From 40ad34b0b110abfc8220e7f4c271859eae8fbad2 Mon Sep 17 00:00:00 2001
From: Ivan Santiago Paunovic <ivanpauno@ekumenlabs.com>
Date: Thu, 17 Sep 2020 14:43:32 -0300
Subject: [PATCH] Reapply "Use system installed yaml-cpp 0.6 if available (#8)"
 (#16)

Signed-off-by: Ivan Santiago Paunovic <ivanpauno@ekumenlabs.com>
---
 CMakeLists.txt                  | 32 ++++++++++++++++++++------------
 yaml_cpp_vendor-extras.cmake.in | 10 ++++------
 2 files changed, 24 insertions(+), 18 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2ffee5f..b52d930 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -65,22 +65,30 @@ macro(build_yaml_cpp)
   )
 endmacro()
 
-build_yaml_cpp()
+# NO_CMAKE_PACKAGE_REGISTRY used to avoid finding the library downloaded in WORKSPACE B
+# when building workspace A.
+# This should only find a system installed yaml-cpp and thus the environment hook isn't needed.
+find_package(yaml-cpp 0.6 QUIET NO_CMAKE_PACKAGE_REGISTRY)
+if(NOT yaml-cpp_FOUND)
+  build_yaml_cpp()
 
-if(WIN32)
-  ament_environment_hooks(env_hook/yaml_cpp_vendor_library_path.bat)
-  set(ENV_VAR_NAME "PATH")
-  set(ENV_VAR_VALUE "opt\\yaml_cpp_vendor\\bin")
-else()
-  ament_environment_hooks(env_hook/yaml_cpp_vendor_library_path.sh)
-  if(APPLE)
-    set(ENV_VAR_NAME "DYLD_LIBRARY_PATH")
+  if(WIN32)
+    ament_environment_hooks(env_hook/yaml_cpp_vendor_library_path.bat)
+    set(ENV_VAR_NAME "PATH")
+    set(ENV_VAR_VALUE "opt\\yaml_cpp_vendor\\bin")
   else()
-    set(ENV_VAR_NAME "LD_LIBRARY_PATH")
+    ament_environment_hooks(env_hook/yaml_cpp_vendor_library_path.sh)
+    if(APPLE)
+      set(ENV_VAR_NAME "DYLD_LIBRARY_PATH")
+    else()
+      set(ENV_VAR_NAME "LD_LIBRARY_PATH")
+    endif()
+    set(ENV_VAR_VALUE "opt/yaml_cpp_vendor/lib")
   endif()
-  set(ENV_VAR_VALUE "opt/yaml_cpp_vendor/lib")
+  ament_environment_hooks(env_hook/yaml_cpp_vendor_library_path.dsv.in)
+else()
+  message(STATUS "Found yaml-cpp ${yaml-cpp_VERSION} in path ${yaml-cpp_CONFIG}")
 endif()
-ament_environment_hooks(env_hook/yaml_cpp_vendor_library_path.dsv.in)
 
 ament_package(
   CONFIG_EXTRAS "yaml_cpp_vendor-extras.cmake.in"
diff --git a/yaml_cpp_vendor-extras.cmake.in b/yaml_cpp_vendor-extras.cmake.in
index 6141812..a09422d 100644
--- a/yaml_cpp_vendor-extras.cmake.in
+++ b/yaml_cpp_vendor-extras.cmake.in
@@ -1,8 +1,6 @@
-## mjbogusz: find_package() and if() disabled until ament can handle complex paths resolving to /usr/include
-## always use locally built yaml-cpp for now
-# find_package(yaml-cpp QUIET)
+find_package(yaml-cpp 0.6 QUIET)
 
-# if(NOT yaml-cpp_FOUND)
+if(NOT yaml-cpp_FOUND)
   # add the local Modules directory to the modules path
   if(WIN32)
     set(yaml-cpp_DIR "${@PROJECT_NAME@_DIR}/../../../opt/yaml_cpp_vendor/CMake")
@@ -10,9 +8,9 @@
     set(yaml-cpp_DIR "${@PROJECT_NAME@_DIR}/../../../opt/yaml_cpp_vendor/lib/cmake/yaml-cpp")
   endif()
   message(STATUS "Setting yaml-cpp_DIR to: '${yaml-cpp_DIR}'")
-# endif()
 
-find_package(yaml-cpp CONFIG REQUIRED QUIET)
+  find_package(yaml-cpp CONFIG REQUIRED QUIET)
+endif()
 
 set(yaml_cpp_vendor_LIBRARIES ${YAML_CPP_LIBRARIES})
 set(yaml_cpp_vendor_INCLUDE_DIRS ${YAML_CPP_INCLUDE_DIR})