libcimpp now does not build in Windows

[leonardocarreras]

Dear Maintainers,

These lines

libcimpp/arabica/CMakeLists.txt

Lines 20 to 30 in 23d2dab

	# options: USE_MSXML, USE_EXPAT, USE_LIBXML2, USE_XERCES
	set(ARABICA_XML_BACKEND USE_LIBXML2)
	#
	# find libxml2: LIBXML2_INCLUDE_DIR LIBXML2_LIBRARIES
	if(ARABICA_XML_BACKEND STREQUAL USE_LIBXML2)
	set(ARABICA_USE_LIBXML2 TRUE)
	find_package(LibXml2 REQUIRED)
	set(ADDITIONAL_INC ${LIBXML2_INCLUDE_DIRS})
	set(ADDITIONAL_LIB ${LIBXML2_LIBRARIES})
	endif()

Makes the compilation to break in windows, when building from source. This is because it is trying to use libxml2. This is the situation now when trying to update in sogno/dpsim to v2.2.0
https://github.com/sogno-platform/dpsim/actions/runs/17471671938/job/49621380615#step:5:146

This seems not to be the expected behaviour here in the original repository used for arabica
https://github.com/jezhiggins/arabica/blob/110d524d2ab638855921a0c53eced7b3d08878be/CMakeLists.txt#L82-L95

Is stopping support in Windows intended in libcimpp? Is maybe a configuration option that I might be missing to add to the compilation command?

[ADam-LVA]

Hello,

It is possible to build with USE_MSXML, but result will not pass encoding tests.
It is still possible to build with libxml2 by vcpkg (include "legacy" feature and make sure to use version 2.13):

--- a/arabica/CMakeLists.txt
+++ b/arabica/CMakeLists.txt
@@ -29,6 +29,12 @@ if(ARABICA_XML_BACKEND STREQUAL USE_LIBXML2)
   set(ADDITIONAL_LIB ${LIBXML2_LIBRARIES})
 endif()
 
+if(WIN32)
+  set(CMAKE_WINDOWS_EXPORT_ALL_SYMBOLS ON)
+  set(USE_WINSOCK TRUE)
+  set(ADDITIONAL_LIB ${ADDITIONAL_LIB} wsock32 ws2_32)
+endif()
+
 #
 # platform check
 set(BUILD_X64 TRUE)

Another problem is arabica uses legacy functions xmlSetFeature and xmlGetFeature from libxml2.
These are removed starting libxml2 version 2.14.
Only 2 features are checked in arabica, so I copied corresponding code from libxml2 2.13:

--- a/arabica/src/SAX/wrappers/saxlibxml2.cpp
+++ b/arabica/src/SAX/wrappers/saxlibxml2.cpp
@@ -220,25 +220,38 @@ xmlSAXHandler* lwit_SaxHandler()
 
 void lwit_setFeature(xmlParserCtxtPtr context, const char* name, bool value)
 {
-  int v = value;
-  if(xmlSetFeature(context, name, reinterpret_cast<void*>(&v)) == -1)
-  {
-    std::ostringstream os; 
-    os << "Feature not recognized " << name;
-    throw SAX::SAXNotRecognizedException(os.str());
+  if (!strcmp(name, "validate")) {
+    int newvalidate = *((int *) value);
+     if ((!context->validate) && (newvalidate != 0)) {
+      if (context->vctxt.warning == NULL)
+        context->vctxt.warning = xmlParserValidityWarning;
+      if (context->vctxt.error == NULL)
+        context->vctxt.error = xmlParserValidityError;
+      context->vctxt.nodeMax = 0;
+    }
+    context->validate = newvalidate;
+  } else if (!strcmp(name, "fetch external entities")) {
+    context->loadsubset = *((int *) value);
+  } else {
+      std::ostringstream os; 
+      os << "Feature not recognized " << name;
+      throw SAX::SAXNotRecognizedException(os.str());
   } // if ...
 } // lwitSetFeature
 
 bool lwit_getFeature(xmlParserCtxtPtr context, const char* name)
 {
-  int v;
-  if(xmlGetFeature(context, name, reinterpret_cast<void*>(&v)) == -1)
-  {
+  int result;
+  if (!strcmp(name, "validate")) {
+    *((int *) result) = context->validate;
+  } else if (!strcmp(name, "fetch external entities")) {
+    *((int *) result) = context->loadsubset;
+  } else {
     std::ostringstream os; 
     os << "Feature not recognized " << name;
     throw SAX::SAXNotRecognizedException(os.str());
   } // if ...
-  return static_cast<bool>(v);
+  return static_cast<bool>(result);
 } // lwit_getFeature
 
 } // namespace libxml2_wrapper_impl_tiddle

With these 2 patches libcimpp builds on Windows with vcpkg and current library versions.

[m-mirz]

I would like to get rid of arabica since libxml2 can be used on all common platforms. Using vcpkg to get libxml2 looks like a good idea. I would support a PR implementing this.

[leonardocarreras]

Thank you both for your responses.

I will for the moment try to patch or keep our windows compilation in a previous version.

The proposal of unifying on libxml2 also seems like a good idea, but we may not have resources to support it as we would like.