fuzzer: excersizes query code on xml doc

tests/fuzz_xpath.cpp

@@ -1,26 +1,46 @@
 #include "../src/pugixml.hpp"
+#include "fuzzer/FuzzedDataProvider.h"
 
 #include <stdint.h>
 #include <string.h>
+#include <string>
 
-extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size)
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* Data, size_t Size)
 {
-	char* text = new char[Size + 1];
-	memcpy(text, Data, Size);
-	text[Size] = 0;
+	FuzzedDataProvider fdp(Data, Size);
+	std::string text = fdp.ConsumeRandomLengthString(1024);
 
-#ifdef PUGIXML_NO_EXCEPTIONS
-	pugi::xpath_query q(text);
-#else
+#ifndef PUGIXML_NO_EXCEPTIONS
 	try
+#endif
 	{
-		pugi::xpath_query q(text);
+		pugi::xpath_variable_set vars;
+		size_t var_count = fdp.ConsumeIntegralInRange<size_t>(0, 50);
+		std::vector<std::string> var_name_storage;
+		for (size_t i = 0; i < var_count; ++i)
+		{
+			var_name_storage.push_back(fdp.ConsumeRandomLengthString(128));
+
+			const int xpath_value_type_count = pugi::xpath_type_boolean + 1;
+			pugi::xpath_value_type value_type = static_cast<pugi::xpath_value_type>(fdp.ConsumeIntegralInRange(0, xpath_value_type_count));
+			vars.add(var_name_storage.back().c_str(), value_type);
+		}
+		pugi::xpath_query q(text.c_str(), &vars);
+
+		std::vector<uint8_t> xml_buffer = fdp.ConsumeBytes<uint8_t>(fdp.ConsumeIntegralInRange(0, 1024));
+		pugi::xml_document doc;
+		doc.load_buffer(xml_buffer.data(), xml_buffer.size(), pugi::parse_full);
+
+		q.evaluate_boolean(doc);
+		q.evaluate_number(doc);
+		q.evaluate_string(doc);
+		q.evaluate_node(doc);
+		q.evaluate_node_set(doc);
 	}
+#ifndef PUGIXML_NO_EXCEPTIONS
 	catch (pugi::xpath_exception&)
 	{
 	}
 #endif
-
-	delete[] text;
 	return 0;
 }