From 3d3b66865f84544edd7057621e0121cbaa86c455 Mon Sep 17 00:00:00 2001
From: Kenneth Moreland <morelandkd@ornl.gov>
Date: Fri, 18 Aug 2023 15:04:08 -0400
Subject: [PATCH] Add option to turn off Doxygen html

The Doxygen html generation takes a lot more time than the xml
generation. If all you want from Doxygen is the xml for the user's
guide, that can be frustrating. Add an option to turn off the xml.
---
 CMake/VTKmBuildDocumentation.cmake | 14 ++++++++++++++
 CMake/doxyfile.in                  |  4 ++--
 CMakeLists.txt                     |  9 +++++++++
 3 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/CMake/VTKmBuildDocumentation.cmake b/CMake/VTKmBuildDocumentation.cmake
index 783cad567..cdf07438a 100644
--- a/CMake/VTKmBuildDocumentation.cmake
+++ b/CMake/VTKmBuildDocumentation.cmake
@@ -13,6 +13,17 @@
 #-----------------------------------------------------------------------------
 find_package(Doxygen REQUIRED)
 
+#-----------------------------------------------------------------------------
+# Function to turn CMake booleans to `YES` or `NO` as expected by Doxygen
+#-----------------------------------------------------------------------------
+function(to_yes_no variable)
+  if(${variable})
+    set(${variable} YES PARENT_SCOPE)
+  else()
+    set(${variable} NO PARENT_SCOPE)
+  endif()
+endfunction()
+
 #-----------------------------------------------------------------------------
 # Configure Doxygen
 #-----------------------------------------------------------------------------
@@ -20,6 +31,9 @@ set(VTKm_DOXYGEN_HAVE_DOT ${DOXYGEN_DOT_FOUND})
 set(VTKm_DOXYGEN_DOT_PATH ${DOXYGEN_DOT_PATH})
 set(VTKm_DOXYFILE ${CMAKE_CURRENT_BINARY_DIR}/docs/doxyfile)
 
+to_yes_no(VTKm_ENABLE_USERS_GUIDE)
+to_yes_no(VTKm_Doxygen_HTML_output)
+
 configure_file(${CMAKE_CURRENT_SOURCE_DIR}/CMake/doxyfile.in ${VTKm_DOXYFILE}
     @ONLY)
 
diff --git a/CMake/doxyfile.in b/CMake/doxyfile.in
index d8f8f1b4e..ff74e0387 100644
--- a/CMake/doxyfile.in
+++ b/CMake/doxyfile.in
@@ -202,7 +202,7 @@ IGNORE_PREFIX          =
 # configuration options related to the HTML output
 #---------------------------------------------------------------------------
 
-GENERATE_HTML          = YES
+GENERATE_HTML          = @VTKm_Doxygen_HTML_output@
 
 HTML_OUTPUT            = html
 
@@ -294,7 +294,7 @@ MAN_LINKS              = NO
 # configuration options related to the XML output
 #---------------------------------------------------------------------------
 
-GENERATE_XML           = YES
+GENERATE_XML           = @VTKm_ENABLE_USERS_GUIDE@
 
 XML_OUTPUT             = xml
 
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 51bd48faa..ff6f823d6 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -126,6 +126,15 @@ cmake_dependent_option(VTKm_ENABLE_USERS_GUIDE
   "VTKm_ENABLE_DOCUMENTATION"
   OFF
   )
+# If you are building the User's Guide, you may only need the XML output from Doxygen, which
+# is much faster than generating the HTML. Thus, give the option to turn on/off the HTML output.
+cmake_dependent_option(VTKm_Doxygen_HTML_output
+  "Build HTML output"
+  ON
+  "VTKm_ENABLE_USERS_GUIDE"
+  ON
+  )
+mark_as_advanced(VTKm_Doxygen_HTML_output)
 
 # We may want to make finer controls on whether libraries/modules get built.
 # VTK uses the concept of groups for its modules