1 files changed, 146 insertions, 0 deletions
diff --git a/src/xml/XmlElementHandler.hpp b/src/xml/XmlElementHandler.hpp
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+++ b/src/xml/XmlElementHandler.hpp
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+/*
+    Ousía
+    Copyright (C) 2014  Benjamin Paaßen, Andreas Stöckel
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef _OUSIA_XML_XML_ELEMENT_HANDLER_HPP_
+#define _OUSIA_XML_XML_ELEMENT_HANDLER_HPP_
+
+#include <functional>
+
+namespace ousia {
+namespace xml {
+
+/**
+ * Structure used internally for representing a function that is capable of
+ * handling a certain xml element tag.
+ */
+class XmlElementHandler {
+
+private:
+	/**
+	 * Name of the XML element the handler is capable of handling.
+	 */
+	const char *name;
+
+	/**
+	 * Handler function.
+	 */
+	std::function<bool()> handler;
+
+	/**
+	 * Counter that can be used in order to realize elements that may only
+	 * appear a certain number of times.
+	 */
+	int count;
+
+	/**
+	 * Contains the current count of matches. Contains the maximum count a
+	 * certain element must appear. If -1 the element may appear a unlimited
+	 * number of times.
+	 */
+	int maxCount;
+
+	/**
+	 * A certain other handler this one depends on (the other element must have
+	 * appeared at least once in order for this handler to match). If set to
+	 * nullptr no requirement relationship is established.
+	 */
+	const XmlElementHandler *requiredElement;
+
+public:
+
+	/**
+	 * Constructor of the XmlElementHandler structure.
+	 */
+	XmlElementHandler(const char *name, const std::function<bool()> &handler,
+			int maxCount = -1, const XmlElementHandler *requiredElement = nullptr) :
+		name(name), handler(handler), count(0), maxCount(maxCount),
+		requiredElement(requiredElement)
+	{
+		// Do nothing here
+	}
+
+	/**
+	 * Returns the name of the handler.
+	 */
+	const char* getName() const
+	{
+		return name;
+	}
+
+	/**
+	 * Returns true if this handler is currently valid.
+	 */
+	bool valid() const
+	{
+		return ((maxCount < 0) || (count < maxCount))
+			&& (!requiredElement || (requiredElement->count > 0));
+	}
+
+	/**
+	 * Returns true if this handler matches the current state of the given
+	 * QXmlStreamReader.
+	 */
+	template<typename StrType>
+	bool matches(const StrType &tagName) const
+	{
+		return valid() && (tagName == name);
+	}
+
+	/**
+	 * Executes the given handler.
+	 */
+	bool execute()
+	{
+		count++;
+		return handler();
+	}
+
+	/**
+	 * Function which assembles a string containing the names of the expected
+	 * element types. Used for displaying error messages.
+	 */
+	static std::string expectedElementsStr(const std::vector<XmlElementHandler> &handlers)
+	{
+		// Calculate a list of valid element handlers
+		std::vector<const XmlElementHandler*> validHandlers;
+		for (auto &h : handlers) {
+			if (h.valid()) {
+				validHandlers.push_back(&h);
+			}
+		}
+
+		// Assemble the string containing the list of expected elements
+		std::stringstream ss;
+		bool first = true;
+		for (auto &h : validHandlers) {
+			if (!first) {
+				ss << ", ";
+			}
+			ss << h->getName();
+			first = false;
+		}
+		return ss.str();
+	}
+
+};
+
+}
+}
+
+#endif /* _OUSIA_XML_XML_ELEMENT_HANDLER_HPP_ */
+