From 15d7196bf3a3244f078f63645783c4c3f2534d92 Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Tue, 21 Feb 2023 00:57:37 +0000
Subject: Implement XML deserializer with SAXParse

---
 lib/saxParse-persistence.cpp | 50 ++++++++++++++++++++++++++++++++++++++++++++
 lib/saxParse-persistence.h   | 43 +++++++++++++++++++++++++++++++++++++
 2 files changed, 93 insertions(+)
 create mode 100644 lib/saxParse-persistence.cpp
 create mode 100644 lib/saxParse-persistence.h

diff --git a/lib/saxParse-persistence.cpp b/lib/saxParse-persistence.cpp
new file mode 100644
index 0000000..a6a0d23
--- /dev/null
+++ b/lib/saxParse-persistence.cpp
@@ -0,0 +1,50 @@
+#include "saxParse-persistence.h"
+
+namespace Persistence {
+
+	void
+	SAXParsePersistence::loadStateInternal(FILE * in)
+	{
+		stk.top()->beforeValue(stk);
+		stk.top()->beginObject(stk);
+		parseFile(in);
+		stk.pop();
+		stk.pop();
+	}
+
+	void
+	SAXParsePersistence::elementOpen(mxml_node_t * n)
+	{
+		stk.push(stk.top()->select(mxmlGetElement(n)));
+		stk.top()->beforeValue(stk);
+		stk.top()->beginObject(stk);
+		for (int attrCount = mxmlElementGetAttrCount(n), attrIdx {0}; attrIdx < attrCount; ++attrIdx) {
+			const char *name, *value = mxmlElementGetAttrByIndex(n, attrIdx, &name);
+			auto sel = stk.top()->select(name);
+			sel->beforeValue(stk);
+			sel->setValue(std::string {value});
+		}
+	}
+
+	void
+	SAXParsePersistence::elementClose(mxml_node_t *)
+	{
+		stk.top()->endObject(stk);
+		stk.top()->endObject(stk);
+	}
+
+	void
+	SAXParsePersistence::data(mxml_node_t *)
+	{
+	}
+
+	void
+	SAXParsePersistence::directive(mxml_node_t *)
+	{
+	}
+
+	void
+	SAXParsePersistence::cdata(mxml_node_t *)
+	{
+	}
+}
diff --git a/lib/saxParse-persistence.h b/lib/saxParse-persistence.h
new file mode 100644
index 0000000..91daecc
--- /dev/null
+++ b/lib/saxParse-persistence.h
@@ -0,0 +1,43 @@
+#pragma once
+
+#include "persistence.h"
+#include "saxParse.h"
+#include <cstdio>
+#include <mxml.h>
+
+namespace Persistence {
+	class SAXParsePersistence : public SAXParse {
+	private:
+		template<typename T> struct Root : public Persistable {
+			T t {};
+			bool
+			persist(PersistenceStore & store)
+			{
+				return STORE_TYPE && STORE_NAME_MEMBER("ilt", t);
+			}
+		};
+
+		void loadStateInternal(FILE * in);
+
+	public:
+		template<typename T>
+		auto
+		loadState(FILE * in)
+		{
+			std::unique_ptr<Root<T>> root;
+			stk.push(std::make_unique<SelectionT<decltype(root)>>(std::ref(root)));
+			loadStateInternal(in);
+			return std::move(root->t);
+		}
+
+	protected:
+		void elementOpen(mxml_node_t * n) override;
+		void elementClose(mxml_node_t *) override;
+		void data(mxml_node_t *) override;
+		void directive(mxml_node_t *) override;
+		void cdata(mxml_node_t *) override;
+
+	private:
+		Stack stk;
+	};
+}
-- 
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