determine gflags namespace automatically

CMakeLists.txt

@@ -24,6 +24,8 @@ set (CPACK_PACKAGE_VERSION ${GLOG_VERSION})
 
 option (WITH_GFLAGS "Use gflags" ON)
 
+list (APPEND CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR}/cmake)
+
 include (CMakePackageConfigHelpers)
 include (CPack)
 include (CheckCSourceCompiles)
@@ -36,6 +38,7 @@ include (CheckLibraryExists)
 include (CheckStructHasMember)
 include (CheckSymbolExists)
 include (CheckTypeSize)
+include (DetermineGflagsNamespace)
 
 set (CMAKE_THREAD_PREFER_PTHREAD 1)
 
@@ -44,6 +47,7 @@ if (WITH_GFLAGS)
 
   if (gflags_FOUND)
     set (HAVE_LIB_GFLAGS 1)
+    determine_gflags_namespace (gflags_NAMESPACE)
   endif (gflags_FOUND)
 endif (WITH_GFLAGS)
 

cmake/DetermineGflagsNamespace.cmake

+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 ${CMAKE_REQUIRED_FLAGS})
+
+    set(_NAMESPACES gflags google)
+    set(_check_code
+"
+#include <gflags/gflags.h>
+
+int main(int argc, char**argv)
+{
+  GFLAGS_NAMESPACE::ParseCommandLineFlags(&argc, &argv, true);
+}
+")
+    if (NOT CMAKE_REQUIRED_QUIET)
+      message (STATUS "Looking for gflags namespace")
+    endif ()
+    if (${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 "${CMAKE_REQUIRED_DEFINITIONS}" -DGFLAGS_NAMESPACE=${_namespace}
+        LINK_LIBRARIES "${gflags_LIBRARIES}"
+        CMAKE_FLAGS -DINCLUDE_DIRECTORIES:STRING="${gflags_INCLUDE_DIR}"
+        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 ()

src/demangle_unittest.cc

@@ -41,6 +41,11 @@
 #include "googletest.h"
 #include "config.h"
 
+#ifdef HAVE_LIB_GFLAGS
+#include <gflags/gflags.h>
+using namespace GFLAGS_NAMESPACE;
+#endif
+
 GLOG_DEFINE_bool(demangle_filter, false,
                  "Run demangle_unittest in filter mode");
 

src/logging_unittest.cc

@@ -61,6 +61,7 @@ DECLARE_string(log_backtrace_at);  // logging.cc
 
 #ifdef HAVE_LIB_GFLAGS
 #include <gflags/gflags.h>
+using namespace GFLAGS_NAMESPACE;
 #endif
 
 #ifdef HAVE_LIB_GMOCK

src/signalhandler_unittest.cc

@@ -41,6 +41,11 @@
 #include <string>
 #include "glog/logging.h"
 
+#ifdef HAVE_LIB_GFLAGS
+#include <gflags/gflags.h>
+using namespace gflags;
+#endif
+
 using namespace GOOGLE_NAMESPACE;
 
 void* DieInThread(void*) {

src/symbolize_unittest.cc

@@ -41,6 +41,11 @@
 #include "googletest.h"
 #include "config.h"
 
+#ifdef HAVE_LIB_GFLAGS
+#include <gflags/gflags.h>
+using namespace GFLAGS_NAMESPACE;
+#endif
+
 using namespace std;
 using namespace GOOGLE_NAMESPACE;
 

src/utilities_unittest.cc

@@ -28,11 +28,15 @@
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 //
 // Author: Shinichiro Hamaji
-
 #include "utilities.h"
 #include "googletest.h"
 #include "glog/logging.h"
 
+#ifdef HAVE_LIB_GFLAGS
+#include <gflags/gflags.h>
+using namespace GFLAGS_NAMESPACE;
+#endif
+
 using namespace GOOGLE_NAMESPACE;
 
 TEST(utilities, sync_val_compare_and_swap) {