lib: Folder marker is now a folder

GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/4341
LGTM: calmh

lib/fs/filesystem.go

@@ -11,6 +11,7 @@ import (
 	"io"
 	"os"
 	"path/filepath"
+	"strings"
 	"time"
 )
 
@@ -133,3 +134,20 @@ func NewFilesystem(fsType FilesystemType, uri string) Filesystem {
 	}
 	return fs
 }
+
+// IsInternal returns true if the file, as a path relative to the folder
+// root, represents an internal file that should always be ignored. The file
+// path must be clean (i.e., in canonical shortest form).
+func IsInternal(file string) bool {
+	internals := []string{".stfolder", ".stignore", ".stversions"}
+	pathSep := string(PathSeparator)
+	for _, internal := range internals {
+		if file == internal {
+			return true
+		}
+		if strings.HasPrefix(file, internal+pathSep) {
+			return true
+		}
+	}
+	return false
+}

lib/fs/filesystem_test.go

@@ -0,0 +1,43 @@
+// Copyright (C) 2017 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
+package fs
+
+import (
+	"path/filepath"
+	"testing"
+)
+
+func TestIsInternal(t *testing.T) {
+	cases := []struct {
+		file     string
+		internal bool
+	}{
+		{".stfolder", true},
+		{".stignore", true},
+		{".stversions", true},
+		{".stfolder/foo", true},
+		{".stignore/foo", true},
+		{".stversions/foo", true},
+
+		{".stfolderfoo", false},
+		{".stignorefoo", false},
+		{".stversionsfoo", false},
+		{"foo.stfolder", false},
+		{"foo.stignore", false},
+		{"foo.stversions", false},
+		{"foo/.stfolder", false},
+		{"foo/.stignore", false},
+		{"foo/.stversions", false},
+	}
+
+	for _, tc := range cases {
+		res := IsInternal(filepath.FromSlash(tc.file))
+		if res != tc.internal {
+			t.Errorf("Unexpected result: IsInteral(%q): %v should be %v", tc.file, res, tc.internal)
+		}
+	}
+}

lib/fs/tempname.go

@@ -0,0 +1,59 @@
+// Copyright (C) 2015 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
+package fs
+
+import (
+	"crypto/md5"
+	"fmt"
+	"path/filepath"
+	"runtime"
+	"strings"
+)
+
+const (
+	WindowsTempPrefix = "~syncthing~"
+	UnixTempPrefix    = ".syncthing."
+)
+
+var TempPrefix string
+
+// Real filesystems usually handle 255 bytes. encfs has varying and
+// confusing file name limits. We take a safe way out and switch to hashing
+// quite early.
+const maxFilenameLength = 160 - len(UnixTempPrefix) - len(".tmp")
+
+func init() {
+	if runtime.GOOS == "windows" {
+		TempPrefix = WindowsTempPrefix
+	} else {
+		TempPrefix = UnixTempPrefix
+	}
+}
+
+// IsTemporary is true if the file name has the temporary prefix. Regardless
+// of the normally used prefix, the standard Windows and Unix temp prefixes
+// are always recognized as temp files.
+func IsTemporary(name string) bool {
+	name = filepath.Base(name)
+	if strings.HasPrefix(name, WindowsTempPrefix) ||
+		strings.HasPrefix(name, UnixTempPrefix) {
+		return true
+	}
+	return false
+}
+
+func TempName(name string) string {
+	tdir := filepath.Dir(name)
+	tbase := filepath.Base(name)
+	if len(tbase) > maxFilenameLength {
+		hash := md5.New()
+		hash.Write([]byte(name))
+		tbase = fmt.Sprintf("%x", hash.Sum(nil))
+	}
+	tname := fmt.Sprintf("%s%s.tmp", TempPrefix, tbase)
+	return filepath.Join(tdir, tname)
+}

lib/fs/tempname_test.go

@@ -0,0 +1,26 @@
+// Copyright (C) 2015 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
+package fs
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestLongTempFilename(t *testing.T) {
+	filename := ""
+	for i := 0; i < 300; i++ {
+		filename += "l"
+	}
+	tFile := TempName(filename)
+	if len(tFile) < 10 || len(tFile) > 200 {
+		t.Fatal("Invalid long filename")
+	}
+	if !strings.HasSuffix(TempName("short"), "short.tmp") {
+		t.Fatal("Invalid short filename", TempName("short"))
+	}
+}