gremlin/libs/yaml-cpp/src/parser.cpp

156 lines
3.5 KiB
C++

#include "parser.h"
#include "scanner.h"
#include "token.h"
#include "exceptions.h"
#include "parserstate.h"
#include <sstream>
#include <cstdio>
namespace YAML
{
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_pState.reset(new ParserState);
}
// GetNextDocument
// . Reads the next document in the queue (of tokens).
// . Throws a ParserException on error.
bool Parser::GetNextDocument(Node& document)
{
if(!m_pScanner.get())
return false;
// clear node
document.Clear();
// first read directives
ParseDirectives();
// we better have some tokens in the queue
if(m_pScanner->empty())
return false;
// first eat doc start (optional)
if(m_pScanner->peek().type == Token::DOC_START)
m_pScanner->pop();
// now parse our root node
document.Parse(m_pScanner.get(), *m_pState);
// and finally eat any doc ends we see
while(!m_pScanner->empty() && m_pScanner->peek().type == Token::DOC_END)
m_pScanner->pop();
// clear anchors from the scanner, which are no longer relevant
m_pScanner->ClearAnchors();
return true;
}
// 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_pState.reset(new ParserState);
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_pState->version.isDefault)
throw ParserException(token.mark, ErrorMsg::REPEATED_YAML_DIRECTIVE);
std::stringstream str(token.params[0]);
str >> m_pState->version.major;
str.get();
str >> m_pState->version.minor;
if(!str || str.peek() != EOF)
throw ParserException(token.mark, ErrorMsg::YAML_VERSION + token.params[0]);
if(m_pState->version.major > 1)
throw ParserException(token.mark, ErrorMsg::YAML_MAJOR_VERSION);
m_pState->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_pState->tags.find(handle) != m_pState->tags.end())
throw ParserException(token.mark, ErrorMsg::REPEATED_TAG_DIRECTIVE);
m_pState->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();
}
}
}