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_FWD_BASE wxVariant;
 109
 110 WX_DECLARE_LIST_WITH_DECL(wxVariant, wxVariantList, class WXDLLIMPEXP_BASE);
 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     // these overloads are necessary to prevent the compiler from using bool
 218     // version instead of wxString one:
 219     wxVariant(const char* val, const wxString& name = wxEmptyString);
 220     wxVariant(const wchar_t* val, const wxString& name = wxEmptyString);
 221     wxVariant(const wxCStrData& val, const wxString& name = wxEmptyString);
 222     wxVariant(const wxCharBuffer& val, const wxString& name = wxEmptyString);
 223     wxVariant(const wxWCharBuffer& val, const wxString& name = wxEmptyString);
 224
 225     bool operator== (const wxString& value) const;
 226     bool operator!= (const wxString& value) const;
 227     wxVariant& operator=(const wxString& value);
 228     // these overloads are necessary to prevent the compiler from using bool
 229     // version instead of wxString one:
 230     wxVariant& operator=(const char* value)
 231         { return *this = wxString(value); }
 232     wxVariant& operator=(const wchar_t* value)
 233         { return *this = wxString(value); }
 234     wxVariant& operator=(const wxCStrData& value)
 235         { return *this = value.AsString(); }
 236     template<typename T>
 237     wxVariant& operator=(const wxCharTypeBuffer<T>& value)
 238         { return *this = value.data(); }
 239
 240     inline operator wxString () const {  return MakeString(); }
 241     wxString GetString() const;
 242
 243     // wxUniChar
 244     wxVariant(const wxUniChar& val, const wxString& name = wxEmptyString);
 245     wxVariant(const wxUniCharRef& val, const wxString& name = wxEmptyString);
 246     wxVariant(char val, const wxString& name = wxEmptyString);
 247     wxVariant(wchar_t val, const wxString& name = wxEmptyString);
 248     bool operator==(const wxUniChar& value) const;
 249     bool operator==(const wxUniCharRef& value) const { return *this == wxUniChar(value); }
 250     bool operator==(char value) const { return *this == wxUniChar(value); }
 251     bool operator==(wchar_t value) const { return *this == wxUniChar(value); }
 252     bool operator!=(const wxUniChar& value) const { return !(*this == value); }
 253     bool operator!=(const wxUniCharRef& value) const { return !(*this == value); }
 254     bool operator!=(char value) const { return !(*this == value); }
 255     bool operator!=(wchar_t value) const { return !(*this == value); }
 256     wxVariant& operator=(const wxUniChar& value);
 257     wxVariant& operator=(const wxUniCharRef& value) { return *this = wxUniChar(value); }
 258     wxVariant& operator=(char value) { return *this = wxUniChar(value); }
 259     wxVariant& operator=(wchar_t value) { return *this = wxUniChar(value); }
 260     operator wxUniChar() const { return GetChar(); }
 261     operator char() const { return GetChar(); }
 262     operator wchar_t() const { return GetChar(); }
 263     wxUniChar GetChar() const;
 264
 265     // wxArrayString
 266     wxVariant(const wxArrayString& val, const wxString& name = wxEmptyString);
 267     bool operator== (const wxArrayString& value) const;
 268     bool operator!= (const wxArrayString& value) const;
 269     void operator= (const wxArrayString& value);
 270     operator wxArrayString () const { return GetArrayString(); }
 271     wxArrayString GetArrayString() const;
 272
 273     // void*
 274     wxVariant(void* ptr, const wxString& name = wxEmptyString);
 275     bool operator== (void* value) const;
 276     bool operator!= (void* value) const;
 277     void operator= (void* value);
 278     operator void* () const {  return GetVoidPtr(); }
 279     void* GetVoidPtr() const;
 280
 281     // wxObject*
 282     wxVariant(wxObject* ptr, const wxString& name = wxEmptyString);
 283     bool operator== (wxObject* value) const;
 284     bool operator!= (wxObject* value) const;
 285     void operator= (wxObject* value);
 286     wxObject* GetWxObjectPtr() const;
 287
 288
 289     // ------------------------------
 290     // list operations
 291     // ------------------------------
 292
 293     wxVariant(const wxList& val, const wxString& name = wxEmptyString); // List of variants
 294     bool operator== (const wxList& value) const;
 295     bool operator!= (const wxList& value) const;
 296     void operator= (const wxList& value) ;
 297     // Treat a list variant as an array
 298     wxVariant operator[] (size_t idx) const;
 299     wxVariant& operator[] (size_t idx) ;
 300     wxList& GetList() const ;
 301
 302     // Return the number of elements in a list
 303     size_t GetCount() const;
 304
 305     // Make empty list
 306     void NullList();
 307
 308     // Append to list
 309     void Append(const wxVariant& value);
 310
 311     // Insert at front of list
 312     void Insert(const wxVariant& value);
 313
 314     // Returns true if the variant is a member of the list
 315     bool Member(const wxVariant& value) const;
 316
 317     // Deletes the nth element of the list
 318     bool Delete(size_t item);
 319
 320     // Clear list
 321     void ClearList();
 322
 323 public:
 324     // Type conversion
 325     bool Convert(long* value) const;
 326     bool Convert(bool* value) const;
 327     bool Convert(double* value) const;
 328     bool Convert(wxString* value) const;
 329     bool Convert(wxUniChar* value) const;
 330     bool Convert(char* value) const;
 331     bool Convert(wchar_t* value) const;
 332 #if wxUSE_DATETIME
 333     bool Convert(wxDateTime* value) const;
 334 #endif // wxUSE_DATETIME
 335
 336 // Attributes
 337 protected:
 338     wxVariantData*  m_data;
 339     wxString        m_name;
 340
 341 private:
 342     DECLARE_DYNAMIC_CLASS(wxVariant)
 343 };
 344
 345 #define DECLARE_VARIANT_OBJECT(classname) \
 346     DECLARE_VARIANT_OBJECT_EXPORTED(classname, wxEMPTY_PARAMETER_VALUE)
 347
 348 #define DECLARE_VARIANT_OBJECT_EXPORTED(classname,expdecl) \
 349 expdecl classname& operator << ( classname &object, const wxVariant &variant ); \
 350 expdecl wxVariant& operator << ( wxVariant &variant, const classname &object );
 351
 352 #define IMPLEMENT_VARIANT_OBJECT(classname) \
 353     IMPLEMENT_VARIANT_OBJECT_EXPORTED(classname, wxEMPTY_PARAMETER_VALUE)
 354
 355 #define IMPLEMENT_VARIANT_OBJECT_EXPORTED_NO_EQ(classname,expdecl) \
 356 class classname##VariantData: public wxVariantData \
 357 { \
 358 public:\
 359     classname##VariantData() {} \
 360     classname##VariantData( const classname &value ) { m_value = value; } \
 361 \
 362     classname &GetValue() { return m_value; } \
 363 \
 364     virtual bool Eq(wxVariantData& data) const; \
 365 \
 366     virtual wxString GetType() const; \
 367     virtual wxClassInfo* GetValueClassInfo(); \
 368 \
 369 protected:\
 370     classname m_value; \
 371 };\
 372 \
 373 wxString classname##VariantData::GetType() const\
 374 {\
 375     return m_value.GetClassInfo()->GetClassName();\
 376 }\
 377 \
 378 wxClassInfo* classname##VariantData::GetValueClassInfo()\
 379 {\
 380     return m_value.GetClassInfo();\
 381 }\
 382 \
 383 expdecl classname& operator << ( classname &value, const wxVariant &variant )\
 384 {\
 385     wxASSERT( variant.GetType() == #classname );\
 386     \
 387     classname##VariantData *data = (classname##VariantData*) variant.GetData();\
 388     value = data->GetValue();\
 389     return value;\
 390 }\
 391 \
 392 expdecl wxVariant& operator << ( wxVariant &variant, const classname &value )\
 393 {\
 394     classname##VariantData *data = new classname##VariantData( value );\
 395     variant.SetData( data );\
 396     return variant;\
 397 }
 398
 399 // implements a wxVariantData-derived class using for the Eq() method the
 400 // operator== which must have been provided by "classname"
 401 #define IMPLEMENT_VARIANT_OBJECT_EXPORTED(classname,expdecl) \
 402 IMPLEMENT_VARIANT_OBJECT_EXPORTED_NO_EQ(classname,wxEMPTY_PARAMETER_VALUE expdecl) \
 403 \
 404 bool classname##VariantData::Eq(wxVariantData& data) const \
 405 {\
 406     wxASSERT( GetType() == data.GetType() );\
 407 \
 408     classname##VariantData & otherData = (classname##VariantData &) data;\
 409 \
 410     return otherData.m_value == m_value;\
 411 }\
 412
 413
 414 // implements a wxVariantData-derived class using for the Eq() method a shallow
 415 // comparison (through wxObject::IsSameAs function)
 416 #define IMPLEMENT_VARIANT_OBJECT_SHALLOWCMP(classname) \
 417     IMPLEMENT_VARIANT_OBJECT_EXPORTED_SHALLOWCMP(classname, wxEMPTY_PARAMETER_VALUE)
 418 #define IMPLEMENT_VARIANT_OBJECT_EXPORTED_SHALLOWCMP(classname,expdecl) \
 419 IMPLEMENT_VARIANT_OBJECT_EXPORTED_NO_EQ(classname,wxEMPTY_PARAMETER_VALUE expdecl) \
 420 \
 421 bool classname##VariantData::Eq(wxVariantData& data) const \
 422 {\
 423     wxASSERT( GetType() == data.GetType() );\
 424 \
 425     classname##VariantData & otherData = (classname##VariantData &) data;\
 426 \
 427     return (otherData.m_value.IsSameAs(m_value));\
 428 }\
 429
 430
 431 // Since we want type safety wxVariant we need to fetch and dynamic_cast
 432 // in a seemingly safe way so the compiler can check, so we define
 433 // a dynamic_cast /wxDynamicCast analogue.
 434
 435 #define wxGetVariantCast(var,classname) \
 436     ((classname*)(var.IsValueKindOf(&classname::ms_classInfo) ?\
 437                   var.GetWxObjectPtr() : NULL));
 438
 439 extern wxVariant WXDLLIMPEXP_BASE wxNullVariant;
 440
 441 #endif // wxUSE_VARIANT
 442
 443 #endif // _WX_VARIANT_H_