Use type aliases FilePath, FilePaths...

... for wxString and wxArrayStringEx, holding file paths (absolute or relative,
directory or plain file); to be replaced later with different types

(not yet using std::vector, becase of some uses of wxArrayString::Index with
two arguments)

src/xml/XMLFileReader.cpp

@@ -38,7 +38,7 @@ XMLFileReader::~XMLFileReader()
 }
 
 bool XMLFileReader::Parse(XMLTagHandler *baseHandler,
-                          const wxString &fname)
+                          const FilePath &fname)
 {
    wxFFile theXMLFile(fname, wxT("rb"));
    if (!theXMLFile.IsOpened()) {

src/xml/XMLFileReader.h

@@ -14,6 +14,7 @@
 #include "expat.h"
 
 #include "XMLTagHandler.h"
+#include "audacity/Types.h"
 
 class AUDACITY_DLL_API XMLFileReader final {
  public:
@@ -21,7 +22,7 @@ class AUDACITY_DLL_API XMLFileReader final {
    ~XMLFileReader();
 
    bool Parse(XMLTagHandler *baseHandler,
-              const wxString &fname);
+              const FilePath &fname);
 
    wxString GetErrorStr();
 

src/xml/XMLTagHandler.cpp

@@ -59,7 +59,7 @@ bool XMLValueChecker::IsGoodLongString(const wxString & str)
 
 
 // "Good" means the name is well-formed and names an existing file or folder.
-bool XMLValueChecker::IsGoodFileName(const wxString & strFileName, const wxString & strDirName /* = {} */)
+bool XMLValueChecker::IsGoodFileName(const FilePath & strFileName, const FilePath & strDirName /* = "{} */)
 {
    // Test strFileName.
    if (!IsGoodFileString(strFileName) ||
@@ -71,7 +71,7 @@ bool XMLValueChecker::IsGoodFileName(const wxString & strFileName, const wxStrin
    return (fileName.IsOk() && fileName.FileExists());
 }
 
-bool XMLValueChecker::IsGoodFileString(const wxString &str)
+bool XMLValueChecker::IsGoodFileString(const FilePath &str)
 {
    return (IsGoodString(str) &&
             !str.empty() &&
@@ -83,7 +83,7 @@ bool XMLValueChecker::IsGoodFileString(const wxString &str)
             (str.Find(wxFileName::GetPathSeparator()) == -1)); // No path separator characters.
 }
 
-bool XMLValueChecker::IsGoodSubdirName(const wxString & strSubdirName, const wxString & strDirName /* = {} */)
+bool XMLValueChecker::IsGoodSubdirName(const FilePath & strSubdirName, const FilePath & strDirName /* = {} */)
 {
    // Test strSubdirName.
    // Note this prevents path separators, and relative path to parents (strDirName),
@@ -99,14 +99,14 @@ bool XMLValueChecker::IsGoodSubdirName(const wxString & strSubdirName, const wxS
    return (fileName.IsOk() && fileName.DirExists());
 }
 
-bool XMLValueChecker::IsGoodPathName(const wxString & strPathName)
+bool XMLValueChecker::IsGoodPathName(const FilePath & strPathName)
 {
    // Test the corresponding wxFileName.
    wxFileName fileName(strPathName);
    return XMLValueChecker::IsGoodFileName(fileName.GetFullName(), fileName.GetPath(wxPATH_GET_VOLUME));
 }
 
-bool XMLValueChecker::IsGoodPathString(const wxString &str)
+bool XMLValueChecker::IsGoodPathString(const FilePath &str)
 {
    return (IsGoodString(str) &&
             !str.empty() &&

src/xml/XMLTagHandler.h

@@ -22,6 +22,8 @@
 #include <wx/string.h>
 #include <stdio.h>
 
+#include "audacity/Types.h"
+
 #include "XMLWriter.h"
 class XMLValueChecker
 {
@@ -33,11 +35,11 @@ public:
    // Labels are allowed to be very long.  At some future date we will format long labels nicely.
    static bool IsGoodLongString(const wxString & str);
 
-   static bool IsGoodFileName(const wxString & strFileName, const wxString & strDirName = {});
-   static bool IsGoodFileString(const wxString &str);
-   static bool IsGoodSubdirName(const wxString & strSubdirName, const wxString & strDirName = {});
-   static bool IsGoodPathName(const wxString & strPathName);
-   static bool IsGoodPathString(const wxString &str);
+   static bool IsGoodFileName(const FilePath & strFileName, const FilePath & strDirName = {});
+   static bool IsGoodFileString(const FilePath &str);
+   static bool IsGoodSubdirName(const FilePath & strSubdirName, const FilePath & strDirName = {});
+   static bool IsGoodPathName(const FilePath & strPathName);
+   static bool IsGoodPathString(const FilePath &str);
 
    /** @brief Check that the supplied string can be converted to a long (32bit)
 	* integer.

src/xml/XMLWriter.cpp

@@ -294,7 +294,7 @@ wxString XMLWriter::XMLEsc(const wxString & s)
 /// XMLFileWriter class
 ///
 XMLFileWriter::XMLFileWriter
-   ( const wxString &outputPath, const wxString &caption, bool keepBackup )
+   ( const FilePath &outputPath, const wxString &caption, bool keepBackup )
    : mOutputPath{ outputPath }
    , mCaption{ caption }
    , mKeepBackup{ keepBackup }
@@ -359,7 +359,7 @@ void XMLFileWriter::PreCommit()
 void XMLFileWriter::PostCommit()
 // may throw
 {
-   auto tempPath = GetName();
+   FilePath tempPath = GetName();
    if (mKeepBackup) {
       if (! mBackupFile.Close() ||
           ! wxRenameFile( mOutputPath, mBackupName ) )

src/xml/XMLWriter.h

@@ -16,6 +16,8 @@
 
 #include "../FileException.h"
 
+#include "audacity/Types.h"
+
 ///
 /// XMLWriter
 ///
@@ -78,7 +80,7 @@ class AUDACITY_DLL_API XMLFileWriter final : private wxFFile, public XMLWriter {
    /// The caption is for message boxes to show in case of errors.
    /// Might throw.
    XMLFileWriter
-      ( const wxString &outputPath, const wxString &caption,
+      ( const FilePath &outputPath, const wxString &caption,
         bool keepBackup = false );
 
    virtual ~XMLFileWriter();
@@ -99,7 +101,7 @@ class AUDACITY_DLL_API XMLFileWriter final : private wxFFile, public XMLWriter {
    /// Write to file. Might throw.
    void Write(const wxString &data) override;
 
-   wxString GetBackupName() const { return mBackupName; }
+   FilePath GetBackupName() const { return mBackupName; }
 
  private:
 
@@ -113,9 +115,9 @@ class AUDACITY_DLL_API XMLFileWriter final : private wxFFile, public XMLWriter {
    /// Might throw.
    void CloseWithoutEndingTags(); // for auto-save files
 
-   const wxString mOutputPath;
+   const FilePath mOutputPath;
    const wxString mCaption;
-   wxString mBackupName;
+   FilePath mBackupName;
    const bool mKeepBackup;
 
    wxFFile mBackupFile;