1 files changed, 69 insertions, 0 deletions
diff --git a/cmake/DetermineGflagsNamespace.cmake b/cmake/DetermineGflagsNamespace.cmake
new file mode 100644
index 000000000000..3dde42b4b332
--- /dev/null
+++ b/cmake/DetermineGflagsNamespace.cmake
@@ -0,0 +1,69 @@
+macro(determine_gflags_namespace VARIABLE)
+  if (NOT DEFINED "${VARIABLE}")
+    if (CMAKE_REQUIRED_INCLUDES)
+      set (CHECK_INCLUDE_FILE_CXX_INCLUDE_DIRS "-DINCLUDE_DIRECTORIES=${CMAKE_REQUIRED_INCLUDES}")
+    else ()
+      set (CHECK_INCLUDE_FILE_CXX_INCLUDE_DIRS)
+    endif ()
+
+    set(MACRO_CHECK_INCLUDE_FILE_FLAGS ${CMAKE_REQUIRED_FLAGS})
+
+    set(_NAMESPACES gflags google)
+    set(_check_code
+"
+#include <gflags/gflags.h>
+
+int main(int argc, char**argv)
+{
+  GLOG_GFLAGS_NAMESPACE::ParseCommandLineFlags(&argc, &argv, true);
+}
+")
+    if (NOT CMAKE_REQUIRED_QUIET)
+      message (STATUS "Looking for gflags namespace")
+    endif ()
+    if (${ARGC} EQUAL 3)
+      set (CMAKE_CXX_FLAGS_SAVE ${CMAKE_CXX_FLAGS})
+      set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${ARGV2}")
+    endif ()
+
+    set (_check_file
+        ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp/DetermineGflagsNamespace.cxx)
+
+    foreach (_namespace ${_NAMESPACES})
+      file (WRITE "${_check_file}" "${_check_code}")
+      try_compile (${VARIABLE}
+        "${CMAKE_BINARY_DIR}" "${_check_file}"
+        COMPILE_DEFINITIONS "${CMAKE_REQUIRED_DEFINITIONS}" -DGLOG_GFLAGS_NAMESPACE=${_namespace}
+        LINK_LIBRARIES gflags
+        CMAKE_FLAGS -DCMAKE_BUILD_TYPE=${CMAKE_BUILD_TYPE}
+        OUTPUT_VARIABLE OUTPUT)
+
+      if (${VARIABLE})
+        set (${VARIABLE} ${_namespace} CACHE INTERNAL "gflags namespace" FORCE)
+        break ()
+      else ()
+        file(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeError.log
+          "Determining the gflags namespace ${_namespace} failed with the following output:\n"
+          "${OUTPUT}\n\n")
+      endif ()
+    endforeach (_namespace)
+
+    if (${ARGC} EQUAL 3)
+      set (CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS_SAVE})
+    endif ()
+
+    if (${VARIABLE})
+      if (NOT CMAKE_REQUIRED_QUIET)
+        message (STATUS "Looking for gflags namespace - ${${VARIABLE}}")
+      endif ()
+      file (APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeOutput.log
+        "Determining the gflags namespace passed with the following output:\n"
+        "${OUTPUT}\n\n")
+    else ()
+      if (NOT CMAKE_REQUIRED_QUIET)
+        message (STATUS "Looking for gflags namespace - failed")
+      endif ()
+      set (${VARIABLE} ${_namespace} CACHE INTERNAL "gflags namespace")
+    endif ()
+  endif ()
+endmacro ()