Applied ref-couting patch.

Completely reorganized code (more readable to me).
  Minor other changes.


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@41519 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

docs/latex/wx/variant.tex

@@ -15,7 +15,18 @@ The {\bf wxVariant} class represents a container for any type.
 A variant's value can be changed at run time, possibly to a different type of value.
 
 As standard, wxVariant can store values of type bool, char, double, long, string,
-string list, time, date, void pointer, list of strings, and list of variants. However, an application can extend wxVariant's capabilities by deriving from the class \helpref{wxVariantData}{wxvariantdata} and using the wxVariantData form of the wxVariant constructor or assignment operator to assign this data to a variant. Actual values for user-defined types will need to be accessed via the wxVariantData object, unlike the case for basic data types where convenience functions such as GetLong can be used.
+string list, time, date, void pointer, list of strings, and list of variants. 
+However, an application can extend wxVariant's capabilities by deriving from the
+class \helpref{wxVariantData}{wxvariantdata} and using the wxVariantData form of
+the wxVariant constructor or assignment operator to assign this data to a variant.
+Actual values for user-defined types will need to be accessed via the wxVariantData
+object, unlike the case for basic data types where convenience functions such as
+\helpref{GetLong}{wxvariantgetlong} can be used.
+
+Pointers to any \helpref{wxObject}{helpref} derived class can also easily be stored
+in a wxVariant. wxVariant will then use wxWidgets' built-in RTTI system to set the
+type name (returned by \helpref{GetType}{wxvariantgettype}) and to perform 
+type-safety checks at runtime.
 
 This class is useful for reducing the programming for certain tasks, such as an editor
 for different data types, or a remote procedure call protocol.
@@ -23,6 +34,8 @@ for different data types, or a remote procedure call protocol.
 An optional name member is associated with a wxVariant. This might be used, for example, in CORBA
 or OLE automation classes, where named parameters are required.
 
+Note that as of wxWidgets 2.7.1, wxVariant is reference counted.
+
 \wxheading{Derived from}
 
 \helpref{wxObject}{wxobject}
@@ -114,6 +127,9 @@ Construction from a odbc timestamp value.  Represented internally by a \helpref{
 
 Destructor.
 
+Note that destructor is protected, so wxVariantData cannot usually
+be deleted. Instead, \helpref{DecRef}{wxvariantdatadecref} should be called.
+
 
 \membersection{wxVariant::Append}\label{wxvariantappend}
 
@@ -121,6 +137,13 @@ Destructor.
 
 Appends a value to the list.
 
+\membersection{wxVariant::Clear}\label{wxvariantclear}
+
+\func{void}{Clear}{\void}
+
+Makes the variant null by deleting the internal data and
+set the name to {\it wxEmptyString}.
+
 \membersection{wxVariant::ClearList}\label{wxvariantclearlist}
 
 \func{void}{ClearList}{\void}
@@ -179,7 +202,10 @@ Returns the character value.
 
 \constfunc{wxVariantData*}{GetData}{\void}
 
-Returns a pointer to the internal variant data.
+Returns a pointer to the internal variant data. To take ownership
+of this data, you must call its \helpref{IncRef}{wxvariantdataincref}
+method. When you stop using it, \helpref{DecRef}{wxvariantdatadecref}
+must be likewise called.
 
 \membersection{wxVariant::GetDateTime}\label{wxvariantgetdatetime}
 
@@ -428,6 +454,15 @@ Operator for implicit conversion to a pointer to a \helpref{wxDateTime}{wxdateti
 The {\bf wxVariantData} is used to implement a new type for wxVariant. Derive from wxVariantData,
 and override the pure virtual functions.
 
+wxVariantData is reference counted, but you don't normally have to care about this, as
+wxVariant manages the count automatically. However, incase your application needs to take
+ownership of wxVariantData, be aware that the object is created with reference count of 1,
+and passing it to wxVariant will not increase this. In other words, \helpref{IncRef}{wxvariantdataincref}
+needs to be called only if you both take ownership of wxVariantData and pass it to a wxVariant.
+Also note that the destructor is protected, so you can never explicitly delete a wxVariantData
+instance. Instead, \helpref{DecRef}{wxvariantdatadecref} will delete the object automatically
+when the reference count reaches zero.
+
 \wxheading{Derived from}
 
 \helpref{wxObject}{wxobject}
@@ -448,11 +483,15 @@ and override the pure virtual functions.
 
 Default constructor.
 
-\membersection{wxVariantData::Copy}\label{wxvariantdatacopy}
+\membersection{wxVariantData::DecRef}\label{wxvariantdatadecref}
 
-\func{void}{Copy}{\param{wxVariantData\&}{ data}}
+\func{void}{DecRef}{\void}
 
-Copy the data from `this' object to {\it data}.
+Decreases reference count. If the count reaches zero, the object is
+automatically deleted.
+
+Note that destructor of wxVariantData is protected, so delete
+cannot be used as normal. Instead, DecRef should be called.
 
 \membersection{wxVariantData::Eq}\label{wxvariantdataeq}
 
@@ -473,6 +512,12 @@ Returns the string type of the data.
 If the data is a wxObject returns a pointer to the objects wxClassInfo structure, if
 the data isn't a wxObject the method returns NULL.
 
+\membersection{wxVariantData::IncRef}\label{wxvariantdataincref}
+
+\func{void}{IncRef}{\void}
+
+Increases reference count. Note that initially wxVariantData has reference count of 1.
+
 \membersection{wxVariantData::Read}\label{wxvariantdataread}
 
 \func{bool}{Read}{\param{ostream\&}{ stream}}

include/wx/variant.h

@@ -36,6 +36,19 @@
  * to allow it to store any type of data.
  * Derive from this to provide custom data handling.
  *
+ * NB: To prevent addition of extra vtbl pointer to wxVariantData,
+ *     we don't multiple-inherit from wxObjectRefData. Instead,
+ *     we simply replicate the wxObject ref-counting scheme.
+ *
+ * NB: When you construct a wxVariantData, it will have refcount
+ *     of one. Refcount will not be further increased when
+ *     it is passed to wxVariant. This simulates old common
+ *     scenario where wxVariant took ownership of wxVariantData
+ *     passed to it.
+ *     If you create wxVariantData for other reasons than passing
+ *     it to wxVariant, technically you are not required to call
+ *     DecRef() before deleting it.
+ *
  * TODO: in order to replace wxPropertyValue, we would need
  * to consider adding constructors that take pointers to C++ variables,
  * or removing that functionality from the wxProperty library.
@@ -47,165 +60,98 @@
 
 class WXDLLIMPEXP_BASE wxVariantData: public wxObject
 {
-DECLARE_ABSTRACT_CLASS(wxVariantData)
+    friend class wxVariant;
 public:
+    wxVariantData()
+        : wxObject(), m_count(1)
+    { }
 
-// Construction & destruction
+    // Override these to provide common functionality
-    wxVariantData() {}
-
-// Override these to provide common functionality
-    // Copy to data
-    virtual void Copy(wxVariantData& data) = 0;
     virtual bool Eq(wxVariantData& data) const = 0;
+    
 #if wxUSE_STD_IOSTREAM
-    virtual bool Write(wxSTD ostream& str) const = 0;
+    virtual bool Write(wxSTD ostream& str) const { return false; }
 #endif
-    virtual bool Write(wxString& str) const = 0;
+    virtual bool Write(wxString& str) const { return false; }
 #if wxUSE_STD_IOSTREAM
-    virtual bool Read(wxSTD istream& str) = 0;
+    virtual bool Read(wxSTD istream& str) { return false; }
 #endif
-    virtual bool Read(wxString& str) = 0;
+    virtual bool Read(wxString& str) { return false; }
     // What type is it? Return a string name.
     virtual wxString GetType() const = 0;
     // If it based on wxObject return the ClassInfo.
     virtual wxClassInfo* GetValueClassInfo() { return NULL; }
+
+    void IncRef() { m_count++; }
+    void DecRef()
+    {
+        if ( --m_count == 0 )
+            delete this;
+    }
+
+    int GetRefCount() const { return m_count; }
+
+protected:
+    // Protected dtor should make some incompatible code
+    // break more louder. That is, they should do data->DecRef()
+    // instead of delete data.
+    virtual ~wxVariantData() { }
+
+private:
+    int     m_count;
+    
+private:
+    DECLARE_ABSTRACT_CLASS(wxVariantData)
 };
 
 /*
  * wxVariant can store any kind of data, but has some basic types
  * built in.
- * NOTE: this eventually should have a reference-counting implementation.
- * PLEASE, if you change it to ref-counting, make sure it doesn't involve bloating
- * this class too much.
  */
 
 class WXDLLIMPEXP_BASE wxVariant: public wxObject
 {
-DECLARE_DYNAMIC_CLASS(wxVariant)
 public:
-
-// Construction & destruction
     wxVariant();
-    wxVariant(double val, const wxString& name = wxEmptyString);
-    wxVariant(long val, const wxString& name = wxEmptyString);
-#ifdef HAVE_BOOL
-    wxVariant(bool val, const wxString& name = wxEmptyString);
-#endif
-    wxVariant(char val, const wxString& name = wxEmptyString);
-    wxVariant(const wxString& val, const wxString& name = wxEmptyString);
-    wxVariant(const wxChar* val, const wxString& name = wxEmptyString); // Necessary or VC++ assumes bool!
-#if WXWIN_COMPATIBILITY_2_4
-    wxDEPRECATED( wxVariant(const wxStringList& val, const wxString& name = wxEmptyString) );
-#endif
-    wxVariant(const wxList& val, const wxString& name = wxEmptyString); // List of variants
-    wxVariant(void* ptr, const wxString& name = wxEmptyString); // void* (general purpose)
-    wxVariant(wxObject* ptr, const wxString& name = wxEmptyString); //wxObject
-    wxVariant(wxVariantData* data, const wxString& name = wxEmptyString); // User-defined data
-#if wxUSE_DATETIME
-    wxVariant(const wxDateTime& val, const wxString& name = wxEmptyString); // Date
-#endif // wxUSE_DATETIME
-    wxVariant(const wxArrayString& val, const wxString& name = wxEmptyString); // String array
-#if wxUSE_ODBC
-    wxVariant(const DATE_STRUCT* valptr, const wxString& name = wxEmptyString); // DateTime
-    wxVariant(const TIME_STRUCT* valptr, const wxString& name = wxEmptyString); // DateTime
-    wxVariant(const TIMESTAMP_STRUCT* valptr, const wxString& name = wxEmptyString); // DateTime
-#endif
     
     wxVariant(const wxVariant& variant);
+    wxVariant(wxVariantData* data, const wxString& name = wxEmptyString);
     virtual ~wxVariant();
 
-// Generic operators
+    // generic assignment
-    // Assignment
     void operator= (const wxVariant& variant);
 
-#if wxUSE_DATETIME
-    bool operator== (const wxDateTime& value) const;
-    bool operator!= (const wxDateTime& value) const;
-    void operator= (const wxDateTime& value) ;
-#endif // wxUSE_DATETIME
-
-    bool operator== (const wxArrayString& value) const;
-    bool operator!= (const wxArrayString& value) const;
-    void operator= (const wxArrayString& value) ;
-#if wxUSE_ODBC
-    void operator= (const DATE_STRUCT* value) ;
-    void operator= (const TIME_STRUCT* value) ;
-    void operator= (const TIMESTAMP_STRUCT* value) ;
-#endif
-
     // Assignment using data, e.g.
     // myVariant = new wxStringVariantData("hello");
     void operator= (wxVariantData* variantData);
+    
     bool operator== (const wxVariant& variant) const;
     bool operator!= (const wxVariant& variant) const;
 
-// Specific operators
-    bool operator== (double value) const;
-    bool operator!= (double value) const;
-    void operator= (double value) ;
-    bool operator== (long value) const;
-    bool operator!= (long value) const;
-    void operator= (long value) ;
-    bool operator== (char value) const;
-    bool operator!= (char value) const;
-    void operator= (char value) ;
-#ifdef HAVE_BOOL
-    bool operator== (bool value) const;
-    bool operator!= (bool value) const;
-    void operator= (bool value) ;
-#endif
-    bool operator== (const wxString& value) const;
-    bool operator!= (const wxString& value) const;
-    void operator= (const wxString& value) ;
-    void operator= (const wxChar* value) ; // Necessary or VC++ assumes bool!
-#if WXWIN_COMPATIBILITY_2_4
-    wxDEPRECATED( bool operator== (const wxStringList& value) const );
-    wxDEPRECATED( bool operator!= (const wxStringList& value) const );
-    wxDEPRECATED( void operator= (const wxStringList& value) );
-#endif
-    bool operator== (const wxList& value) const;
-    bool operator!= (const wxList& value) const;
-    void operator= (const wxList& value) ;
-    bool operator== (void* value) const;
-    bool operator!= (void* value) const;
-    void operator= (void* value);
-    bool operator== (wxObject* value) const;
-    bool operator!= (wxObject* value) const;
-    void operator= (wxObject* value);
-    
-
-    // Treat a list variant as an array
-    wxVariant operator[] (size_t idx) const;
-    wxVariant& operator[] (size_t idx) ;
-
-    // Implicit conversion to a wxString
-    inline operator wxString () const {  return MakeString(); }
-    wxString MakeString() const;
-
-    // Other implicit conversions
-    inline operator double () const {  return GetDouble(); }
-    inline operator char () const {  return GetChar(); }
-    inline operator long () const {  return GetLong(); }
-    inline operator bool () const {  return GetBool(); }
-    inline operator void* () const {  return GetVoidPtr(); }
-    // No implicit conversion to wxObject, as that would really
-    //  confuse people between conversion to our contained data
-    //  and downcasting to see our base type.
-#if wxUSE_DATETIME
-    inline operator wxDateTime () const { return GetDateTime(); }
-#endif // wxUSE_DATETIME
-
-// Accessors
     // Sets/gets name
     inline void SetName(const wxString& name) { m_name = name; }
     inline const wxString& GetName() const { return m_name; }
 
     // Tests whether there is data
-    inline bool IsNull() const { return (m_data == (wxVariantData*) NULL); }
+    bool IsNull() const; 
 
+    // For compatibility with wxWidgets <= 2.6, this doesn't increase
+    // reference count.
     wxVariantData* GetData() const { return m_data; }
     void SetData(wxVariantData* data) ;
 
+    // make a 'clone' of the object
+    void Ref(const wxVariant& clone);
+
+    // destroy a reference
+    void UnRef();
+
+    // Make NULL (i.e. delete the data)
+    void MakeNull();
+    
+    // Delete data and name
+    void Clear();
+    
     // Returns a string representing the type of the variant,
     // e.g. "string", "bool", "stringlist", "list", "double", "long"
     wxString GetType() const;
@@ -213,31 +159,124 @@ public:
     bool IsType(const wxString& type) const;
     bool IsValueKindOf(const wxClassInfo* type) const;
 
-    // Return the number of elements in a list
+    // write contents to a string (e.g. for debugging)    
-    size_t GetCount() const;
+    wxString MakeString() const;
     
-// Value accessors
+    // double
-    double GetReal() const ;
+    wxVariant(double val, const wxString& name = wxEmptyString);
-    inline double GetDouble() const { return GetReal(); };
+    bool operator== (double value) const;
-    long GetInteger() const ;
+    bool operator!= (double value) const;
-    inline long GetLong() const { return GetInteger(); };
+    void operator= (double value) ;
-    char GetChar() const ;
+    inline operator double () const {  return GetDouble(); }
+    inline double GetReal() const { return GetDouble(); }
+    double GetDouble() const;
+    
+    // long
+    wxVariant(long val, const wxString& name = wxEmptyString);
+    wxVariant(int val, const wxString& name = wxEmptyString);
+    wxVariant(short val, const wxString& name = wxEmptyString);
+    bool operator== (long value) const;
+    bool operator!= (long value) const;
+    void operator= (long value) ;
+    inline operator long () const {  return GetLong(); }
+    inline long GetInteger() const { return GetLong(); }
+    long GetLong() const;
+    
+    // bool    
+#ifdef HAVE_BOOL
+    wxVariant(bool val, const wxString& name = wxEmptyString);
+    bool operator== (bool value) const;
+    bool operator!= (bool value) const;
+    void operator= (bool value) ;
+    inline operator bool () const {  return GetBool(); }
     bool GetBool() const ;
-    wxString GetString() const ;
-    wxList& GetList() const ;
-#if WXWIN_COMPATIBILITY_2_4
-    wxDEPRECATED( wxStringList& GetStringList() const );
 #endif
-    void* GetVoidPtr() const;
+
-    wxObject* GetWxObjectPtr() const;
+    // wxDateTime
 #if wxUSE_DATETIME
-    wxDateTime GetDateTime() const ;
+    wxVariant(const wxDateTime& val, const wxString& name = wxEmptyString); 
-#endif // wxUSE_DATETIME
+#if wxUSE_ODBC
+    wxVariant(const DATE_STRUCT* valptr, const wxString& name = wxEmptyString);
+    wxVariant(const TIME_STRUCT* valptr, const wxString& name = wxEmptyString);
+    wxVariant(const TIMESTAMP_STRUCT* valptr, const wxString& name = wxEmptyString);
+#endif
+    bool operator== (const wxDateTime& value) const;
+    bool operator!= (const wxDateTime& value) const;
+    void operator= (const wxDateTime& value) ;
+#if wxUSE_ODBC
+    void operator= (const DATE_STRUCT* value) ;
+    void operator= (const TIME_STRUCT* value) ;
+    void operator= (const TIMESTAMP_STRUCT* value) ;
+#endif
+    inline operator wxDateTime () const { return GetDateTime(); }
+    wxDateTime GetDateTime() const;
+#endif
+
+    // wxString
+    wxVariant(const wxString& val, const wxString& name = wxEmptyString);
+    wxVariant(const wxChar* val, const wxString& name = wxEmptyString); // Necessary or VC++ assumes bool!
+    bool operator== (const wxString& value) const;
+    bool operator!= (const wxString& value) const;
+    void operator= (const wxString& value) ;
+    void operator= (const wxChar* value) ; // Necessary or VC++ assumes bool!
+    inline operator wxString () const {  return MakeString(); }
+    wxString GetString() const;
+
+    // char (wxChar?)
+    wxVariant(char val, const wxString& name = wxEmptyString);
+    bool operator== (char value) const;
+    bool operator!= (char value) const;
+    void operator= (char value) ;
+    inline operator char () const { return GetChar(); }
+    char GetChar() const ;
+    
+    // wxArrayString
+    wxVariant(const wxArrayString& val, const wxString& name = wxEmptyString);
+    bool operator== (const wxArrayString& value) const;
+    bool operator!= (const wxArrayString& value) const;
+    void operator= (const wxArrayString& value);
+    inline operator wxArrayString () const { return GetArrayString(); }
     wxArrayString GetArrayString() const;
 
-// Operations
+    // void*
-    // Make NULL (i.e. delete the data)
+    wxVariant(void* ptr, const wxString& name = wxEmptyString);
-    void MakeNull();
+    bool operator== (void* value) const;
+    bool operator!= (void* value) const;
+    void operator= (void* value);
+    inline operator void* () const {  return GetVoidPtr(); }
+    void* GetVoidPtr() const;
+
+    // wxObject*
+    wxVariant(wxObject* ptr, const wxString& name = wxEmptyString);
+    bool operator== (wxObject* value) const;
+    bool operator!= (wxObject* value) const;
+    void operator= (wxObject* value);
+    wxObject* GetWxObjectPtr() const;
+
+
+#if WXWIN_COMPATIBILITY_2_4
+    wxDEPRECATED( wxVariant(const wxStringList& val, const wxString& name = wxEmptyString) );
+    wxDEPRECATED( bool operator== (const wxStringList& value) const );
+    wxDEPRECATED( bool operator!= (const wxStringList& value) const );
+    wxDEPRECATED( void operator= (const wxStringList& value) );
+    wxDEPRECATED( wxStringList& GetStringList() const );
+#endif
+
+    // ------------------------------
+    // list operations
+    // ------------------------------
+
+    wxVariant(const wxList& val, const wxString& name = wxEmptyString); // List of variants
+    bool operator== (const wxList& value) const;
+    bool operator!= (const wxList& value) const;
+    void operator= (const wxList& value) ;
+    // Treat a list variant as an array
+    wxVariant operator[] (size_t idx) const;
+    wxVariant& operator[] (size_t idx) ;
+    wxList& GetList() const ;
+
+    // Return the number of elements in a list
+    size_t GetCount() const;
     
     // Make empty list
     void NullList();
@@ -257,9 +296,8 @@ public:
     // Clear list
     void ClearList();
 
-// Implementation
 public:
-// Type conversion
+    // Type conversion
     bool Convert(long* value) const;
     bool Convert(bool* value) const;
     bool Convert(double* value) const;
@@ -273,6 +311,9 @@ public:
 protected:
     wxVariantData*  m_data;
     wxString        m_name;
+    
+private:
+    DECLARE_DYNAMIC_CLASS(wxVariant)
 };
 
 //Since we want type safety wxVariant we need to fetch and dynamic_cast