Add wxDD_MULTIPLE wxDirDialog style and implement it for GTK

Add wxDirDialog::GetPaths() similar to the existing member of
wxFileDialog with the same name and also taking, for consistency,
wxArrayString as the output parameter.

include/wx/dirdlg.h

@@ -25,8 +25,21 @@ extern WXDLLIMPEXP_DATA_CORE(const char) wxDirDialogNameStr[];
 extern WXDLLIMPEXP_DATA_CORE(const char) wxDirDialogDefaultFolderStr[];
 extern WXDLLIMPEXP_DATA_CORE(const char) wxDirSelectorPromptStr[];
 
+
+/*
+    The flags below must coexist with the following flags in m_windowStyle
+    #define wxCAPTION               0x20000000
+    #define wxMAXIMIZE              0x00002000
+    #define wxCLOSE_BOX             0x00001000
+    #define wxSYSTEM_MENU           0x00000800
+    wxBORDER_NONE   =               0x00200000
+    #define wxRESIZE_BORDER         0x00000040
+    #define wxDIALOG_NO_PARENT      0x00000020
+*/
+
 #define wxDD_CHANGE_DIR         0x0100
 #define wxDD_DIR_MUST_EXIST     0x0200
+#define wxDD_MULTIPLE           0x0400
 
 // deprecated, on by default now, use wxDD_DIR_MUST_EXIST to disable it
 #define wxDD_NEW_DIR_BUTTON     0
@@ -75,6 +88,7 @@ public:
 
     virtual wxString GetMessage() const { return m_message; }
     virtual wxString GetPath() const { return m_path; }
+    virtual void GetPaths(wxArrayString& paths) const { paths.Empty(); paths.Add(m_path); }
 
 protected:
     wxString m_message;

include/wx/gtk/dirdlg.h

@@ -39,6 +39,7 @@ public:     // overrides from wxGenericDirDialog
 
     wxString GetPath() const wxOVERRIDE;
     void SetPath(const wxString& path) wxOVERRIDE;
+    void GetPaths(wxArrayString& paths) const wxOVERRIDE;
 
 
     // Implementation only.
@@ -55,7 +56,7 @@ protected:
 
 
 private:
-    wxString m_selectedDirectory;
+    wxArrayString m_paths;
 
     wxDECLARE_DYNAMIC_CLASS(wxDirDialog);
 };

interface/wx/dirdlg.h

@@ -7,6 +7,8 @@
 
 #define wxDD_CHANGE_DIR         0x0100
 #define wxDD_DIR_MUST_EXIST     0x0200
+#define wxDD_MULTIPLE           0x0400
+
 #define wxDD_NEW_DIR_BUTTON     0 // deprecated, on by default now,
 
 #define wxDD_DEFAULT_STYLE      (wxDEFAULT_DIALOG_STYLE|wxRESIZE_BORDER)
@@ -43,6 +45,11 @@ const char wxDirDialogNameStr[] = "wxDirCtrl";
     @style{wxDD_CHANGE_DIR}
            Change the current working directory to the directory chosen by the
            user.
+          @note This flag cannot be used with the @c wxDD_MULTIPLE style.
+    @style{wxDD_MULTIPLE}
+           Allow the user to select multiple directories.
+           This flag is only available since wxWidgets 3.1.4
+
     @endStyleTable
 
     Notice that @c wxRESIZE_BORDER has special side effect under Windows
@@ -109,6 +116,16 @@ public:
     */
     virtual wxString GetPath() const;
 
+    /**
+        Fills the array @a paths with the full paths of the chosen directories.
+
+        @note This function should only be used with the dialogs which have @c wxDD_MULTIPLE style,
+              use GetPath() for the others.
+
+        @since 3.1.4
+    */
+    virtual void GetPaths(wxArrayString& paths) const;
+
     /**
         Sets the message that will be displayed on the dialog.
     */

src/gtk/dirdlg.cpp

@@ -71,6 +71,9 @@ bool wxDirDialog::Create(wxWindow* parent,
 {
     m_message = title;
 
+    wxASSERT_MSG( !( (style & wxDD_MULTIPLE) && (style & wxDD_CHANGE_DIR) ),
+                  "wxDD_CHANGE_DIR can't be used together with wxDD_MULTIPLE" );
+
     parent = GetParentForModalDialog(parent, style);
 
     if (!PreCreation(parent, pos, wxDefaultSize) ||
@@ -110,10 +113,15 @@ bool wxDirDialog::Create(wxWindow* parent,
     if (wx_is_at_least_gtk2(18))
     {
         gtk_file_chooser_set_create_folders(
-            GTK_FILE_CHOOSER(m_widget), (style & wxDD_DIR_MUST_EXIST) == 0);
+            GTK_FILE_CHOOSER(m_widget), !HasFlag(wxDD_DIR_MUST_EXIST) );
     }
 #endif
 
+    // Enable multiple selection if desired
+    gtk_file_chooser_set_select_multiple(
+        GTK_FILE_CHOOSER(m_widget), HasFlag(wxDD_MULTIPLE) );
+
+
     // local-only property could be set to false to allow non-local files to be loaded.
     // In that case get/set_uri(s) should be used instead of get/set_filename(s) everywhere
     // and the GtkFileChooserDialog should probably also be created with a backend,
@@ -132,13 +140,24 @@ bool wxDirDialog::Create(wxWindow* parent,
 
 void wxDirDialog::GTKOnAccept()
 {
-    wxGtkString str(gtk_file_chooser_get_filename(GTK_FILE_CHOOSER(m_widget)));
+    GSList *fnamesi = gtk_file_chooser_get_filenames(GTK_FILE_CHOOSER(m_widget));
-    m_selectedDirectory = wxString::FromUTF8(str);
+    GSList *fnames = fnamesi;
+
+    while ( fnamesi )
+    {
+        wxString dir(wxString::FromUTF8(static_cast<gchar *>(fnamesi->data)));
+        m_paths.Add(dir);
+
+        g_free(fnamesi->data);
+        fnamesi = fnamesi->next;
+    }
+
+    g_slist_free(fnames);
 
     // change to the directory where the user went if asked
     if (HasFlag(wxDD_CHANGE_DIR))
     {
-        wxSetWorkingDirectory(m_selectedDirectory);
+        wxSetWorkingDirectory(m_paths.Last());
     }
 
     EndDialog(wxID_OK);
@@ -168,7 +187,13 @@ void wxDirDialog::SetPath(const wxString& dir)
 
 wxString wxDirDialog::GetPath() const
 {
-    return m_selectedDirectory;
+    return m_paths.Last();
+}
+
+void wxDirDialog::GetPaths(wxArrayString& paths) const
+{
+    paths.Empty();
+    paths = m_paths;
 }
 
 #endif // wxUSE_DIRDLG