that MkdirAll creates.
-// If path is already a directory, MkdirAll does nothing
-// and returns nil.
-func MkdirAll(path string, perm os.FileMode) error {
-	return os.MkdirAll(fixpath(path), perm)
-}
-
 // Readlink returns the destination of the named symbolic link.
 // If there is an error, it will be of type *PathError.
 func Readlink(name string) (string, error) {
diff --git a/src/restic/fs/file_unix.go b/src/restic/fs/file_unix.go
new file mode 100644
index 000000000..4c6da3964
--- /dev/null
+++ b/src/restic/fs/file_unix.go
@@ -0,0 +1,19 @@
+// +build !windows
+
+package fs
+
+import "os"
+
+// fixpath returns an absolute path on windows, so restic can open long file
+// names.
+func fixpath(name string) string {
+	return name
+}
+
+// MkdirAll creates a directory named path, along with any necessary parents,
+// and returns nil, or else returns an error. The permission bits perm are used
+// for all directories that MkdirAll creates. If path is already a directory,
+// MkdirAll does nothing and returns nil.
+func MkdirAll(path string, perm os.FileMode) error {
+	return os.MkdirAll(fixpath(path), perm)
+}
diff --git a/src/restic/fs/file_windows.go b/src/restic/fs/file_windows.go
new file mode 100644
index 000000000..8f1df7967
--- /dev/null
+++ b/src/restic/fs/file_windows.go
@@ -0,0 +1,87 @@
+package fs
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"syscall"
+)
+
+// fixpath returns an absolute path on windows, so restic can open long file
+// names.
+func fixpath(name string) string {
+	abspath, err := filepath.Abs(name)
+	if err == nil {
+		// Check if \\?\UNC\ already exist
+		if strings.HasPrefix(abspath, `\\?\UNC\`) {
+			return abspath
+		}
+		// Check if \\?\ already exist
+		if strings.HasPrefix(abspath, `\\?\`) {
+			return abspath
+		}
+		// Check if path starts with \\
+		if strings.HasPrefix(abspath, `\\`) {
+			return strings.Replace(abspath, `\\`, `\\?\UNC\`, 1)
+		}
+		// Normal path
+		return `\\?\` + abspath
+	}
+	return name
+}
+
+// MkdirAll creates a directory named path, along with any necessary parents,
+// and returns nil, or else returns an error. The permission bits perm are used
+// for all directories that MkdirAll creates. If path is already a directory,
+// MkdirAll does nothing and returns nil.
+//
+// Adapted from the stdlib MkdirAll, added test for volume name.
+func MkdirAll(path string, perm os.FileMode) error {
+	// Fast path: if we can tell whether path is a directory or file, stop with success or error.
+	dir, err := os.Stat(path)
+	if err == nil {
+		if dir.IsDir() {
+			return nil
+		}
+		return &os.PathError{
+			Op:   "mkdir",
+			Path: path,
+			Err:  syscall.ENOTDIR,
+		}
+	}
+
+	// Slow path: make sure parent exists and then call Mkdir for path.
+	i := len(path)
+	for i > 0 && os.IsPathSeparator(path[i-1]) { // Skip trailing path separator.
+		i--
+	}
+
+	j := i
+	for j > 0 && !os.IsPathSeparator(path[j-1]) { // Scan backward over element.
+		j--
+	}
+
+	if j > 1 {
+		// Create parent
+		parent := path[0 : j-1]
+		if parent != filepath.VolumeName(parent) {
+			err = MkdirAll(parent, perm)
+			if err != nil {
+				return err
+			}
+		}
+	}
+
+	// Parent now exists; invoke Mkdir and use its result.
+	err = os.Mkdir(path, perm)
+	if err != nil {
+		// Handle arguments like "foo/." by
+		// double-checking that directory doesn't exist.
+		dir, err1 := os.Lstat(path)
+		if err1 == nil && dir.IsDir() {
+			return nil
+		}
+		return err
+	}
+	return nil
+}