Minor cmake changes (#961)

Abstract adding natvis file.

Move call to find_package(Git) as well as making it required/quiet.

3 files changed, 23 insertions, 19 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index f44425c..7ad13f7 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -5,9 +5,6 @@ include(guidelineSupportLibrary)
 
 project(GSL VERSION 3.1.0 LANGUAGES CXX)
 
-include(ExternalProject)
-find_package(Git)
-
 # Use GNUInstallDirs to provide the right locations on all platforms
 include(GNUInstallDirs)
 
@@ -51,21 +48,8 @@ else()
     )
 endif()
 
-
-if (CMAKE_VERSION VERSION_GREATER 3.7.8)
-    if (MSVC_IDE)
-        option(GSL_VS_ADD_NATIVE_VISUALIZERS "Configure project to use Visual Studio native visualizers" TRUE)
-    else()
-        set(GSL_VS_ADD_NATIVE_VISUALIZERS FALSE CACHE INTERNAL "Native visualizers are Visual Studio extension" FORCE)
-    endif()
-
-    # add natvis file to the library so it will automatically be loaded into Visual Studio
-    if(GSL_VS_ADD_NATIVE_VISUALIZERS)
-        target_sources(GSL INTERFACE
-            $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/GSL.natvis>
-        )
-    endif()
-endif()
+# Add natvis file
+gsl_add_native_visualizer_support()
 
 install(TARGETS GSL EXPORT Microsoft.GSLConfig)
 install(
@@ -104,4 +88,4 @@ if (GSL_TEST)
         )
     endif()
     add_subdirectory(tests)
-endif ()
+endif()
diff --git a/cmake/guidelineSupportLibrary.cmake b/cmake/guidelineSupportLibrary.cmake
index e29e80c..39d8920 100644
--- a/cmake/guidelineSupportLibrary.cmake
+++ b/cmake/guidelineSupportLibrary.cmake
@@ -59,3 +59,19 @@ function(gsl_client_set_cxx_standard min_cxx_standard)
     # Otherwise pick a reasonable default
     gsl_set_default_cxx_standard(${min_cxx_standard})
 endfunction()
+
+# Adding the GSL.natvis files improves the debugging experience for users of this library.
+function(gsl_add_native_visualizer_support)
+    if (CMAKE_VERSION VERSION_GREATER 3.7.8)
+        if (MSVC_IDE)
+            option(GSL_VS_ADD_NATIVE_VISUALIZERS "Configure project to use Visual Studio native visualizers" TRUE)
+        else()
+            set(GSL_VS_ADD_NATIVE_VISUALIZERS FALSE CACHE INTERNAL "Native visualizers are Visual Studio extension" FORCE)
+        endif()
+
+        # add natvis file to the library so it will automatically be loaded into Visual Studio
+        if(GSL_VS_ADD_NATIVE_VISUALIZERS)
+            target_sources(GSL INTERFACE $<BUILD_INTERFACE:${GSL_SOURCE_DIR}/GSL.natvis>)
+        endif()
+    endif()
+endfunction()
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index c323961..2e7c2dc 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -1,7 +1,11 @@
 cmake_minimum_required(VERSION 3.0.2)
 
 project(GSLTests CXX)
+
 include(FindPkgConfig)
+include(ExternalProject)
+
+find_package(Git REQUIRED QUIET)
 
 # will make visual studio generated project group files
 set_property(GLOBAL PROPERTY USE_FOLDERS ON)