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/*
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;
}
}
}
}
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