Build file macro for testing unordered_map C++ container support.

Using unordered_map and unordered_set C++ container types currently
requires careful testing or usage of boost, due to the various confusing
C++ version differences in include paths and namespaces.

Libmv defines tests for these cases in cmake and scons, such that ceres
can use any available implementation, or fall back too std::map/std::set
if none can be found.

This patch generalizes this buildfile code by providing a Blender macro.
* cmake: defines both the variables used by libmv at them moment as well
as 2 variables UNORDERED_MAP_INCLUDE_PREFIX and UNORDERED_MAP_NAMESPACE,
which can later be used in other C++ parts for convenience.
* scons: adds a tool script returning the include prefix and namespace.
Libmv checks these to define the appropriate definitions for ceres.

Differential Revision: https://developer.blender.org/D425

2 files changed, 26 insertions, 66 deletions

diff --git a/extern/libmv/third_party/ceres/CMakeLists.txt b/extern/libmv/third_party/ceres/CMakeLists.txt
index 7fd86b69dcf..baa619f930c 100644
--- a/extern/libmv/third_party/ceres/CMakeLists.txt
+++ b/extern/libmv/third_party/ceres/CMakeLists.txt
@@ -309,58 +309,25 @@ if(WITH_OPENMP)
 	)
 endif()
 
-include(CheckIncludeFileCXX)
-CHECK_INCLUDE_FILE_CXX(unordered_map HAVE_STD_UNORDERED_MAP_HEADER)
+TEST_UNORDERED_MAP_SUPPORT()
 if(HAVE_STD_UNORDERED_MAP_HEADER)
-	# Even so we've found unordered_map header file it doesn't
-	# mean unordered_map and unordered_set will be declared in
-	# std namespace.
-	#
-	# Namely, MSVC 2008 have unordered_map header which declares
-	# unordered_map class in std::tr1 namespace. In order to support
-	# this, we do extra check to see which exactly namespace is
-	# to be used.
-
-	include(CheckCXXSourceCompiles)
-	CHECK_CXX_SOURCE_COMPILES("#include <unordered_map>
-	                          int main() {
-	                            std::unordered_map<int, int> map;
-	                            return 0;
-	                          }"
-	                          HAVE_UNURDERED_MAP_IN_STD_NAMESPACE)
-	if(HAVE_UNURDERED_MAP_IN_STD_NAMESPACE)
+	if(HAVE_UNORDERED_MAP_IN_STD_NAMESPACE)
 		add_definitions(-DCERES_STD_UNORDERED_MAP)
-		message(STATUS "Found unordered_map/set in std namespace.")
 	else()
-		CHECK_CXX_SOURCE_COMPILES("#include <unordered_map>
-		                          int main() {
-		                            std::tr1::unordered_map<int, int> map;
-		                            return 0;
-		                          }"
-		                          HAVE_UNURDERED_MAP_IN_TR1_NAMESPACE)
-		if(HAVE_UNURDERED_MAP_IN_TR1_NAMESPACE)
+		if(HAVE_UNORDERED_MAP_IN_TR1_NAMESPACE)
 			add_definitions(-DCERES_STD_UNORDERED_MAP_IN_TR1_NAMESPACE)
-			message(STATUS "Found unordered_map/set in std::tr1 namespace.")
 		else()
-			message(STATUS "Found <unordered_map> but cannot find either std::unordered_map "
-			        "or std::tr1::unordered_map.")
-			message(STATUS "Replacing unordered_map/set with map/set (warning: slower!)")
 			add_definitions(-DCERES_NO_UNORDERED_MAP)
+			message(STATUS "Replacing unordered_map/set with map/set (warning: slower!)")
 		endif()
 	endif()
 else()
-	CHECK_INCLUDE_FILE_CXX("tr1/unordered_map" UNORDERED_MAP_IN_TR1_NAMESPACE)
-	if(UNORDERED_MAP_IN_TR1_NAMESPACE)
-		add_definitions(-DCERES_TR1_UNORDERED_MAP)
-		message(STATUS "Found unordered_map/set in std::tr1 namespace.")
+	if(HAVE_UNORDERED_MAP_IN_TR1_NAMESPACE)
+		add_definitions(-DCERES_STD_UNORDERED_MAP_IN_TR1_NAMESPACE)
 	else()
-		message(STATUS "Unable to find <unordered_map> or <tr1/unordered_map>. ")
-		message(STATUS "Replacing unordered_map/set with map/set (warning: slower!)")
 		add_definitions(-DCERES_NO_UNORDERED_MAP)
+		message(STATUS "Replacing unordered_map/set with map/set (warning: slower!)")
 	endif()
 endif()
 
-unset(HAVE_UNURDERED_MAP_IN_TR1_NAMESPACE)
-unset(HAVE_STD_UNORDERED_MAP_HEADER)
-
 blender_add_lib(extern_ceres "${SRC}" "${INC}" "${INC_SYS}")
diff --git a/extern/libmv/third_party/ceres/SConscript b/extern/libmv/third_party/ceres/SConscript
index 2573a9742ad..406e1593ded 100644
--- a/extern/libmv/third_party/ceres/SConscript
+++ b/extern/libmv/third_party/ceres/SConscript
@@ -7,6 +7,8 @@
 import sys
 import os
 
+from unordered_map import test_unordered_map
+
 Import('env')
 
 src = []
@@ -27,35 +29,26 @@ defs.append('CERES_HAVE_RWLOCK')
 if env['WITH_BF_OPENMP']:
     defs.append('CERES_USE_OPENMP')
 
-conf = Configure(env)
-if conf.CheckCXXHeader("unordered_map"):
-    # Even so we've found unordered_map header file it doesn't
-    # mean unordered_map and unordered_set will be declared in
-    # std namespace.
-    #
-    # Namely, MSVC 2008 have unordered_map header which declares
-    # unordered_map class in std::tr1 namespace. In order to support
-    # this, we do extra check to see which exactly namespace is
-    # to be used.
+def define_unordered_map(conf):
+    found, namespace, include_prefix = test_unordered_map(conf)
+    if found:
+        if not include_prefix:
+            if namespace == 'std':
+                defs.append('CERES_STD_UNORDERED_MAP')
+                return True
+            elif namespace == 'std::tr1':
+                defs.append('CERES_STD_UNORDERED_MAP_IN_TR1_NAMESPACE')
+                return True
+        else:
+            if namespace == 'std::tr1':
+                defs.append('CERES_TR1_UNORDERED_MAP')
+                return True
+    return False
 
-    if conf.CheckType('std::unordered_map<int, int>', language = 'CXX', includes="#include <unordered_map>"):
-        defs.append('CERES_STD_UNORDERED_MAP')
-        print("-- Found unordered_map/set in std namespace.")
-    elif conf.CheckType('std::tr1::unordered_map<int, int>', language = 'CXX', includes="#include <unordered_map>"):
-        defs.append('CERES_STD_UNORDERED_MAP_IN_TR1_NAMESPACE')
-        print("-- Found unordered_map/set in std::tr1 namespace.")
-    else:
-        print("-- Found <unordered_map> but can not find neither std::unordered_map nor std::tr1::unordered_map.")
-        print("-- Replacing unordered_map/set with map/set (warning: slower!)")
-        defs.append('CERES_NO_UNORDERED_MAP')
-elif conf.CheckCXXHeader("tr1/unordered_map"):
-    defs.append('CERES_TR1_UNORDERED_MAP')
-    print("-- Found unordered_map/set in std::tr1 namespace.")
-else:
-    print("-- Unable to find <unordered_map> or <tr1/unordered_map>. ")
+conf = Configure(env)
+if not define_unordered_map(conf):
     print("-- Replacing unordered_map/set with map/set (warning: slower!)")
     defs.append('CERES_NO_UNORDERED_MAP')
-
 env = conf.Finish()
 
 incs = '. ../../ ../../../Eigen3 ./include ./internal ../gflags'