freebsd-dev/contrib/lutok/operations.cpp
Brooks Davis c697fb7f7c Add liblutok a lightweight C++ API for lua.
It is added an INTERNALLIB and not installed.  It will be used by kyua.

This is a preparatory commit for D24103.

Reviewed by:	emaste
Obtained from:	CheriBSD
Sponsored by:	DARPA
2020-03-23 18:26:23 +00:00

154 lines
5.4 KiB
C++

// Copyright 2011 Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
// * Neither the name of Google Inc. nor the names of its contributors
// may be used to endorse or promote products derived from this software
// without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include <cassert>
#include <lua.hpp>
#include "exceptions.hpp"
#include "operations.hpp"
#include "stack_cleaner.hpp"
#include "state.hpp"
/// Creates a module: i.e. a table with a set of methods in it.
///
/// \param s The Lua state.
/// \param name The name of the module to create.
/// \param members The list of member functions to add to the module.
void
lutok::create_module(state& s, const std::string& name,
const std::map< std::string, cxx_function >& members)
{
stack_cleaner cleaner(s);
s.new_table();
for (std::map< std::string, cxx_function >::const_iterator
iter = members.begin(); iter != members.end(); iter++) {
s.push_string((*iter).first);
s.push_cxx_function((*iter).second);
s.set_table(-3);
}
s.set_global(name);
}
/// Loads and processes a Lua file.
///
/// This is a replacement for luaL_dofile but with proper error reporting
/// and stack control.
///
/// \param s The Lua state.
/// \param file The file to load.
/// \param nargs The number of arguments on the stack to pass to the file.
/// \param nresults The number of results to expect; -1 for any.
/// \param errfunc If not 0, index of a function in the stack to act as an
/// error handler.
///
/// \return The number of results left on the stack.
///
/// \throw error If there is a problem processing the file.
unsigned int
lutok::do_file(state& s, const std::string& file, const int nargs,
const int nresults, const int errfunc)
{
assert(nresults >= -1);
const int height = s.get_top() - nargs;
try {
s.load_file(file);
if (nargs > 0)
s.insert(-nargs - 1);
s.pcall(nargs, nresults == -1 ? LUA_MULTRET : nresults,
errfunc == 0 ? 0 : errfunc - 1);
} catch (const lutok::api_error& e) {
throw lutok::error("Failed to load Lua file '" + file + "': " +
e.what());
}
const int actual_results = s.get_top() - height;
assert(nresults == -1 || actual_results == nresults);
assert(actual_results >= 0);
return static_cast< unsigned int >(actual_results);
}
/// Processes a Lua script.
///
/// This is a replacement for luaL_dostring but with proper error reporting
/// and stack control.
///
/// \param s The Lua state.
/// \param str The string to process.
/// \param nargs The number of arguments on the stack to pass to the chunk.
/// \param nresults The number of results to expect; -1 for any.
/// \param errfunc If not 0, index of a function in the stack to act as an
/// error handler.
///
/// \return The number of results left on the stack.
///
/// \throw error If there is a problem processing the string.
unsigned int
lutok::do_string(state& s, const std::string& str, const int nargs,
const int nresults, const int errfunc)
{
assert(nresults >= -1);
const int height = s.get_top() - nargs;
try {
s.load_string(str);
if (nargs > 0)
s.insert(-nargs - 1);
s.pcall(nargs, nresults == -1 ? LUA_MULTRET : nresults,
errfunc == 0 ? 0 : errfunc - 1);
} catch (const lutok::api_error& e) {
throw lutok::error("Failed to process Lua string '" + str + "': " +
e.what());
}
const int actual_results = s.get_top() - height;
assert(nresults == -1 || actual_results == nresults);
assert(actual_results >= 0);
return static_cast< unsigned int >(actual_results);
}
/// Convenience function to evaluate a Lua expression.
///
/// \param s The Lua state.
/// \param expression The textual expression to evaluate.
/// \param nresults The number of results to leave on the stack. Must be
/// positive.
///
/// \throw api_error If there is a problem evaluating the expression.
void
lutok::eval(state& s, const std::string& expression, const int nresults)
{
assert(nresults > 0);
do_string(s, "return " + expression, 0, nresults, 0);
}