Generate unique IDs for XmlOutput and serialize those

2 files changed, 45 insertions, 6 deletions

diff --git a/src/core/common/VariantConverter.cpp b/src/core/common/VariantConverter.cpp
index 699576b..ad0da83 100644
--- a/src/core/common/VariantConverter.cpp
+++ b/src/core/common/VariantConverter.cpp
@@ -304,15 +304,27 @@ bool VariantConverter::toString(Variant &var, Logger &logger, Mode mode)
 				return true;
 			}
 			case VariantType::OBJECT: {
-				// Print object address and type
+				// Fetch the attached object, abort if it is a nullptr
 				Variant::objectType obj = var.asObject();
-				std::stringstream ss;
-				ss << "<object " << obj.get();
-				if (obj.get() != nullptr) {
-					ss << " (" << obj->type()->name << ")";
+				if (obj == nullptr) {
+					var = "<null>";
+					return true;
+				}
+
+				// Check whether the object has an id attached -- if yes, output
+				// that id
+				Rooted<ManagedVariant> id = obj->readData<ManagedVariant>("id");
+				if (id != nullptr && id->v.isString()) {
+					var = id->v;
+					return true;
 				}
-				ss << ">";
+
+				// Otherwise print object address and type
+				std::stringstream ss;
+				ss << "<object " << obj.get() << " (" << obj->type()->name
+				   << ")>";
 				var = ss.str().c_str();
+
 				return true;
 			}
 			case VariantType::FUNCTION: {
diff --git a/src/plugins/xml/XmlOutput.cpp b/src/plugins/xml/XmlOutput.cpp
index e1703c4..cd1d187 100644
--- a/src/plugins/xml/XmlOutput.cpp
+++ b/src/plugins/xml/XmlOutput.cpp
@@ -24,6 +24,10 @@
 #include <core/common/Variant.hpp>
 #include <core/common/VariantWriter.hpp>
 
+// TODO: This should not be here -- remove this once we have a proper
+// transformation system.
+#include <transformations/uniqueid/UniqueIdTransformation.hpp>
+
 namespace ousia {
 namespace xml {
 
@@ -53,6 +57,23 @@ struct TransformParams {
 	}
 };
 
+/**
+ * Helper function used for attaching the unique id of nodes (if available) to
+ * the XML elements.
+ *
+ * @param elem is the XML element to which the unique id should be attached.
+ * @param managed is the managed object from which the id should be looked up.
+ */
+static void attachId(Handle<Element> elem, Handle<Managed> managed)
+{
+	// Check whether the managed object has an "id" attached to it
+	Rooted<ManagedVariant> id = managed->readData<ManagedVariant>("id");
+	if (id != nullptr && id->v.isString()) {
+		// We have an id that is a string, add it to the element
+		elem->getAttributes().emplace("id", id->v.asString());
+	}
+}
+
 /*
  * These are forward method declarations to allow for cross-references of
  * methods.
@@ -156,6 +177,9 @@ void XmlTransformer::writeXml(Handle<Document> doc, std::ostream &out,
                               Logger &logger, ResourceManager &resourceManager,
                               bool pretty, bool flat)
 {
+	// Create unique ids for the nodes
+	UniqueIdTransformation::transform(doc);
+
 	Manager &mgr = doc->getManager();
 	// the outermost tag is the document itself.
 	Rooted<Element> document{new Element{mgr, {nullptr}, "document"}};
@@ -741,6 +765,9 @@ static Rooted<Element> transformAnchor(Handle<Element> parent, Handle<Anchor> a,
 		    attrs, "a:start")};
 		// and handle the children.
 		transformChildren(a->getAnnotation().get(), elem, P);
+
+		// attach a possible id to the anchor
+		attachId(elem, a->getAnnotation());
 	} else if (a->isEnd()) {
 		/*
 		 * in principle !a->isStart() should imply a->isEnd() but if no