Improvements to XInclude processing

- Skip intermediate XInclude files when serializing multi-level document hierarchies.
- Rename XmlReadOptions::parentFilenames to XmlReadOptions::parentXIncludes for clarity.
- Remove a duplicate call to setSourceUri.

source/MaterialXFormat/XmlIo.cpp

@@ -157,15 +157,19 @@ void processXIncludes(DocumentPtr doc, xml_node& xmlNode, const string& searchPa
                 string filename = xmlChild.attribute("href").value();
 
                 // Check for XInclude cycles.
-                if (readOptions && readOptions->parentFilenames.count(filename))
+                if (readOptions)
                 {
-                    throw ExceptionParseError("XInclude cycle detected.");
+                    const StringVec& parents = readOptions->parentXIncludes;
+                    if (std::find(parents.begin(), parents.end(), filename) != parents.end())
+                    {
+                        throw ExceptionParseError("XInclude cycle detected.");
+                    }
                 }
 
                 // Read the included file into a library document.
                 DocumentPtr library = createDocument();
                 XmlReadOptions xiReadOptions = readOptions ? *readOptions : XmlReadOptions();
-                xiReadOptions.parentFilenames.insert(filename);
+                xiReadOptions.parentXIncludes.push_back(filename);
                 readXIncludeFunction(library, filename, searchPath, &xiReadOptions);
 
                 // Import the library document.
@@ -256,7 +260,14 @@ void readFromXmlFile(DocumentPtr doc, const string& filename, const string& sear
     xmlDocumentFromFile(xmlDoc, filename, searchPath);
 
     documentFromXml(doc, xmlDoc, searchPath, readOptions);
-    doc->setSourceUri(filename);
+    if (readOptions && !readOptions->parentXIncludes.empty())
+    {
+        doc->setSourceUri(readOptions->parentXIncludes[0]);
+    }
+    else
+    {
+        doc->setSourceUri(filename);
+    }
 }
 
 void readFromXmlString(DocumentPtr doc, const string& str, const XmlReadOptions* readOptions)

source/MaterialXFormat/XmlIo.h

@@ -36,9 +36,9 @@ class XmlReadOptions : public CopyOptions
     /// needs to be read into a document.  Defaults to readFromXmlFile.
     XmlReadFunction readXIncludeFunction;
 
-    /// The set of parent filenames at the scope of the current document.
-    /// Defaults to an empty set.
-    StringSet parentFilenames;
+    /// The vector of parent XIncludes at the scope of the current document.
+    /// Defaults to an empty vector.
+    StringVec parentXIncludes;
 };
 
 /// @class XmlWriteOptions

source/MaterialXTest/GenShaderUtil.cpp

@@ -21,7 +21,6 @@ void loadLibrary(const mx::FilePath& file, mx::DocumentPtr doc)
 {
     mx::DocumentPtr libDoc = mx::createDocument();
     mx::readFromXmlFile(libDoc, file);
-    libDoc->setSourceUri(file);
     mx::CopyOptions copyOptions;
     copyOptions.skipDuplicateElements = true;
     doc->importLibrary(libDoc, &copyOptions);

source/PyMaterialX/PyMaterialXFormat/PyXmlIo.cpp

@@ -16,7 +16,7 @@ void bindPyXmlIo(py::module& mod)
     py::class_<mx::XmlReadOptions, mx::CopyOptions>(mod, "XmlReadOptions")
         .def(py::init())
         .def_readwrite("readXIncludeFunction", &mx::XmlReadOptions::readXIncludeFunction)
-        .def_readwrite("parentFilenames", &mx::XmlReadOptions::parentFilenames);
+        .def_readwrite("parentXIncludes", &mx::XmlReadOptions::parentXIncludes);
 
     py::class_<mx::XmlWriteOptions>(mod, "XmlWriteOptions")
         .def(py::init())