parser.cpp

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#include "yaml-cpp-pm/parser.h"
#include "yaml-cpp-pm/eventhandler.h"
#include "yaml-cpp-pm/exceptions.h"
#include "yaml-cpp-pm/node.h"
#include "directives.h"
#include "nodebuilder.h"
#include "scanner.h"
#include "singledocparser.h"
#include "tag.h"
#include "token.h"
#include <sstream>
#include <cstdio>

namespace YAML_PM
{
        Parser::Parser()
        {
        }
        
        Parser::Parser(std::istream& in)
        {
                Load(in);
        }

        Parser::~Parser()
        {
        }

        Parser::operator bool() const
        {
                return m_pScanner.get() && !m_pScanner->empty();
        }

        void Parser::Load(std::istream& in)
        {
                m_pScanner.reset(new Scanner(in));
                m_pDirectives.reset(new Directives);
        }

        // HandleNextDocument
        // . Handles the next document
        // . Throws a ParserException on error.
        // . Returns false if there are no more documents
        bool Parser::HandleNextDocument(EventHandler& eventHandler)
        {
                if(!m_pScanner.get())
                        return false;

                ParseDirectives();
                if(m_pScanner->empty())
                        return false;
                
                SingleDocParser sdp(*m_pScanner, *m_pDirectives);
                sdp.HandleDocument(eventHandler);
                return true;
        }

        // GetNextDocument
        // . Reads the next document in the queue (of tokens).
        // . Throws a ParserException on error.
        bool Parser::GetNextDocument(Node& document)
        {
                NodeBuilder builder(document);
                return HandleNextDocument(builder);
        }

        // ParseDirectives
        // . Reads any directives that are next in the queue.
        void Parser::ParseDirectives()
        {
                bool readDirective = false;

                while(1) {
                        if(m_pScanner->empty())
                                break;

                        Token& token = m_pScanner->peek();
                        if(token.type != Token::DIRECTIVE)
                                break;

                        // we keep the directives from the last document if none are specified;
                        // but if any directives are specific, then we reset them
                        if(!readDirective)
                                m_pDirectives.reset(new Directives);

                        readDirective = true;
                        HandleDirective(token);
                        m_pScanner->pop();
                }
        }

        void Parser::HandleDirective(const Token& token)
        {
                if(token.value == "YAML")
                        HandleYamlDirective(token);
                else if(token.value == "TAG")
                        HandleTagDirective(token);
        }

        // HandleYamlDirective
        // . Should be of the form 'major.minor' (like a version number)
        void Parser::HandleYamlDirective(const Token& token)
        {
                if(token.params.size() != 1)
                        throw ParserException(token.mark, ErrorMsg::YAML_DIRECTIVE_ARGS);
                
                if(!m_pDirectives->version.isDefault)
                        throw ParserException(token.mark, ErrorMsg::REPEATED_YAML_DIRECTIVE);

                std::stringstream str(token.params[0]);
                str >> m_pDirectives->version.major;
                str.get();
                str >> m_pDirectives->version.minor;
                if(!str || str.peek() != EOF)
                        throw ParserException(token.mark, std::string(ErrorMsg::YAML_VERSION) + token.params[0]);

                if(m_pDirectives->version.major > 1)
                        throw ParserException(token.mark, ErrorMsg::YAML_MAJOR_VERSION);

                m_pDirectives->version.isDefault = false;
                // TODO: warning on major == 1, minor > 2?
        }

        // HandleTagDirective
        // . Should be of the form 'handle prefix', where 'handle' is converted to 'prefix' in the file.
        void Parser::HandleTagDirective(const Token& token)
        {
                if(token.params.size() != 2)
                        throw ParserException(token.mark, ErrorMsg::TAG_DIRECTIVE_ARGS);

                const std::string& handle = token.params[0];
                const std::string& prefix = token.params[1];
                if(m_pDirectives->tags.find(handle) != m_pDirectives->tags.end())
                        throw ParserException(token.mark, ErrorMsg::REPEATED_TAG_DIRECTIVE);
                
                m_pDirectives->tags[handle] = prefix;
        }

        void Parser::PrintTokens(std::ostream& out)
        {
                if(!m_pScanner.get())
                        return;
                
                while(1) {
                        if(m_pScanner->empty())
                                break;

                        out << m_pScanner->peek() << "\n";
                        m_pScanner->pop();
                }
        }
}