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https://github.com/pocoproject/poco.git
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implement Poco::SharedPtr using std::shared_ptr (#1993)
This commit is contained in:
Günter Obiltschnig
Aleksandar Fabijanic
parent
3ada2d9084
commit
e12458a63a
@ -20,147 +20,67 @@
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#include "Poco/Foundation.h"
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#include "Poco/Exception.h"
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#include "Poco/AtomicCounter.h"
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#include <memory>
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#include <algorithm>
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namespace Poco {
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class ReferenceCounter
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/// Simple ReferenceCounter object, does not delete itself when count reaches 0.
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{
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public:
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ReferenceCounter(): _cnt(1)
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{
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}
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void duplicate()
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{
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++_cnt;
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}
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int release()
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{
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return --_cnt;
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}
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int referenceCount() const
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{
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return _cnt.value();
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}
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private:
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AtomicCounter _cnt;
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};
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//@ deprecated
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template <class C>
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class ReleasePolicy
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/// The default release policy for SharedPtr, which
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/// simply uses the delete operator to delete an object.
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{
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public:
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static void release(C* pObj)
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/// Delete the object.
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/// Note that pObj can be 0.
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{
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delete pObj;
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}
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};
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template <class C>
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class ReleaseArrayPolicy
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/// The release policy for SharedPtr holding arrays.
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{
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public:
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static void release(C* pObj)
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/// Delete the object.
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/// Note that pObj can be 0.
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{
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delete [] pObj;
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}
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};
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template <class C, class RC = ReferenceCounter, class RP = ReleasePolicy<C> >
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class SharedPtr
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/// SharedPtr is a "smart" pointer for classes implementing
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/// reference counting based garbage collection.
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/// SharedPtr is thus similar to AutoPtr. Unlike the
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/// AutoPtr template, which can only be used with
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/// classes that support reference counting, SharedPtr
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/// can be used with any class. For this to work, a
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/// SharedPtr manages a reference count for the object
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/// it manages.
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/// As of POCO C++ Libraries Release 2.0, SharedPtr is a small wrapper around
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/// std::shared_ptr, providing basic backwards compatibility to the 1.x SharedPtr
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/// implementation.
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///
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/// SharedPtr works in the following way:
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/// If an SharedPtr is assigned an ordinary pointer to
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/// an object (via the constructor or the assignment operator),
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/// it takes ownership of the object and the object's reference
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/// count is initialized to one.
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/// If the SharedPtr is assigned another SharedPtr, the
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/// object's reference count is incremented by one.
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/// The destructor of SharedPtr decrements the object's
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/// reference count by one and deletes the object if the
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/// reference count reaches zero.
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/// SharedPtr supports dereferencing with both the ->
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/// and the * operator. An attempt to dereference a null
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/// SharedPtr results in a NullPointerException being thrown.
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/// SharedPtr also implements all relational operators and
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/// a cast operator in case dynamic casting of the encapsulated data types
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/// is required.
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/// Note: ReleasePolicy is no longer supported.
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///
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/// SharedPtr will be removed in a future release. New code should use
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/// std::shared_ptr and existing code should be changed to use std::shared_ptr
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/// instead of Poco::SharedPtr.
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{
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public:
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SharedPtr(): _pCounter(new RC), _ptr(0)
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SharedPtr()
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{
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}
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SharedPtr(C* ptr)
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try:
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_pCounter(new RC),
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SharedPtr(C* ptr):
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_ptr(ptr)
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{
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}
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catch (...)
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SharedPtr(const std::shared_ptr<C>& ptr):
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_ptr(ptr)
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{
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RP::release(ptr);
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}
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template <class Other, class OtherRP>
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SharedPtr(const SharedPtr<Other, RC, OtherRP>& ptr): _pCounter(ptr._pCounter), _ptr(const_cast<Other*>(ptr.get()))
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template <class Other>
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SharedPtr(const SharedPtr<Other>& ptr):
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_ptr(std::dynamic_pointer_cast<C>(ptr.shared_ptr()))
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{
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_pCounter->duplicate();
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}
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SharedPtr(const SharedPtr& ptr): _pCounter(ptr._pCounter), _ptr(ptr._ptr)
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SharedPtr(const SharedPtr& ptr):
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_ptr(ptr._ptr)
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{
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}
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SharedPtr(SharedPtr&& ptr):
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_ptr(std::move(ptr._ptr))
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{
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_pCounter->duplicate();
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}
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~SharedPtr()
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{
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try
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{
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release();
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}
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catch (...)
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{
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poco_unexpected();
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}
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}
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SharedPtr& assign(C* ptr)
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{
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if (get() != ptr)
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{
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SharedPtr tmp(ptr);
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swap(tmp);
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}
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_ptr.reset(ptr);
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return *this;
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}
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SharedPtr& assign(const SharedPtr& ptr)
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{
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if (&ptr != this)
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@ -170,9 +90,9 @@ public:
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}
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return *this;
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}
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template <class Other, class OtherRP>
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SharedPtr& assign(const SharedPtr<Other, RC, OtherRP>& ptr)
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template <class Other>
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SharedPtr& assign(const SharedPtr<Other>& ptr)
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{
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if (ptr.get() != _ptr)
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{
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@ -192,8 +112,8 @@ public:
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return assign(ptr);
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}
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template <class Other, class OtherRP>
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SharedPtr& operator = (const SharedPtr<Other, RC, OtherRP>& ptr)
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template <class Other>
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SharedPtr& operator = (const SharedPtr<Other>& ptr)
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{
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return assign<Other>(ptr);
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}
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@ -201,11 +121,10 @@ public:
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void swap(SharedPtr& ptr)
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{
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std::swap(_ptr, ptr._ptr);
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std::swap(_pCounter, ptr._pCounter);
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}
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template <class Other>
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SharedPtr<Other, RC, RP> cast() const
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SharedPtr<Other> cast() const
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/// Casts the SharedPtr via a dynamic cast to the given type.
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/// Returns an SharedPtr containing NULL if the cast fails.
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/// Example: (assume class Sub: public Super)
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@ -213,22 +132,33 @@ public:
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/// SharedPtr<Sub> sub = super.cast<Sub>();
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/// poco_assert (sub.get());
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{
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Other* pOther = dynamic_cast<Other*>(_ptr);
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if (pOther)
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return SharedPtr<Other, RC, RP>(_pCounter, pOther);
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return SharedPtr<Other, RC, RP>();
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return SharedPtr(std::dynamic_pointer_cast<Other>(_ptr));
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}
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template <class Other>
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SharedPtr<Other, RC, RP> unsafeCast() const
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SharedPtr<Other> unsafeCast() const
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/// Casts the SharedPtr via a static cast to the given type.
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/// Example: (assume class Sub: public Super)
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/// SharedPtr<Super> super(new Sub());
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/// SharedPtr<Sub> sub = super.unsafeCast<Sub>();
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/// poco_assert (sub.get());
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{
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Other* pOther = static_cast<Other*>(_ptr);
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return SharedPtr<Other, RC, RP>(_pCounter, pOther);
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return SharedPtr(std::static_pointer_cast<Other>(_ptr));
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}
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operator std::shared_ptr<C>()
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{
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return _ptr;
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}
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const std::shared_ptr<C>& shared_ptr() const
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{
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return _ptr;
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}
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std::shared_ptr<C>& shared_ptr()
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{
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return _ptr;
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}
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C* operator -> ()
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@ -253,22 +183,22 @@ public:
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C* get()
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{
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return _ptr;
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return _ptr.get();
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}
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const C* get() const
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{
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return _ptr;
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return _ptr.get();
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}
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operator C* ()
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{
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return _ptr;
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return _ptr.get();
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}
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operator const C* () const
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{
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return _ptr;
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return _ptr.get();
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}
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bool operator ! () const
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@ -370,10 +300,10 @@ public:
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{
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return get() >= ptr;
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}
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int referenceCount() const
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long referenceCount() const
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{
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return _pCounter->referenceCount();
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return _ptr.use_count();
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}
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protected:
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@ -382,40 +312,16 @@ protected:
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if (!_ptr)
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throw NullPointerException();
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return _ptr;
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}
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void release()
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{
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poco_assert_dbg (_pCounter);
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int i = _pCounter->release();
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if (i == 0)
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{
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RP::release(_ptr);
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_ptr = 0;
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delete _pCounter;
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_pCounter = 0;
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}
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}
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SharedPtr(RC* pCounter, C* ptr): _pCounter(pCounter), _ptr(ptr)
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/// for cast operation
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{
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poco_assert_dbg (_pCounter);
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_pCounter->duplicate();
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return _ptr.get();
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}
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protected:
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RC* _pCounter;
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C* _ptr;
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template <class OtherC, class OtherRC, class OtherRP> friend class SharedPtr;
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std::shared_ptr<C> _ptr;
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};
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template <class C, class RC, class RP>
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inline void swap(SharedPtr<C, RC, RP>& p1, SharedPtr<C, RC, RP>& p2)
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template <class C>
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inline void swap(SharedPtr<C>& p1, SharedPtr<C>& p2)
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{
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p1.swap(p2);
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}
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@ -28,27 +28,27 @@ namespace
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{
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++_count;
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}
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virtual ~TestObject()
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{
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--_count;
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}
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const std::string& data()
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{
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return _data;
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}
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static int count()
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{
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return _count;
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}
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private:
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std::string _data;
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static int _count;
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};
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int TestObject::_count = 0;
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class DerivedObject: public TestObject
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@ -62,7 +62,7 @@ namespace
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{
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return _number;
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}
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private:
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int _number;
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};
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@ -104,27 +104,27 @@ void SharedPtrTest::testSharedPtr()
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assert (ptr2 == pTO2);
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assert (ptr3.get() == pTO1);
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assert (ptr3 == pTO1);
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assert (ptr1 == pTO1);
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assert (ptr1 != pTO2);
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assert (ptr1 < pTO2);
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assert (ptr1 <= pTO2);
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assert (ptr2 > pTO1);
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assert (ptr2 >= pTO1);
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assert (ptr1 == ptr3);
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assert (ptr1 != ptr2);
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assert (ptr1 < ptr2);
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assert (ptr1 <= ptr2);
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assert (ptr2 > ptr1);
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assert (ptr2 >= ptr1);
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ptr1.swap(ptr2);
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assert (ptr2 < ptr1);
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ptr2.swap(ptr1);
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assert ((ptr1->data() == "one" && ptr2->data() == "two") || (ptr1->data() == "two" && ptr2->data() == "one"));
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try
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{
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assert (ptr4->data() == "four");
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@ -133,28 +133,34 @@ void SharedPtrTest::testSharedPtr()
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catch (NullPointerException&)
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{
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}
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assert (!(ptr4 == ptr1));
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assert (!(ptr4 == ptr2));
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assert (ptr4 != ptr1);
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assert (ptr4 != ptr2);
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ptr4 = ptr2;
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assert (ptr4 == ptr2);
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assert (!(ptr4 != ptr2));
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assert (TestObject::count() == 2);
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ptr1 = 0;
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ptr2 = 0;
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ptr3 = 0;
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ptr4 = 0;
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assert (TestObject::count() == 0);
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{
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SharedPtr<TestObject> ptr = new TestObject("");
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assert (TestObject::count() == 1);
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}
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assert (TestObject::count() == 0);
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std::shared_ptr<TestObject> stdp(std::make_shared<TestObject>(""));
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Poco::SharedPtr<TestObject> ptr5(stdp);
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std::shared_ptr<TestObject> stdp2 = ptr5;
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assert (stdp == stdp2);
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}
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