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 nargs The number of arguments on the stack to pass to the file.
68/// \param nresults The number of results to expect; -1 for any.
69/// \param errfunc If not 0, index of a function in the stack to act as an
70///     error handler.
71///
72/// \return The number of results left on the stack.
73///
74/// \throw error If there is a problem processing the file.
75unsigned int
76lutok::do_file(state& s, const std::string& file, const int nargs,
77               const int nresults, const int errfunc)
78{
79    assert(nresults >= -1);
80    const int height = s.get_top() - nargs;
81
82    try {
83        s.load_file(file);
84        if (nargs > 0)
85            s.insert(-nargs - 1);
86        s.pcall(nargs, nresults == -1 ? LUA_MULTRET : nresults,
87                errfunc == 0 ? 0 : errfunc - 1);
88    } catch (const lutok::api_error& e) {
89        throw lutok::error("Failed to load Lua file '" + file + "': " +
90                           e.what());
91    }
92
93    const int actual_results = s.get_top() - height;
94    assert(nresults == -1 || actual_results == nresults);
95    assert(actual_results >= 0);
96    return static_cast< unsigned int >(actual_results);
97}
98
99
100/// Processes a Lua script.
101///
102/// This is a replacement for luaL_dostring but with proper error reporting
103/// and stack control.
104///
105/// \param s The Lua state.
106/// \param str The string to process.
107/// \param nargs The number of arguments on the stack to pass to the chunk.
108/// \param nresults The number of results to expect; -1 for any.
109/// \param errfunc If not 0, index of a function in the stack to act as an
110///     error handler.
111///
112/// \return The number of results left on the stack.
113///
114/// \throw error If there is a problem processing the string.
115unsigned int
116lutok::do_string(state& s, const std::string& str, const int nargs,
117                 const int nresults, const int errfunc)
118{
119    assert(nresults >= -1);
120    const int height = s.get_top() - nargs;
121
122    try {
123        s.load_string(str);
124        if (nargs > 0)
125            s.insert(-nargs - 1);
126        s.pcall(nargs, nresults == -1 ? LUA_MULTRET : nresults,
127                errfunc == 0 ? 0 : errfunc - 1);
128    } catch (const lutok::api_error& e) {
129        throw lutok::error("Failed to process Lua string '" + str + "': " +
130                           e.what());
131    }
132
133    const int actual_results = s.get_top() - height;
134    assert(nresults == -1 || actual_results == nresults);
135    assert(actual_results >= 0);
136    return static_cast< unsigned int >(actual_results);
137}
138
139
140/// Convenience function to evaluate a Lua expression.
141///
142/// \param s The Lua state.
143/// \param expression The textual expression to evaluate.
144/// \param nresults The number of results to leave on the stack.  Must be
145///     positive.
146///
147/// \throw api_error If there is a problem evaluating the expression.
148void
149lutok::eval(state& s, const std::string& expression, const int nresults)
150{
151    assert(nresults > 0);
152    do_string(s, "return " + expression, 0, nresults, 0);
153}
154