1 // Copyright 2012 The Kyua Authors. 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 /// \file utils/config/parser.hpp 30 /// Utilities to read a configuration file into memory. 31 32 #if !defined(UTILS_CONFIG_PARSER_HPP) 33 #define UTILS_CONFIG_PARSER_HPP 34 35 #include "utils/config/parser_fwd.hpp" 36 37 #include <memory> 38 39 #include "utils/config/tree_fwd.hpp" 40 #include "utils/fs/path_fwd.hpp" 41 #include "utils/noncopyable.hpp" 42 43 namespace utils { 44 namespace config { 45 46 47 /// A configuration parser. 48 /// 49 /// This parser is a class rather than a function because we need to support 50 /// callbacks to perform the initialization of the config file schema. The 51 /// configuration files always start with a call to syntax(), which define the 52 /// particular version of the schema being used. Depending on such version, the 53 /// layout of the internal tree representation needs to be different. 54 /// 55 /// A parser implementation must provide a setup() method to set up the 56 /// configuration schema based on the particular combination of syntax format 57 /// and version specified on the file. 58 /// 59 /// Parser objects are not supposed to be reused, and specific trees are not 60 /// supposed to be passed to multiple parsers (even if sequentially). Doing so 61 /// will cause all kinds of inconsistencies in the managed tree itself or in the 62 /// Lua state. 63 class parser : noncopyable { 64 public: 65 struct impl; 66 67 private: 68 /// Pointer to the internal implementation. 69 std::auto_ptr< impl > _pimpl; 70 71 /// Hook to initialize the tree keys before reading the file. 72 /// 73 /// This hook gets called when the configuration file defines its specific 74 /// format by calling the syntax() function. We have to delay the tree 75 /// initialization until this point because, before we know what version of 76 /// a configuration file we are parsing, we cannot know what keys are valid. 77 /// 78 /// \param [in,out] config_tree The tree in which to define the key 79 /// structure. 80 /// \param syntax_version The version of the file format as specified in the 81 /// configuration file. 82 virtual void setup(tree& config_tree, const int syntax_version) = 0; 83 84 public: 85 explicit parser(tree&); 86 virtual ~parser(void); 87 88 void parse(const fs::path&); 89 }; 90 91 92 } // namespace config 93 } // namespace utils 94 95 #endif // !defined(UTILS_CONFIG_PARSER_HPP) 96