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     // Implement this to make wxVariant::AllocExcusive work. Returns
  85     // a copy of the data.
  86     virtual wxVariantData* Clone() const { return NULL; }
  87
  88     void IncRef() { m_count++; }
  89     void DecRef()
  90     {
  91         if ( --m_count == 0 )
  92             delete this;
  93     }
  94
  95     int GetRefCount() const { return m_count; }
  96
  97 protected:
  98     // Protected dtor should make some incompatible code
  99     // break more louder. That is, they should do data->DecRef()
 100     // instead of delete data.
 101     virtual ~wxVariantData() { }
 102
 103 private:
 104     int     m_count;
 105 };
 106
 107 /*
 108  * wxVariant can store any kind of data, but has some basic types
 109  * built in.
 110  */
 111
 112 class WXDLLIMPEXP_FWD_BASE wxVariant;
 113
 114 WX_DECLARE_LIST_WITH_DECL(wxVariant, wxVariantList, class WXDLLIMPEXP_BASE);
 115
 116 class WXDLLIMPEXP_BASE wxVariant: public wxObject
 117 {
 118 public:
 119     wxVariant();
 120
 121     wxVariant(const wxVariant& variant);
 122     wxVariant(wxVariantData* data, const wxString& name = wxEmptyString);
 123     virtual ~wxVariant();
 124
 125     // generic assignment
 126     void operator= (const wxVariant& variant);
 127
 128     // Assignment using data, e.g.
 129     // myVariant = new wxStringVariantData("hello");
 130     void operator= (wxVariantData* variantData);
 131
 132     bool operator== (const wxVariant& variant) const;
 133     bool operator!= (const wxVariant& variant) const;
 134
 135     // Sets/gets name
 136     inline void SetName(const wxString& name) { m_name = name; }
 137     inline const wxString& GetName() const { return m_name; }
 138
 139     // Tests whether there is data
 140     bool IsNull() const;
 141
 142     // For compatibility with wxWidgets <= 2.6, this doesn't increase
 143     // reference count.
 144     wxVariantData* GetData() const { return m_data; }
 145     void SetData(wxVariantData* data) ;
 146
 147     // make a 'clone' of the object
 148     void Ref(const wxVariant& clone);
 149
 150     // destroy a reference
 151     void UnRef();
 152
 153     // ensure that the data is exclusive to this variant, and not shared
 154     bool Unshare();
 155
 156     // Make NULL (i.e. delete the data)
 157     void MakeNull();
 158
 159     // Delete data and name
 160     void Clear();
 161
 162     // Returns a string representing the type of the variant,
 163     // e.g. "string", "bool", "stringlist", "list", "double", "long"
 164     wxString GetType() const;
 165
 166     bool IsType(const wxString& type) const;
 167     bool IsValueKindOf(const wxClassInfo* type) const;
 168
 169     // write contents to a string (e.g. for debugging)
 170     wxString MakeString() const;
 171
 172     // double
 173     wxVariant(double val, const wxString& name = wxEmptyString);
 174     bool operator== (double value) const;
 175     bool operator!= (double value) const;
 176     void operator= (double value) ;
 177     inline operator double () const {  return GetDouble(); }
 178     inline double GetReal() const { return GetDouble(); }
 179     double GetDouble() const;
 180
 181     // long
 182     wxVariant(long val, const wxString& name = wxEmptyString);
 183     wxVariant(int val, const wxString& name = wxEmptyString);
 184     wxVariant(short val, const wxString& name = wxEmptyString);
 185     bool operator== (long value) const;
 186     bool operator!= (long value) const;
 187     void operator= (long value) ;
 188     inline operator long () const {  return GetLong(); }
 189     inline long GetInteger() const { return GetLong(); }
 190     long GetLong() const;
 191
 192     // bool
 193 #ifdef HAVE_BOOL
 194     wxVariant(bool val, const wxString& name = wxEmptyString);
 195     bool operator== (bool value) const;
 196     bool operator!= (bool value) const;
 197     void operator= (bool value) ;
 198     inline operator bool () const {  return GetBool(); }
 199     bool GetBool() const ;
 200 #endif
 201
 202     // wxDateTime
 203 #if wxUSE_DATETIME
 204     wxVariant(const wxDateTime& val, const wxString& name = wxEmptyString);
 205 #if wxUSE_ODBC
 206     wxVariant(const DATE_STRUCT* valptr, const wxString& name = wxEmptyString);
 207     wxVariant(const TIME_STRUCT* valptr, const wxString& name = wxEmptyString);
 208     wxVariant(const TIMESTAMP_STRUCT* valptr, const wxString& name = wxEmptyString);
 209 #endif
 210     bool operator== (const wxDateTime& value) const;
 211     bool operator!= (const wxDateTime& value) const;
 212     void operator= (const wxDateTime& value) ;
 213 #if wxUSE_ODBC
 214     void operator= (const DATE_STRUCT* value) ;
 215     void operator= (const TIME_STRUCT* value) ;
 216     void operator= (const TIMESTAMP_STRUCT* value) ;
 217 #endif
 218     inline operator wxDateTime () const { return GetDateTime(); }
 219     wxDateTime GetDateTime() const;
 220 #endif
 221
 222     // wxString
 223     wxVariant(const wxString& val, const wxString& name = wxEmptyString);
 224     // these overloads are necessary to prevent the compiler from using bool
 225     // version instead of wxString one:
 226     wxVariant(const char* val, const wxString& name = wxEmptyString);
 227     wxVariant(const wchar_t* val, const wxString& name = wxEmptyString);
 228     wxVariant(const wxCStrData& val, const wxString& name = wxEmptyString);
 229     wxVariant(const wxCharBuffer& val, const wxString& name = wxEmptyString);
 230     wxVariant(const wxWCharBuffer& val, const wxString& name = wxEmptyString);
 231
 232     bool operator== (const wxString& value) const;
 233     bool operator!= (const wxString& value) const;
 234     wxVariant& operator=(const wxString& value);
 235     // these overloads are necessary to prevent the compiler from using bool
 236     // version instead of wxString one:
 237     wxVariant& operator=(const char* value)
 238         { return *this = wxString(value); }
 239     wxVariant& operator=(const wchar_t* value)
 240         { return *this = wxString(value); }
 241     wxVariant& operator=(const wxCStrData& value)
 242         { return *this = value.AsString(); }
 243     template<typename T>
 244     wxVariant& operator=(const wxCharTypeBuffer<T>& value)
 245         { return *this = value.data(); }
 246
 247     inline operator wxString () const {  return MakeString(); }
 248     wxString GetString() const;
 249
 250     // wxUniChar
 251     wxVariant(const wxUniChar& val, const wxString& name = wxEmptyString);
 252     wxVariant(const wxUniCharRef& val, const wxString& name = wxEmptyString);
 253     wxVariant(char val, const wxString& name = wxEmptyString);
 254     wxVariant(wchar_t val, const wxString& name = wxEmptyString);
 255     bool operator==(const wxUniChar& value) const;
 256     bool operator==(const wxUniCharRef& value) const { return *this == wxUniChar(value); }
 257     bool operator==(char value) const { return *this == wxUniChar(value); }
 258     bool operator==(wchar_t value) const { return *this == wxUniChar(value); }
 259     bool operator!=(const wxUniChar& value) const { return !(*this == value); }
 260     bool operator!=(const wxUniCharRef& value) const { return !(*this == value); }
 261     bool operator!=(char value) const { return !(*this == value); }
 262     bool operator!=(wchar_t value) const { return !(*this == value); }
 263     wxVariant& operator=(const wxUniChar& value);
 264     wxVariant& operator=(const wxUniCharRef& value) { return *this = wxUniChar(value); }
 265     wxVariant& operator=(char value) { return *this = wxUniChar(value); }
 266     wxVariant& operator=(wchar_t value) { return *this = wxUniChar(value); }
 267     operator wxUniChar() const { return GetChar(); }
 268     operator char() const { return GetChar(); }
 269     operator wchar_t() const { return GetChar(); }
 270     wxUniChar GetChar() const;
 271
 272     // wxArrayString
 273     wxVariant(const wxArrayString& val, const wxString& name = wxEmptyString);
 274     bool operator== (const wxArrayString& value) const;
 275     bool operator!= (const wxArrayString& value) const;
 276     void operator= (const wxArrayString& value);
 277     operator wxArrayString () const { return GetArrayString(); }
 278     wxArrayString GetArrayString() const;
 279
 280     // void*
 281     wxVariant(void* ptr, const wxString& name = wxEmptyString);
 282     bool operator== (void* value) const;
 283     bool operator!= (void* value) const;
 284     void operator= (void* value);
 285     operator void* () const {  return GetVoidPtr(); }
 286     void* GetVoidPtr() const;
 287
 288     // wxObject*
 289     wxVariant(wxObject* ptr, const wxString& name = wxEmptyString);
 290     bool operator== (wxObject* value) const;
 291     bool operator!= (wxObject* value) const;
 292     void operator= (wxObject* value);
 293     wxObject* GetWxObjectPtr() const;
 294
 295
 296     // ------------------------------
 297     // list operations
 298     // ------------------------------
 299
 300     wxVariant(const wxVariantList& val, const wxString& name = wxEmptyString); // List of variants
 301     bool operator== (const wxVariantList& value) const;
 302     bool operator!= (const wxVariantList& value) const;
 303     void operator= (const wxVariantList& value) ;
 304     // Treat a list variant as an array
 305     wxVariant operator[] (size_t idx) const;
 306     wxVariant& operator[] (size_t idx) ;
 307     wxVariantList& GetList() const ;
 308
 309     // Return the number of elements in a list
 310     size_t GetCount() const;
 311
 312     // Make empty list
 313     void NullList();
 314
 315     // Append to list
 316     void Append(const wxVariant& value);
 317
 318     // Insert at front of list
 319     void Insert(const wxVariant& value);
 320
 321     // Returns true if the variant is a member of the list
 322     bool Member(const wxVariant& value) const;
 323
 324     // Deletes the nth element of the list
 325     bool Delete(size_t item);
 326
 327     // Clear list
 328     void ClearList();
 329
 330 public:
 331     // Type conversion
 332     bool Convert(long* value) const;
 333     bool Convert(bool* value) const;
 334     bool Convert(double* value) const;
 335     bool Convert(wxString* value) const;
 336     bool Convert(wxUniChar* value) const;
 337     bool Convert(char* value) const;
 338     bool Convert(wchar_t* value) const;
 339 #if wxUSE_DATETIME
 340     bool Convert(wxDateTime* value) const;
 341 #endif // wxUSE_DATETIME
 342
 343 // Attributes
 344 protected:
 345     wxVariantData*  m_data;
 346     wxString        m_name;
 347
 348 private:
 349     DECLARE_DYNAMIC_CLASS(wxVariant)
 350 };
 351
 352 #define DECLARE_VARIANT_OBJECT(classname) \
 353     DECLARE_VARIANT_OBJECT_EXPORTED(classname, wxEMPTY_PARAMETER_VALUE)
 354
 355 #define DECLARE_VARIANT_OBJECT_EXPORTED(classname,expdecl) \
 356 expdecl classname& operator << ( classname &object, const wxVariant &variant ); \
 357 expdecl wxVariant& operator << ( wxVariant &variant, const classname &object );
 358
 359 #define IMPLEMENT_VARIANT_OBJECT(classname) \
 360     IMPLEMENT_VARIANT_OBJECT_EXPORTED(classname, wxEMPTY_PARAMETER_VALUE)
 361
 362 #define IMPLEMENT_VARIANT_OBJECT_EXPORTED_NO_EQ(classname,expdecl) \
 363 class classname##VariantData: public wxVariantData \
 364 { \
 365 public:\
 366     classname##VariantData() {} \
 367     classname##VariantData( const classname &value ) { m_value = value; } \
 368 \
 369     classname &GetValue() { return m_value; } \
 370 \
 371     virtual bool Eq(wxVariantData& data) const; \
 372 \
 373     virtual wxString GetType() const; \
 374     virtual wxClassInfo* GetValueClassInfo(); \
 375 \
 376     virtual wxVariantData* Clone() const { return new classname##VariantData(m_value); } \
 377 \
 378 protected:\
 379     classname m_value; \
 380 };\
 381 \
 382 wxString classname##VariantData::GetType() const\
 383 {\
 384     return m_value.GetClassInfo()->GetClassName();\
 385 }\
 386 \
 387 wxClassInfo* classname##VariantData::GetValueClassInfo()\
 388 {\
 389     return m_value.GetClassInfo();\
 390 }\
 391 \
 392 expdecl classname& operator << ( classname &value, const wxVariant &variant )\
 393 {\
 394     wxASSERT( variant.GetType() == #classname );\
 395     \
 396     classname##VariantData *data = (classname##VariantData*) variant.GetData();\
 397     value = data->GetValue();\
 398     return value;\
 399 }\
 400 \
 401 expdecl wxVariant& operator << ( wxVariant &variant, const classname &value )\
 402 {\
 403     classname##VariantData *data = new classname##VariantData( value );\
 404     variant.SetData( data );\
 405     return variant;\
 406 }
 407
 408 // implements a wxVariantData-derived class using for the Eq() method the
 409 // operator== which must have been provided by "classname"
 410 #define IMPLEMENT_VARIANT_OBJECT_EXPORTED(classname,expdecl) \
 411 IMPLEMENT_VARIANT_OBJECT_EXPORTED_NO_EQ(classname,wxEMPTY_PARAMETER_VALUE expdecl) \
 412 \
 413 bool classname##VariantData::Eq(wxVariantData& data) const \
 414 {\
 415     wxASSERT( GetType() == data.GetType() );\
 416 \
 417     classname##VariantData & otherData = (classname##VariantData &) data;\
 418 \
 419     return otherData.m_value == m_value;\
 420 }\
 421
 422
 423 // implements a wxVariantData-derived class using for the Eq() method a shallow
 424 // comparison (through wxObject::IsSameAs function)
 425 #define IMPLEMENT_VARIANT_OBJECT_SHALLOWCMP(classname) \
 426     IMPLEMENT_VARIANT_OBJECT_EXPORTED_SHALLOWCMP(classname, wxEMPTY_PARAMETER_VALUE)
 427 #define IMPLEMENT_VARIANT_OBJECT_EXPORTED_SHALLOWCMP(classname,expdecl) \
 428 IMPLEMENT_VARIANT_OBJECT_EXPORTED_NO_EQ(classname,wxEMPTY_PARAMETER_VALUE expdecl) \
 429 \
 430 bool classname##VariantData::Eq(wxVariantData& data) const \
 431 {\
 432     wxASSERT( GetType() == data.GetType() );\
 433 \
 434     classname##VariantData & otherData = (classname##VariantData &) data;\
 435 \
 436     return (otherData.m_value.IsSameAs(m_value));\
 437 }\
 438
 439
 440 // Since we want type safety wxVariant we need to fetch and dynamic_cast
 441 // in a seemingly safe way so the compiler can check, so we define
 442 // a dynamic_cast /wxDynamicCast analogue.
 443
 444 #define wxGetVariantCast(var,classname) \
 445     ((classname*)(var.IsValueKindOf(&classname::ms_classInfo) ?\
 446                   var.GetWxObjectPtr() : NULL));
 447
 448 // Replacement for using wxDynamicCast on a wxVariantData object
 449 #define wxDynamicCastVariantData(data, classname) dynamic_cast<classname*>(data)
 450
 451 extern wxVariant WXDLLIMPEXP_BASE wxNullVariant;
 452
 453 #endif // wxUSE_VARIANT
 454
 455 #endif // _WX_VARIANT_H_