/[svn]/libgig/trunk/src/Serialization.h
ViewVC logotype

Contents of /libgig/trunk/src/Serialization.h

Parent Directory Parent Directory | Revision Log Revision Log


Revision 3183 - (show annotations) (download) (as text)
Mon May 15 18:44:32 2017 UTC (3 years, 2 months ago) by schoenebeck
File MIME type: text/x-c++hdr
File size: 51378 byte(s)
* Wrote API documentation for entire new Serialization
  framework.
* Hide some of the method implementation of the Serialization
  framework.

1 /***************************************************************************
2 * *
3 * Copyright (C) 2017 Christian Schoenebeck *
4 * <cuse@users.sourceforge.net> *
5 * *
6 * This library is part of libgig. *
7 * *
8 * This library is free software; you can redistribute it and/or modify *
9 * it under the terms of the GNU General Public License as published by *
10 * the Free Software Foundation; either version 2 of the License, or *
11 * (at your option) any later version. *
12 * *
13 * This library is distributed in the hope that it will be useful, *
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of *
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
16 * GNU General Public License for more details. *
17 * *
18 * You should have received a copy of the GNU General Public License *
19 * along with this library; if not, write to the Free Software *
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, *
21 * MA 02111-1307 USA *
22 ***************************************************************************/
23
24 #ifndef LIBGIG_SERIALIZATION_H
25 #define LIBGIG_SERIALIZATION_H
26
27 #ifdef HAVE_CONFIG_H
28 # include <config.h>
29 #endif
30
31 #include <stdint.h>
32 #include <stdio.h>
33 #include <typeinfo>
34 #include <string>
35 #include <vector>
36 #include <map>
37 #include <time.h>
38
39 #ifndef __has_extension
40 # define __has_extension(x) 0
41 #endif
42
43 #ifndef HAS_BUILTIN_TYPE_TRAITS
44 # if __cplusplus >= 201103L
45 # define HAS_BUILTIN_TYPE_TRAITS 1
46 # elif ( __has_extension(is_class) && __has_extension(is_enum) )
47 # define HAS_BUILTIN_TYPE_TRAITS 1
48 # elif ( __GNUC__ > 4 || ( __GNUC__ == 4 && __GNUC_MINOR__ >= 3 ) )
49 # define HAS_BUILTIN_TYPE_TRAITS 1
50 # elif _MSC_VER >= 1400 /* MS Visual C++ 8.0 (Visual Studio 2005) */
51 # define HAS_BUILTIN_TYPE_TRAITS 1
52 # elif __INTEL_COMPILER >= 1100
53 # define HAS_BUILTIN_TYPE_TRAITS 1
54 # else
55 # define HAS_BUILTIN_TYPE_TRAITS 0
56 # endif
57 #endif
58
59 #if !HAS_BUILTIN_TYPE_TRAITS
60 # include <tr1/type_traits>
61 # define LIBGIG_IS_CLASS(type) std::tr1::__is_union_or_class<type>::value //NOTE: without compiler support we cannot distinguish union from class
62 #else
63 # define LIBGIG_IS_CLASS(type) __is_class(type)
64 #endif
65
66 /** @brief Serialization / deserialization framework.
67 *
68 * See class Archive as starting point for how to implement serialization and
69 * deserialization with your application.
70 *
71 * The classes in this namespace allow to serialize and deserialize native
72 * C++ objects in a portable, easy and flexible way. Serialization is a
73 * technique that allows to transform the current state and data of native
74 * (in this case C++) objects into a data stream (including all other objects
75 * the "serialized" objects relate to); the data stream may then be sent over
76 * "wire" (for example via network connection to another computer, which might
77 * also have a different OS, CPU architecture, native memory word size and
78 * endian type); and finally the data stream would be "deserialized" on that
79 * receiver side, that is transformed again to modify all objects and data
80 * structures on receiver side to resemble the objects' state and data as it
81 * was originally on sender side.
82 *
83 * In contrast to many other already existing serialization frameworks, this
84 * implementation has a strong focus on robustness regarding long-term changes
85 * to the serialized C++ classes of the serialized objects. So even if sender
86 * and receiver are using different versions of their serialized/deserialized
87 * C++ classes, structures and data types (thus having different data structure
88 * layout to a certain extent), this framework aims trying to automatically
89 * adapt its serialization and deserialization process in that case so that
90 * the deserialized objects on receiver side would still reflect the overall
91 * expected states and overall data as intended by the sender. For being able to
92 * do so, this framework stores all kind of additional information about each
93 * serialized object and each data structure member (for example name of each
94 * data structure member, but also the offset of each member within its
95 * containing data structure, precise data types, and more).
96 *
97 * Like most other serialization frameworks, this frameworks does not require a
98 * tree-structured layout of the serialized data structures. So it automatically
99 * handles also cyclic dependencies between serialized data structures
100 * correctly, without i.e. causing endless recursion or redundancy.
101 *
102 * Additionally this framework also allows partial deserialization. Which means
103 * the receiver side may for example decide that it wants to restrict
104 * deserialization so that it would only modify certain objects or certain
105 * members by the deserialization process, leaving all other ones untouched.
106 * So this partial deserialization technique for example allows to implement
107 * flexible preset features for applications in a powerful and easy way.
108 */
109 namespace Serialization {
110
111 // just symbol prototyping
112 class DataType;
113 class Object;
114 class Member;
115 class Archive;
116 class ObjectPool;
117 class Exception;
118
119 typedef std::string String;
120
121 /** @brief Raw data stream of serialized C++ objects.
122 *
123 * This data type is used for the data stream as a result of serializing
124 * your C++ objects with Archive::serialize(), and for native raw data
125 * representation of individual serialized C/C++ objects, members and variables.
126 *
127 * @see Archive::rawData(), Object::rawData()
128 */
129 typedef std::vector<uint8_t> RawData;
130
131 /** @brief Abstract identifier for serialized C++ objects.
132 *
133 * This data type is used for identifying serialized C++ objects and members
134 * of your C++ objects. It is important to know that such an ID might not
135 * necessarily be unique. For example the ID of one C++ object might often
136 * be identical to the ID of the first member of that particular C++ object.
137 * That's why there is additionally the concept of an UID in this framework.
138 *
139 * @see UID
140 */
141 typedef void* ID;
142
143 /** @brief Version number data type.
144 *
145 * This data type is used for maintaining version number information of
146 * your C++ class implementations.
147 *
148 * @see Archive::setVersion() and Archive::setMinVersion()
149 */
150 typedef uint32_t Version;
151
152 /** @brief To which time zone a certain timing information relates to.
153 *
154 * The constants in this enum type are used to define to which precise time
155 * zone a time stamp relates to.
156 */
157 enum time_base_t {
158 LOCAL_TIME, ///< The time stamp relates to the machine's local time zone. Request a time stamp in local time if you want to present that time stamp to the end user.
159 UTC_TIME ///< The time stamp relates to "Greenwhich Mean Time" zone, also known as "Coordinated Universal Time". Request time stamp with UTC if you want to compare that time stamp with other time stamps.
160 };
161
162 /** @brief Check whether data is a C/C++ @c enum type.
163 *
164 * Returns true if the supplied C++ variable or object is of a C/C++ @c enum
165 * type.
166 *
167 * @param data - the variable or object whose data type shall be checked
168 */
169 template<typename T>
170 bool IsEnum(const T& data) {
171 #if !HAS_BUILTIN_TYPE_TRAITS
172 return std::tr1::is_enum<T>::value;
173 #else
174 return __is_enum(T);
175 #endif
176 }
177
178 /** @brief Check whether data is a C++ @c union type.
179 *
180 * Returns true if the supplied C++ variable or object is of a C/C++ @c union
181 * type. Note that the result of this function is only reliable if the C++
182 * compiler you are using has support for built-in type traits. If your C++
183 * compiler does not have built-in type traits support, then this function
184 * will simply return @c false on all your calls.
185 *
186 * @param data - the variable or object whose data type shall be checked
187 */
188 template<typename T>
189 bool IsUnion(const T& data) {
190 #if !HAS_BUILTIN_TYPE_TRAITS
191 return false; // without compiler support we cannot distinguish union from class
192 #else
193 return __is_union(T);
194 #endif
195 }
196
197 /** @brief Check whether data is a C/C++ @c struct or C++ @c class type.
198 *
199 * Returns true if the supplied C++ variable or object is of C/C++ @c struct
200 * or C++ @c class type. Note that if you are using a C++ compiler which
201 * does have built-in type traits support, then this function will also
202 * return @c true on C/C++ @c union types.
203 *
204 * @param data - the variable or object whose data type shall be checked
205 */
206 template<typename T>
207 bool IsClass(const T& data) {
208 #if !HAS_BUILTIN_TYPE_TRAITS
209 return std::tr1::__is_union_or_class<T>::value; // without compiler support we cannot distinguish union from class
210 #else
211 return __is_class(T);
212 #endif
213 }
214
215 /*template<typename T>
216 bool IsTrivial(T data) {
217 return __is_trivial(T);
218 }*/
219
220 /*template<typename T>
221 bool IsPOD(T data) {
222 return __is_pod(T);
223 }*/
224
225 /** @brief Unique identifier for one specific C++ object, member or fundamental variable.
226 *
227 * Reflects a unique identifier for one specific serialized C++ class
228 * instance, C/C++ struct instance, member, primitive pointer, or
229 * fundamental variables.
230 *
231 * A unique identifier is composed of an id (an identifier which is not
232 * necessarily unique) and a size. Since the underlying ID is derived from
233 * the original C++ object's memory location, such an ID is not sufficient
234 * to distinguish a particular C++ object from the first member of that C++
235 * object, since both typically share the same memory address. So
236 * additionally the memory size of the respective object or member is
237 * bundled with UID objects to make them unique and distinguishable.
238 */
239 class UID {
240 public:
241 ID id; ///< Abstract non-unique ID of the object or member in question.
242 size_t size; ///< Memory size of the object or member in question.
243
244 bool isValid() const;
245 operator bool() const { return isValid(); } ///< Same as calling isValid().
246 //bool operator()() const { return isValid(); }
247 bool operator==(const UID& other) const { return id == other.id && size == other.size; }
248 bool operator!=(const UID& other) const { return id != other.id || size != other.size; }
249 bool operator<(const UID& other) const { return id < other.id || (id == other.id && size < other.size); }
250 bool operator>(const UID& other) const { return id > other.id || (id == other.id && size > other.size); }
251
252 /** @brief Create an unique indentifier for a native C++ object/member/variable.
253 *
254 * Creates and returns an unique identifier for the passed native C++
255 * object, object member or variable. For the same C++ object/member/variable
256 * this function will always return the same UID. For all other ones,
257 * this function is guaranteed to return a different UID.
258 */
259 template<typename T>
260 static UID from(const T& obj) {
261 return Resolver<T>::resolve(obj);
262 }
263
264 protected:
265 // UID resolver for non-pointer types
266 template<typename T>
267 struct Resolver {
268 static UID resolve(const T& obj) {
269 const UID uid = { (ID) &obj, sizeof(obj) };
270 return uid;
271 }
272 };
273
274 // UID resolver for pointer types (of 1st degree)
275 template<typename T>
276 struct Resolver<T*> {
277 static UID resolve(const T* const & obj) {
278 const UID uid = { (ID) obj, sizeof(*obj) };
279 return uid;
280 }
281 };
282 };
283
284 /**
285 * Reflects an invalid UID and behaves similar to NULL as invalid value for
286 * pointer types. All UID objects are first initialized with this value,
287 * and it essentially an all zero object.
288 */
289 extern const UID NO_UID;
290
291 /** @brief Chain of UIDs.
292 *
293 * This data type is used for native C++ pointers. The first member of the
294 * UID chain is the unique identifier of the C++ pointer itself, then the
295 * following UIDs are the respective objects or variables the pointer is
296 * pointing to. The size (the amount of elements) of the UIDChain depends
297 * solely on the degree of the pointer type. For example the following C/C++
298 * pointer:
299 * @code
300 * int* pNumber;
301 * @endcode
302 * is an integer pointer of first degree. Such a pointer would have a
303 * UIDChain with 2 members: the first element would be the UID of the
304 * pointer itself, the second element of the chain would be the integer data
305 * that pointer is pointing to. In the following example:
306 * @code
307 * bool*** pppSomeFlag;
308 * @endcode
309 * That boolean pointer would be of third degree, and thus its UIDChain
310 * would have a size of 4 (elements).
311 *
312 * Accordingly a non pointer type like:
313 * @code
314 * float f;
315 * @endcode
316 * would yield in a UIDChain of size 1.
317 *
318 * Since however this serialization framework currently only supports
319 * pointers of first degree yet, all UIDChains are currently either of
320 * size 1 or 2, which might change in future though.
321 */
322 typedef std::vector<UID> UIDChain;
323
324 // prototyping of private internal friend functions
325 static String _encodePrimitiveValue(const Object& obj);
326 static DataType _popDataTypeBlob(const char*& p, const char* end);
327 static Member _popMemberBlob(const char*& p, const char* end);
328 static Object _popObjectBlob(const char*& p, const char* end);
329 static void _popPrimitiveValue(const char*& p, const char* end, Object& obj);
330 static String _primitiveObjectValueToString(const Object& obj);
331 // |
332 template<typename T>
333 static T _primitiveObjectValueToNumber(const Object& obj);
334
335 /** @brief Abstract reflection of a native C++ data type.
336 *
337 * Provides detailed information about a serialized C++ data type, whether
338 * it is a fundamental C/C++ data type (like @c int, @c float, @c char,
339 * etc.) or custom defined data types like a C++ @c class, C/C++ @c struct,
340 * @c enum, as well as other features of the respective data type like its
341 * native memory size and more.
342 *
343 * All informations provided by this class are retrieved from the
344 * respective individual C++ objects, their members and other data when
345 * they are serialized, and all those information are stored with the
346 * serialized archive and its resulting data stream. Due to the availability
347 * of these extensive data type information within serialized archives, this
348 * framework is capable to use them in order to adapt its deserialization
349 * process upon subsequent changes to your individual C++ classes.
350 */
351 class DataType {
352 public:
353 DataType();
354 size_t size() const { return m_size; } ///< Returns native memory size of the respective C++ object or variable.
355 bool isValid() const;
356 bool isPointer() const;
357 bool isClass() const;
358 bool isPrimitive() const;
359 bool isInteger() const;
360 bool isReal() const;
361 bool isBool() const;
362 bool isEnum() const;
363 bool isSigned() const;
364 operator bool() const { return isValid(); } ///< Same as calling isValid().
365 //bool operator()() const { return isValid(); }
366 bool operator==(const DataType& other) const;
367 bool operator!=(const DataType& other) const;
368 bool operator<(const DataType& other) const;
369 bool operator>(const DataType& other) const;
370 String asLongDescr() const;
371 String baseTypeName() const;
372 String customTypeName(bool demangle = false) const;
373
374 /** @brief Construct a DataType object for the given native C++ data.
375 *
376 * Use this function to create corresponding DataType objects for
377 * native C/C++ objects, members and variables.
378 *
379 * @param data - native C/C++ object/member/variable a DataType object
380 * shall be created for
381 * @returns corresponding DataType object for the supplied native C/C++
382 * object/member/variable
383 */
384 template<typename T>
385 static DataType dataTypeOf(const T& data) {
386 return Resolver<T>::resolve(data);
387 }
388
389 protected:
390 DataType(bool isPointer, int size, String baseType, String customType = "");
391
392 template<typename T, bool T_isPointer>
393 struct ResolverBase {
394 static DataType resolve(const T& data) {
395 const std::type_info& type = typeid(data);
396 const int sz = sizeof(data);
397
398 // for primitive types we are using our own type names instead of
399 // using std:::type_info::name(), because the precise output of the
400 // latter may vary between compilers
401 if (type == typeid(int8_t)) return DataType(T_isPointer, sz, "int8");
402 if (type == typeid(uint8_t)) return DataType(T_isPointer, sz, "uint8");
403 if (type == typeid(int16_t)) return DataType(T_isPointer, sz, "int16");
404 if (type == typeid(uint16_t)) return DataType(T_isPointer, sz, "uint16");
405 if (type == typeid(int32_t)) return DataType(T_isPointer, sz, "int32");
406 if (type == typeid(uint32_t)) return DataType(T_isPointer, sz, "uint32");
407 if (type == typeid(int64_t)) return DataType(T_isPointer, sz, "int64");
408 if (type == typeid(uint64_t)) return DataType(T_isPointer, sz, "uint64");
409 if (type == typeid(bool)) return DataType(T_isPointer, sz, "bool");
410 if (type == typeid(float)) return DataType(T_isPointer, sz, "real32");
411 if (type == typeid(double)) return DataType(T_isPointer, sz, "real64");
412
413 if (IsEnum(data)) return DataType(T_isPointer, sz, "enum", rawCppTypeNameOf(data));
414 if (IsUnion(data)) return DataType(T_isPointer, sz, "union", rawCppTypeNameOf(data));
415 if (IsClass(data)) return DataType(T_isPointer, sz, "class", rawCppTypeNameOf(data));
416
417 return DataType();
418 }
419 };
420
421 // DataType resolver for non-pointer types
422 template<typename T>
423 struct Resolver : ResolverBase<T,false> {
424 static DataType resolve(const T& data) {
425 return ResolverBase<T,false>::resolve(data);
426 }
427 };
428
429 // DataType resolver for pointer types (of 1st degree)
430 template<typename T>
431 struct Resolver<T*> : ResolverBase<T,true> {
432 static DataType resolve(const T*& data) {
433 return ResolverBase<T,true>::resolve(*data);
434 }
435 };
436
437 template<typename T>
438 static String rawCppTypeNameOf(const T& data) {
439 #if defined _MSC_VER // Microsoft compiler ...
440 # warning type_info::raw_name() demangling has not been tested yet with Microsoft compiler! Feedback appreciated!
441 String name = typeid(data).raw_name(); //NOTE: I haven't checked yet what MSC actually outputs here exactly
442 #else // i.e. especially GCC and clang ...
443 String name = typeid(data).name();
444 #endif
445 //while (!name.empty() && name[0] >= 0 && name[0] <= 9)
446 // name = name.substr(1);
447 return name;
448 }
449
450 private:
451 String m_baseTypeName;
452 String m_customTypeName;
453 int m_size;
454 bool m_isPointer;
455
456 friend DataType _popDataTypeBlob(const char*& p, const char* end);
457 friend class Archive;
458 };
459
460 /** @brief Abstract reflection of a native C++ class/struct's member variable.
461 *
462 * Provides detailed information about a specific C++ member variable of
463 * serialized C++ object, like its C++ data type, offset of this member
464 * within its containing data structure/class, its C++ member variable name
465 * and more.
466 *
467 * Consider you defined the following user defined C/C++ @c struct type in
468 * your application:
469 * @code
470 * struct Foo {
471 * int a;
472 * bool b;
473 * double someValue;
474 * };
475 * @endcode
476 * Then @c a, @c b and @c someValue are "members" of @c struct @c Foo for
477 * instance. So that @c struct would have 3 members in the latter example.
478 *
479 * @see Object::members()
480 */
481 class Member {
482 public:
483 Member();
484 UID uid() const;
485 String name() const;
486 size_t offset() const;
487 const DataType& type() const;
488 bool isValid() const;
489 operator bool() const { return isValid(); } ///< Same as calling isValid().
490 //bool operator()() const { return isValid(); }
491 bool operator==(const Member& other) const;
492 bool operator!=(const Member& other) const;
493 bool operator<(const Member& other) const;
494 bool operator>(const Member& other) const;
495
496 protected:
497 Member(String name, UID uid, size_t offset, DataType type);
498 friend class Archive;
499
500 private:
501 UID m_uid;
502 size_t m_offset;
503 String m_name;
504 DataType m_type;
505
506 friend Member _popMemberBlob(const char*& p, const char* end);
507 };
508
509 /** @brief Abstract reflection of a native C++ class/struct instance.
510 *
511 * Provides detailed information about a specific serialized C++ object,
512 * like its C++ member variables, its C++ class/struct name, its native
513 * memory size and more. When your native C++ objects are serialized, all
514 * native data is translated reflected by such an Object reflection. So each
515 * instance of your serialized C++ class objects become available as an
516 * Object, but also each member variable of your C++ objects, and all other
517 * native C/C++ data. So essentially every native data is turned into its
518 * own Object and accessible by this API.
519 *
520 * Even though this framework allows you to adjust abstract Object instances
521 * to a certain extent, most of the methods of this Object class are
522 * read-only though and the actual modifyable methods are made available
523 * not as part of this Object class, but as part of the Archive class
524 * instead. This was designed like this for performance and safety reasons.
525 *
526 * @see Archive::setIntValue() as an example for modifying Object instances.
527 */
528 class Object {
529 public:
530 Object();
531 Object(UIDChain uidChain, DataType type);
532
533 UID uid(int index = 0) const;
534 const UIDChain& uidChain() const;
535 const DataType& type() const;
536 const RawData& rawData() const;
537 Version version() const;
538 Version minVersion() const;
539 bool isVersionCompatibleTo(const Object& other) const;
540 std::vector<Member>& members();
541 const std::vector<Member>& members() const;
542 Member memberNamed(String name) const;
543 Member memberByUID(const UID& uid) const;
544 std::vector<Member> membersOfType(const DataType& type) const;
545 int sequenceIndexOf(const Member& member) const;
546 bool isValid() const;
547 operator bool() const { return isValid(); } ///< Same as calling isValid().
548 //bool operator()() const { return isValid(); }
549 bool operator==(const Object& other) const;
550 bool operator!=(const Object& other) const;
551 bool operator<(const Object& other) const;
552 bool operator>(const Object& other) const;
553
554 protected:
555 void remove(const Member& member);
556 void setVersion(Version v);
557 void setMinVersion(Version v);
558
559 private:
560 DataType m_type;
561 UIDChain m_uid;
562 Version m_version;
563 Version m_minVersion;
564 RawData m_data;
565 std::vector<Member> m_members;
566
567 friend String _encodePrimitiveValue(const Object& obj);
568 friend Object _popObjectBlob(const char*& p, const char* end);
569 friend void _popPrimitiveValue(const char*& p, const char* end, Object& obj);
570 friend String _primitiveObjectValueToString(const Object& obj);
571
572 template<typename T>
573 friend T _primitiveObjectValueToNumber(const Object& obj);
574
575 friend class Archive;
576 };
577
578 /** @brief Destination container for serialization, and source container for deserialization.
579 *
580 * This is the main class for implementing serialization and deserialization
581 * with your C++ application. This framework does not require a a tree
582 * structured layout of your C++ objects being serialized/deserialized, it
583 * uses a concept of a "root" object though. So to start serialization
584 * construct an empty Archive object and then instruct it to serialize your
585 * C++ objects by pointing it to your "root" object:
586 * @code
587 * Archive a;
588 * a.serialize(&myRootObject);
589 * @endcode
590 * Or if you prefer the look of operator based code:
591 * @code
592 * Archive a;
593 * a << myRootObject;
594 * @endcode
595 * The Archive object will then serialize all members of the passed C++
596 * object, and will recursively serialize all other C++ objects which it
597 * contains or points to. So the root object is the starting point for the
598 * overall serialization. After the serialize() method returned, you can
599 * then access the serialized data stream by calling rawData() and send that
600 * data stream over "wire", or store it on disk or whatever you may intend
601 * to do with it.
602 *
603 * Then on receiver side likewise, you create a new Archive object, pass the
604 * received data stream i.e. via constructor to the Archive object and call
605 * deserialize() by pointing it to the root object on receiver side:
606 * @code
607 * Archive a(rawDataStream);
608 * a.deserialize(&myRootObject);
609 * @endcode
610 * Or with operator instead:
611 * @code
612 * Archive a(rawDataStream);
613 * a >> myRootObject;
614 * @endcode
615 * Now this framework automatically handles serialization and
616 * deserialization of fundamental data types automatically for you (like
617 * i.e. char, int, long int, float, double, etc.). However for your own
618 * custom C++ classes and structs you must implement one method which
619 * defines which members of your class should actually be serialized and
620 * deserialized. That method to be added must have the following signature:
621 * @code
622 * void serialize(Serialization::Archive* archive);
623 * @endcode
624 * So let's say you have the following simple data structures:
625 * @code
626 * struct Foo {
627 * int a;
628 * bool b;
629 * double c;
630 * };
631 *
632 * struct Bar {
633 * char one;
634 * float two;
635 * Foo foo1;
636 * Foo* pFoo2;
637 * Foo* pFoo3DontTouchMe; // shall not be serialized/deserialized
638 * };
639 * @endcode
640 * So in order to be able to serialize and deserialize objects of those two
641 * structures you would first add the mentioned method to each struct
642 * definition (i.e. in your header file):
643 * @code
644 * struct Foo {
645 * int a;
646 * bool b;
647 * double c;
648 *
649 * void serialize(Serialization::Archive* archive);
650 * };
651 *
652 * struct Bar {
653 * char one;
654 * float two;
655 * Foo foo1;
656 * Foo* pFoo2;
657 * Foo* pFoo3DontTouchMe; // shall not be serialized/deserialized
658 *
659 * void serialize(Serialization::Archive* archive);
660 * };
661 * @endcode
662 * And then you would implement those two new methods like this (i.e. in
663 * your .cpp file):
664 * @code
665 * #define SRLZ(member) \
666 * archive->serializeMember(*this, member, #member);
667 *
668 * void Foo::serialize(Serialization::Archive* archive) {
669 * SRLZ(a);
670 * SRLZ(b);
671 * SRLZ(c);
672 * }
673 *
674 * void Bar::serialize(Serialization::Archive* archive) {
675 * SRLZ(one);
676 * SRLZ(two);
677 * SRLZ(foo1);
678 * SRLZ(pFoo2);
679 * // leaving out pFoo3DontTouchMe here
680 * }
681 * @endcode
682 * Now when you serialize such a Bar object, this framework will also
683 * automatically serialize the respective Foo object(s) accordingly, also
684 * for the pFoo2 pointer for instance (as long as it is not a NULL pointer
685 * that is).
686 *
687 * Note that there is only one method that you need to implement. So the
688 * respective serialize() method implementation of your classes/structs are
689 * both called for serialization, as well as for deserialization!
690 *
691 * In case you need to enforce backward incompatiblity for one of your C++
692 * classes, you can do so by setting a version and minimum version for your
693 * class (see @c setVersion() and @c setMinVersion() for details).
694 */
695 class Archive {
696 public:
697 Archive();
698 Archive(const RawData& data);
699 Archive(const uint8_t* data, size_t size);
700 virtual ~Archive();
701
702 /** @brief Initiate serialization.
703 *
704 * Initiates serialization of all native C++ objects, which means
705 * capturing and storing the current data of all your C++ objects as
706 * content of this Archive.
707 *
708 * This framework has a concept of a "root" object which you must pass
709 * to this method. The root object is the starting point for
710 * serialization of your C++ objects. The framework will then
711 * recursively serialize all members of that C++ object an continue to
712 * serialize all other C++ objects that it might contain or point to.
713 *
714 * After this method returned, you might traverse all serialized objects
715 * by walking them starting from the rootObject(). You might then modify
716 * that abstract reflection of your C++ objects and finally you might
717 * call rawData() to get an encoded raw data stream which you might use
718 * for sending it "over wire" to somewhere where it is going to be
719 * deserialized later on.
720 *
721 * Note that whenever you call this method, the previous content of this
722 * Archive will first be cleared.
723 *
724 * @param obj - native C++ root object where serialization shall start
725 * @see Archive::operator<<()
726 */
727 template<typename T>
728 void serialize(const T* obj) {
729 m_operation = OPERATION_SERIALIZE;
730 m_allObjects.clear();
731 m_rawData.clear();
732 m_root = UID::from(obj);
733 const_cast<T*>(obj)->serialize(this);
734 encode();
735 m_operation = OPERATION_NONE;
736 }
737
738 /** @brief Initiate deserialization.
739 *
740 * Initiates deserialization of all native C++ objects, which means all
741 * your C++ objects will be restored with the values contained in this
742 * Archive. So that also means calling deserialize() only makes sense if
743 * this a non-empty Archive, which i.e. is the case if you either called
744 * serialize() with this Archive object before or if you passed a
745 * previously serialized raw data stream to the constructor of this
746 * Archive object.
747 *
748 * This framework has a concept of a "root" object which you must pass
749 * to this method. The root object is the starting point for
750 * deserialization of your C++ objects. The framework will then
751 * recursively deserialize all members of that C++ object an continue to
752 * deserialize all other C++ objects that it might contain or point to,
753 * according to the values stored in this Archive.
754 *
755 * @param obj - native C++ root object where deserialization shall start
756 * @see Archive::operator>>()
757 *
758 * @throws Exception if the data stored in this Archive cannot be
759 * restored to the C++ objects passed to this method, i.e.
760 * because of version or type incompatibilities.
761 */
762 template<typename T>
763 void deserialize(T* obj) {
764 Archive a;
765 m_operation = OPERATION_DESERIALIZE;
766 obj->serialize(&a);
767 a.m_root = UID::from(obj);
768 Syncer s(a, *this);
769 m_operation = OPERATION_NONE;
770 }
771
772 /** @brief Initiate serialization of your C++ objects.
773 *
774 * Same as calling @c serialize(), this is just meant if you prefer
775 * to use operator based code instead, which you might find to be more
776 * intuitive.
777 *
778 * Example:
779 * @code
780 * Archive a;
781 * a << myRootObject;
782 * @endcode
783 *
784 * @see Archive::serialize() for more details.
785 */
786 template<typename T>
787 void operator<<(const T& obj) {
788 serialize(&obj);
789 }
790
791 /** @brief Initiate deserialization of your C++ objects.
792 *
793 * Same as calling @c deserialize(), this is just meant if you prefer
794 * to use operator based code instead, which you might find to be more
795 * intuitive.
796 *
797 * Example:
798 * @code
799 * Archive a(rawDataStream);
800 * a >> myRootObject;
801 * @endcode
802 *
803 * @throws Exception if the data stored in this Archive cannot be
804 * restored to the C++ objects passed to this method, i.e.
805 * because of version or type incompatibilities.
806 *
807 * @see Archive::deserialize() for more details.
808 */
809 template<typename T>
810 void operator>>(T& obj) {
811 deserialize(&obj);
812 }
813
814 const RawData& rawData();
815 virtual String rawDataFormat() const;
816
817 /** @brief Serialize a native C/C++ member variable.
818 *
819 * This method is usually called by the serialize() method
820 * implementation of your C/C++ structs and classes, for each of the
821 * member variables that shall be serialized and deserialized
822 * automatically with this framework. It is recommend that you are not
823 * using this method name directly, but rather define a short hand C
824 * macro in your .cpp file like:
825 * @code
826 * #define SRLZ(member) \
827 * archive->serializeMember(*this, member, #member);
828 *
829 * void Foo::serialize(Serialization::Archive* archive) {
830 * SRLZ(a);
831 * SRLZ(b);
832 * SRLZ(c);
833 * }
834 * @endcode
835 * As you can see, using such a macro makes your code more readable and
836 * less error prone.
837 *
838 * It is completely up to you to decide which ones of your member
839 * variables shall automatically be serialized and deserialized with
840 * this framework. Only those member variables which are registered by
841 * calling this method will be serialized and deserialized. It does not
842 * really matter in which order you register your individiual member
843 * variables by calling this method, but the sequence is actually stored
844 * as meta information with the resulting archive and the resulting raw
845 * data stream. That meta information might then be used by this
846 * framework to automatically correct and adapt deserializing that
847 * archive later on for a future (or older) and potentially heavily
848 * modified version of your software. So it is recommended, even though
849 * also not required, that you may retain the sequence of your
850 * serializeMember() calls for your individual C++ classes' members over
851 * all your software versions, to retain backward compatibility of older
852 * archives as much as possible.
853 *
854 * @param nativeObject - native C++ object to be registered for
855 * serialization / deserialization
856 * @param nativeMember - native C++ member variable of @a nativeObject
857 * to be registered for serialization /
858 * deserialization
859 * @param memberName - name of @a nativeMember to be stored with this
860 * archive
861 */
862 template<typename T_classType, typename T_memberType>
863 void serializeMember(const T_classType& nativeObject, const T_memberType& nativeMember, const char* memberName) {
864 const size_t offset =
865 ((const uint8_t*)(const void*)&nativeMember) -
866 ((const uint8_t*)(const void*)&nativeObject);
867 const UIDChain uids = UIDChainResolver<T_memberType>(nativeMember);
868 const DataType type = DataType::dataTypeOf(nativeMember);
869 const Member member(memberName, uids[0], offset, type);
870 const UID parentUID = UID::from(nativeObject);
871 Object& parent = m_allObjects[parentUID];
872 if (!parent) {
873 const UIDChain uids = UIDChainResolver<T_classType>(nativeObject);
874 const DataType type = DataType::dataTypeOf(nativeObject);
875 parent = Object(uids, type);
876 }
877 parent.members().push_back(member);
878 const Object obj(uids, type);
879 const bool bExistsAlready = m_allObjects.count(uids[0]);
880 const bool isValidObject = obj;
881 const bool bExistingObjectIsInvalid = !m_allObjects[uids[0]];
882 if (!bExistsAlready || (bExistingObjectIsInvalid && isValidObject)) {
883 m_allObjects[uids[0]] = obj;
884 // recurse serialization for all members of this member
885 // (only for struct/class types, noop for primitive types)
886 SerializationRecursion<T_memberType>::serializeObject(this, nativeMember);
887 }
888 }
889
890 /** @brief Set current version number for your C++ class.
891 *
892 * By calling this method you can define a version number for your
893 * current C++ class (that is a version for its current data structure
894 * layout and method implementations) that is going to be stored along
895 * with the serialized archive. Only call this method if you really want
896 * to constrain compatibility of your C++ class.
897 *
898 * Along with calling @c setMinVersion() this provides a way for you
899 * to constrain backward compatibility regarding serialization and
900 * deserialization of your C++ class which the Archive class will obey
901 * to. If required, then typically you might do so in your
902 * @c serialize() method implementation like:
903 * @code
904 * #define SRLZ(member) \
905 * archive->serializeMember(*this, member, #member);
906 *
907 * void Foo::serialize(Serialization::Archive* archive) {
908 * // when serializing: the current version of this class that is
909 * // going to be stored with the serialized archive
910 * archive->setVersion(*this, 6);
911 * // when deserializing: the minimum version this C++ class is
912 * // compatible with
913 * archive->setMinVersion(*this, 3);
914 * // actual data mebers to serialize / deserialize
915 * SRLZ(a);
916 * SRLZ(b);
917 * SRLZ(c);
918 * }
919 * @endcode
920 * In this example above, the C++ class "Foo" would be serialized along
921 * with the version number @c 6 and minimum version @c 3 as additional
922 * meta information in the resulting archive (and its raw data stream
923 * respectively).
924 *
925 * When deserializing archives with the example C++ class code above,
926 * the Archive object would check whether your originally serialized
927 * C++ "Foo" object had at least version number @c 3, if not the
928 * deserialization process would automatically be stopped with a
929 * @c Serialization::Exception, claiming that the classes are version
930 * incompatible.
931 *
932 * But also consider the other way around: you might have serialized
933 * your latest version of your C++ class, and might deserialize that
934 * archive with an older version of your C++ class. In that case it will
935 * likewise be checked whether the version of that old C++ class is at
936 * least as high as the minimum version set with the already seralized
937 * bleeding edge C++ class.
938 *
939 * Since this Serialization / deserialization framework is designed to
940 * be robust on changes to your C++ classes and aims trying to
941 * deserialize all your C++ objects correctly even if your C++ classes
942 * have seen substantial software changes in the meantime; you might
943 * sometimes see it as necessary to constrain backward compatibility
944 * this way. Because obviously there are certain things this framework
945 * can cope with, like for example that you renamed a data member while
946 * keeping the layout consistent, or that you have added new members to
947 * your C++ class or simply changed the order of your members in your
948 * C++ class. But what this framework cannot detect is for example if
949 * you changed the semantics of the values stored with your members, or
950 * even substantially changed the algorithms in your class methods such
951 * that they would not handle the data of your C++ members in the same
952 * and correct way anymore.
953 *
954 * @param nativeObject - your C++ object you want to set a version for
955 * @param v - the version number to set for your C++ class (by default,
956 * that is if you do not explicitly call this method, then
957 * your C++ object will be stored with version number @c 0 ).
958 */
959 template<typename T_classType>
960 void setVersion(const T_classType& nativeObject, Version v) {
961 const UID uid = UID::from(nativeObject);
962 Object& obj = m_allObjects[uid];
963 if (!obj) {
964 const UIDChain uids = UIDChainResolver<T_classType>(nativeObject);
965 const DataType type = DataType::dataTypeOf(nativeObject);
966 obj = Object(uids, type);
967 }
968 setVersion(obj, v);
969 }
970
971 /** @brief Set a minimum version number for your C++ class.
972 *
973 * Call this method to define a minimum version that your current C++
974 * class implementation would be compatible with when it comes to
975 * deserialization of an archive containing an object of your C++ class.
976 * Like the version information, the minimum version will also be stored
977 * for objects of your C++ class with the resulting archive (and its
978 * resulting raw data stream respectively).
979 *
980 * When you start to constrain version compatibility of your C++ class
981 * you usually start by using 1 as version and 1 as minimum version.
982 * So it is eligible to set the same number to both version and minimum
983 * version. However you must @b not set a minimum version higher than
984 * version. Doing so would not raise an exception, but the resulting
985 * behavior would be undefined.
986 *
987 * It is not relevant whether you first set version and then minimum
988 * version or vice versa. It is also not relevant when exactly you set
989 * those two numbers, even though usually you would set both in your
990 * serialize() method implementation.
991 *
992 * @see @c setVersion() for more details about this overall topic.
993 *
994 * @param nativeObject - your C++ object you want to set a version for
995 * @param v - the minimum version you want to define for your C++ class
996 * (by default, that is if you do not explicitly call this
997 * method, then a minium version of @c 0 is assumed for your
998 * C++ class instead).
999 */
1000 template<typename T_classType>
1001 void setMinVersion(const T_classType& nativeObject, Version v) {
1002 const UID uid = UID::from(nativeObject);
1003 Object& obj = m_allObjects[uid];
1004 if (!obj) {
1005 const UIDChain uids = UIDChainResolver<T_classType>(nativeObject);
1006 const DataType type = DataType::dataTypeOf(nativeObject);
1007 obj = Object(uids, type);
1008 }
1009 setMinVersion(obj, v);
1010 }
1011
1012 virtual void decode(const RawData& data);
1013 virtual void decode(const uint8_t* data, size_t size);
1014 void clear();
1015 bool isModified() const;
1016 void removeMember(Object& parent, const Member& member);
1017 void remove(const Object& obj);
1018 Object& rootObject();
1019 Object& objectByUID(const UID& uid);
1020 void setAutoValue(Object& object, String value);
1021 void setIntValue(Object& object, int64_t value);
1022 void setRealValue(Object& object, double value);
1023 void setBoolValue(Object& object, bool value);
1024 void setEnumValue(Object& object, uint64_t value);
1025 String valueAsString(const Object& object);
1026 int64_t valueAsInt(const Object& object);
1027 double valueAsReal(const Object& object);
1028 bool valueAsBool(const Object& object);
1029 void setVersion(Object& object, Version v);
1030 void setMinVersion(Object& object, Version v);
1031 String name() const;
1032 void setName(String name);
1033 String comment() const;
1034 void setComment(String comment);
1035 time_t timeStampCreated() const;
1036 time_t timeStampModified() const;
1037 tm dateTimeCreated(time_base_t base = LOCAL_TIME) const;
1038 tm dateTimeModified(time_base_t base = LOCAL_TIME) const;
1039
1040 protected:
1041 // UID resolver for non-pointer types
1042 template<typename T>
1043 class UIDChainResolver {
1044 public:
1045 UIDChainResolver(const T& data) {
1046 m_uid.push_back(UID::from(data));
1047 }
1048
1049 operator UIDChain() const { return m_uid; }
1050 UIDChain operator()() const { return m_uid; }
1051 private:
1052 UIDChain m_uid;
1053 };
1054
1055 // UID resolver for pointer types (of 1st degree)
1056 template<typename T>
1057 class UIDChainResolver<T*> {
1058 public:
1059 UIDChainResolver(const T*& data) {
1060 const UID uids[2] = {
1061 { &data, sizeof(data) },
1062 { data, sizeof(*data) }
1063 };
1064 m_uid.push_back(uids[0]);
1065 m_uid.push_back(uids[1]);
1066 }
1067
1068 operator UIDChain() const { return m_uid; }
1069 UIDChain operator()() const { return m_uid; }
1070 private:
1071 UIDChain m_uid;
1072 };
1073
1074 // SerializationRecursion for non-pointer class/struct types.
1075 template<typename T, bool T_isRecursive>
1076 struct SerializationRecursionImpl {
1077 static void serializeObject(Archive* archive, const T& obj) {
1078 const_cast<T&>(obj).serialize(archive);
1079 }
1080 };
1081
1082 // SerializationRecursion for pointers (of 1st degree) to class/structs.
1083 template<typename T, bool T_isRecursive>
1084 struct SerializationRecursionImpl<T*,T_isRecursive> {
1085 static void serializeObject(Archive* archive, const T*& obj) {
1086 if (!obj) return;
1087 const_cast<T*&>(obj)->serialize(archive);
1088 }
1089 };
1090
1091 // NOOP SerializationRecursion for primitive types.
1092 template<typename T>
1093 struct SerializationRecursionImpl<T,false> {
1094 static void serializeObject(Archive* archive, const T& obj) {}
1095 };
1096
1097 // NOOP SerializationRecursion for pointers (of 1st degree) to primitive types.
1098 template<typename T>
1099 struct SerializationRecursionImpl<T*,false> {
1100 static void serializeObject(Archive* archive, const T*& obj) {}
1101 };
1102
1103 // Automatically handles recursion for class/struct types, while ignoring all primitive types.
1104 template<typename T>
1105 struct SerializationRecursion : SerializationRecursionImpl<T, LIBGIG_IS_CLASS(T)> {
1106 };
1107
1108 class ObjectPool : public std::map<UID,Object> {
1109 public:
1110 // prevent passing obvious invalid UID values from creating a new pair entry
1111 Object& operator[](const UID& k) {
1112 static Object invalid;
1113 if (!k.isValid()) {
1114 invalid = Object();
1115 return invalid;
1116 }
1117 return std::map<UID,Object>::operator[](k);
1118 }
1119 };
1120
1121 friend String _encode(const ObjectPool& objects);
1122
1123 private:
1124 String _encodeRootBlob();
1125 void _popRootBlob(const char*& p, const char* end);
1126 void _popObjectsBlob(const char*& p, const char* end);
1127
1128 protected:
1129 class Syncer {
1130 public:
1131 Syncer(Archive& dst, Archive& src);
1132 protected:
1133 void syncObject(const Object& dst, const Object& src);
1134 void syncPrimitive(const Object& dst, const Object& src);
1135 void syncPointer(const Object& dst, const Object& src);
1136 void syncMember(const Member& dstMember, const Member& srcMember);
1137 static Member dstMemberMatching(const Object& dstObj, const Object& srcObj, const Member& srcMember);
1138 private:
1139 Archive& m_dst;
1140 Archive& m_src;
1141 };
1142
1143 enum operation_t {
1144 OPERATION_NONE,
1145 OPERATION_SERIALIZE,
1146 OPERATION_DESERIALIZE
1147 };
1148
1149 virtual void encode();
1150
1151 ObjectPool m_allObjects;
1152 operation_t m_operation;
1153 UID m_root;
1154 RawData m_rawData;
1155 bool m_isModified;
1156 String m_name;
1157 String m_comment;
1158 time_t m_timeCreated;
1159 time_t m_timeModified;
1160 };
1161
1162 /**
1163 * Will be thrown whenever an error occurs during an serialization or
1164 * deserialization process.
1165 */
1166 class Exception {
1167 public:
1168 String Message;
1169
1170 Exception(String Message) { Exception::Message = Message; }
1171 void PrintMessage();
1172 virtual ~Exception() {}
1173 };
1174
1175 } // namespace Serialization
1176
1177 #endif // LIBGIG_SERIALIZATION_H

  ViewVC Help
Powered by ViewVC