include/wx/variant.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        wx/variant.h
   3 // Purpose:     wxVariant class, container for any type
   4 // Author:      Julian Smart
   5 // Modified by:
   6 // Created:     10/09/98
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) Julian Smart
   9 // Licence:     wxWindows licence
  10 /////////////////////////////////////////////////////////////////////////////
  11
  12 #ifndef _WX_VARIANT_H_
  13 #define _WX_VARIANT_H_
  14
  15 #include "wx/defs.h"
  16
  17 #if wxUSE_VARIANT
  18
  19 #include "wx/object.h"
  20 #include "wx/string.h"
  21 #include "wx/arrstr.h"
  22 #include "wx/list.h"
  23
  24 #if wxUSE_DATETIME
  25     #include "wx/datetime.h"
  26 #endif // wxUSE_DATETIME
  27
  28 #if wxUSE_ODBC
  29     #include "wx/db.h"  // will #include sqltypes.h
  30 #endif //ODBC
  31
  32 #include "wx/iosfwrap.h"
  33
  34 /*
  35  * wxVariantData stores the actual data in a wxVariant object,
  36  * to allow it to store any type of data.
  37  * Derive from this to provide custom data handling.
  38  *
  39  * NB: To prevent addition of extra vtbl pointer to wxVariantData,
  40  *     we don't multiple-inherit from wxObjectRefData. Instead,
  41  *     we simply replicate the wxObject ref-counting scheme.
  42  *
  43  * NB: When you construct a wxVariantData, it will have refcount
  44  *     of one. Refcount will not be further increased when
  45  *     it is passed to wxVariant. This simulates old common
  46  *     scenario where wxVariant took ownership of wxVariantData
  47  *     passed to it.
  48  *     If you create wxVariantData for other reasons than passing
  49  *     it to wxVariant, technically you are not required to call
  50  *     DecRef() before deleting it.
  51  *
  52  * TODO: in order to replace wxPropertyValue, we would need
  53  * to consider adding constructors that take pointers to C++ variables,
  54  * or removing that functionality from the wxProperty library.
  55  * Essentially wxPropertyValue takes on some of the wxValidator functionality
  56  * by storing pointers and not just actual values, allowing update of C++ data
  57  * to be handled automatically. Perhaps there's another way of doing this without
  58  * overloading wxVariant with unnecessary functionality.
  59  */
  60
  61 class WXDLLIMPEXP_BASE wxVariantData: public wxObject
  62 {
  63     friend class wxVariant;
  64 public:
  65     wxVariantData()
  66         : wxObject(), m_count(1)
  67     { }
  68
  69     // Override these to provide common functionality
  70     virtual bool Eq(wxVariantData& data) const = 0;
  71
  72 #if wxUSE_STD_IOSTREAM
  73     virtual bool Write(wxSTD ostream& WXUNUSED(str)) const { return false; }
  74 #endif
  75     virtual bool Write(wxString& WXUNUSED(str)) const { return false; }
  76 #if wxUSE_STD_IOSTREAM
  77     virtual bool Read(wxSTD istream& WXUNUSED(str)) { return false; }
  78 #endif
  79     virtual bool Read(wxString& WXUNUSED(str)) { return false; }
  80     // What type is it? Return a string name.
  81     virtual wxString GetType() const = 0;
  82     // If it based on wxObject return the ClassInfo.
  83     virtual wxClassInfo* GetValueClassInfo() { return NULL; }
  84
  85     void IncRef() { m_count++; }
  86     void DecRef()
  87     {
  88         if ( --m_count == 0 )
  89             delete this;
  90     }
  91
  92     int GetRefCount() const { return m_count; }
  93
  94 protected:
  95     // Protected dtor should make some incompatible code
  96     // break more louder. That is, they should do data->DecRef()
  97     // instead of delete data.
  98     virtual ~wxVariantData() { }
  99
 100 private:
 101     int     m_count;
 102
 103 private:
 104     DECLARE_ABSTRACT_CLASS(wxVariantData)
 105 };
 106
 107 /*
 108  * wxVariant can store any kind of data, but has some basic types
 109  * built in.
 110  */
 111
 112 class WXDLLIMPEXP_BASE wxVariant: public wxObject
 113 {
 114 public:
 115     wxVariant();
 116
 117     wxVariant(const wxVariant& variant);
 118     wxVariant(wxVariantData* data, const wxString& name = wxEmptyString);
 119     virtual ~wxVariant();
 120
 121     // generic assignment
 122     void operator= (const wxVariant& variant);
 123
 124     // Assignment using data, e.g.
 125     // myVariant = new wxStringVariantData("hello");
 126     void operator= (wxVariantData* variantData);
 127
 128     bool operator== (const wxVariant& variant) const;
 129     bool operator!= (const wxVariant& variant) const;
 130
 131     // Sets/gets name
 132     inline void SetName(const wxString& name) { m_name = name; }
 133     inline const wxString& GetName() const { return m_name; }
 134
 135     // Tests whether there is data
 136     bool IsNull() const;
 137
 138     // For compatibility with wxWidgets <= 2.6, this doesn't increase
 139     // reference count.
 140     wxVariantData* GetData() const { return m_data; }
 141     void SetData(wxVariantData* data) ;
 142
 143     // make a 'clone' of the object
 144     void Ref(const wxVariant& clone);
 145
 146     // destroy a reference
 147     void UnRef();
 148
 149     // Make NULL (i.e. delete the data)
 150     void MakeNull();
 151
 152     // Delete data and name
 153     void Clear();
 154
 155     // Returns a string representing the type of the variant,
 156     // e.g. "string", "bool", "stringlist", "list", "double", "long"
 157     wxString GetType() const;
 158
 159     bool IsType(const wxString& type) const;
 160     bool IsValueKindOf(const wxClassInfo* type) const;
 161
 162     // write contents to a string (e.g. for debugging)
 163     wxString MakeString() const;
 164
 165     // double
 166     wxVariant(double val, const wxString& name = wxEmptyString);
 167     bool operator== (double value) const;
 168     bool operator!= (double value) const;
 169     void operator= (double value) ;
 170     inline operator double () const {  return GetDouble(); }
 171     inline double GetReal() const { return GetDouble(); }
 172     double GetDouble() const;
 173
 174     // long
 175     wxVariant(long val, const wxString& name = wxEmptyString);
 176     wxVariant(int val, const wxString& name = wxEmptyString);
 177     wxVariant(short val, const wxString& name = wxEmptyString);
 178     bool operator== (long value) const;
 179     bool operator!= (long value) const;
 180     void operator= (long value) ;
 181     inline operator long () const {  return GetLong(); }
 182     inline long GetInteger() const { return GetLong(); }
 183     long GetLong() const;
 184
 185     // bool
 186 #ifdef HAVE_BOOL
 187     wxVariant(bool val, const wxString& name = wxEmptyString);
 188     bool operator== (bool value) const;
 189     bool operator!= (bool value) const;
 190     void operator= (bool value) ;
 191     inline operator bool () const {  return GetBool(); }
 192     bool GetBool() const ;
 193 #endif
 194
 195     // wxDateTime
 196 #if wxUSE_DATETIME
 197     wxVariant(const wxDateTime& val, const wxString& name = wxEmptyString);
 198 #if wxUSE_ODBC
 199     wxVariant(const DATE_STRUCT* valptr, const wxString& name = wxEmptyString);
 200     wxVariant(const TIME_STRUCT* valptr, const wxString& name = wxEmptyString);
 201     wxVariant(const TIMESTAMP_STRUCT* valptr, const wxString& name = wxEmptyString);
 202 #endif
 203     bool operator== (const wxDateTime& value) const;
 204     bool operator!= (const wxDateTime& value) const;
 205     void operator= (const wxDateTime& value) ;
 206 #if wxUSE_ODBC
 207     void operator= (const DATE_STRUCT* value) ;
 208     void operator= (const TIME_STRUCT* value) ;
 209     void operator= (const TIMESTAMP_STRUCT* value) ;
 210 #endif
 211     inline operator wxDateTime () const { return GetDateTime(); }
 212     wxDateTime GetDateTime() const;
 213 #endif
 214
 215     // wxString
 216     wxVariant(const wxString& val, const wxString& name = wxEmptyString);
 217     wxVariant(const wxChar* val, const wxString& name = wxEmptyString); // Necessary or VC++ assumes bool!
 218     bool operator== (const wxString& value) const;
 219     bool operator!= (const wxString& value) const;
 220     void operator= (const wxString& value) ;
 221     void operator= (const wxChar* value) ; // Necessary or VC++ assumes bool!
 222     inline operator wxString () const {  return MakeString(); }
 223     wxString GetString() const;
 224
 225     // wxChar
 226     wxVariant(wxChar val, const wxString& name = wxEmptyString);
 227     bool operator== (wxChar value) const;
 228     bool operator!= (wxChar value) const;
 229     void operator= (wxChar value) ;
 230     inline operator wxChar () const { return GetChar(); }
 231     wxChar GetChar() const ;
 232
 233     // wxArrayString
 234     wxVariant(const wxArrayString& val, const wxString& name = wxEmptyString);
 235     bool operator== (const wxArrayString& value) const;
 236     bool operator!= (const wxArrayString& value) const;
 237     void operator= (const wxArrayString& value);
 238     inline operator wxArrayString () const { return GetArrayString(); }
 239     wxArrayString GetArrayString() const;
 240
 241     // void*
 242     wxVariant(void* ptr, const wxString& name = wxEmptyString);
 243     bool operator== (void* value) const;
 244     bool operator!= (void* value) const;
 245     void operator= (void* value);
 246     inline operator void* () const {  return GetVoidPtr(); }
 247     void* GetVoidPtr() const;
 248
 249     // wxObject*
 250     wxVariant(wxObject* ptr, const wxString& name = wxEmptyString);
 251     bool operator== (wxObject* value) const;
 252     bool operator!= (wxObject* value) const;
 253     void operator= (wxObject* value);
 254     wxObject* GetWxObjectPtr() const;
 255
 256
 257 #if WXWIN_COMPATIBILITY_2_4
 258     wxDEPRECATED( wxVariant(const wxStringList& val, const wxString& name = wxEmptyString) );
 259     wxDEPRECATED( bool operator== (const wxStringList& value) const );
 260     wxDEPRECATED( bool operator!= (const wxStringList& value) const );
 261     wxDEPRECATED( void operator= (const wxStringList& value) );
 262     wxDEPRECATED( wxStringList& GetStringList() const );
 263 #endif
 264
 265     // ------------------------------
 266     // list operations
 267     // ------------------------------
 268
 269     wxVariant(const wxList& val, const wxString& name = wxEmptyString); // List of variants
 270     bool operator== (const wxList& value) const;
 271     bool operator!= (const wxList& value) const;
 272     void operator= (const wxList& value) ;
 273     // Treat a list variant as an array
 274     wxVariant operator[] (size_t idx) const;
 275     wxVariant& operator[] (size_t idx) ;
 276     wxList& GetList() const ;
 277
 278     // Return the number of elements in a list
 279     size_t GetCount() const;
 280
 281     // Make empty list
 282     void NullList();
 283
 284     // Append to list
 285     void Append(const wxVariant& value);
 286
 287     // Insert at front of list
 288     void Insert(const wxVariant& value);
 289
 290     // Returns true if the variant is a member of the list
 291     bool Member(const wxVariant& value) const;
 292
 293     // Deletes the nth element of the list
 294     bool Delete(size_t item);
 295
 296     // Clear list
 297     void ClearList();
 298
 299 public:
 300     // Type conversion
 301     bool Convert(long* value) const;
 302     bool Convert(bool* value) const;
 303     bool Convert(double* value) const;
 304     bool Convert(wxString* value) const;
 305     bool Convert(wxChar* value) const;
 306 #if wxUSE_DATETIME
 307     bool Convert(wxDateTime* value) const;
 308 #endif // wxUSE_DATETIME
 309
 310 // Attributes
 311 protected:
 312     wxVariantData*  m_data;
 313     wxString        m_name;
 314
 315 private:
 316     DECLARE_DYNAMIC_CLASS(wxVariant)
 317 };
 318
 319 /* Fake macro parameter value */
 320 #ifdef EMPTY_PARAMETER_VALUE
 321     #undef EMPTY_PARAMETER_VALUE
 322 #endif
 323 #define EMPTY_PARAMETER_VALUE
 324
 325 #define DECLARE_VARIANT_OBJECT(classname) \
 326     DECLARE_VARIANT_OBJECT_EXPORTED(classname,EMPTY_PARAMETER_VALUE)
 327
 328 #define DECLARE_VARIANT_OBJECT_EXPORTED(classname,expdecl) \
 329 expdecl classname& operator << ( classname &object, const wxVariant &variant ); \
 330 expdecl wxVariant& operator << ( wxVariant &variant, const classname &object );
 331
 332 #define IMPLEMENT_VARIANT_OBJECT(classname) \
 333     IMPLEMENT_VARIANT_OBJECT_EXPORTED(classname,EMPTY_PARAMETER_VALUE)
 334
 335 #define IMPLEMENT_VARIANT_OBJECT_EXPORTED_NO_EQ(classname,expdecl) \
 336 class classname##VariantData: public wxVariantData \
 337 { \
 338 public:\
 339     classname##VariantData() {} \
 340     classname##VariantData( const classname &value ) { m_value = value; } \
 341 \
 342     classname &GetValue() { return m_value; } \
 343 \
 344     virtual bool Eq(wxVariantData& data) const; \
 345 \
 346     virtual wxString GetType() const; \
 347     virtual wxClassInfo* GetValueClassInfo(); \
 348 \
 349 protected:\
 350     classname m_value; \
 351 \
 352 private: \
 353     DECLARE_CLASS(classname##VariantData) \
 354 };\
 355 \
 356 IMPLEMENT_CLASS(classname##VariantData, wxVariantData)\
 357 \
 358 wxString classname##VariantData::GetType() const\
 359 {\
 360     return m_value.GetClassInfo()->GetClassName();\
 361 }\
 362 \
 363 wxClassInfo* classname##VariantData::GetValueClassInfo()\
 364 {\
 365     return m_value.GetClassInfo();\
 366 }\
 367 \
 368 expdecl classname& operator << ( classname &value, const wxVariant &variant )\
 369 {\
 370     wxASSERT( wxIsKindOf( variant.GetData(), classname##VariantData ) );\
 371     \
 372     classname##VariantData *data = (classname##VariantData*) variant.GetData();\
 373     value = data->GetValue();\
 374     return value;\
 375 }\
 376 \
 377 expdecl wxVariant& operator << ( wxVariant &variant, const classname &value )\
 378 {\
 379     classname##VariantData *data = new classname##VariantData( value );\
 380     variant.SetData( data );\
 381     return variant;\
 382 }
 383
 384 // implements a wxVariantData-derived class using for the Eq() method the operator==
 385 // which must have been provided by "classname"
 386 #define IMPLEMENT_VARIANT_OBJECT_EXPORTED(classname,expdecl) \
 387 IMPLEMENT_VARIANT_OBJECT_EXPORTED_NO_EQ(classname,expdecl) \
 388 \
 389 bool classname##VariantData::Eq(wxVariantData& data) const \
 390 {\
 391     wxASSERT( wxIsKindOf((&data), classname##VariantData) );\
 392 \
 393     classname##VariantData & otherData = (classname##VariantData &) data;\
 394 \
 395     return otherData.m_value == m_value;\
 396 }\
 397
 398
 399 // implements a wxVariantData-derived class using for the Eq() method a shallow
 400 // comparison (through wxObject::IsRefTo function)
 401 #define IMPLEMENT_VARIANT_OBJECT_EXPORTED_SHALLOWCMP(classname,expdecl) \
 402 IMPLEMENT_VARIANT_OBJECT_EXPORTED_NO_EQ(classname,expdecl) \
 403 \
 404 bool classname##VariantData::Eq(wxVariantData& data) const \
 405 {\
 406     wxASSERT( wxIsKindOf((&data), classname##VariantData) );\
 407 \
 408     classname##VariantData & otherData = (classname##VariantData &) data;\
 409 \
 410     return (otherData.m_value.IsRefTo(&m_value));\
 411 }\
 412
 413
 414 // Since we want type safety wxVariant we need to fetch and dynamic_cast
 415 // in a seemingly safe way so the compiler can check, so we define
 416 // a dynamic_cast /wxDynamicCast analogue.
 417
 418 #define wxGetVariantCast(var,classname) \
 419     ((classname*)(var.IsValueKindOf(&classname::ms_classInfo) ?\
 420                   var.GetWxObjectPtr() : NULL));
 421
 422 extern wxVariant WXDLLIMPEXP_BASE wxNullVariant;
 423
 424 #endif // wxUSE_VARIANT
 425
 426 #endif // _WX_VARIANT_H_