default data dir's Backward compatibility

src/common/util.cpp

@@ -597,6 +597,32 @@ std::string get_nix_version_display_string()
   }
 #endif
   
+  std::string DEPRECATED_get_default_data_dir()
+  {
+    // Kept for backward compatibility
+    /* Please for the love of god refactor  the ifdefs out of this */
+
+    // namespace fs = boost::filesystem;
+    // Windows < Vista: C:\Documents and Settings\Username\Application Data\CRYPTONOTE_NAME
+    // Windows >= Vista: C:\Users\Username\AppData\Roaming\CRYPTONOTE_NAME
+    // Unix & Mac: ~/.CRYPTONOTE_NAME
+    std::string config_folder;
+
+#ifdef WIN32
+    config_folder = get_special_folder_path(CSIDL_COMMON_APPDATA, true) + "\\" + CRYPTONOTE_NAME;
+#else
+    std::string pathRet;
+    char* pszHome = getenv("HOME");
+    if (pszHome == NULL || strlen(pszHome) == 0)
+      pathRet = "/";
+    else
+      pathRet = pszHome;
+    config_folder = (pathRet + "/." + CRYPTONOTE_NAME);
+#endif
+
+    return config_folder;
+  }
+
   std::string get_default_data_dir()
   {
     /* Please for the love of god refactor  the ifdefs out of this */
@@ -606,10 +632,10 @@ std::string get_nix_version_display_string()
     // Windows >= Vista: C:\Users\Username\AppData\Roaming\CRYPTONOTE_NAME
     // Linux: XDG_DATA_HOME or ~/.local/share/CRYPTONOTE_NAME
     // Mac:   ~/Library/Application Support/CRYPTONOTE_NAME
-    std::string config_folder;
+    std::string data_folder;
 
 #ifdef WIN32
-    config_folder = get_special_folder_path(CSIDL_COMMON_APPDATA, true) + "\\" + CRYPTONOTE_NAME;
+    data_folder = get_special_folder_path(CSIDL_COMMON_APPDATA, true) + "\\" + CRYPTONOTE_NAME;
 #else // Posix
     std::string pathRet;
     const std::string dirSep = "/";
@@ -635,10 +661,22 @@ std::string get_nix_version_display_string()
     {
         pathRet = pszFallback;
     }
-    config_folder = (pathRet + dirSep + CRYPTONOTE_NAME);
+    data_folder = (pathRet + dirSep + CRYPTONOTE_NAME);
 #endif
 
-    return config_folder;
+    const std::string & data_folder_deprecated = DEPRECATED_get_default_data_dir();
+    if (boost::filesystem::exists(data_folder_deprecated))
+    {
+        MWARNING("Your data are still located in the deprecated folder: '" << data_folder_deprecated << "'. "
+                 << "Please consider moving the data to the new folder: '" << data_folder << "'. "
+                 << "Until then, the deprecated folder shall be used."
+                 );
+        return data_folder_deprecated;
+    }
+    else
+    {
+        return data_folder;
+    }
   }
 
   bool create_directories_if_necessary(const std::string& path)