util: Improve and rename EscapePath() to DetermineEscapePath()

If the new URL encoded path is found then it has precedence over the '%' escaped
path. In case none of both is found the new URL approach is used.

internal/buffer/backup.go

@@ -79,7 +79,7 @@ func (b *Buffer) Backup() error {
 		os.Mkdir(backupdir, os.ModePerm)
 	}
 
-	name := filepath.Join(backupdir, util.EscapePath(b.AbsPath))
+	name := util.DetermineEscapePath(backupdir, b.AbsPath)
 
 	err = overwriteFile(name, encoding.Nop, func(file io.Writer) (e error) {
 		b.Lock()
@@ -123,7 +123,7 @@ func (b *Buffer) RemoveBackup() {
 	if !b.Settings["backup"].(bool) || b.Settings["permbackup"].(bool) || b.Path == "" || b.Type != BTDefault {
 		return
 	}
-	f := filepath.Join(config.ConfigDir, "backups", util.EscapePath(b.AbsPath))
+	f := util.DetermineEscapePath(filepath.Join(config.ConfigDir, "backups"), b.AbsPath)
 	os.Remove(f)
 }
 
@@ -131,13 +131,13 @@ func (b *Buffer) RemoveBackup() {
 // Returns true if a backup was applied
 func (b *Buffer) ApplyBackup(fsize int64) (bool, bool) {
 	if b.Settings["backup"].(bool) && !b.Settings["permbackup"].(bool) && len(b.Path) > 0 && b.Type == BTDefault {
-		backupfile := filepath.Join(config.ConfigDir, "backups", util.EscapePath(b.AbsPath))
+		backupfile := util.DetermineEscapePath(filepath.Join(config.ConfigDir, "backups"), b.AbsPath)
 		if info, err := os.Stat(backupfile); err == nil {
 			backup, err := os.Open(backupfile)
 			if err == nil {
 				defer backup.Close()
 				t := info.ModTime()
-				msg := fmt.Sprintf(backupMsg, t.Format("Mon Jan _2 at 15:04, 2006"), util.EscapePath(b.AbsPath))
+				msg := fmt.Sprintf(backupMsg, t.Format("Mon Jan _2 at 15:04, 2006"), backupfile)
 				choice := screen.TermPrompt(msg, []string{"r", "i", "a", "recover", "ignore", "abort"}, true)
 
 				if choice%3 == 0 {

internal/buffer/serialize.go

@@ -31,7 +31,7 @@ func (b *Buffer) Serialize() error {
 		return nil
 	}
 
-	name := filepath.Join(config.ConfigDir, "buffers", util.EscapePath(b.AbsPath))
+	name := util.DetermineEscapePath(filepath.Join(config.ConfigDir, "buffers"), b.AbsPath)
 
 	return overwriteFile(name, encoding.Nop, func(file io.Writer) error {
 		err := gob.NewEncoder(file).Encode(SerializedBuffer{
@@ -50,7 +50,7 @@ func (b *Buffer) Unserialize() error {
 	if b.Path == "" {
 		return nil
 	}
-	file, err := os.Open(filepath.Join(config.ConfigDir, "buffers", util.EscapePath(b.AbsPath)))
+	file, err := os.Open(util.DetermineEscapePath(filepath.Join(config.ConfigDir, "buffers"), b.AbsPath))
 	if err == nil {
 		defer file.Close()
 		var buffer SerializedBuffer

internal/util/util.go

@@ -7,6 +7,7 @@ import (
 	"fmt"
 	"io"
 	"net/http"
+	"net/url"
 	"os"
 	"os/user"
 	"path/filepath"
@@ -408,8 +409,13 @@ func GetModTime(path string) (time.Time, error) {
 	return info.ModTime(), nil
 }
 
-// EscapePath replaces every path separator in a given path with a %
+// EscapePathUrl encodes the path in URL query form
-func EscapePath(path string) string {
+func EscapePathUrl(path string) string {
+	return url.QueryEscape(filepath.ToSlash(path))
+}
+
+// EscapePathLegacy replaces every path separator in a given path with a %
+func EscapePathLegacy(path string) string {
 	path = filepath.ToSlash(path)
 	if runtime.GOOS == "windows" {
 		// ':' is not valid in a path name on Windows but is ok on Unix
@@ -418,6 +424,24 @@ func EscapePath(path string) string {
 	return strings.ReplaceAll(path, "/", "%")
 }
 
+// DetermineEscapePath escapes a path, determining whether it should be escaped
+// using URL encoding (preferred, since it encodes unambiguously) or
+// legacy encoding with '%' (for backward compatibility, if the legacy-escaped
+// path exists in the given directory).
+func DetermineEscapePath(dir string, path string) string {
+	url := filepath.Join(dir, EscapePathUrl(path))
+	if _, err := os.Stat(url); err == nil {
+		return url
+	}
+
+	legacy := filepath.Join(dir, EscapePathLegacy(path))
+	if _, err := os.Stat(legacy); err == nil {
+		return legacy
+	}
+
+	return url
+}
+
 // GetLeadingWhitespace returns the leading whitespace of the given byte array
 func GetLeadingWhitespace(b []byte) []byte {
 	ws := []byte{}