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