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//-----------------------------------------------------------------------------
/** @file libboardgame_gtp/GtpEngine.cpp
@author Markus Enzenberger
@copyright GNU General Public License version 3 or later */
//-----------------------------------------------------------------------------
#include "GtpEngine.h"
#include <cctype>
#include <iostream>
#include "CmdLine.h"
namespace libboardgame_gtp {
//-----------------------------------------------------------------------------
/** Utility functions. */
namespace {
/** Check, if line contains a command. */
bool is_cmd_line(const string& line)
{
for (char c : line)
if (isspace(static_cast<unsigned char>(c)) == 0)
return c != '#';
return false;
}
/** Read next command from stream.
@param in The input stream.
@param[out] c The command (reused for efficiency)
@return @c false on end-of-stream or read error. */
bool read_cmd(CmdLine& c, istream& in)
{
string line;
while (getline(in, line))
if (is_cmd_line(line))
break;
if (! in.fail())
{
c.init(line);
return true;
}
return false;
}
} // namespace
//-----------------------------------------------------------------------------
GtpEngine::GtpEngine()
{
add("known_command", &GtpEngine::cmd_known_command);
add("list_commands", &GtpEngine::cmd_list_commands);
add("quit", &GtpEngine::cmd_quit);
}
GtpEngine::~GtpEngine() = default; // Non-inline to avoid GCC -Winline warning
void GtpEngine::add(const string& name, const Handler& f)
{
m_handlers[name] = f;
}
void GtpEngine::add(const string& name, const HandlerNoArgs& f)
{
add(name, [f](Arguments args, Response& response) {
args.check_empty();
f(response);
});
}
void GtpEngine::add(const string& name, const HandlerNoResponse& f)
{
add(name, [f](Arguments args, Response&) {
f(args);
});
}
void GtpEngine::add(const string& name, const HandlerNoArgsNoResponse& f)
{
add(name, [f](Arguments args, Response&) {
args.check_empty();
f();
});
}
/** Return @c true if command is known, @c false otherwise. */
void GtpEngine::cmd_known_command(Arguments args, Response& response)
{
response.set(contains(args.get<string>()) ? "true" : "false");
}
/** List all known commands. */
void GtpEngine::cmd_list_commands(Response& response)
{
for (auto& i : m_handlers)
response << i.first << '\n';
}
/** Quit command loop. */
void GtpEngine::cmd_quit()
{
m_quit = true;
}
bool GtpEngine::contains(const string& name) const
{
return m_handlers.count(name) > 0;
}
bool GtpEngine::exec(istream& in, bool throw_on_fail, ostream* log)
{
string line;
Response response;
string buffer;
CmdLine cmd;
while (getline(in, line))
{
if (! is_cmd_line(line))
continue;
cmd.init(line);
if (log != nullptr)
*log << cmd.get_line() << '\n';
bool status = handle_cmd(cmd, log, response, buffer);
if (! status && throw_on_fail)
{
ostringstream msg;
msg << "executing '" << cmd.get_line() << "' failed";
throw Failure(msg.str());
}
}
return ! in.fail();
}
void GtpEngine::exec_main_loop(istream& in, ostream& out)
{
m_quit = false;
CmdLine cmd;
Response response;
string buffer;
while (! m_quit)
{
if (read_cmd(cmd, in))
handle_cmd(cmd, &out, response, buffer);
else
break;
}
}
/** Call the handler of a command and write its response.
@param line The command
@param out The output stream for the response
@param response A reusable response instance to avoid memory allocation in
each function call
@param buffer A reusable string instance to avoid memory allocation in each
function call */
bool GtpEngine::handle_cmd(
CmdLine& line, ostream* out, Response& response, string& buffer)
{
on_handle_cmd_begin();
bool status = true;
try
{
response.clear();
auto pos = m_handlers.find(string(line.get_name()));
if (pos != m_handlers.end())
{
Arguments args(line);
(pos->second)(args, response);
}
else
{
status = false;
response << "unknown command (" << line.get_name() << ')';
}
}
catch (const Failure& failure)
{
status = false;
response.set(failure.what());
}
if (out != nullptr)
{
*out << (status ? '=' : '?');
line.write_id(*out);
*out << ' ';
response.write(*out, buffer);
out->flush();
}
return status;
}
void GtpEngine::on_handle_cmd_begin()
{
// Default implementation does nothing
}
//-----------------------------------------------------------------------------
} // namespace libboardgame_gtp
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