1// Copyright 2011 Google Inc.
2// All rights reserved.
3//
4// Redistribution and use in source and binary forms, with or without
5// modification, are permitted provided that the following conditions are
6// met:
7//
8// * Redistributions of source code must retain the above copyright
9//   notice, this list of conditions and the following disclaimer.
10// * Redistributions in binary form must reproduce the above copyright
11//   notice, this list of conditions and the following disclaimer in the
12//   documentation and/or other materials provided with the distribution.
13// * Neither the name of Google Inc. nor the names of its contributors
14//   may be used to endorse or promote products derived from this software
15//   without specific prior written permission.
16//
17// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
18// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
19// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
20// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
21// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
22// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
23// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
27// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28
29#include <cassert>
30
31#include <lua.hpp>
32
33#include "exceptions.hpp"
34#include "operations.hpp"
35#include "stack_cleaner.hpp"
36#include "state.hpp"
37
38
39/// Creates a module: i.e. a table with a set of methods in it.
40///
41/// \param s The Lua state.
42/// \param name The name of the module to create.
43/// \param members The list of member functions to add to the module.
44void
45lutok::create_module(state& s, const std::string& name,
46                     const std::map< std::string, cxx_function >& members)
47{
48    stack_cleaner cleaner(s);
49    s.new_table();
50    for (std::map< std::string, cxx_function >::const_iterator
51         iter = members.begin(); iter != members.end(); iter++) {
52        s.push_string((*iter).first);
53        s.push_cxx_function((*iter).second);
54        s.set_table(-3);
55    }
56    s.set_global(name);
57}
58
59
60/// Loads and processes a Lua file.
61///
62/// This is a replacement for luaL_dofile but with proper error reporting
63/// and stack control.
64///
65/// \param s The Lua state.
66/// \param file The file to load.
67/// \param nresults The number of results to expect; -1 for any.
68///
69/// \return The number of results left on the stack.
70///
71/// \throw error If there is a problem processing the file.
72unsigned int
73lutok::do_file(state& s, const std::string& file, const int nresults)
74{
75    assert(nresults >= -1);
76    const int height = s.get_top();
77
78    stack_cleaner cleaner(s);
79    try {
80        s.load_file(file);
81        s.pcall(0, nresults == -1 ? LUA_MULTRET : nresults, 0);
82    } catch (const lutok::api_error& e) {
83        throw lutok::error("Failed to load Lua file '" + file + "': " +
84                           e.what());
85    }
86    cleaner.forget();
87
88    const int actual_results = s.get_top() - height;
89    assert(nresults == -1 || actual_results == nresults);
90    assert(actual_results >= 0);
91    return static_cast< unsigned int >(actual_results);
92}
93
94
95/// Processes a Lua script.
96///
97/// This is a replacement for luaL_dostring but with proper error reporting
98/// and stack control.
99///
100/// \param s The Lua state.
101/// \param str The string to process.
102/// \param nresults The number of results to expect; -1 for any.
103///
104/// \return The number of results left on the stack.
105///
106/// \throw error If there is a problem processing the string.
107unsigned int
108lutok::do_string(state& s, const std::string& str, const int nresults)
109{
110    assert(nresults >= -1);
111    const int height = s.get_top();
112
113    stack_cleaner cleaner(s);
114    try {
115        s.load_string(str);
116        s.pcall(0, nresults == -1 ? LUA_MULTRET : nresults, 0);
117    } catch (const lutok::api_error& e) {
118        throw lutok::error("Failed to process Lua string '" + str + "': " +
119                           e.what());
120    }
121    cleaner.forget();
122
123    const int actual_results = s.get_top() - height;
124    assert(nresults == -1 || actual_results == nresults);
125    assert(actual_results >= 0);
126    return static_cast< unsigned int >(actual_results);
127}
128
129
130/// Convenience function to evaluate a Lua expression.
131///
132/// \param s The Lua state.
133/// \param expression The textual expression to evaluate.
134/// \param nresults The number of results to leave on the stack.  Must be
135///     positive.
136///
137/// \throw api_error If there is a problem evaluating the expression.
138void
139lutok::eval(state& s, const std::string& expression, const int nresults)
140{
141    assert(nresults > 0);
142    do_string(s, "return " + expression, nresults);
143}
144