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. 44 void 45 lutok::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. 72 unsigned int 73 lutok::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. 107 unsigned int 108 lutok::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. 138 void 139 lutok::eval(state& s, const std::string& expression, const int nresults) 140 { 141 assert(nresults > 0); 142 do_string(s, "return " + expression, nresults); 143 } 144