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     wxVariant(bool val, const wxString& name = wxEmptyString);
 190     bool operator== (bool value) const;
 191     bool operator!= (bool value) const;
 192     void operator= (bool value) ;
 193     inline operator bool () const {  return GetBool(); }
 194     bool GetBool() const ;
 195
 196     // wxDateTime
 197 #if wxUSE_DATETIME
 198     wxVariant(const wxDateTime& val, const wxString& name = wxEmptyString);
 199     bool operator== (const wxDateTime& value) const;
 200     bool operator!= (const wxDateTime& value) const;
 201     void operator= (const wxDateTime& value) ;
 202     inline operator wxDateTime () const { return GetDateTime(); }
 203     wxDateTime GetDateTime() const;
 204 #endif
 205
 206     // wxString
 207     wxVariant(const wxString& val, const wxString& name = wxEmptyString);
 208     // these overloads are necessary to prevent the compiler from using bool
 209     // version instead of wxString one:
 210     wxVariant(const char* val, const wxString& name = wxEmptyString);
 211     wxVariant(const wchar_t* val, const wxString& name = wxEmptyString);
 212     wxVariant(const wxCStrData& val, const wxString& name = wxEmptyString);
 213     wxVariant(const wxScopedCharBuffer& val, const wxString& name = wxEmptyString);
 214     wxVariant(const wxScopedWCharBuffer& val, const wxString& name = wxEmptyString);
 215
 216     bool operator== (const wxString& value) const;
 217     bool operator!= (const wxString& value) const;
 218     wxVariant& operator=(const wxString& value);
 219     // these overloads are necessary to prevent the compiler from using bool
 220     // version instead of wxString one:
 221     wxVariant& operator=(const char* value)
 222         { return *this = wxString(value); }
 223     wxVariant& operator=(const wchar_t* value)
 224         { return *this = wxString(value); }
 225     wxVariant& operator=(const wxCStrData& value)
 226         { return *this = value.AsString(); }
 227     template<typename T>
 228     wxVariant& operator=(const wxScopedCharTypeBuffer<T>& value)
 229         { return *this = value.data(); }
 230
 231     inline operator wxString () const {  return MakeString(); }
 232     wxString GetString() const;
 233
 234     // wxUniChar
 235     wxVariant(const wxUniChar& val, const wxString& name = wxEmptyString);
 236     wxVariant(const wxUniCharRef& val, const wxString& name = wxEmptyString);
 237     wxVariant(char val, const wxString& name = wxEmptyString);
 238     wxVariant(wchar_t val, const wxString& name = wxEmptyString);
 239     bool operator==(const wxUniChar& value) const;
 240     bool operator==(const wxUniCharRef& value) const { return *this == wxUniChar(value); }
 241     bool operator==(char value) const { return *this == wxUniChar(value); }
 242     bool operator==(wchar_t value) const { return *this == wxUniChar(value); }
 243     bool operator!=(const wxUniChar& value) const { return !(*this == value); }
 244     bool operator!=(const wxUniCharRef& value) const { return !(*this == value); }
 245     bool operator!=(char value) const { return !(*this == value); }
 246     bool operator!=(wchar_t value) const { return !(*this == value); }
 247     wxVariant& operator=(const wxUniChar& value);
 248     wxVariant& operator=(const wxUniCharRef& value) { return *this = wxUniChar(value); }
 249     wxVariant& operator=(char value) { return *this = wxUniChar(value); }
 250     wxVariant& operator=(wchar_t value) { return *this = wxUniChar(value); }
 251     operator wxUniChar() const { return GetChar(); }
 252     operator char() const { return GetChar(); }
 253     operator wchar_t() const { return GetChar(); }
 254     wxUniChar GetChar() const;
 255
 256     // wxArrayString
 257     wxVariant(const wxArrayString& val, const wxString& name = wxEmptyString);
 258     bool operator== (const wxArrayString& value) const;
 259     bool operator!= (const wxArrayString& value) const;
 260     void operator= (const wxArrayString& value);
 261     operator wxArrayString () const { return GetArrayString(); }
 262     wxArrayString GetArrayString() const;
 263
 264     // void*
 265     wxVariant(void* ptr, const wxString& name = wxEmptyString);
 266     bool operator== (void* value) const;
 267     bool operator!= (void* value) const;
 268     void operator= (void* value);
 269     operator void* () const {  return GetVoidPtr(); }
 270     void* GetVoidPtr() const;
 271
 272     // wxObject*
 273     wxVariant(wxObject* ptr, const wxString& name = wxEmptyString);
 274     bool operator== (wxObject* value) const;
 275     bool operator!= (wxObject* value) const;
 276     void operator= (wxObject* value);
 277     wxObject* GetWxObjectPtr() const;
 278
 279
 280     // ------------------------------
 281     // list operations
 282     // ------------------------------
 283
 284     wxVariant(const wxVariantList& val, const wxString& name = wxEmptyString); // List of variants
 285     bool operator== (const wxVariantList& value) const;
 286     bool operator!= (const wxVariantList& value) const;
 287     void operator= (const wxVariantList& value) ;
 288     // Treat a list variant as an array
 289     wxVariant operator[] (size_t idx) const;
 290     wxVariant& operator[] (size_t idx) ;
 291     wxVariantList& GetList() const ;
 292
 293     // Return the number of elements in a list
 294     size_t GetCount() const;
 295
 296     // Make empty list
 297     void NullList();
 298
 299     // Append to list
 300     void Append(const wxVariant& value);
 301
 302     // Insert at front of list
 303     void Insert(const wxVariant& value);
 304
 305     // Returns true if the variant is a member of the list
 306     bool Member(const wxVariant& value) const;
 307
 308     // Deletes the nth element of the list
 309     bool Delete(size_t item);
 310
 311     // Clear list
 312     void ClearList();
 313
 314 public:
 315     // Type conversion
 316     bool Convert(long* value) const;
 317     bool Convert(bool* value) const;
 318     bool Convert(double* value) const;
 319     bool Convert(wxString* value) const;
 320     bool Convert(wxUniChar* value) const;
 321     bool Convert(char* value) const;
 322     bool Convert(wchar_t* value) const;
 323 #if wxUSE_DATETIME
 324     bool Convert(wxDateTime* value) const;
 325 #endif // wxUSE_DATETIME
 326
 327 // Attributes
 328 protected:
 329     wxVariantData*  m_data;
 330     wxString        m_name;
 331
 332 private:
 333     DECLARE_DYNAMIC_CLASS(wxVariant)
 334 };
 335
 336 #define DECLARE_VARIANT_OBJECT(classname) \
 337     DECLARE_VARIANT_OBJECT_EXPORTED(classname, wxEMPTY_PARAMETER_VALUE)
 338
 339 #define DECLARE_VARIANT_OBJECT_EXPORTED(classname,expdecl) \
 340 expdecl classname& operator << ( classname &object, const wxVariant &variant ); \
 341 expdecl wxVariant& operator << ( wxVariant &variant, const classname &object );
 342
 343 #define IMPLEMENT_VARIANT_OBJECT(classname) \
 344     IMPLEMENT_VARIANT_OBJECT_EXPORTED(classname, wxEMPTY_PARAMETER_VALUE)
 345
 346 #define IMPLEMENT_VARIANT_OBJECT_EXPORTED_NO_EQ(classname,expdecl) \
 347 class classname##VariantData: public wxVariantData \
 348 { \
 349 public:\
 350     classname##VariantData() {} \
 351     classname##VariantData( const classname &value ) { m_value = value; } \
 352 \
 353     classname &GetValue() { return m_value; } \
 354 \
 355     virtual bool Eq(wxVariantData& data) const; \
 356 \
 357     virtual wxString GetType() const; \
 358     virtual wxClassInfo* GetValueClassInfo(); \
 359 \
 360     virtual wxVariantData* Clone() const { return new classname##VariantData(m_value); } \
 361 \
 362 protected:\
 363     classname m_value; \
 364 };\
 365 \
 366 wxString classname##VariantData::GetType() const\
 367 {\
 368     return m_value.GetClassInfo()->GetClassName();\
 369 }\
 370 \
 371 wxClassInfo* classname##VariantData::GetValueClassInfo()\
 372 {\
 373     return m_value.GetClassInfo();\
 374 }\
 375 \
 376 expdecl classname& operator << ( classname &value, const wxVariant &variant )\
 377 {\
 378     wxASSERT( variant.GetType() == #classname );\
 379     \
 380     classname##VariantData *data = (classname##VariantData*) variant.GetData();\
 381     value = data->GetValue();\
 382     return value;\
 383 }\
 384 \
 385 expdecl wxVariant& operator << ( wxVariant &variant, const classname &value )\
 386 {\
 387     classname##VariantData *data = new classname##VariantData( value );\
 388     variant.SetData( data );\
 389     return variant;\
 390 }
 391
 392 // implements a wxVariantData-derived class using for the Eq() method the
 393 // operator== which must have been provided by "classname"
 394 #define IMPLEMENT_VARIANT_OBJECT_EXPORTED(classname,expdecl) \
 395 IMPLEMENT_VARIANT_OBJECT_EXPORTED_NO_EQ(classname,wxEMPTY_PARAMETER_VALUE expdecl) \
 396 \
 397 bool classname##VariantData::Eq(wxVariantData& data) const \
 398 {\
 399     wxASSERT( GetType() == data.GetType() );\
 400 \
 401     classname##VariantData & otherData = (classname##VariantData &) data;\
 402 \
 403     return otherData.m_value == m_value;\
 404 }\
 405
 406
 407 // implements a wxVariantData-derived class using for the Eq() method a shallow
 408 // comparison (through wxObject::IsSameAs function)
 409 #define IMPLEMENT_VARIANT_OBJECT_SHALLOWCMP(classname) \
 410     IMPLEMENT_VARIANT_OBJECT_EXPORTED_SHALLOWCMP(classname, wxEMPTY_PARAMETER_VALUE)
 411 #define IMPLEMENT_VARIANT_OBJECT_EXPORTED_SHALLOWCMP(classname,expdecl) \
 412 IMPLEMENT_VARIANT_OBJECT_EXPORTED_NO_EQ(classname,wxEMPTY_PARAMETER_VALUE expdecl) \
 413 \
 414 bool classname##VariantData::Eq(wxVariantData& data) const \
 415 {\
 416     wxASSERT( GetType() == data.GetType() );\
 417 \
 418     classname##VariantData & otherData = (classname##VariantData &) data;\
 419 \
 420     return (otherData.m_value.IsSameAs(m_value));\
 421 }\
 422
 423
 424 // Since we want type safety wxVariant we need to fetch and dynamic_cast
 425 // in a seemingly safe way so the compiler can check, so we define
 426 // a dynamic_cast /wxDynamicCast analogue.
 427
 428 #define wxGetVariantCast(var,classname) \
 429     ((classname*)(var.IsValueKindOf(&classname::ms_classInfo) ?\
 430                   var.GetWxObjectPtr() : NULL));
 431
 432 // Replacement for using wxDynamicCast on a wxVariantData object
 433 #define wxDynamicCastVariantData(data, classname) dynamic_cast<classname*>(data)
 434
 435 extern wxVariant WXDLLIMPEXP_BASE wxNullVariant;
 436
 437 #endif // wxUSE_VARIANT
 438
 439 #endif // _WX_VARIANT_H_