1 #ifndef MSP_DATAFILE_LOADER_H_
2 #define MSP_DATAFILE_LOADER_H_
5 #include <msp/io/file.h>
6 #include "loaderaction.h"
15 Base class for data loaders. This class only provides core functionality.
16 You'll almost certainly want to use one of the BasicLoader classes instead.
18 Under normal circumstances, a class capable of being loaded should have a
19 nested typed called Loader which resolves to a descendant of this class. If
20 another structure is used, the loader object must be constructed manually.
22 A loader class should execute one or more calls to the various add() functions
23 to register actions with expected keywords. Currently possible actions are
24 calling a function of the loader, storing values in member variables of an
25 object and ignoring the statement. If a unexpected keyword is encountered, an
26 exception is thrown and the loading is aborted.
28 A sub-object can be loaded with one of the load_sub functions.
30 When loading has finished successfully, the virtual function finish() is
31 called. Any post-processing of the data should be placed here and not in the
34 See also classes ObjectLoader and CollectionObjectLoader in objectloader.h.
39 typedef std::map<StatementKey, LoaderAction *> ActionMap;
44 const Statement *cur_st;
47 std::vector<Loader *> aux_loaders;
55 /** Loads statements from a parser. */
59 /** Loads data from a statement. */
60 void load(const Statement &st);
62 /** Loads statemsnts from a parser, feeding them directly to actions. */
63 void load_direct(Parser &, unsigned);
65 /** Processes a single statement */
66 void load_statement(const Statement &st);
69 /** Loads a sub-object from the statement being processed. The Loader class
70 of the sub-object is automatically used. */
74 typename S::Loader ldr(s);
78 /** Loads a sub-object from the statement being processed with an extra
79 parameter for the Loader. The Loader class of the sub-object is
80 automatically used. */
81 template<typename S, typename T>
82 void load_sub(S &s, T &p)
84 typename S::Loader ldr(s, p);
88 /** Processes the current statement's substatements with another Loader. */
89 void load_sub_with(Loader &);
91 /** Adds a keyword that is loaded by calling a function. */
93 void add(const std::string &k, void (L::*func)())
94 { add(k, new LoaderFunc0<L>(func)); }
96 template<typename L, typename A0>
97 void add(const std::string &k, void (L::*func)(A0))
98 { add(k, new LoaderFunc1<L, A0>(func)); }
100 template<typename L, typename A0, typename A1>
101 void add(const std::string &k, void (L::*func)(A0, A1))
102 { add(k, new LoaderFunc2<L, A0, A1>(func)); }
104 template<typename L, typename A0, typename A1, typename A2>
105 void add(const std::string &k, void (L::*func)(A0, A1, A2))
106 { add(k, new LoaderFunc3<L, A0, A1, A2>(func)); }
108 template<typename L, typename A0, typename A1, typename A2, typename A3>
109 void add(const std::string &k, void (L::*func)(A0, A1, A2, A3))
110 { add(k, new LoaderFunc4<L, A0, A1, A2, A3>(func)); }
112 template<typename L, typename A0, typename A1, typename A2, typename A3, typename A4>
113 void add(const std::string &k, void (L::*func)(A0, A1, A2, A3, A4))
114 { add(k, new LoaderFunc5<L, A0, A1, A2, A3, A4>(func)); }
116 /** Adds a keyword that is loaded into a member of the loaded object. */
117 template<typename L, typename T0>
118 void add(const std::string &k, T0 L::*p0)
119 { add(k, new LoadValue1<L, T0>(p0)); }
121 template<typename L, typename T0, typename T1>
122 void add(const std::string &k, T0 L::*p0, T1 L::*p1)
123 { add(k, new LoadValue2<L, T0, T1>(p0, p1)); }
125 /** Adds a keyword that is recognized but ignored. */
126 void add(const std::string &k)
130 void add(const std::string &, LoaderAction *);
133 void add_auxiliary_loader(Loader &);
136 bool has_action(const StatementKey &) const;
137 LoaderAction *find_action(const StatementKey &) const;
140 /** Returns the source of the statement being processed. This can be used
141 to implement relative paths in include-like statements. Note that the
142 source may not necessarily be a file. */
143 const std::string &get_source() const;
145 /** Returns the keyword of the statement being processed. Can be used to
146 implement dynamic keywords. */
147 const std::string &get_keyword() const;
149 virtual void finish() { }
153 #if __cplusplus>=201103L
155 Loads an object from a file. The object must have a public Loader class. Any
156 extra arguments are passed to the Loader constructor.
158 template<typename T, typename... Args>
159 void load(T &obj, const std::string &fn, Args &... args)
161 IO::BufferedFile in(fn);
163 Parser parser(in, fn);
164 typename T::Loader loader(obj, args...);
169 Loads an object from a file stored in a collection. The object must havea
170 public Loader class. The collection is passed to the Loader constructor,
171 followed by any extra arguments.
173 template<typename T, typename... Args>
174 void load(T &obj, typename T::Loader::Collection &coll, const std::string &fn, Args &... args)
176 RefPtr<IO::Seekable> in = coll.open_raw(fn);
178 throw IO::file_not_found(fn);
180 Parser parser(*in, fn);
181 typename T::Loader loader(obj, coll, args...);
186 Loads an object from a file stored in a collection. The object must havea
187 public Loader class. Any extra arguments are passed to the Loader constructor.
189 template<typename T, typename C, typename... Args>
190 typename EnableIf<NeedsCollection<typename T::Loader>::value, void>::No load(T &obj, C &coll, const std::string &fn, Args &... args)
192 RefPtr<IO::Seekable> in = coll.open_raw(fn);
194 throw IO::file_not_found(fn);
196 Parser parser(*in, fn);
197 typename T::Loader loader(obj, args...);
204 Loads an object from a file. The object must have a public Loader class.
207 void load(T &obj, const std::string &fn)
209 IO::BufferedFile in(fn);
211 Parser parser(in, fn);
212 typename T::Loader loader(obj);
217 Loads an object from a file, passing one extra argument to the Loader
218 constructor. The object must have a public Loader class.
220 template<typename T, typename U>
221 void load(T &obj, const std::string &fn, U &arg)
223 IO::BufferedFile in(fn);
225 Parser parser(in, fn);
226 typename T::Loader loader(obj, arg);
231 } // namespace DataFile