external/bsd/kyua-cli/dist/utils/config/tree.hpp

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  28
  29 /// \file utils/config/tree.hpp
  30 /// Data type to represent a tree of arbitrary values with string keys.
  31
  32 #if !defined(UTILS_CONFIG_TREE_HPP)
  33 #define UTILS_CONFIG_TREE_HPP
  34
  35 #include <map>
  36 #include <string>
  37
  38 #include <lutok/state.hpp>
  39
  40 #include "utils/config/keys.hpp"
  41 #include "utils/config/nodes.hpp"
  42 #include "utils/shared_ptr.hpp"
  43
  44 namespace utils {
  45 namespace config {
  46
  47
  48 /// Flat representation of all properties as strings.
  49 typedef std::map< std::string, std::string > properties_map;
  50
  51
  52 /// Representation of a tree.
  53 ///
  54 /// The string keys of the tree are in dotted notation and actually represent
  55 /// path traversals through the nodes.
  56 ///
  57 /// Our trees are "strictly-keyed": keys must be defined as "existent" before
  58 /// their values can be set.  Defining a key is a separate action from setting
  59 /// its value.  The rationale is that we want to be able to control what keys
  60 /// get defined: because trees are used to hold configuration, we want to catch
  61 /// typos as early as possible.  Also, users cannot set keys unless the types
  62 /// are known in advance because our leaf nodes are strictly typed.
  63 ///
  64 /// However, there is an exception to the strict keys: the inner nodes of the
  65 /// tree can be static or dynamic.  Static inner nodes have a known subset of
  66 /// children and attempting to set keys not previously defined will result in an
  67 /// error.  Dynamic inner nodes do not have a predefined set of keys and can be
  68 /// used to accept arbitrary user input.
  69 ///
  70 /// For simplicity reasons, we force the root of the tree to be a static inner
  71 /// node.  In other words, the root can never contain a value by itself and this
  72 /// is not a problem because the root is not addressable by the key space.
  73 /// Additionally, the root is strict so all of its direct children must be
  74 /// explicitly defined.
  75 ///
  76 /// This is, effectively, a simple wrapper around the node representing the
  77 /// root.  Having a separate class aids in clearly representing the concept of a
  78 /// tree and all of its public methods.  Also, the tree accepts dotted notations
  79 /// for the keys while the internal structures do not.
  80 ///
  81 /// Note that trees are shallow-copied unless a deep copy is requested with
  82 /// deep_copy().
  83 class tree {
  84     /// The root of the tree.
  85     std::shared_ptr< detail::static_inner_node > _root;
  86
  87     explicit tree(detail::static_inner_node*);
  88
  89 public:
  90     tree(void);
  91     ~tree(void);
  92
  93     tree deep_copy(void) const;
  94
  95     template< class LeafType >
  96     void define(const std::string&);
  97
  98     void define_dynamic(const std::string&);
  99
 100     bool is_set(const std::string&) const;
 101
 102     template< class LeafType >
 103     const typename LeafType::value_type& lookup(const std::string&) const;
 104     template< class LeafType >
 105     typename LeafType::value_type& lookup_rw(const std::string&);
 106
 107     template< class LeafType >
 108     void set(const std::string&, const typename LeafType::value_type&);
 109
 110     void push_lua(const std::string&, lutok::state&) const;
 111     void set_lua(const std::string&, lutok::state&, const int);
 112
 113     std::string lookup_string(const std::string&) const;
 114     void set_string(const std::string&, const std::string&);
 115
 116     properties_map all_properties(const std::string& = "",
 117                                   const bool = false) const;
 118
 119     bool operator==(const tree&) const;
 120     bool operator!=(const tree&) const;
 121 };
 122
 123
 124 }  // namespace config
 125 }  // namespace utils
 126
 127 #endif  // !defined(UTILS_CONFIG_TREE_HPP)