ENH: Add support to INSTALL(DIRECTORY) to install an empty directory. This addresses bug#3572.

Source/cmFileCommand.cxx

@@ -519,6 +519,11 @@ bool cmFileInstaller::InstallDirectory(const char* source,
     return true;
     }
 
+  // Inform the user about this directory installation.
+  std::string message = "Installing ";
+  message += destination;
+  this->Makefile->DisplayStatus(message.c_str(), -1);
+
   // Make sure the destination directory exists.
   if(!cmSystemTools::MakeDirectory(destination))
     {
@@ -568,7 +573,10 @@ bool cmFileInstaller::InstallDirectory(const char* source,
 
   // Load the directory contents to traverse it recursively.
   cmsys::Directory dir;
-  dir.Load(source);
+  if(source && *source)
+    {
+    dir.Load(source);
+    }
   unsigned long numFiles = static_cast<unsigned long>(dir.GetNumberOfFiles());
   for(unsigned long fileNum = 0; fileNum < numFiles; ++fileNum)
     {
@@ -1280,7 +1288,8 @@ bool cmFileCommand::HandleInstallCommand(
     if(!cmSystemTools::SameFile(fromFile.c_str(), toFile.c_str()))
       {
       if(itype == cmTarget::INSTALL_DIRECTORY &&
-        cmSystemTools::FileIsDirectory(fromFile.c_str()))
+         (fromFile.empty() ||
+          cmSystemTools::FileIsDirectory(fromFile.c_str())))
         {
         // Try installing this directory.
         if(!installer.InstallDirectory(fromFile.c_str(), toFile.c_str(),

Source/cmInstallCommand.cxx

@@ -1000,6 +1000,12 @@ cmInstallCommand::HandleDirectoryMode(std::vector<std::string> const& args)
       }
     }
 
+  // Support installing an empty directory.
+  if(dirs.empty() && destination)
+    {
+    dirs.push_back("");
+    }
+
   // Check if there is something to do.
   if(dirs.empty())
     {

Tests/SimpleInstall/CMakeLists.txt

@@ -107,6 +107,15 @@ IF(STAGE2)
     MESSAGE(FATAL_ERROR "Bad sample script output: [${SAMPLE_SCRIPT_OUTPUT}]")
   ENDIF(NOT "${SAMPLE_SCRIPT_OUTPUT}" MATCHES "Sample Script Output")
 
+  # Check for failure of empty directory installation.
+  IF(NOT EXISTS "${CMAKE_INSTALL_PREFIX}/MyTest/share/empty")
+    MESSAGE(FATAL_ERROR "Empty directory installation did not install.")
+  ENDIF(NOT EXISTS "${CMAKE_INSTALL_PREFIX}/MyTest/share/empty")
+  FILE(GLOB EMPTY_FILES "${CMAKE_INSTALL_PREFIX}/MyTest/share/empty/*")
+  IF(EMPTY_FILES)
+    MESSAGE(FATAL_ERROR "Empty directory installed [${EMPTY_FILES}].")
+  ENDIF(EMPTY_FILES)
+
   # Make sure the test executable can run from the install tree.
   SET_TARGET_PROPERTIES(SimpleInstallS2 PROPERTIES
     INSTALL_RPATH ${CMAKE_INSTALL_PREFIX}/MyTest/lib)
@@ -174,6 +183,9 @@ ELSE(STAGE2)
     PATTERN "scripts/*" PERMISSIONS OWNER_EXECUTE OWNER_WRITE OWNER_READ
     )
 
+  # Test empty directory installation.
+  INSTALL(DIRECTORY DESTINATION MyTest/share/empty)
+
   # Test user-specified install scripts.
   INSTALL(
     SCRIPT InstallScript1.cmake

Tests/SimpleInstallS2/CMakeLists.txt

@@ -107,6 +107,15 @@ IF(STAGE2)
     MESSAGE(FATAL_ERROR "Bad sample script output: [${SAMPLE_SCRIPT_OUTPUT}]")
   ENDIF(NOT "${SAMPLE_SCRIPT_OUTPUT}" MATCHES "Sample Script Output")
 
+  # Check for failure of empty directory installation.
+  IF(NOT EXISTS "${CMAKE_INSTALL_PREFIX}/MyTest/share/empty")
+    MESSAGE(FATAL_ERROR "Empty directory installation did not install.")
+  ENDIF(NOT EXISTS "${CMAKE_INSTALL_PREFIX}/MyTest/share/empty")
+  FILE(GLOB EMPTY_FILES "${CMAKE_INSTALL_PREFIX}/MyTest/share/empty/*")
+  IF(EMPTY_FILES)
+    MESSAGE(FATAL_ERROR "Empty directory installed [${EMPTY_FILES}].")
+  ENDIF(EMPTY_FILES)
+
   # Make sure the test executable can run from the install tree.
   SET_TARGET_PROPERTIES(SimpleInstallS2 PROPERTIES
     INSTALL_RPATH ${CMAKE_INSTALL_PREFIX}/MyTest/lib)
@@ -174,6 +183,9 @@ ELSE(STAGE2)
     PATTERN "scripts/*" PERMISSIONS OWNER_EXECUTE OWNER_WRITE OWNER_READ
     )
 
+  # Test empty directory installation.
+  INSTALL(DIRECTORY DESTINATION MyTest/share/empty)
+
   # Test user-specified install scripts.
   INSTALL(
     SCRIPT InstallScript1.cmake