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 : public wxRefCounter
  59 {
  60     friend class wxVariant;
  61 public:
  62     wxVariantData() { }
  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 protected:
  85     // Protected dtor should make some incompatible code
  86     // break more louder. That is, they should do data->DecRef()
  87     // instead of delete data.
  88     virtual ~wxVariantData() { }
  89 };
  90
  91 /*
  92  * wxVariant can store any kind of data, but has some basic types
  93  * built in.
  94  */
  95
  96 class WXDLLIMPEXP_FWD_BASE wxVariant;
  97
  98 WX_DECLARE_LIST_WITH_DECL(wxVariant, wxVariantList, class WXDLLIMPEXP_BASE);
  99
 100 class WXDLLIMPEXP_BASE wxVariant: public wxObject
 101 {
 102 public:
 103     wxVariant();
 104
 105     wxVariant(const wxVariant& variant);
 106     wxVariant(wxVariantData* data, const wxString& name = wxEmptyString);
 107     virtual ~wxVariant();
 108
 109     // generic assignment
 110     void operator= (const wxVariant& variant);
 111
 112     // Assignment using data, e.g.
 113     // myVariant = new wxStringVariantData("hello");
 114     void operator= (wxVariantData* variantData);
 115
 116     bool operator== (const wxVariant& variant) const;
 117     bool operator!= (const wxVariant& variant) const;
 118
 119     // Sets/gets name
 120     inline void SetName(const wxString& name) { m_name = name; }
 121     inline const wxString& GetName() const { return m_name; }
 122
 123     // Tests whether there is data
 124     bool IsNull() const;
 125
 126     // For compatibility with wxWidgets <= 2.6, this doesn't increase
 127     // reference count.
 128     wxVariantData* GetData() const { return m_data; }
 129     void SetData(wxVariantData* data) ;
 130
 131     // make a 'clone' of the object
 132     void Ref(const wxVariant& clone);
 133
 134     // destroy a reference
 135     void UnRef();
 136
 137     // ensure that the data is exclusive to this variant, and not shared
 138     bool Unshare();
 139
 140     // Make NULL (i.e. delete the data)
 141     void MakeNull();
 142
 143     // Delete data and name
 144     void Clear();
 145
 146     // Returns a string representing the type of the variant,
 147     // e.g. "string", "bool", "stringlist", "list", "double", "long"
 148     wxString GetType() const;
 149
 150     bool IsType(const wxString& type) const;
 151     bool IsValueKindOf(const wxClassInfo* type) const;
 152
 153     // write contents to a string (e.g. for debugging)
 154     wxString MakeString() const;
 155
 156     // double
 157     wxVariant(double val, const wxString& name = wxEmptyString);
 158     bool operator== (double value) const;
 159     bool operator!= (double value) const;
 160     void operator= (double value) ;
 161     inline operator double () const {  return GetDouble(); }
 162     inline double GetReal() const { return GetDouble(); }
 163     double GetDouble() const;
 164
 165     // long
 166     wxVariant(long val, const wxString& name = wxEmptyString);
 167     wxVariant(int val, const wxString& name = wxEmptyString);
 168     wxVariant(short val, const wxString& name = wxEmptyString);
 169     bool operator== (long value) const;
 170     bool operator!= (long value) const;
 171     void operator= (long value) ;
 172     inline operator long () const {  return GetLong(); }
 173     inline long GetInteger() const { return GetLong(); }
 174     long GetLong() const;
 175
 176     // bool
 177     wxVariant(bool val, const wxString& name = wxEmptyString);
 178     bool operator== (bool value) const;
 179     bool operator!= (bool value) const;
 180     void operator= (bool value) ;
 181     inline operator bool () const {  return GetBool(); }
 182     bool GetBool() const ;
 183
 184     // wxDateTime
 185 #if wxUSE_DATETIME
 186     wxVariant(const wxDateTime& val, const wxString& name = wxEmptyString);
 187     bool operator== (const wxDateTime& value) const;
 188     bool operator!= (const wxDateTime& value) const;
 189     void operator= (const wxDateTime& value) ;
 190     inline operator wxDateTime () const { return GetDateTime(); }
 191     wxDateTime GetDateTime() const;
 192 #endif
 193
 194     // wxString
 195     wxVariant(const wxString& val, const wxString& name = wxEmptyString);
 196     // these overloads are necessary to prevent the compiler from using bool
 197     // version instead of wxString one:
 198     wxVariant(const char* val, const wxString& name = wxEmptyString);
 199     wxVariant(const wchar_t* val, const wxString& name = wxEmptyString);
 200     wxVariant(const wxCStrData& val, const wxString& name = wxEmptyString);
 201     wxVariant(const wxScopedCharBuffer& val, const wxString& name = wxEmptyString);
 202     wxVariant(const wxScopedWCharBuffer& val, const wxString& name = wxEmptyString);
 203
 204     bool operator== (const wxString& value) const;
 205     bool operator!= (const wxString& value) const;
 206     wxVariant& operator=(const wxString& value);
 207     // these overloads are necessary to prevent the compiler from using bool
 208     // version instead of wxString one:
 209     wxVariant& operator=(const char* value)
 210         { return *this = wxString(value); }
 211     wxVariant& operator=(const wchar_t* value)
 212         { return *this = wxString(value); }
 213     wxVariant& operator=(const wxCStrData& value)
 214         { return *this = value.AsString(); }
 215     template<typename T>
 216     wxVariant& operator=(const wxScopedCharTypeBuffer<T>& value)
 217         { return *this = value.data(); }
 218
 219     inline operator wxString () const {  return MakeString(); }
 220     wxString GetString() const;
 221
 222     // wxUniChar
 223     wxVariant(const wxUniChar& val, const wxString& name = wxEmptyString);
 224     wxVariant(const wxUniCharRef& val, const wxString& name = wxEmptyString);
 225     wxVariant(char val, const wxString& name = wxEmptyString);
 226     wxVariant(wchar_t val, const wxString& name = wxEmptyString);
 227     bool operator==(const wxUniChar& value) const;
 228     bool operator==(const wxUniCharRef& value) const { return *this == wxUniChar(value); }
 229     bool operator==(char value) const { return *this == wxUniChar(value); }
 230     bool operator==(wchar_t value) const { return *this == wxUniChar(value); }
 231     bool operator!=(const wxUniChar& value) const { return !(*this == value); }
 232     bool operator!=(const wxUniCharRef& value) const { return !(*this == value); }
 233     bool operator!=(char value) const { return !(*this == value); }
 234     bool operator!=(wchar_t value) const { return !(*this == value); }
 235     wxVariant& operator=(const wxUniChar& value);
 236     wxVariant& operator=(const wxUniCharRef& value) { return *this = wxUniChar(value); }
 237     wxVariant& operator=(char value) { return *this = wxUniChar(value); }
 238     wxVariant& operator=(wchar_t value) { return *this = wxUniChar(value); }
 239     operator wxUniChar() const { return GetChar(); }
 240     operator char() const { return GetChar(); }
 241     operator wchar_t() const { return GetChar(); }
 242     wxUniChar GetChar() const;
 243
 244     // wxArrayString
 245     wxVariant(const wxArrayString& val, const wxString& name = wxEmptyString);
 246     bool operator== (const wxArrayString& value) const;
 247     bool operator!= (const wxArrayString& value) const;
 248     void operator= (const wxArrayString& value);
 249     operator wxArrayString () const { return GetArrayString(); }
 250     wxArrayString GetArrayString() const;
 251
 252     // void*
 253     wxVariant(void* ptr, const wxString& name = wxEmptyString);
 254     bool operator== (void* value) const;
 255     bool operator!= (void* value) const;
 256     void operator= (void* value);
 257     operator void* () const {  return GetVoidPtr(); }
 258     void* GetVoidPtr() const;
 259
 260     // wxObject*
 261     wxVariant(wxObject* ptr, const wxString& name = wxEmptyString);
 262     bool operator== (wxObject* value) const;
 263     bool operator!= (wxObject* value) const;
 264     void operator= (wxObject* value);
 265     wxObject* GetWxObjectPtr() const;
 266
 267
 268     // ------------------------------
 269     // list operations
 270     // ------------------------------
 271
 272     wxVariant(const wxVariantList& val, const wxString& name = wxEmptyString); // List of variants
 273     bool operator== (const wxVariantList& value) const;
 274     bool operator!= (const wxVariantList& value) const;
 275     void operator= (const wxVariantList& value) ;
 276     // Treat a list variant as an array
 277     wxVariant operator[] (size_t idx) const;
 278     wxVariant& operator[] (size_t idx) ;
 279     wxVariantList& GetList() const ;
 280
 281     // Return the number of elements in a list
 282     size_t GetCount() const;
 283
 284     // Make empty list
 285     void NullList();
 286
 287     // Append to list
 288     void Append(const wxVariant& value);
 289
 290     // Insert at front of list
 291     void Insert(const wxVariant& value);
 292
 293     // Returns true if the variant is a member of the list
 294     bool Member(const wxVariant& value) const;
 295
 296     // Deletes the nth element of the list
 297     bool Delete(size_t item);
 298
 299     // Clear list
 300     void ClearList();
 301
 302 public:
 303     // Type conversion
 304     bool Convert(long* value) const;
 305     bool Convert(bool* value) const;
 306     bool Convert(double* value) const;
 307     bool Convert(wxString* value) const;
 308     bool Convert(wxUniChar* value) const;
 309     bool Convert(char* value) const;
 310     bool Convert(wchar_t* value) const;
 311 #if wxUSE_DATETIME
 312     bool Convert(wxDateTime* value) const;
 313 #endif // wxUSE_DATETIME
 314
 315 // Attributes
 316 protected:
 317     wxVariantData*  m_data;
 318     wxString        m_name;
 319
 320 private:
 321     DECLARE_DYNAMIC_CLASS(wxVariant)
 322 };
 323
 324 #define DECLARE_VARIANT_OBJECT(classname) \
 325     DECLARE_VARIANT_OBJECT_EXPORTED(classname, wxEMPTY_PARAMETER_VALUE)
 326
 327 #define DECLARE_VARIANT_OBJECT_EXPORTED(classname,expdecl) \
 328 expdecl classname& operator << ( classname &object, const wxVariant &variant ); \
 329 expdecl wxVariant& operator << ( wxVariant &variant, const classname &object );
 330
 331 #define IMPLEMENT_VARIANT_OBJECT(classname) \
 332     IMPLEMENT_VARIANT_OBJECT_EXPORTED(classname, wxEMPTY_PARAMETER_VALUE)
 333
 334 #define IMPLEMENT_VARIANT_OBJECT_EXPORTED_NO_EQ(classname,expdecl) \
 335 class classname##VariantData: public wxVariantData \
 336 { \
 337 public:\
 338     classname##VariantData() {} \
 339     classname##VariantData( const classname &value ) { m_value = value; } \
 340 \
 341     classname &GetValue() { return m_value; } \
 342 \
 343     virtual bool Eq(wxVariantData& data) const; \
 344 \
 345     virtual wxString GetType() const; \
 346     virtual wxClassInfo* GetValueClassInfo(); \
 347 \
 348     virtual wxVariantData* Clone() const { return new classname##VariantData(m_value); } \
 349 \
 350 protected:\
 351     classname m_value; \
 352 };\
 353 \
 354 wxString classname##VariantData::GetType() const\
 355 {\
 356     return m_value.GetClassInfo()->GetClassName();\
 357 }\
 358 \
 359 wxClassInfo* classname##VariantData::GetValueClassInfo()\
 360 {\
 361     return m_value.GetClassInfo();\
 362 }\
 363 \
 364 expdecl classname& operator << ( classname &value, const wxVariant &variant )\
 365 {\
 366     wxASSERT( variant.GetType() == #classname );\
 367     \
 368     classname##VariantData *data = (classname##VariantData*) variant.GetData();\
 369     value = data->GetValue();\
 370     return value;\
 371 }\
 372 \
 373 expdecl wxVariant& operator << ( wxVariant &variant, const classname &value )\
 374 {\
 375     classname##VariantData *data = new classname##VariantData( value );\
 376     variant.SetData( data );\
 377     return variant;\
 378 }
 379
 380 // implements a wxVariantData-derived class using for the Eq() method the
 381 // operator== which must have been provided by "classname"
 382 #define IMPLEMENT_VARIANT_OBJECT_EXPORTED(classname,expdecl) \
 383 IMPLEMENT_VARIANT_OBJECT_EXPORTED_NO_EQ(classname,wxEMPTY_PARAMETER_VALUE expdecl) \
 384 \
 385 bool classname##VariantData::Eq(wxVariantData& data) const \
 386 {\
 387     wxASSERT( GetType() == data.GetType() );\
 388 \
 389     classname##VariantData & otherData = (classname##VariantData &) data;\
 390 \
 391     return otherData.m_value == m_value;\
 392 }\
 393
 394
 395 // implements a wxVariantData-derived class using for the Eq() method a shallow
 396 // comparison (through wxObject::IsSameAs function)
 397 #define IMPLEMENT_VARIANT_OBJECT_SHALLOWCMP(classname) \
 398     IMPLEMENT_VARIANT_OBJECT_EXPORTED_SHALLOWCMP(classname, wxEMPTY_PARAMETER_VALUE)
 399 #define IMPLEMENT_VARIANT_OBJECT_EXPORTED_SHALLOWCMP(classname,expdecl) \
 400 IMPLEMENT_VARIANT_OBJECT_EXPORTED_NO_EQ(classname,wxEMPTY_PARAMETER_VALUE expdecl) \
 401 \
 402 bool classname##VariantData::Eq(wxVariantData& data) const \
 403 {\
 404     wxASSERT( GetType() == data.GetType() );\
 405 \
 406     classname##VariantData & otherData = (classname##VariantData &) data;\
 407 \
 408     return (otherData.m_value.IsSameAs(m_value));\
 409 }\
 410
 411
 412 // Since we want type safety wxVariant we need to fetch and dynamic_cast
 413 // in a seemingly safe way so the compiler can check, so we define
 414 // a dynamic_cast /wxDynamicCast analogue.
 415
 416 #define wxGetVariantCast(var,classname) \
 417     ((classname*)(var.IsValueKindOf(&classname::ms_classInfo) ?\
 418                   var.GetWxObjectPtr() : NULL));
 419
 420 // Replacement for using wxDynamicCast on a wxVariantData object
 421 #define wxDynamicCastVariantData(data, classname) dynamic_cast<classname*>(data)
 422
 423 extern wxVariant WXDLLIMPEXP_BASE wxNullVariant;
 424
 425 #endif // wxUSE_VARIANT
 426
 427 #endif // _WX_VARIANT_H_