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 #include "wx/iosfwrap.h"
  30
  31 /*
  32  * wxVariantData stores the actual data in a wxVariant object,
  33  * to allow it to store any type of data.
  34  * Derive from this to provide custom data handling.
  35  *
  36  * NB: To prevent addition of extra vtbl pointer to wxVariantData,
  37  *     we don't multiple-inherit from wxObjectRefData. Instead,
  38  *     we simply replicate the wxObject ref-counting scheme.
  39  *
  40  * NB: When you construct a wxVariantData, it will have refcount
  41  *     of one. Refcount will not be further increased when
  42  *     it is passed to wxVariant. This simulates old common
  43  *     scenario where wxVariant took ownership of wxVariantData
  44  *     passed to it.
  45  *     If you create wxVariantData for other reasons than passing
  46  *     it to wxVariant, technically you are not required to call
  47  *     DecRef() before deleting it.
  48  *
  49  * TODO: in order to replace wxPropertyValue, we would need
  50  * to consider adding constructors that take pointers to C++ variables,
  51  * or removing that functionality from the wxProperty library.
  52  * Essentially wxPropertyValue takes on some of the wxValidator functionality
  53  * by storing pointers and not just actual values, allowing update of C++ data
  54  * to be handled automatically. Perhaps there's another way of doing this without
  55  * overloading wxVariant with unnecessary functionality.
  56  */
  57
  58 class WXDLLIMPEXP_BASE wxVariantData
  59 {
  60     friend class wxVariant;
  61 public:
  62     wxVariantData() : m_count(1) { }
  63
  64     // Override these to provide common functionality
  65     virtual bool Eq(wxVariantData& data) const = 0;
  66
  67 #if wxUSE_STD_IOSTREAM
  68     virtual bool Write(wxSTD ostream& WXUNUSED(str)) const { return false; }
  69 #endif
  70     virtual bool Write(wxString& WXUNUSED(str)) const { return false; }
  71 #if wxUSE_STD_IOSTREAM
  72     virtual bool Read(wxSTD istream& WXUNUSED(str)) { return false; }
  73 #endif
  74     virtual bool Read(wxString& WXUNUSED(str)) { return false; }
  75     // What type is it? Return a string name.
  76     virtual wxString GetType() const = 0;
  77     // If it based on wxObject return the ClassInfo.
  78     virtual wxClassInfo* GetValueClassInfo() { return NULL; }
  79
  80     // Implement this to make wxVariant::AllocExcusive work. Returns
  81     // a copy of the data.
  82     virtual wxVariantData* Clone() const { 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     // ensure that the data is exclusive to this variant, and not shared
 150     bool Unshare();
 151
 152     // Make NULL (i.e. delete the data)
 153     void MakeNull();
 154
 155     // Delete data and name
 156     void Clear();
 157
 158     // Returns a string representing the type of the variant,
 159     // e.g. "string", "bool", "stringlist", "list", "double", "long"
 160     wxString GetType() const;
 161
 162     bool IsType(const wxString& type) const;
 163     bool IsValueKindOf(const wxClassInfo* type) const;
 164
 165     // write contents to a string (e.g. for debugging)
 166     wxString MakeString() const;
 167
 168     // double
 169     wxVariant(double val, const wxString& name = wxEmptyString);
 170     bool operator== (double value) const;
 171     bool operator!= (double value) const;
 172     void operator= (double value) ;
 173     inline operator double () const {  return GetDouble(); }
 174     inline double GetReal() const { return GetDouble(); }
 175     double GetDouble() const;
 176
 177     // long
 178     wxVariant(long val, const wxString& name = wxEmptyString);
 179     wxVariant(int val, const wxString& name = wxEmptyString);
 180     wxVariant(short val, const wxString& name = wxEmptyString);
 181     bool operator== (long value) const;
 182     bool operator!= (long value) const;
 183     void operator= (long value) ;
 184     inline operator long () const {  return GetLong(); }
 185     inline long GetInteger() const { return GetLong(); }
 186     long GetLong() const;
 187
 188     // bool
 189 #ifdef HAVE_BOOL
 190     wxVariant(bool val, const wxString& name = wxEmptyString);
 191     bool operator== (bool value) const;
 192     bool operator!= (bool value) const;
 193     void operator= (bool value) ;
 194     inline operator bool () const {  return GetBool(); }
 195     bool GetBool() const ;
 196 #endif
 197
 198     // wxDateTime
 199 #if wxUSE_DATETIME
 200     wxVariant(const wxDateTime& val, const wxString& name = wxEmptyString);
 201     bool operator== (const wxDateTime& value) const;
 202     bool operator!= (const wxDateTime& value) const;
 203     void operator= (const wxDateTime& value) ;
 204     inline operator wxDateTime () const { return GetDateTime(); }
 205     wxDateTime GetDateTime() const;
 206 #endif
 207
 208     // wxString
 209     wxVariant(const wxString& val, const wxString& name = wxEmptyString);
 210     // these overloads are necessary to prevent the compiler from using bool
 211     // version instead of wxString one:
 212     wxVariant(const char* val, const wxString& name = wxEmptyString);
 213     wxVariant(const wchar_t* val, const wxString& name = wxEmptyString);
 214     wxVariant(const wxCStrData& val, const wxString& name = wxEmptyString);
 215     wxVariant(const wxCharBuffer& val, const wxString& name = wxEmptyString);
 216     wxVariant(const wxWCharBuffer& val, const wxString& name = wxEmptyString);
 217
 218     bool operator== (const wxString& value) const;
 219     bool operator!= (const wxString& value) const;
 220     wxVariant& operator=(const wxString& value);
 221     // these overloads are necessary to prevent the compiler from using bool
 222     // version instead of wxString one:
 223     wxVariant& operator=(const char* value)
 224         { return *this = wxString(value); }
 225     wxVariant& operator=(const wchar_t* value)
 226         { return *this = wxString(value); }
 227     wxVariant& operator=(const wxCStrData& value)
 228         { return *this = value.AsString(); }
 229     template<typename T>
 230     wxVariant& operator=(const wxCharTypeBuffer<T>& value)
 231         { return *this = value.data(); }
 232
 233     inline operator wxString () const {  return MakeString(); }
 234     wxString GetString() const;
 235
 236     // wxUniChar
 237     wxVariant(const wxUniChar& val, const wxString& name = wxEmptyString);
 238     wxVariant(const wxUniCharRef& val, const wxString& name = wxEmptyString);
 239     wxVariant(char val, const wxString& name = wxEmptyString);
 240     wxVariant(wchar_t val, const wxString& name = wxEmptyString);
 241     bool operator==(const wxUniChar& value) const;
 242     bool operator==(const wxUniCharRef& value) const { return *this == wxUniChar(value); }
 243     bool operator==(char value) const { return *this == wxUniChar(value); }
 244     bool operator==(wchar_t value) const { return *this == wxUniChar(value); }
 245     bool operator!=(const wxUniChar& value) const { return !(*this == value); }
 246     bool operator!=(const wxUniCharRef& value) const { return !(*this == value); }
 247     bool operator!=(char value) const { return !(*this == value); }
 248     bool operator!=(wchar_t value) const { return !(*this == value); }
 249     wxVariant& operator=(const wxUniChar& value);
 250     wxVariant& operator=(const wxUniCharRef& value) { return *this = wxUniChar(value); }
 251     wxVariant& operator=(char value) { return *this = wxUniChar(value); }
 252     wxVariant& operator=(wchar_t value) { return *this = wxUniChar(value); }
 253     operator wxUniChar() const { return GetChar(); }
 254     operator char() const { return GetChar(); }
 255     operator wchar_t() const { return GetChar(); }
 256     wxUniChar GetChar() const;
 257
 258     // wxArrayString
 259     wxVariant(const wxArrayString& val, const wxString& name = wxEmptyString);
 260     bool operator== (const wxArrayString& value) const;
 261     bool operator!= (const wxArrayString& value) const;
 262     void operator= (const wxArrayString& value);
 263     operator wxArrayString () const { return GetArrayString(); }
 264     wxArrayString GetArrayString() const;
 265
 266     // void*
 267     wxVariant(void* ptr, const wxString& name = wxEmptyString);
 268     bool operator== (void* value) const;
 269     bool operator!= (void* value) const;
 270     void operator= (void* value);
 271     operator void* () const {  return GetVoidPtr(); }
 272     void* GetVoidPtr() const;
 273
 274     // wxObject*
 275     wxVariant(wxObject* ptr, const wxString& name = wxEmptyString);
 276     bool operator== (wxObject* value) const;
 277     bool operator!= (wxObject* value) const;
 278     void operator= (wxObject* value);
 279     wxObject* GetWxObjectPtr() const;
 280
 281
 282     // ------------------------------
 283     // list operations
 284     // ------------------------------
 285
 286     wxVariant(const wxVariantList& val, const wxString& name = wxEmptyString); // List of variants
 287     bool operator== (const wxVariantList& value) const;
 288     bool operator!= (const wxVariantList& value) const;
 289     void operator= (const wxVariantList& value) ;
 290     // Treat a list variant as an array
 291     wxVariant operator[] (size_t idx) const;
 292     wxVariant& operator[] (size_t idx) ;
 293     wxVariantList& GetList() const ;
 294
 295     // Return the number of elements in a list
 296     size_t GetCount() const;
 297
 298     // Make empty list
 299     void NullList();
 300
 301     // Append to list
 302     void Append(const wxVariant& value);
 303
 304     // Insert at front of list
 305     void Insert(const wxVariant& value);
 306
 307     // Returns true if the variant is a member of the list
 308     bool Member(const wxVariant& value) const;
 309
 310     // Deletes the nth element of the list
 311     bool Delete(size_t item);
 312
 313     // Clear list
 314     void ClearList();
 315
 316 public:
 317     // Type conversion
 318     bool Convert(long* value) const;
 319     bool Convert(bool* value) const;
 320     bool Convert(double* value) const;
 321     bool Convert(wxString* value) const;
 322     bool Convert(wxUniChar* value) const;
 323     bool Convert(char* value) const;
 324     bool Convert(wchar_t* value) const;
 325 #if wxUSE_DATETIME
 326     bool Convert(wxDateTime* value) const;
 327 #endif // wxUSE_DATETIME
 328
 329 // Attributes
 330 protected:
 331     wxVariantData*  m_data;
 332     wxString        m_name;
 333
 334 private:
 335     DECLARE_DYNAMIC_CLASS(wxVariant)
 336 };
 337
 338 #define DECLARE_VARIANT_OBJECT(classname) \
 339     DECLARE_VARIANT_OBJECT_EXPORTED(classname, wxEMPTY_PARAMETER_VALUE)
 340
 341 #define DECLARE_VARIANT_OBJECT_EXPORTED(classname,expdecl) \
 342 expdecl classname& operator << ( classname &object, const wxVariant &variant ); \
 343 expdecl wxVariant& operator << ( wxVariant &variant, const classname &object );
 344
 345 #define IMPLEMENT_VARIANT_OBJECT(classname) \
 346     IMPLEMENT_VARIANT_OBJECT_EXPORTED(classname, wxEMPTY_PARAMETER_VALUE)
 347
 348 #define IMPLEMENT_VARIANT_OBJECT_EXPORTED_NO_EQ(classname,expdecl) \
 349 class classname##VariantData: public wxVariantData \
 350 { \
 351 public:\
 352     classname##VariantData() {} \
 353     classname##VariantData( const classname &value ) { m_value = value; } \
 354 \
 355     classname &GetValue() { return m_value; } \
 356 \
 357     virtual bool Eq(wxVariantData& data) const; \
 358 \
 359     virtual wxString GetType() const; \
 360     virtual wxClassInfo* GetValueClassInfo(); \
 361 \
 362     virtual wxVariantData* Clone() const { return new classname##VariantData(m_value); } \
 363 \
 364 protected:\
 365     classname m_value; \
 366 };\
 367 \
 368 wxString classname##VariantData::GetType() const\
 369 {\
 370     return m_value.GetClassInfo()->GetClassName();\
 371 }\
 372 \
 373 wxClassInfo* classname##VariantData::GetValueClassInfo()\
 374 {\
 375     return m_value.GetClassInfo();\
 376 }\
 377 \
 378 expdecl classname& operator << ( classname &value, const wxVariant &variant )\
 379 {\
 380     wxASSERT( variant.GetType() == #classname );\
 381     \
 382     classname##VariantData *data = (classname##VariantData*) variant.GetData();\
 383     value = data->GetValue();\
 384     return value;\
 385 }\
 386 \
 387 expdecl wxVariant& operator << ( wxVariant &variant, const classname &value )\
 388 {\
 389     classname##VariantData *data = new classname##VariantData( value );\
 390     variant.SetData( data );\
 391     return variant;\
 392 }
 393
 394 // implements a wxVariantData-derived class using for the Eq() method the
 395 // operator== which must have been provided by "classname"
 396 #define IMPLEMENT_VARIANT_OBJECT_EXPORTED(classname,expdecl) \
 397 IMPLEMENT_VARIANT_OBJECT_EXPORTED_NO_EQ(classname,wxEMPTY_PARAMETER_VALUE expdecl) \
 398 \
 399 bool classname##VariantData::Eq(wxVariantData& data) const \
 400 {\
 401     wxASSERT( GetType() == data.GetType() );\
 402 \
 403     classname##VariantData & otherData = (classname##VariantData &) data;\
 404 \
 405     return otherData.m_value == m_value;\
 406 }\
 407
 408
 409 // implements a wxVariantData-derived class using for the Eq() method a shallow
 410 // comparison (through wxObject::IsSameAs function)
 411 #define IMPLEMENT_VARIANT_OBJECT_SHALLOWCMP(classname) \
 412     IMPLEMENT_VARIANT_OBJECT_EXPORTED_SHALLOWCMP(classname, wxEMPTY_PARAMETER_VALUE)
 413 #define IMPLEMENT_VARIANT_OBJECT_EXPORTED_SHALLOWCMP(classname,expdecl) \
 414 IMPLEMENT_VARIANT_OBJECT_EXPORTED_NO_EQ(classname,wxEMPTY_PARAMETER_VALUE expdecl) \
 415 \
 416 bool classname##VariantData::Eq(wxVariantData& data) const \
 417 {\
 418     wxASSERT( GetType() == data.GetType() );\
 419 \
 420     classname##VariantData & otherData = (classname##VariantData &) data;\
 421 \
 422     return (otherData.m_value.IsSameAs(m_value));\
 423 }\
 424
 425
 426 // Since we want type safety wxVariant we need to fetch and dynamic_cast
 427 // in a seemingly safe way so the compiler can check, so we define
 428 // a dynamic_cast /wxDynamicCast analogue.
 429
 430 #define wxGetVariantCast(var,classname) \
 431     ((classname*)(var.IsValueKindOf(&classname::ms_classInfo) ?\
 432                   var.GetWxObjectPtr() : NULL));
 433
 434 // Replacement for using wxDynamicCast on a wxVariantData object
 435 #define wxDynamicCastVariantData(data, classname) dynamic_cast<classname*>(data)
 436
 437 extern wxVariant WXDLLIMPEXP_BASE wxNullVariant;
 438
 439 #endif // wxUSE_VARIANT
 440
 441 #endif // _WX_VARIANT_H_