From d3f0da06ebba7d4e3571cc4dbd787069ace1c8a1 Mon Sep 17 00:00:00 2001
From: Andrea Ponza <laboratorio@cobotica.it>
Date: Sat, 28 Mar 2020 19:37:25 +0100
Subject: [PATCH] add a stamp file to build documentation once

---
 doc/doxygen/.gitignore     |  1 +
 doc/doxygen/CMakeLists.txt | 21 +++++++++++++++++++--
 2 files changed, 20 insertions(+), 2 deletions(-)
 create mode 100644 doc/doxygen/.gitignore

diff --git a/doc/doxygen/.gitignore b/doc/doxygen/.gitignore
new file mode 100644
index 00000000000..695b5edf900
--- /dev/null
+++ b/doc/doxygen/.gitignore
@@ -0,0 +1 @@
+pcl.tag
diff --git a/doc/doxygen/CMakeLists.txt b/doc/doxygen/CMakeLists.txt
index 831bbe8e4d1..c2eff7b03b3 100644
--- a/doc/doxygen/CMakeLists.txt
+++ b/doc/doxygen/CMakeLists.txt
@@ -37,11 +37,28 @@ endif()
 
 set(STRIPPED_HEADERS "${PCL_SOURCE_DIR}/${PCL_MODULES_NAMES}/include")
 string(REPLACE ";" "/include \\\n                         ${PCL_SOURCE_DIR}/" STRIPPED_HEADERS "${STRIPPED_HEADERS}")
-set(DOC_SOURCE_DIR "\"${PCL_SOURCE_DIR}\"\\")
+set(DOC_SOURCE_DIR "${PCL_SOURCE_DIR}")
 file(MAKE_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/html")
 set(doxyfile "${CMAKE_CURRENT_BINARY_DIR}/doxyfile")
 configure_file("${CMAKE_CURRENT_SOURCE_DIR}/doxyfile.in" "${doxyfile}")
-add_custom_target(doc ALL "${DOXYGEN_EXECUTABLE}" "${doxyfile}")
+
+# The following process to use a stamp file is customized from the CMake 3.16.5 `doxygen_add_docs` command
+set(STAMP_FILE "${CMAKE_CURRENT_BINARY_DIR}/doc.stamp")
+add_custom_command(
+    VERBATIM
+    OUTPUT ${STAMP_FILE}
+    COMMAND ${CMAKE_COMMAND} -E make_directory ${CMAKE_CURRENT_BINARY_DIR}
+    COMMAND "${DOXYGEN_EXECUTABLE}" "${doxyfile}"
+    COMMAND ${CMAKE_COMMAND} -E touch ${STAMP_FILE}
+    WORKING_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}"
+    DEPENDS "${doxyfile}" ${DOC_SOURCE_DIR}
+    COMMENT "Generate stamp file for target doc"
+)
+add_custom_target(doc ALL
+    DEPENDS ${STAMP_FILE}
+    SOURCES ${DOC_SOURCE_DIR}
+)
+
 set_target_properties(doc PROPERTIES FOLDER "Documentation (Doxygen)")
 if(DOCUMENTATION_HTML_HELP STREQUAL YES)
   install(DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/html"