posix: Support UNC paths on windows.

This allows us to now use 32K paths names on windows.

Fixes minio#1620

config-migrate.go

@@ -49,7 +49,7 @@ func purgeV1() {
 		fatalIf(err, "Unable to retrieve config path.")
 
 		configFile := filepath.Join(configPath, "fsUsers.json")
-		os.RemoveAll(configFile)
+		removeAll(configFile)
 	}
 	fatalIf(errors.New(""), "Failed to migrate unrecognized config version ‘"+cv1.Version+"’.")
 }

object-api-getobjectinfo_test.go

@@ -21,7 +21,6 @@ import (
 	"crypto/md5"
 	"encoding/hex"
 	"io/ioutil"
-	"os"
 	"strconv"
 	"testing"
 )
@@ -116,7 +115,7 @@ func BenchmarkGetObjectFS(b *testing.B) {
 	if err != nil {
 		b.Fatal(err)
 	}
-	defer os.RemoveAll(directory)
+	defer removeAll(directory)
 
 	// Create the obj.
 	obj, err := newFSObjects(directory)

object-api-listobjects_test.go

@@ -577,7 +577,7 @@ func BenchmarkListObjects(b *testing.B) {
 	if err != nil {
 		b.Fatal(err)
 	}
-	defer os.RemoveAll(directory)
+	defer removeAll(directory)
 
 	// Create the obj.
 	obj, err := newFSObjects(directory)

object-api_test.go

@@ -69,6 +69,6 @@ func (s *MySuite) TestXLAPISuite(c *C) {
 
 func removeRootsC(c *C, roots []string) {
 	for _, root := range roots {
-		os.RemoveAll(root)
+		removeAll(root)
 	}
 }

posix-list-dir-others.go

@@ -19,17 +19,19 @@
 package main
 
 import (
+	"fmt"
 	"io"
 	"os"
 	"strings"
 )
 
 // Return all the entries at the directory dirPath.
 func readDir(dirPath string) (entries []string, err error) {
-	d, err := os.Open(dirPath)
+	d, err := os.Open(longPath(dirPath))
 	if err != nil {
 		// File is really not found.
 		if os.IsNotExist(err) {
+			fmt.Println(longPath(dirPath))
 			return nil, errFileNotFound
 		}
 
@@ -50,12 +52,12 @@ func readDir(dirPath string) (entries []string, err error) {
 			return nil, err
 		}
 		for _, fi := range fis {
-			// Skip special files.
+			// Skip special files, if found.
 			if hasPosixReservedPrefix(fi.Name()) {
 				continue
 			}
 			if fi.Mode().IsDir() {
-				// append "/" instead of "\" so that sorting is done as expected.
+				// Append "/" instead of "\" so that sorting is achieved as expected.
 				entries = append(entries, fi.Name()+slashSeparator)
 			} else if fi.Mode().IsRegular() {
 				entries = append(entries, fi.Name())

posix-unc-path.go

@@ -0,0 +1,48 @@
+/*
+ * Minio Cloud Storage, (C) 2016 Minio, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package main
+
+import (
+	"fmt"
+	"path/filepath"
+	"runtime"
+	"strings"
+)
+
+// longPath converts a absolute windows path to a UNC long path.
+func longPath(path string) string {
+	if runtime.GOOS == "windows" {
+		// UNC can NOT use "/", so convert all to "\"
+		path = filepath.FromSlash(path)
+
+		// If prefix is "\\", we already have a UNC path or server.
+		if strings.HasPrefix(path, `\\`) {
+
+			// If already long path, just keep it
+			if strings.HasPrefix(path, `\\?\`) {
+				return path
+			}
+
+			// Trim "\\" from path and add UNC prefix.
+			return `\\?\UNC\` + strings.TrimPrefix(path, `\\`)
+		}
+		path = `\\?\` + path
+		fmt.Println(path)
+		return path
+	}
+	return path
+}

posix-utils.go

@@ -17,8 +17,11 @@
 package main
 
 import (
+	"io"
+	"os"
 	"runtime"
 	"strings"
+	"syscall"
 	"unicode/utf8"
 )
 
@@ -70,3 +73,122 @@ func hasPosixReservedPrefix(name string) (isReserved bool) {
 	}
 	return isReserved
 }
+
+// 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 {
+	// Fast path: if we can tell whether path is a directory or file, stop with success or error.
+	dir, err := os.Stat(longPath(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
+		err = mkdirAll(path[0:j-1], perm)
+		if err != nil {
+			return err
+		}
+	}
+
+	// Parent now exists; invoke Mkdir and use its result.
+	err = os.Mkdir(longPath(path), perm)
+	if err != nil {
+		// Handle arguments like "foo/." by
+		// double-checking that directory doesn't exist.
+		dir, err1 := os.Lstat(longPath(path))
+		if err1 == nil && dir.IsDir() {
+			return nil
+		}
+		return err
+	}
+	return nil
+}
+
+// removeAll removes path and any children it contains.
+// It removes everything it can but returns the first error
+// it encounters.  If the path does not exist, RemoveAll
+// returns nil (no error).
+func removeAll(path string) error {
+	// Simple case: if Remove works, we're done.
+	err := os.Remove(longPath(path))
+	if err == nil || os.IsNotExist(err) {
+		return nil
+	}
+
+	// Otherwise, is this a directory we need to recurse into?
+	dir, serr := os.Lstat(longPath(path))
+	if serr != nil {
+		if serr, ok := serr.(*os.PathError); ok && (os.IsNotExist(serr.Err) || serr.Err == syscall.ENOTDIR) {
+			return nil
+		}
+		return serr
+	}
+	if !dir.IsDir() {
+		// Not a directory; return the error from Remove.
+		return err
+	}
+
+	// Directory.
+	fd, err := os.Open(longPath(path))
+	if err != nil {
+		if os.IsNotExist(err) {
+			// Race. It was deleted between the Lstat and Open.
+			// Return nil per RemoveAll's docs.
+			return nil
+		}
+		return err
+	}
+
+	// Remove contents & return first error.
+	err = nil
+	for {
+		names, err1 := fd.Readdirnames(1000)
+		for _, name := range names {
+			err1 = removeAll(path + string(os.PathSeparator) + name)
+			if err == nil {
+				err = err1
+			}
+		}
+		if err1 == io.EOF {
+			break
+		}
+		// If Readdirnames returned an error, use it.
+		if err == nil {
+			err = err1
+		}
+		if len(names) == 0 {
+			break
+		}
+	}
+
+	// Close directory, because windows won't remove opened directory.
+	fd.Close()
+
+	// Remove directory.
+	err1 := os.Remove(longPath(path))
+	if err1 == nil || os.IsNotExist(err1) {
+		return nil
+	}
+	if err == nil {
+		err = err1
+	}
+	return err
+}