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- /////////////////////////////////////////////////////////////////////////////
- // Name: wx/scopedptr.h
- // Purpose: interface of wxScopedPtr
- // Author: wxWidgets team
- // Licence: wxWindows licence
- /////////////////////////////////////////////////////////////////////////////
- /**
- @class wxScopedPtr
- This is a simple scoped smart pointer implementation that is similar to
- the Boost smart pointers (see http://www.boost.org) but rewritten
- to use macros instead.
- Since wxWidgets 2.9.0 there is also a templated version of this class
- with the same name. See wxScopedPtr<T>.
- A smart pointer holds a pointer to an object. The memory used by the object is
- deleted when the smart pointer goes out of scope. This class is different from
- the @c std::auto_ptr<> in so far as it doesn't provide copy constructor
- nor assignment operator. This limits what you can do with it but is much less
- surprising than the "destructive copy" behaviour of the standard class.
- @b Example:
- Below is an example of using a wxWidgets scoped smart pointer and pointer array.
- @code
- class MyClass{ ... };
- // declare a smart pointer to a MyClass called wxMyClassPtr
- wxDECLARE_SCOPED_PTR(MyClass, wxMyClassPtr)
- // declare a smart pointer to an array of chars
- wxDECLARE_SCOPED_ARRAY(char, wxCharArray)
- ...
- // define the first pointer class, must be complete
- wxDEFINE_SCOPED_PTR(MyClass, wxMyClassPtr)
- // define the second pointer class
- wxDEFINE_SCOPED_ARRAY(char, wxCharArray)
- // create an object with a new pointer to MyClass
- wxMyClassPtr theObj(new MyClass());
- // reset the pointer (deletes the previous one)
- theObj.reset(new MyClass());
- // access the pointer
- theObj->MyFunc();
- // create an object with a new array of chars
- wxCharArray theCharObj(new char[100]);
- // access the array
- theCharObj[0] = "!";
- @endcode
- @section scopedptr_newpointers Declaring new smart pointer types
- To declare the smart pointer class @c CLASSNAME containing pointer to
- a (possibly incomplete) type @c TYPE you should use
- @code
- wxDECLARE_SCOPED_PTR( TYPE, // type of the values
- CLASSNAME ); // name of the class
- @endcode
- And later, when @c TYPE is fully defined, you must also use
- @code
- wxDEFINE_SCOPED_PTR( TYPE, CLASSNAME );
- @endcode
- to implement the scoped pointer class.
- The first argument of these macro is the pointer type, the second is the name
- of the new smart pointer class being created. Below we will use wxScopedPtr
- to represent the scoped pointer class, but the user may create the class with
- any legal name.
- Alternatively, if you don't have to separate the point of declaration and
- definition of this class and if you accept the standard naming convention,
- that is that the scoped pointer for the class @c Foo is called @c FooPtr,
- you can use a single macro which replaces two macros above:
- @code
- wxDEFINE_SCOPED_PTR_TYPE( TYPE );
- @endcode
- Once again, in this cass @c CLASSNAME will be @c TYPEPtr.
- @library{wxbase}
- @category{smartpointers}
- @see wxScopedArray
- */
- class wxScopedPtr
- {
- public:
- /**
- Creates the smart pointer with the given pointer or none if @NULL.
- On compilers that support it, this uses the explicit keyword.
- */
- explicit wxScopedPtr(type* T = NULL);
- /**
- Destructor frees the pointer help by this object if it is not @NULL.
- */
- ~wxScopedPtr();
- /**
- This operator gets the pointer stored in the smart pointer or returns
- @NULL if there is none.
- */
- T* get() const;
- /**
- This operator works like the standard C++ pointer operator to return the object
- being pointed to by the pointer.
- If the internal pointer is @NULL this method will cause an assert in debug mode.
- */
- T& operator *() const;
- /**
- Smart pointer member access. Returns pointer to its object.
- If the internal pointer is @NULL this method will cause an assert in debug mode.
- */
- T* operator ->() const;
- /**
- Returns the currently hold pointer and resets the smart pointer object to
- @NULL.
- @remarks
- After a call to this function the caller is responsible for deleting the
- pointer.
- */
- T* release();
- /**
- Deletes the currently held pointer and sets it to @a p or to @NULL if no
- arguments are specified.
- @note
- This function does check to make sure that the pointer you are assigning
- is not the same pointer that is already stored.
- */
- reset(T* p = NULL);
- /**
- Swap the pointer inside the smart pointer with @a other. The pointer being
- swapped must be of the same type (hence the same class name).
- */
- swap(wxScopedPtr& other);
- };
- /**
- @class wxScopedTiedPtr
- This is a variation on the topic of wxScopedPtr. This class is also a smart pointer
- but in addition it "ties" the pointer value to another variable. In other words,
- during the life time of this class the value of that variable is set to be the same
- as the value of the pointer itself and it is reset to its old value when the object
- is destroyed. This class is especially useful when converting the existing code
- (which may already store the pointers value in some variable) to the smart pointers.
- @library{wxbase}
- @category{smartpointers}
- */
- class wxScopedTiedPtr : public wxScopedPtr
- {
- public:
- /**
- Constructor creates a smart pointer initialized with @a ptr and stores
- @a ptr in the location specified by @a ppTie which must not be @NULL.
- */
- wxScopedTiedPtr(T** ppTie, T* ptr);
- /**
- Destructor frees the pointer help by this object and restores the value
- stored at the tied location (as specified in the @ref wxScopedTiedPtr() constructor)
- to the old value.
- @warning
- This location may now contain an uninitialized value if it hadn't been
- initialized previously, in particular don't count on it magically being @NULL!
- */
- ~wxScopedTiedPtr();
- };
- /**
- A scoped pointer template class.
- It is the template version of the old-style @ref wxScopedPtr "scoped pointer macros".
- Notice that objects of this class intentionally cannot be copied.
- @library{wxbase}
- @category{smartpointers}
- @see wxSharedPtr<T>, wxWeakRef<T>
- */
- template<typename T>
- class wxScopedPtr<T>
- {
- public:
- /**
- Constructor takes ownership of the pointer.
- @param ptr
- Pointer allocated with @c new or @NULL.
- */
- wxScopedPtr(T* ptr = NULL);
- /**
- Destructor deletes the pointer.
- */
- ~wxScopedPtr();
- /**
- Returns pointer to object or @NULL.
- */
- T* get() const;
- /**
- Conversion to a boolean expression (in a variant which is not
- convertible to anything but a boolean expression).
- If this class contains a valid pointer it will return @true, if it contains
- a @NULL pointer it will return @false.
- */
- operator unspecified_bool_type() const;
- /**
- Returns a reference to the object.
- If the internal pointer is @NULL this method will cause an assert in debug mode.
- */
- T& operator*() const;
- /**
- Smart pointer member access. Returns pointer to object.
-
- If the internal pointer is @NULL this method will cause an assert in debug mode.
- */
- T* operator->() const;
- /**
- Releases the current pointer and returns it.
- @remarks
- Afterwards the caller is responsible for deleting
- the data contained in the scoped pointer before.
- */
- T* release();
- /**
- Reset pointer to the value of @a ptr.
- The previous pointer will be deleted.
- */
- void reset(T* ptr = NULL);
- /**
- Swaps pointers.
- */
- void swap(wxScopedPtr<T>& ot);
- };
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