Merge branch 'master' of somweyr.de:ousia

1 files changed, 226 insertions, 0 deletions

diff --git a/src/plugins/xml/XmlParser.cpp b/src/plugins/xml/XmlParser.cpp
new file mode 100644
index 0000000..afc7f14
--- /dev/null
+++ b/src/plugins/xml/XmlParser.cpp
@@ -0,0 +1,226 @@
+/*
+    Ousía
+    Copyright (C) 2014, 2015  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/>.
+*/
+
+#include <iostream>
+
+#include <expat.h>
+
+#include <core/Utils.hpp>
+#include <core/parser/ParserStack.hpp>
+
+#include "XmlParser.hpp"
+
+namespace ousia {
+namespace parser {
+namespace xml {
+
+/* Document structure */
+static const State STATE_DOCUMENT = 0;
+static const State STATE_HEAD = 1;
+static const State STATE_BODY = 2;
+
+/* Special commands */
+static const State STATE_USE = 100;
+static const State STATE_INCLUDE = 101;
+static const State STATE_INLINE = 102;
+
+/* Type system definitions */
+static const State STATE_TYPES = 200;
+static const State STATE_CONSTANT = 201;
+static const State STATE_ENUM = 202;
+static const State STATE_STRUCT = 203;
+
+class TestHandler : public Handler {
+public:
+	using Handler::Handler;
+
+	void start(const Variant &args) override
+	{
+		std::cout << this->name << ": start (isChild: " << (this->isChild)
+		          << ", args: " << args << ")" << std::endl;
+	}
+
+	void end() override
+	{
+		// TODO
+	}
+
+	void data(const std::string &data, int field) override
+	{
+		std::cout << this->name << ": data \"" << data << "\"" << std::endl;
+	}
+
+	void child(std::shared_ptr<Handler> handler) override
+	{
+		// TODO
+	}
+};
+
+static Handler *createTestHandler(const ParserContext &ctx, std::string name,
+                                  State state, State parentState, bool isChild)
+{
+	return new TestHandler{ctx, name, state, parentState, isChild};
+}
+
+static const std::multimap<std::string, HandlerDescriptor> XML_HANDLERS{
+    /* Documents */
+    {"document", {{STATE_NONE}, createTestHandler, STATE_DOCUMENT}},
+    {"head", {{STATE_DOCUMENT}, createTestHandler, STATE_HEAD}},
+    {"body", {{STATE_DOCUMENT}, createTestHandler, STATE_BODY, true}},
+
+    /* Special commands */
+    {"use", {{STATE_HEAD}, createTestHandler, STATE_USE}},
+    {"include", {{STATE_ALL}, createTestHandler, STATE_INCLUDE}},
+    {"inline", {{STATE_ALL}, createTestHandler, STATE_INLINE}},
+
+    /* Typesystem definitions */
+    {"typesystem", {{STATE_NONE, STATE_HEAD}, createTestHandler, STATE_TYPES}},
+    {"enum", {{STATE_TYPES}, createTestHandler, STATE_ENUM}},
+    {"struct", {{STATE_TYPES}, createTestHandler, STATE_STRUCT}},
+    {"constant", {{STATE_TYPES}, createTestHandler, STATE_CONSTANT}}};
+
+/**
+ * Wrapper class around the XML_Parser pointer which safely frees it whenever
+ * the scope is left (e.g. because an exception was thrown).
+ */
+class ScopedExpatXmlParser {
+private:
+	/**
+	 * Internal pointer to the XML_Parser instance.
+	 */
+	XML_Parser parser;
+
+public:
+	/**
+	 * Constructor of the ScopedExpatXmlParser class. Calls XML_ParserCreateNS
+	 * from the expat library. Throws a parser exception if the XML parser
+	 * cannot be initialized.
+	 *
+	 * @param encoding is the protocol-defined encoding passed to expat (or
+	 * nullptr if expat should determine the encoding by itself).
+	 */
+	ScopedExpatXmlParser(const XML_Char *encoding) : parser(nullptr)
+	{
+		parser = XML_ParserCreate(encoding);
+		if (!parser) {
+			throw ParserException{
+			    "Internal error: Could not create expat XML parser!"};
+		}
+	}
+
+	/**
+	 * Destuctor of the ScopedExpatXmlParser, frees the XML parser instance.
+	 */
+	~ScopedExpatXmlParser()
+	{
+		if (parser) {
+			XML_ParserFree(parser);
+			parser = nullptr;
+		}
+	}
+
+	/**
+	 * Returns the XML_Parser pointer.
+	 */
+	XML_Parser operator&() { return parser; }
+};
+
+/* Adapter Expat -> ParserStack */
+
+static void xmlStartElementHandler(void *userData, const XML_Char *name,
+                                   const XML_Char **attrs)
+{
+	Variant::mapType args;
+	const XML_Char **attr = attrs;
+	while (*attr) {
+		const std::string key{*(attr++)};
+		args.emplace(std::make_pair(key, Variant{*(attr++)}));
+	}
+	(static_cast<ParserStack *>(userData))->start(std::string(name), args);
+}
+
+static void xmlEndElementHandler(void *userData, const XML_Char *name)
+{
+	(static_cast<ParserStack *>(userData))->end();
+}
+
+static void xmlCharacterDataHandler(void *userData, const XML_Char *s, int len)
+{
+	const std::string data =
+	    Utils::trim(std::string{s, static_cast<size_t>(len)});
+	if (!data.empty()) {
+		(static_cast<ParserStack *>(userData))->data(data);
+	}
+}
+
+/* Class XmlParser */
+
+std::set<std::string> XmlParser::mimetypes()
+{
+	return std::set<std::string>{{"text/vnd.ousia.oxm", "text/vnd.ousia.oxd"}};
+}
+
+Rooted<Node> XmlParser::parse(std::istream &is, ParserContext &ctx)
+{
+	// Create the parser object
+	ScopedExpatXmlParser p{"UTF-8"};
+
+	// Create the parser stack instance and pass the reference to the state
+	// machine descriptor
+	ParserStack stack{ctx, XML_HANDLERS};
+	XML_SetUserData(&p, &stack);
+
+	// Set the callback functions
+	XML_SetStartElementHandler(&p, xmlStartElementHandler);
+	XML_SetEndElementHandler(&p, xmlEndElementHandler);
+	XML_SetCharacterDataHandler(&p, xmlCharacterDataHandler);
+
+	// Feed data into expat while there is data to process
+	const std::streamsize BUFFER_SIZE = 4096;  // TODO: Move to own header?
+	while (true) {
+		// Fetch a buffer from expat for the input data
+		char *buf = static_cast<char *>(XML_GetBuffer(&p, BUFFER_SIZE));
+		if (!buf) {
+			throw ParserException{"Internal error: XML parser out of memory!"};
+		}
+
+		// Read the input data from the stream
+		const std::streamsize bytesRead = is.read(buf, BUFFER_SIZE).gcount();
+
+		// Parse the data and handle any XML error
+		if (!XML_ParseBuffer(&p, bytesRead, bytesRead == 0)) {
+			const int line = XML_GetCurrentLineNumber(&p);
+			const int column = XML_GetCurrentColumnNumber(&p);
+			const XML_Error code = XML_GetErrorCode(&p);
+			const std::string msg = std::string{XML_ErrorString(code)};
+			throw ParserException{"XML Syntax Error: " + msg, line, column,
+			                      false};
+		}
+
+		// Abort once there are no more bytes in the stream
+		if (bytesRead == 0) {
+			break;
+		}
+	}
+
+	return nullptr;
+}
+}
+}
+}
+