CPackWIX: support installation of empty directories

Source/CPack/WiX/cmCPackWIXGenerator.cxx

@@ -814,6 +814,16 @@ void cmCPackWIXGenerator::AddDirectoryAndFileDefinitons(
   cmsys::Directory dir;
   dir.Load(topdir.c_str());
 
+  if(dir.GetNumberOfFiles() == 2)
+    {
+    std::string componentId = fileDefinitions.EmitComponentCreateFolder(
+      directoryId, GenerateGUID());
+
+    featureDefinitions.EmitComponentRef(componentId);
+
+    return;
+    }
+
   for(size_t i = 0; i < dir.GetNumberOfFiles(); ++i)
     {
     std::string fileName = dir.GetFile(static_cast<unsigned long>(i));

Source/CPack/WiX/cmWIXFilesSourceWriter.cxx

@@ -109,6 +109,28 @@ void cmWIXFilesSourceWriter::EmitUninstallShortcut(
   EndElement("Shortcut");
 }
 
+std::string cmWIXFilesSourceWriter::EmitComponentCreateFolder(
+  std::string const& directoryId, std::string const& guid)
+{
+  std::string componentId =
+    std::string("CM_C_EMPTY_") + directoryId;
+
+  BeginElement("DirectoryRef");
+  AddAttribute("Id", directoryId);
+
+  BeginElement("Component");
+  AddAttribute("Id", componentId);
+  AddAttribute("Guid", guid);
+
+  BeginElement("CreateFolder");
+
+  EndElement("CreateFolder");
+  EndElement("Component");
+  EndElement("DirectoryRef");
+
+  return componentId;
+}
+
 std::string cmWIXFilesSourceWriter::EmitComponentFile(
   std::string const& directoryId,
   std::string const& id,

Source/CPack/WiX/cmWIXFilesSourceWriter.h

@@ -45,6 +45,10 @@ public:
 
   void EmitUninstallShortcut(std::string const& packageName);
 
+  std::string EmitComponentCreateFolder(
+    std::string const& directoryId,
+    std::string const& guid);
+
   std::string EmitComponentFile(
     std::string const& directoryId,
     std::string const& id,

Tests/CPackWiXGenerator/CMakeLists.txt

@@ -9,6 +9,11 @@ target_link_libraries(my-libapp mylib)
 
 add_executable(my-other-app myotherapp.cpp)
 
+file(MAKE_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/empty)
+install(DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/empty
+  DESTINATION extras
+  COMPONENT extras)
+
 install(TARGETS mylib
   ARCHIVE
   DESTINATION lib
@@ -72,6 +77,12 @@ cpack_add_component_group(Development
   EXPANDED
   DESCRIPTION "All of the tools you'll ever need to develop software")
 
+cpack_add_component(extras
+  DISPLAY_NAME "Extras"
+  DESCRIPTION "Extras"
+  GROUP Runtime
+  INSTALL_TYPES Full)
+
 cpack_add_component(applications
   REQUIRED
   DISPLAY_NAME "MyLib Application"