1 // Copyright 2012 The Kyua Authors.
2 // All rights reserved.
3 //
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5 // modification, are permitted provided that the following conditions are
6 // met:
7 //
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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
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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
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27 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28
29 #include "utils/config/parser.hpp"
30
31 #include <lutok/exceptions.hpp>
32 #include <lutok/operations.hpp>
33 #include <lutok/stack_cleaner.hpp>
34 #include <lutok/state.ipp>
35
36 #include "utils/config/exceptions.hpp"
37 #include "utils/config/lua_module.hpp"
38 #include "utils/config/tree.ipp"
39 #include "utils/fs/path.hpp"
40 #include "utils/logging/macros.hpp"
41 #include "utils/noncopyable.hpp"
42
43 namespace config = utils::config;
44
45
46 // History of configuration file versions:
47 //
48 // 2 - Changed the syntax() call to take only a version number, instead of the
49 // word 'config' as the first argument and the version as the second one.
50 // Files now start with syntax(2) instead of syntax('config', 1).
51 //
52 // 1 - Initial version.
53
54
55 /// Internal implementation of the parser.
56 struct utils::config::parser::impl : utils::noncopyable {
57 /// Pointer to the parent parser. Needed for callbacks.
58 parser* _parent;
59
60 /// The Lua state used by this parser to process the configuration file.
61 lutok::state _state;
62
63 /// The tree to be filed in by the configuration parameters, as provided by
64 /// the caller.
65 config::tree& _tree;
66
67 /// Whether syntax() has been called or not.
68 bool _syntax_called;
69
70 /// Constructs a new implementation.
71 ///
72 /// \param parent_ Pointer to the class being constructed.
73 /// \param config_tree_ The configuration tree provided by the user.
implutils::config::parser::impl74 impl(parser* const parent_, tree& config_tree_) :
75 _parent(parent_), _tree(config_tree_), _syntax_called(false)
76 {
77 }
78
79 friend void lua_syntax(lutok::state&);
80
81 /// Callback executed by the Lua syntax() function.
82 ///
83 /// \param syntax_version The syntax format version as provided by the
84 /// configuration file in the call to syntax().
85 void
syntax_callbackutils::config::parser::impl86 syntax_callback(const int syntax_version)
87 {
88 if (_syntax_called)
89 throw syntax_error("syntax() can only be called once");
90 _syntax_called = true;
91
92 // Allow the parser caller to populate the tree with its own schema
93 // depending on the format/version combination.
94 _parent->setup(_tree, syntax_version);
95
96 // Export the config module to the Lua state so that all global variable
97 // accesses are redirected to the configuration tree.
98 config::redirect(_state, _tree);
99 }
100 };
101
102
103 namespace {
104
105
106 static int
lua_syntax(lutok::state & state)107 lua_syntax(lutok::state& state)
108 {
109 if (!state.is_number(-1))
110 throw config::value_error("Last argument to syntax must be a number");
111 const int syntax_version = state.to_integer(-1);
112
113 if (syntax_version == 1) {
114 if (state.get_top() != 2)
115 throw config::value_error("Version 1 files need two arguments to "
116 "syntax()");
117 if (!state.is_string(-2) || state.to_string(-2) != "config")
118 throw config::value_error("First argument to syntax must be "
119 "'config' for version 1 files");
120 } else {
121 if (state.get_top() != 1)
122 throw config::value_error("syntax() only takes one argument");
123 }
124
125 state.get_global("_config_parser");
126 config::parser::impl* impl =
127 *state.to_userdata< config::parser::impl* >(-1);
128 state.pop(1);
129
130 impl->syntax_callback(syntax_version);
131
132 return 0;
133 }
134
135
136 } // anonymous namespace
137
138
139 /// Constructs a new parser.
140 ///
141 /// \param [in,out] config_tree The configuration tree into which the values set
142 /// in the configuration file will be stored.
parser(tree & config_tree)143 config::parser::parser(tree& config_tree) :
144 _pimpl(new impl(this, config_tree))
145 {
146 lutok::stack_cleaner cleaner(_pimpl->_state);
147
148 _pimpl->_state.push_cxx_function(lua_syntax);
149 _pimpl->_state.set_global("syntax");
150 *_pimpl->_state.new_userdata< config::parser::impl* >() = _pimpl.get();
151 _pimpl->_state.set_global("_config_parser");
152 }
153
154
155 /// Destructor.
~parser(void)156 config::parser::~parser(void)
157 {
158 }
159
160
161 /// Parses a configuration file.
162 ///
163 /// \post The tree registered during the construction of this class is updated
164 /// to contain the values read from the configuration file. If the processing
165 /// fails, the state of the output tree is undefined.
166 ///
167 /// \param file The path to the file to process.
168 ///
169 /// \throw syntax_error If there is any problem processing the file.
170 void
parse(const fs::path & file)171 config::parser::parse(const fs::path& file)
172 {
173 try {
174 lutok::do_file(_pimpl->_state, file.str(), 0, 0, 0);
175 } catch (const lutok::error& e) {
176 throw syntax_error(e.what());
177 }
178
179 if (!_pimpl->_syntax_called)
180 throw syntax_error("No syntax defined (no call to syntax() found)");
181 }
182