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
  63 {
  64     friend class wxVariant;
  65 public:
  66     wxVariantData() : m_count(1) { }
  67
  68     // Override these to provide common functionality
  69     virtual bool Eq(wxVariantData& data) const = 0;
  70
  71 #if wxUSE_STD_IOSTREAM
  72     virtual bool Write(wxSTD ostream& WXUNUSED(str)) const { return false; }
  73 #endif
  74     virtual bool Write(wxString& WXUNUSED(str)) const { return false; }
  75 #if wxUSE_STD_IOSTREAM
  76     virtual bool Read(wxSTD istream& WXUNUSED(str)) { return false; }
  77 #endif
  78     virtual bool Read(wxString& WXUNUSED(str)) { return false; }
  79     // What type is it? Return a string name.
  80     virtual wxString GetType() const = 0;
  81     // If it based on wxObject return the ClassInfo.
  82     virtual wxClassInfo* GetValueClassInfo() { return NULL; }
  83
  84     void IncRef() { m_count++; }
  85     void DecRef()
  86     {
  87         if ( --m_count == 0 )
  88             delete this;
  89     }
  90
  91     int GetRefCount() const { return m_count; }
  92
  93 protected:
  94     // Protected dtor should make some incompatible code
  95     // break more louder. That is, they should do data->DecRef()
  96     // instead of delete data.
  97     virtual ~wxVariantData() { }
  98
  99 private:
 100     int     m_count;
 101 };
 102
 103 /*
 104  * wxVariant can store any kind of data, but has some basic types
 105  * built in.
 106  */
 107
 108 class WXDLLIMPEXP_BASE wxVariant: public wxObject
 109 {
 110 public:
 111     wxVariant();
 112
 113     wxVariant(const wxVariant& variant);
 114     wxVariant(wxVariantData* data, const wxString& name = wxEmptyString);
 115     virtual ~wxVariant();
 116
 117     // generic assignment
 118     void operator= (const wxVariant& variant);
 119
 120     // Assignment using data, e.g.
 121     // myVariant = new wxStringVariantData("hello");
 122     void operator= (wxVariantData* variantData);
 123
 124     bool operator== (const wxVariant& variant) const;
 125     bool operator!= (const wxVariant& variant) const;
 126
 127     // Sets/gets name
 128     inline void SetName(const wxString& name) { m_name = name; }
 129     inline const wxString& GetName() const { return m_name; }
 130
 131     // Tests whether there is data
 132     bool IsNull() const;
 133
 134     // For compatibility with wxWidgets <= 2.6, this doesn't increase
 135     // reference count.
 136     wxVariantData* GetData() const { return m_data; }
 137     void SetData(wxVariantData* data) ;
 138
 139     // make a 'clone' of the object
 140     void Ref(const wxVariant& clone);
 141
 142     // destroy a reference
 143     void UnRef();
 144
 145     // Make NULL (i.e. delete the data)
 146     void MakeNull();
 147
 148     // Delete data and name
 149     void Clear();
 150
 151     // Returns a string representing the type of the variant,
 152     // e.g. "string", "bool", "stringlist", "list", "double", "long"
 153     wxString GetType() const;
 154
 155     bool IsType(const wxString& type) const;
 156     bool IsValueKindOf(const wxClassInfo* type) const;
 157
 158     // write contents to a string (e.g. for debugging)
 159     wxString MakeString() const;
 160
 161     // double
 162     wxVariant(double val, const wxString& name = wxEmptyString);
 163     bool operator== (double value) const;
 164     bool operator!= (double value) const;
 165     void operator= (double value) ;
 166     inline operator double () const {  return GetDouble(); }
 167     inline double GetReal() const { return GetDouble(); }
 168     double GetDouble() const;
 169
 170     // long
 171     wxVariant(long val, const wxString& name = wxEmptyString);
 172     wxVariant(int val, const wxString& name = wxEmptyString);
 173     wxVariant(short val, const wxString& name = wxEmptyString);
 174     bool operator== (long value) const;
 175     bool operator!= (long value) const;
 176     void operator= (long value) ;
 177     inline operator long () const {  return GetLong(); }
 178     inline long GetInteger() const { return GetLong(); }
 179     long GetLong() const;
 180
 181     // bool
 182 #ifdef HAVE_BOOL
 183     wxVariant(bool val, const wxString& name = wxEmptyString);
 184     bool operator== (bool value) const;
 185     bool operator!= (bool value) const;
 186     void operator= (bool value) ;
 187     inline operator bool () const {  return GetBool(); }
 188     bool GetBool() const ;
 189 #endif
 190
 191     // wxDateTime
 192 #if wxUSE_DATETIME
 193     wxVariant(const wxDateTime& val, const wxString& name = wxEmptyString);
 194 #if wxUSE_ODBC
 195     wxVariant(const DATE_STRUCT* valptr, const wxString& name = wxEmptyString);
 196     wxVariant(const TIME_STRUCT* valptr, const wxString& name = wxEmptyString);
 197     wxVariant(const TIMESTAMP_STRUCT* valptr, const wxString& name = wxEmptyString);
 198 #endif
 199     bool operator== (const wxDateTime& value) const;
 200     bool operator!= (const wxDateTime& value) const;
 201     void operator= (const wxDateTime& value) ;
 202 #if wxUSE_ODBC
 203     void operator= (const DATE_STRUCT* value) ;
 204     void operator= (const TIME_STRUCT* value) ;
 205     void operator= (const TIMESTAMP_STRUCT* value) ;
 206 #endif
 207     inline operator wxDateTime () const { return GetDateTime(); }
 208     wxDateTime GetDateTime() const;
 209 #endif
 210
 211     // wxString
 212     wxVariant(const wxString& val, const wxString& name = wxEmptyString);
 213     // these overloads are necessary to prevent the compiler from using bool
 214     // version instead of wxString one:
 215     wxVariant(const char* val, const wxString& name = wxEmptyString);
 216     wxVariant(const wchar_t* val, const wxString& name = wxEmptyString);
 217     wxVariant(const wxCStrData& val, const wxString& name = wxEmptyString);
 218     wxVariant(const wxCharBuffer& val, const wxString& name = wxEmptyString);
 219     wxVariant(const wxWCharBuffer& val, const wxString& name = wxEmptyString);
 220
 221     bool operator== (const wxString& value) const;
 222     bool operator!= (const wxString& value) const;
 223     wxVariant& operator=(const wxString& value);
 224     // these overloads are necessary to prevent the compiler from using bool
 225     // version instead of wxString one:
 226     wxVariant& operator=(const char* value)
 227         { return *this = wxString(value); }
 228     wxVariant& operator=(const wchar_t* value)
 229         { return *this = wxString(value); }
 230     wxVariant& operator=(const wxCStrData& value)
 231         { return *this = value.AsString(); }
 232     template<typename T>
 233     wxVariant& operator=(const wxCharTypeBuffer<T>& value)
 234         { return *this = value.data(); }
 235
 236     inline operator wxString () const {  return MakeString(); }
 237     wxString GetString() const;
 238
 239     // wxUniChar
 240     wxVariant(const wxUniChar& val, const wxString& name = wxEmptyString);
 241     wxVariant(const wxUniCharRef& val, const wxString& name = wxEmptyString);
 242     wxVariant(char val, const wxString& name = wxEmptyString);
 243     wxVariant(wchar_t val, const wxString& name = wxEmptyString);
 244     bool operator==(const wxUniChar& value) const;
 245     bool operator==(const wxUniCharRef& value) const { return *this == wxUniChar(value); }
 246     bool operator==(char value) const { return *this == wxUniChar(value); }
 247     bool operator==(wchar_t value) const { return *this == wxUniChar(value); }
 248     bool operator!=(const wxUniChar& value) const { return !(*this == value); }
 249     bool operator!=(const wxUniCharRef& value) const { return !(*this == value); }
 250     bool operator!=(char value) const { return !(*this == value); }
 251     bool operator!=(wchar_t value) const { return !(*this == value); }
 252     wxVariant& operator=(const wxUniChar& value);
 253     wxVariant& operator=(const wxUniCharRef& value) { return *this = wxUniChar(value); }
 254     wxVariant& operator=(char value) { return *this = wxUniChar(value); }
 255     wxVariant& operator=(wchar_t value) { return *this = wxUniChar(value); }
 256     operator wxUniChar() const { return GetChar(); }
 257     operator char() const { return GetChar(); }
 258     operator wchar_t() const { return GetChar(); }
 259     wxUniChar GetChar() const;
 260
 261     // wxArrayString
 262     wxVariant(const wxArrayString& val, const wxString& name = wxEmptyString);
 263     bool operator== (const wxArrayString& value) const;
 264     bool operator!= (const wxArrayString& value) const;
 265     void operator= (const wxArrayString& value);
 266     operator wxArrayString () const { return GetArrayString(); }
 267     wxArrayString GetArrayString() const;
 268
 269     // void*
 270     wxVariant(void* ptr, const wxString& name = wxEmptyString);
 271     bool operator== (void* value) const;
 272     bool operator!= (void* value) const;
 273     void operator= (void* value);
 274     operator void* () const {  return GetVoidPtr(); }
 275     void* GetVoidPtr() const;
 276
 277     // wxObject*
 278     wxVariant(wxObject* ptr, const wxString& name = wxEmptyString);
 279     bool operator== (wxObject* value) const;
 280     bool operator!= (wxObject* value) const;
 281     void operator= (wxObject* value);
 282     wxObject* GetWxObjectPtr() const;
 283
 284
 285     // ------------------------------
 286     // list operations
 287     // ------------------------------
 288
 289     wxVariant(const wxList& val, const wxString& name = wxEmptyString); // List of variants
 290     bool operator== (const wxList& value) const;
 291     bool operator!= (const wxList& value) const;
 292     void operator= (const wxList& value) ;
 293     // Treat a list variant as an array
 294     wxVariant operator[] (size_t idx) const;
 295     wxVariant& operator[] (size_t idx) ;
 296     wxList& GetList() const ;
 297
 298     // Return the number of elements in a list
 299     size_t GetCount() const;
 300
 301     // Make empty list
 302     void NullList();
 303
 304     // Append to list
 305     void Append(const wxVariant& value);
 306
 307     // Insert at front of list
 308     void Insert(const wxVariant& value);
 309
 310     // Returns true if the variant is a member of the list
 311     bool Member(const wxVariant& value) const;
 312
 313     // Deletes the nth element of the list
 314     bool Delete(size_t item);
 315
 316     // Clear list
 317     void ClearList();
 318
 319 public:
 320     // Type conversion
 321     bool Convert(long* value) const;
 322     bool Convert(bool* value) const;
 323     bool Convert(double* value) const;
 324     bool Convert(wxString* value) const;
 325     bool Convert(wxUniChar* value) const;
 326     bool Convert(char* value) const;
 327     bool Convert(wchar_t* value) const;
 328 #if wxUSE_DATETIME
 329     bool Convert(wxDateTime* value) const;
 330 #endif // wxUSE_DATETIME
 331
 332 // Attributes
 333 protected:
 334     wxVariantData*  m_data;
 335     wxString        m_name;
 336
 337 private:
 338     DECLARE_DYNAMIC_CLASS(wxVariant)
 339 };
 340
 341 #define DECLARE_VARIANT_OBJECT(classname) \
 342     DECLARE_VARIANT_OBJECT_EXPORTED(classname, wxEMPTY_PARAMETER_VALUE)
 343
 344 #define DECLARE_VARIANT_OBJECT_EXPORTED(classname,expdecl) \
 345 expdecl classname& operator << ( classname &object, const wxVariant &variant ); \
 346 expdecl wxVariant& operator << ( wxVariant &variant, const classname &object );
 347
 348 #define IMPLEMENT_VARIANT_OBJECT(classname) \
 349     IMPLEMENT_VARIANT_OBJECT_EXPORTED(classname, wxEMPTY_PARAMETER_VALUE)
 350
 351 #define IMPLEMENT_VARIANT_OBJECT_EXPORTED_NO_EQ(classname,expdecl) \
 352 class classname##VariantData: public wxVariantData \
 353 { \
 354 public:\
 355     classname##VariantData() {} \
 356     classname##VariantData( const classname &value ) { m_value = value; } \
 357 \
 358     classname &GetValue() { return m_value; } \
 359 \
 360     virtual bool Eq(wxVariantData& data) const; \
 361 \
 362     virtual wxString GetType() const; \
 363     virtual wxClassInfo* GetValueClassInfo(); \
 364 \
 365 protected:\
 366     classname m_value; \
 367 };\
 368 \
 369 wxString classname##VariantData::GetType() const\
 370 {\
 371     return m_value.GetClassInfo()->GetClassName();\
 372 }\
 373 \
 374 wxClassInfo* classname##VariantData::GetValueClassInfo()\
 375 {\
 376     return m_value.GetClassInfo();\
 377 }\
 378 \
 379 expdecl classname& operator << ( classname &value, const wxVariant &variant )\
 380 {\
 381     wxASSERT( variant.GetType() == #classname );\
 382     \
 383     classname##VariantData *data = (classname##VariantData*) variant.GetData();\
 384     value = data->GetValue();\
 385     return value;\
 386 }\
 387 \
 388 expdecl wxVariant& operator << ( wxVariant &variant, const classname &value )\
 389 {\
 390     classname##VariantData *data = new classname##VariantData( value );\
 391     variant.SetData( data );\
 392     return variant;\
 393 }
 394
 395 // implements a wxVariantData-derived class using for the Eq() method the
 396 // operator== which must have been provided by "classname"
 397 #define IMPLEMENT_VARIANT_OBJECT_EXPORTED(classname,expdecl) \
 398 IMPLEMENT_VARIANT_OBJECT_EXPORTED_NO_EQ(classname,wxEMPTY_PARAMETER_VALUE expdecl) \
 399 \
 400 bool classname##VariantData::Eq(wxVariantData& data) const \
 401 {\
 402     wxASSERT( GetType() == data.GetType() );\
 403 \
 404     classname##VariantData & otherData = (classname##VariantData &) data;\
 405 \
 406     return otherData.m_value == m_value;\
 407 }\
 408
 409
 410 // implements a wxVariantData-derived class using for the Eq() method a shallow
 411 // comparison (through wxObject::IsSameAs function)
 412 #define IMPLEMENT_VARIANT_OBJECT_SHALLOWCMP(classname) \
 413     IMPLEMENT_VARIANT_OBJECT_EXPORTED_SHALLOWCMP(classname, wxEMPTY_PARAMETER_VALUE)
 414 #define IMPLEMENT_VARIANT_OBJECT_EXPORTED_SHALLOWCMP(classname,expdecl) \
 415 IMPLEMENT_VARIANT_OBJECT_EXPORTED_NO_EQ(classname,wxEMPTY_PARAMETER_VALUE expdecl) \
 416 \
 417 bool classname##VariantData::Eq(wxVariantData& data) const \
 418 {\
 419     wxASSERT( GetType() == data.GetType() );\
 420 \
 421     classname##VariantData & otherData = (classname##VariantData &) data;\
 422 \
 423     return (otherData.m_value.IsSameAs(m_value));\
 424 }\
 425
 426
 427 // Since we want type safety wxVariant we need to fetch and dynamic_cast
 428 // in a seemingly safe way so the compiler can check, so we define
 429 // a dynamic_cast /wxDynamicCast analogue.
 430
 431 #define wxGetVariantCast(var,classname) \
 432     ((classname*)(var.IsValueKindOf(&classname::ms_classInfo) ?\
 433                   var.GetWxObjectPtr() : NULL));
 434
 435 extern wxVariant WXDLLIMPEXP_BASE wxNullVariant;
 436
 437 #endif // wxUSE_VARIANT
 438
 439 #endif // _WX_VARIANT_H_