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: When you construct a wxVariantData, it will have refcount
  37  *     of one. Refcount will not be further increased when
  38  *     it is passed to wxVariant. This simulates old common
  39  *     scenario where wxVariant took ownership of wxVariantData
  40  *     passed to it.
  41  *     If you create wxVariantData for other reasons than passing
  42  *     it to wxVariant, technically you are not required to call
  43  *     DecRef() before deleting it.
  44  *
  45  * TODO: in order to replace wxPropertyValue, we would need
  46  * to consider adding constructors that take pointers to C++ variables,
  47  * or removing that functionality from the wxProperty library.
  48  * Essentially wxPropertyValue takes on some of the wxValidator functionality
  49  * by storing pointers and not just actual values, allowing update of C++ data
  50  * to be handled automatically. Perhaps there's another way of doing this without
  51  * overloading wxVariant with unnecessary functionality.
  52  */
  53
  54 class WXDLLIMPEXP_BASE wxVariantData : public wxObjectRefData
  55 {
  56     friend class wxVariant;
  57 public:
  58     wxVariantData() { }
  59
  60     // Override these to provide common functionality
  61     virtual bool Eq(wxVariantData& data) const = 0;
  62
  63 #if wxUSE_STD_IOSTREAM
  64     virtual bool Write(wxSTD ostream& WXUNUSED(str)) const { return false; }
  65 #endif
  66     virtual bool Write(wxString& WXUNUSED(str)) const { return false; }
  67 #if wxUSE_STD_IOSTREAM
  68     virtual bool Read(wxSTD istream& WXUNUSED(str)) { return false; }
  69 #endif
  70     virtual bool Read(wxString& WXUNUSED(str)) { return false; }
  71     // What type is it? Return a string name.
  72     virtual wxString GetType() const = 0;
  73     // If it based on wxObject return the ClassInfo.
  74     virtual wxClassInfo* GetValueClassInfo() { return NULL; }
  75
  76     // Implement this to make wxVariant::UnShare work. Returns
  77     // a copy of the data.
  78     virtual wxVariantData* Clone() const { return NULL; }
  79
  80 protected:
  81     // Protected dtor should make some incompatible code
  82     // break more louder. That is, they should do data->DecRef()
  83     // instead of delete data.
  84     virtual ~wxVariantData() { }
  85 };
  86
  87 /*
  88  * wxVariant can store any kind of data, but has some basic types
  89  * built in.
  90  */
  91
  92 class WXDLLIMPEXP_FWD_BASE wxVariant;
  93
  94 WX_DECLARE_LIST_WITH_DECL(wxVariant, wxVariantList, class WXDLLIMPEXP_BASE);
  95
  96 class WXDLLIMPEXP_BASE wxVariant: public wxObject
  97 {
  98 public:
  99     wxVariant();
 100
 101     wxVariant(const wxVariant& variant);
 102     wxVariant(wxVariantData* data, const wxString& name = wxEmptyString);
 103     virtual ~wxVariant();
 104
 105     // generic assignment
 106     void operator= (const wxVariant& variant);
 107
 108     // Assignment using data, e.g.
 109     // myVariant = new wxStringVariantData("hello");
 110     void operator= (wxVariantData* variantData);
 111
 112     bool operator== (const wxVariant& variant) const;
 113     bool operator!= (const wxVariant& variant) const;
 114
 115     // Sets/gets name
 116     inline void SetName(const wxString& name) { m_name = name; }
 117     inline const wxString& GetName() const { return m_name; }
 118
 119     // Tests whether there is data
 120     bool IsNull() const;
 121
 122     // For compatibility with wxWidgets <= 2.6, this doesn't increase
 123     // reference count.
 124     wxVariantData* GetData() const
 125     {
 126         return (wxVariantData*) m_refData;
 127     }
 128     void SetData(wxVariantData* data) ;
 129
 130     // make a 'clone' of the object
 131     void Ref(const wxVariant& clone) { wxObject::Ref(clone); }
 132
 133     // ensure that the data is exclusive to this variant, and not shared
 134     bool Unshare();
 135
 136     // Make NULL (i.e. delete the data)
 137     void MakeNull();
 138
 139     // Delete data and name
 140     void Clear();
 141
 142     // Returns a string representing the type of the variant,
 143     // e.g. "string", "bool", "stringlist", "list", "double", "long"
 144     wxString GetType() const;
 145
 146     bool IsType(const wxString& type) const;
 147     bool IsValueKindOf(const wxClassInfo* type) const;
 148
 149     // write contents to a string (e.g. for debugging)
 150     wxString MakeString() const;
 151
 152     // double
 153     wxVariant(double val, const wxString& name = wxEmptyString);
 154     bool operator== (double value) const;
 155     bool operator!= (double value) const;
 156     void operator= (double value) ;
 157     inline operator double () const {  return GetDouble(); }
 158     inline double GetReal() const { return GetDouble(); }
 159     double GetDouble() const;
 160
 161     // long
 162     wxVariant(long val, const wxString& name = wxEmptyString);
 163     wxVariant(int val, const wxString& name = wxEmptyString);
 164     wxVariant(short val, const wxString& name = wxEmptyString);
 165     bool operator== (long value) const;
 166     bool operator!= (long value) const;
 167     void operator= (long value) ;
 168     inline operator long () const {  return GetLong(); }
 169     inline long GetInteger() const { return GetLong(); }
 170     long GetLong() const;
 171
 172     // bool
 173     wxVariant(bool val, const wxString& name = wxEmptyString);
 174     bool operator== (bool value) const;
 175     bool operator!= (bool value) const;
 176     void operator= (bool value) ;
 177     inline operator bool () const {  return GetBool(); }
 178     bool GetBool() const ;
 179
 180     // wxDateTime
 181 #if wxUSE_DATETIME
 182     wxVariant(const wxDateTime& val, const wxString& name = wxEmptyString);
 183     bool operator== (const wxDateTime& value) const;
 184     bool operator!= (const wxDateTime& value) const;
 185     void operator= (const wxDateTime& value) ;
 186     inline operator wxDateTime () const { return GetDateTime(); }
 187     wxDateTime GetDateTime() const;
 188 #endif
 189
 190     // wxString
 191     wxVariant(const wxString& val, const wxString& name = wxEmptyString);
 192     // these overloads are necessary to prevent the compiler from using bool
 193     // version instead of wxString one:
 194     wxVariant(const char* val, const wxString& name = wxEmptyString);
 195     wxVariant(const wchar_t* val, const wxString& name = wxEmptyString);
 196     wxVariant(const wxCStrData& val, const wxString& name = wxEmptyString);
 197     wxVariant(const wxScopedCharBuffer& val, const wxString& name = wxEmptyString);
 198     wxVariant(const wxScopedWCharBuffer& val, const wxString& name = wxEmptyString);
 199
 200     bool operator== (const wxString& value) const;
 201     bool operator!= (const wxString& value) const;
 202     wxVariant& operator=(const wxString& value);
 203     // these overloads are necessary to prevent the compiler from using bool
 204     // version instead of wxString one:
 205     wxVariant& operator=(const char* value)
 206         { return *this = wxString(value); }
 207     wxVariant& operator=(const wchar_t* value)
 208         { return *this = wxString(value); }
 209     wxVariant& operator=(const wxCStrData& value)
 210         { return *this = value.AsString(); }
 211     template<typename T>
 212     wxVariant& operator=(const wxScopedCharTypeBuffer<T>& value)
 213         { return *this = value.data(); }
 214
 215     inline operator wxString () const {  return MakeString(); }
 216     wxString GetString() const;
 217
 218     // wxUniChar
 219     wxVariant(const wxUniChar& val, const wxString& name = wxEmptyString);
 220     wxVariant(const wxUniCharRef& val, const wxString& name = wxEmptyString);
 221     wxVariant(char val, const wxString& name = wxEmptyString);
 222     wxVariant(wchar_t val, const wxString& name = wxEmptyString);
 223     bool operator==(const wxUniChar& value) const;
 224     bool operator==(const wxUniCharRef& value) const { return *this == wxUniChar(value); }
 225     bool operator==(char value) const { return *this == wxUniChar(value); }
 226     bool operator==(wchar_t value) const { return *this == wxUniChar(value); }
 227     bool operator!=(const wxUniChar& value) const { return !(*this == value); }
 228     bool operator!=(const wxUniCharRef& value) const { return !(*this == value); }
 229     bool operator!=(char value) const { return !(*this == value); }
 230     bool operator!=(wchar_t value) const { return !(*this == value); }
 231     wxVariant& operator=(const wxUniChar& value);
 232     wxVariant& operator=(const wxUniCharRef& value) { return *this = wxUniChar(value); }
 233     wxVariant& operator=(char value) { return *this = wxUniChar(value); }
 234     wxVariant& operator=(wchar_t value) { return *this = wxUniChar(value); }
 235     operator wxUniChar() const { return GetChar(); }
 236     operator char() const { return GetChar(); }
 237     operator wchar_t() const { return GetChar(); }
 238     wxUniChar GetChar() const;
 239
 240     // wxArrayString
 241     wxVariant(const wxArrayString& val, const wxString& name = wxEmptyString);
 242     bool operator== (const wxArrayString& value) const;
 243     bool operator!= (const wxArrayString& value) const;
 244     void operator= (const wxArrayString& value);
 245     operator wxArrayString () const { return GetArrayString(); }
 246     wxArrayString GetArrayString() const;
 247
 248     // void*
 249     wxVariant(void* ptr, const wxString& name = wxEmptyString);
 250     bool operator== (void* value) const;
 251     bool operator!= (void* value) const;
 252     void operator= (void* value);
 253     operator void* () const {  return GetVoidPtr(); }
 254     void* GetVoidPtr() const;
 255
 256     // wxObject*
 257     wxVariant(wxObject* ptr, const wxString& name = wxEmptyString);
 258     bool operator== (wxObject* value) const;
 259     bool operator!= (wxObject* value) const;
 260     void operator= (wxObject* value);
 261     wxObject* GetWxObjectPtr() const;
 262
 263
 264     // ------------------------------
 265     // list operations
 266     // ------------------------------
 267
 268     wxVariant(const wxVariantList& val, const wxString& name = wxEmptyString); // List of variants
 269     bool operator== (const wxVariantList& value) const;
 270     bool operator!= (const wxVariantList& value) const;
 271     void operator= (const wxVariantList& value) ;
 272     // Treat a list variant as an array
 273     wxVariant operator[] (size_t idx) const;
 274     wxVariant& operator[] (size_t idx) ;
 275     wxVariantList& GetList() const ;
 276
 277     // Return the number of elements in a list
 278     size_t GetCount() const;
 279
 280     // Make empty list
 281     void NullList();
 282
 283     // Append to list
 284     void Append(const wxVariant& value);
 285
 286     // Insert at front of list
 287     void Insert(const wxVariant& value);
 288
 289     // Returns true if the variant is a member of the list
 290     bool Member(const wxVariant& value) const;
 291
 292     // Deletes the nth element of the list
 293     bool Delete(size_t item);
 294
 295     // Clear list
 296     void ClearList();
 297
 298 public:
 299     // Type conversion
 300     bool Convert(long* value) const;
 301     bool Convert(bool* value) const;
 302     bool Convert(double* value) const;
 303     bool Convert(wxString* value) const;
 304     bool Convert(wxUniChar* value) const;
 305     bool Convert(char* value) const;
 306     bool Convert(wchar_t* value) const;
 307 #if wxUSE_DATETIME
 308     bool Convert(wxDateTime* value) const;
 309 #endif // wxUSE_DATETIME
 310
 311 // Attributes
 312 protected:
 313     virtual wxObjectRefData *CreateRefData() const;
 314     virtual wxObjectRefData *CloneRefData(const wxObjectRefData *data) const;
 315
 316     wxString        m_name;
 317
 318 private:
 319     DECLARE_DYNAMIC_CLASS(wxVariant)
 320 };
 321
 322 #define DECLARE_VARIANT_OBJECT(classname) \
 323     DECLARE_VARIANT_OBJECT_EXPORTED(classname, wxEMPTY_PARAMETER_VALUE)
 324
 325 #define DECLARE_VARIANT_OBJECT_EXPORTED(classname,expdecl) \
 326 expdecl classname& operator << ( classname &object, const wxVariant &variant ); \
 327 expdecl wxVariant& operator << ( wxVariant &variant, const classname &object );
 328
 329 #define IMPLEMENT_VARIANT_OBJECT(classname) \
 330     IMPLEMENT_VARIANT_OBJECT_EXPORTED(classname, wxEMPTY_PARAMETER_VALUE)
 331
 332 #define IMPLEMENT_VARIANT_OBJECT_EXPORTED_NO_EQ(classname,expdecl) \
 333 class classname##VariantData: public wxVariantData \
 334 { \
 335 public:\
 336     classname##VariantData() {} \
 337     classname##VariantData( const classname &value ) { m_value = value; } \
 338 \
 339     classname &GetValue() { return m_value; } \
 340 \
 341     virtual bool Eq(wxVariantData& data) const; \
 342 \
 343     virtual wxString GetType() const; \
 344     virtual wxClassInfo* GetValueClassInfo(); \
 345 \
 346     virtual wxVariantData* Clone() const { return new classname##VariantData(m_value); } \
 347 \
 348 protected:\
 349     classname m_value; \
 350 };\
 351 \
 352 wxString classname##VariantData::GetType() const\
 353 {\
 354     return m_value.GetClassInfo()->GetClassName();\
 355 }\
 356 \
 357 wxClassInfo* classname##VariantData::GetValueClassInfo()\
 358 {\
 359     return m_value.GetClassInfo();\
 360 }\
 361 \
 362 expdecl classname& operator << ( classname &value, const wxVariant &variant )\
 363 {\
 364     wxASSERT( variant.GetType() == #classname );\
 365     \
 366     classname##VariantData *data = (classname##VariantData*) variant.GetData();\
 367     value = data->GetValue();\
 368     return value;\
 369 }\
 370 \
 371 expdecl wxVariant& operator << ( wxVariant &variant, const classname &value )\
 372 {\
 373     classname##VariantData *data = new classname##VariantData( value );\
 374     variant.SetData( data );\
 375     return variant;\
 376 }
 377
 378 // implements a wxVariantData-derived class using for the Eq() method the
 379 // operator== which must have been provided by "classname"
 380 #define IMPLEMENT_VARIANT_OBJECT_EXPORTED(classname,expdecl) \
 381 IMPLEMENT_VARIANT_OBJECT_EXPORTED_NO_EQ(classname,wxEMPTY_PARAMETER_VALUE expdecl) \
 382 \
 383 bool classname##VariantData::Eq(wxVariantData& data) const \
 384 {\
 385     wxASSERT( GetType() == data.GetType() );\
 386 \
 387     classname##VariantData & otherData = (classname##VariantData &) data;\
 388 \
 389     return otherData.m_value == m_value;\
 390 }\
 391
 392
 393 // implements a wxVariantData-derived class using for the Eq() method a shallow
 394 // comparison (through wxObject::IsSameAs function)
 395 #define IMPLEMENT_VARIANT_OBJECT_SHALLOWCMP(classname) \
 396     IMPLEMENT_VARIANT_OBJECT_EXPORTED_SHALLOWCMP(classname, wxEMPTY_PARAMETER_VALUE)
 397 #define IMPLEMENT_VARIANT_OBJECT_EXPORTED_SHALLOWCMP(classname,expdecl) \
 398 IMPLEMENT_VARIANT_OBJECT_EXPORTED_NO_EQ(classname,wxEMPTY_PARAMETER_VALUE expdecl) \
 399 \
 400 bool classname##VariantData::Eq(wxVariantData& data) const \
 401 {\
 402     wxASSERT( GetType() == data.GetType() );\
 403 \
 404     classname##VariantData & otherData = (classname##VariantData &) data;\
 405 \
 406     return (otherData.m_value.IsSameAs(m_value));\
 407 }\
 408
 409
 410 // Since we want type safety wxVariant we need to fetch and dynamic_cast
 411 // in a seemingly safe way so the compiler can check, so we define
 412 // a dynamic_cast /wxDynamicCast analogue.
 413
 414 #define wxGetVariantCast(var,classname) \
 415     ((classname*)(var.IsValueKindOf(&classname::ms_classInfo) ?\
 416                   var.GetWxObjectPtr() : NULL));
 417
 418 // Replacement for using wxDynamicCast on a wxVariantData object
 419 #define wxDynamicCastVariantData(data, classname) dynamic_cast<classname*>(data)
 420
 421 extern wxVariant WXDLLIMPEXP_BASE wxNullVariant;
 422
 423 #endif // wxUSE_VARIANT
 424
 425 #endif // _WX_VARIANT_H_