tdf#119890 followup: Forbid HOME to be the default dir

... of user templates

This is kludgy yet better than making innocent users waiting for
the template dialog ~forever as pointed out in the comments in
<https://gerrit.libreoffice.org/#/c/67741/>.

Change-Id: I6dfdc0408effb06cc9175cd976ea6687e52a7136
Reviewed-on: https://gerrit.libreoffice.org/69883
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

shell/source/backends/desktopbe/desktopbackend.cxx

@@ -127,7 +127,7 @@ void Default::setPropertyValue(OUString const &, css::uno::Any const &)
         static_cast< cppu::OWeakObject * >(this), -1);
 }
 
-OUString xdg_user_dir_lookup (const char *type)
+OUString xdg_user_dir_lookup (const char *type, bool bAllowHomeDir)
 {
     size_t nLenType = strlen(type);
     char *config_home;
@@ -218,16 +218,20 @@ OUString xdg_user_dir_lookup (const char *type)
     if (aUserDirBuf.getLength()>0 && !bError)
     {
         aDocumentsDirURL = aUserDirBuf.makeStringAndClear();
-        osl::Directory aDocumentsDir( aDocumentsDirURL );
-        if( osl::FileBase::E_None == aDocumentsDir.open() )
-            return aDocumentsDirURL;
+        if ( bAllowHomeDir ||
+             (aDocumentsDirURL != aHomeDirURL && aDocumentsDirURL != aHomeDirURL + "/") )
+        {
+            osl::Directory aDocumentsDir( aDocumentsDirURL );
+            if( osl::FileBase::E_None == aDocumentsDir.open() )
+                return aDocumentsDirURL;
+        }
     }
     /* Use fallbacks historical compatibility if nothing else exists */
     return aHomeDirURL + "/" + OUString::createFromAscii(type);
 }
 
-css::uno::Any xdgDirectoryIfExists(char const * type) {
-    auto url = xdg_user_dir_lookup(type);
+css::uno::Any xdgDirectoryIfExists(char const * type, bool bAllowHomeDir) {
+    auto url = xdg_user_dir_lookup(type, bAllowHomeDir);
     return css::uno::Any(
         osl::Directory(url).open() == osl::FileBase::E_None
         ? css::beans::Optional<css::uno::Any>(true, css::uno::Any(url))
@@ -238,12 +242,13 @@ css::uno::Any Default::getPropertyValue(OUString const & PropertyName)
 {
     if (PropertyName == "TemplatePathVariable")
     {
-        return xdgDirectoryIfExists("Templates");
+        // Never pick up the HOME directory as the default location of user's templates
+        return xdgDirectoryIfExists("Templates", false);
     }
 
     if (PropertyName == "WorkPathVariable")
     {
-        return xdgDirectoryIfExists("Documents");
+        return xdgDirectoryIfExists("Documents", true);
     }
 
     if ( PropertyName == "EnableATToolSupport" ||