singledocparser.cpp

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

namespace YAML_PM
{
        SingleDocParser::SingleDocParser(Scanner& scanner, const Directives& directives): m_scanner(scanner), m_directives(directives), m_pCollectionStack(new CollectionStack), m_curAnchor(0)
        {
        }

        SingleDocParser::~SingleDocParser()
        {
        }

        // HandleDocument
        // . Handles the next document
        // . Throws a ParserException on error.
        void SingleDocParser::HandleDocument(EventHandler& eventHandler)
        {
                assert(!m_scanner.empty()); // guaranteed that there are tokens
                assert(!m_curAnchor);

                eventHandler.OnDocumentStart(m_scanner.peek().mark);
                
                // eat doc start
                if(m_scanner.peek().type == Token::DOC_START)
                        m_scanner.pop();
                
                // recurse!
                HandleNode(eventHandler);
                
                eventHandler.OnDocumentEnd();
                
                // and finally eat any doc ends we see
                while(!m_scanner.empty() && m_scanner.peek().type == Token::DOC_END)
                        m_scanner.pop();
        }
        
        void SingleDocParser::HandleNode(EventHandler& eventHandler)
        {
                // an empty node *is* a possibility
                if(m_scanner.empty()) {
                        eventHandler.OnNull(Mark::null(), NullAnchor);
                        return;
                }
                
                // save location
                Mark mark = m_scanner.peek().mark;
                
                // special case: a value node by itself must be a map, with no header
                if(m_scanner.peek().type == Token::VALUE) {
                        eventHandler.OnMapStart(mark, "", NullAnchor);
                        HandleMap(eventHandler);
                        eventHandler.OnMapEnd();
                        return;
                }
                
                // special case: an alias node
                if(m_scanner.peek().type == Token::ALIAS) {
                        eventHandler.OnAlias(mark, LookupAnchor(mark, m_scanner.peek().value));
                        m_scanner.pop();
                        return;
                }
                
                std::string tag;
                anchor_t anchor;
                ParseProperties(tag, anchor);
                
                const Token& token = m_scanner.peek();
                
                // add non-specific tags
                if(tag.empty())
                        tag = (token.type == Token::NON_PLAIN_SCALAR ? "!" : "?");
                
                // now split based on what kind of node we should be
                switch(token.type) {
                        case Token::PLAIN_SCALAR:
                        case Token::NON_PLAIN_SCALAR:
                                eventHandler.OnScalar(mark, tag, anchor, token.value);
                                m_scanner.pop();
                                return;
                        case Token::FLOW_SEQ_START:
                        case Token::BLOCK_SEQ_START:
                                eventHandler.OnSequenceStart(mark, tag, anchor);
                                HandleSequence(eventHandler);
                                eventHandler.OnSequenceEnd();
                                return;
                        case Token::FLOW_MAP_START:
                        case Token::BLOCK_MAP_START:
                                eventHandler.OnMapStart(mark, tag, anchor);
                                HandleMap(eventHandler);
                                eventHandler.OnMapEnd();
                                return;
                        case Token::KEY:
                                // compact maps can only go in a flow sequence
                                if(m_pCollectionStack->GetCurCollectionType() == CollectionType::FlowSeq) {
                                        eventHandler.OnMapStart(mark, tag, anchor);
                                        HandleMap(eventHandler);
                                        eventHandler.OnMapEnd();
                                        return;
                                }
                                break;
                        default:
                                break;
                }
                
                if(tag == "?")
                        eventHandler.OnNull(mark, anchor);
                else
                        eventHandler.OnScalar(mark, tag, anchor, "");
        }
        
        void SingleDocParser::HandleSequence(EventHandler& eventHandler)
        {
                // split based on start token
                switch(m_scanner.peek().type) {
                        case Token::BLOCK_SEQ_START: HandleBlockSequence(eventHandler); break;
                        case Token::FLOW_SEQ_START: HandleFlowSequence(eventHandler); break;
                        default: break;
                }
        }
        
        void SingleDocParser::HandleBlockSequence(EventHandler& eventHandler)
        {
                // eat start token
                m_scanner.pop();
                m_pCollectionStack->PushCollectionType(CollectionType::BlockSeq);
                
                while(1) {
                        if(m_scanner.empty())
                                throw ParserException(Mark::null(), ErrorMsg::END_OF_SEQ);
                        
                        Token token = m_scanner.peek();
                        if(token.type != Token::BLOCK_ENTRY && token.type != Token::BLOCK_SEQ_END)
                                throw ParserException(token.mark, ErrorMsg::END_OF_SEQ);
                        
                        m_scanner.pop();
                        if(token.type == Token::BLOCK_SEQ_END)
                                break;
                        
                        // check for null
                        if(!m_scanner.empty()) {
                                const Token& token = m_scanner.peek();
                                if(token.type == Token::BLOCK_ENTRY || token.type == Token::BLOCK_SEQ_END) {
                                        eventHandler.OnNull(token.mark, NullAnchor);
                                        continue;
                                }
                        }
                        
                        HandleNode(eventHandler);
                }
                
                m_pCollectionStack->PopCollectionType(CollectionType::BlockSeq);
        }
        
        void SingleDocParser::HandleFlowSequence(EventHandler& eventHandler)
        {
                // eat start token
                m_scanner.pop();
                m_pCollectionStack->PushCollectionType(CollectionType::FlowSeq);
                
                while(1) {
                        if(m_scanner.empty())
                                throw ParserException(Mark::null(), ErrorMsg::END_OF_SEQ_FLOW);
                        
                        // first check for end
                        if(m_scanner.peek().type == Token::FLOW_SEQ_END) {
                                m_scanner.pop();
                                break;
                        }
                        
                        // then read the node
                        HandleNode(eventHandler);
                        
                        // now eat the separator (or could be a sequence end, which we ignore - but if it's neither, then it's a bad node)
                        Token& token = m_scanner.peek();
                        if(token.type == Token::FLOW_ENTRY)
                                m_scanner.pop();
                        else if(token.type != Token::FLOW_SEQ_END)
                                throw ParserException(token.mark, ErrorMsg::END_OF_SEQ_FLOW);
                }
                
                m_pCollectionStack->PopCollectionType(CollectionType::FlowSeq);
        }
        
        void SingleDocParser::HandleMap(EventHandler& eventHandler)
        {
                // split based on start token
                switch(m_scanner.peek().type) {
                        case Token::BLOCK_MAP_START: HandleBlockMap(eventHandler); break;
                        case Token::FLOW_MAP_START: HandleFlowMap(eventHandler); break;
                        case Token::KEY: HandleCompactMap(eventHandler); break;
                        case Token::VALUE: HandleCompactMapWithNoKey(eventHandler); break;
                        default: break;
                }
        }
        
        void SingleDocParser::HandleBlockMap(EventHandler& eventHandler)
        {
                // eat start token
                m_scanner.pop();
                m_pCollectionStack->PushCollectionType(CollectionType::BlockMap);
                
                while(1) {
                        if(m_scanner.empty())
                                throw ParserException(Mark::null(), ErrorMsg::END_OF_MAP);
                        
                        Token token = m_scanner.peek();
                        if(token.type != Token::KEY && token.type != Token::VALUE && token.type != Token::BLOCK_MAP_END)
                                throw ParserException(token.mark, ErrorMsg::END_OF_MAP);
                        
                        if(token.type == Token::BLOCK_MAP_END) {
                                m_scanner.pop();
                                break;
                        }
                        
                        // grab key (if non-null)
                        if(token.type == Token::KEY) {
                                m_scanner.pop();
                                HandleNode(eventHandler);
                        } else {
                                eventHandler.OnNull(token.mark, NullAnchor);
                        }
                        
                        // now grab value (optional)
                        if(!m_scanner.empty() && m_scanner.peek().type == Token::VALUE) {
                                m_scanner.pop();
                                HandleNode(eventHandler);
                        } else {
                                eventHandler.OnNull(token.mark, NullAnchor);
                        }
                }
                
                m_pCollectionStack->PopCollectionType(CollectionType::BlockMap);
        }
        
        void SingleDocParser::HandleFlowMap(EventHandler& eventHandler)
        {
                // eat start token
                m_scanner.pop();
                m_pCollectionStack->PushCollectionType(CollectionType::FlowMap);
                
                while(1) {
                        if(m_scanner.empty())
                                throw ParserException(Mark::null(), ErrorMsg::END_OF_MAP_FLOW);
                        
                        Token& token = m_scanner.peek();
                        // first check for end
                        if(token.type == Token::FLOW_MAP_END) {
                                m_scanner.pop();
                                break;
                        }
                        
                        // grab key (if non-null)
                        if(token.type == Token::KEY) {
                                m_scanner.pop();
                                HandleNode(eventHandler);
                        } else {
                                eventHandler.OnNull(token.mark, NullAnchor);
                        }
                        
                        // now grab value (optional)
                        if(!m_scanner.empty() && m_scanner.peek().type == Token::VALUE) {
                                m_scanner.pop();
                                HandleNode(eventHandler);
                        } else {
                                eventHandler.OnNull(token.mark, NullAnchor);
                        }
                        
                        // now eat the separator (or could be a map end, which we ignore - but if it's neither, then it's a bad node)
                        Token& nextToken = m_scanner.peek();
                        if(nextToken.type == Token::FLOW_ENTRY)
                                m_scanner.pop();
                        else if(nextToken.type != Token::FLOW_MAP_END)
                                throw ParserException(nextToken.mark, ErrorMsg::END_OF_MAP_FLOW);
                }
                
                m_pCollectionStack->PopCollectionType(CollectionType::FlowMap);
        }
        
        // . Single "key: value" pair in a flow sequence
        void SingleDocParser::HandleCompactMap(EventHandler& eventHandler)
        {
                m_pCollectionStack->PushCollectionType(CollectionType::CompactMap);
                
                // grab key
                Mark mark = m_scanner.peek().mark;
                m_scanner.pop();
                HandleNode(eventHandler);
                
                // now grab value (optional)
                if(!m_scanner.empty() && m_scanner.peek().type == Token::VALUE) {
                        m_scanner.pop();
                        HandleNode(eventHandler);
                } else {
                        eventHandler.OnNull(mark, NullAnchor);
                }
                
                m_pCollectionStack->PopCollectionType(CollectionType::CompactMap);
        }
        
        // . Single ": value" pair in a flow sequence
        void SingleDocParser::HandleCompactMapWithNoKey(EventHandler& eventHandler)
        {
                m_pCollectionStack->PushCollectionType(CollectionType::CompactMap);
                
                // null key
                eventHandler.OnNull(m_scanner.peek().mark, NullAnchor);
                
                // grab value
                m_scanner.pop();
                HandleNode(eventHandler);
                
                m_pCollectionStack->PopCollectionType(CollectionType::CompactMap);
        }
        
        // ParseProperties
        // . Grabs any tag or anchor tokens and deals with them.
        void SingleDocParser::ParseProperties(std::string& tag, anchor_t& anchor)
        {
                tag.clear();
                anchor = NullAnchor;
                
                while(1) {
                        if(m_scanner.empty())
                                return;
                        
                        switch(m_scanner.peek().type) {
                                case Token::TAG: ParseTag(tag); break;
                                case Token::ANCHOR: ParseAnchor(anchor); break;
                                default: return;
                        }
                }
        }
        
        void SingleDocParser::ParseTag(std::string& tag)
        {
                Token& token = m_scanner.peek();
                if(!tag.empty())
                        throw ParserException(token.mark, ErrorMsg::MULTIPLE_TAGS);
                
                Tag tagInfo(token);
                tag = tagInfo.Translate(m_directives);
                m_scanner.pop();
        }
        
        void SingleDocParser::ParseAnchor(anchor_t& anchor)
        {
                Token& token = m_scanner.peek();
                if(anchor)
                        throw ParserException(token.mark, ErrorMsg::MULTIPLE_ANCHORS);
                
                anchor = RegisterAnchor(token.value);
                m_scanner.pop();
        }
        
        anchor_t SingleDocParser::RegisterAnchor(const std::string& name)
        {
                if(name.empty())
                        return NullAnchor;
                
                return m_anchors[name] = ++m_curAnchor;
        }
        
        anchor_t SingleDocParser::LookupAnchor(const Mark& mark, const std::string& name) const
        {
                Anchors::const_iterator it = m_anchors.find(name);
                if(it == m_anchors.end())
                        throw ParserException(mark, ErrorMsg::UNKNOWN_ANCHOR);
                
                return it->second;
        }
}