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/*
* Copyright (C) 2005-2012 Team XBMC
* http://www.xbmc.org
*
* This Program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* This Program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with XBMC; see the file COPYING. If not, write to
* the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
* http://www.gnu.org/copyleft/gpl.html
*
*/
#pragma once
/**
* Defining LOG_LIFECYCLE_EVENTS will log all instantiations, deletions
* and also reference countings (increments and decrements) that take
* place on any Addon* class.
*
* Comment out (or uncomment out) to change the setting.
*/
//#define LOG_LIFECYCLE_EVENTS
/**
* Defining XBMC_ADDON_DEBUG_MEMORY will make the Acquire and Release
* methods virtual allow the developer to overload them in a sub-class
* and set breakpoints to aid in debugging. It will also cause the
* reference counting mechanism to never actually delete any AddonClass
* instance allowing for the tracking of more references to (supposedly)
* deallocated classes.
*
* Comment out (or uncomment out) to change the setting.
*/
//#define XBMC_ADDON_DEBUG_MEMORY
#include "AddonString.h"
#include "threads/SingleLock.h"
#include "threads/Atomics.h"
#include "utils/log.h"
#include "AddonUtils.h"
namespace XBMCAddon
{
class LanguageHook;
/**
* This class is the superclass for all reference counted classes in the api.
* It provides a means for the bindings to handle all api objects generically.
*
* It also provides some means for debugging "lifecycle" events (see the above
* description of LOG_LIFECYCLE_EVENTS).
*
* If a scripting language bindings require specific handling there is a
* hook to add in these language specifics that can be set here.
*/
class AddonClass
{
private:
long refs;
String classname;
CCriticalSection thisLock;
bool m_isDeallocating;
#ifdef XBMC_ADDON_DEBUG_MEMORY
bool isDeleted;
#endif
friend class Synchronize;
protected:
LanguageHook* languageHook;
/**
* This method is meant to be called from the destructor of the
* lowest level class.
*
* It's virtual because it's a conveinent place to receive messages that
* we're about to go be deleted but prior to any real tear-down.
*
* Any overloading classes need to remember to pass the call up the chain.
*/
virtual void deallocating()
{
Synchronize lock(*this);
m_isDeallocating = true;
}
// no copying
inline AddonClass(const AddonClass& other) {}
public:
AddonClass(const char* classname);
virtual ~AddonClass();
inline const String& GetClassname() const { return classname; }
inline LanguageHook* GetLanguageHook() { return languageHook; }
/**
* This method should be called while holding a Synchronize
* on the object. It will prevent the deallocation during
* the time it's held.
*/
bool isDeallocating() { TRACE; return m_isDeallocating; }
#ifdef XBMC_ADDON_DEBUG_MEMORY
virtual
#else
inline
#endif
void Release() const
#ifndef XBMC_ADDON_DEBUG_MEMORY
{
long ct = AtomicDecrement((long*)&refs);
#ifdef LOG_LIFECYCLE_EVENTS
CLog::Log(LOGDEBUG,"NEWADDON REFCNT decrementing to %ld on %s 0x%lx", ct,classname.c_str(), (long)(((void*)this)));
#endif
if(ct == 0)
delete this;
}
#else
;
#endif
#ifdef XBMC_ADDON_DEBUG_MEMORY
virtual
#else
inline
#endif
void Acquire() const
#ifndef XBMC_ADDON_DEBUG_MEMORY
{
#ifdef LOG_LIFECYCLE_EVENTS
CLog::Log(LOGDEBUG,"NEWADDON REFCNT incrementing to %ld on %s 0x%lx",
AtomicIncrement((long*)&refs),classname.c_str(), (long)(((void*)this)));
#else
AtomicIncrement((long*)&refs);
#endif
}
#else
;
#endif
#define refcheck
/**
* This class is a smart pointer for a Referenced class.
*/
template <class T> class Ref
{
T * ac;
public:
inline Ref() : ac(NULL) {}
inline Ref(const T* _ac) : ac((T*)_ac) { if (ac) ac->Acquire(); refcheck; }
// copy semantics
inline Ref(Ref<T> const & oref) : ac((T*)(oref.get())) { if (ac) ac->Acquire(); refcheck; }
template<class O> inline Ref(Ref<O> const & oref) : ac(static_cast<T*>(oref.get())) { if (ac) ac->Acquire(); refcheck; }
/**
* operator= should work with either another smart pointer or a pointer since it will
* be able to convert a pointer to a smart pointer using one of the above constuctors.
*
* Note: There is a trick here. The temporary variable is necessary because otherwise the
* following code will fail:
*
* Ref<T> ptr = new T;
* ptr = ptr;
*
* What happens without the tmp is the dereference is called first so the object ends up
* deleted and then the reference happens on a deleted object. The order is reversed
* in the following.
*
* Note: Operator= is ambiguous if you define both an operator=(Ref<T>&) and an operator=(T*). I'm
* opting for the route the boost took here figuring it has more history behind it.
*/
inline Ref<T>& operator=(Ref<T> const & oref)
{ T* tmp = ac; ac=((T*)oref.get()); if (ac) ac->Acquire(); if (tmp) tmp->Release(); refcheck; return *this; }
inline T* operator->() const { refcheck; return ac; }
/**
* This operator doubles as the value in a boolean expression.
*/
inline operator T*() const { refcheck; return ac; }
inline T* get() const { refcheck; return ac; }
inline T& getRef() const { refcheck; return *ac; }
inline ~Ref() { refcheck; if (ac) ac->Release(); }
inline bool isNull() const { refcheck; return ac == NULL; }
inline bool isNotNull() const { refcheck; return ac != NULL; }
inline bool isSet() const { refcheck; return ac != NULL; }
inline bool operator!() const { refcheck; return ac == NULL; }
inline bool operator==(const AddonClass::Ref<T>& oref) const { refcheck; return ac == oref.ac; }
inline bool operator<(const AddonClass::Ref<T>& oref) const { refcheck; return ac < oref.ac; } // std::set semantics
// This is there only for boost compatibility
template<class O> inline void reset(Ref<O> const & oref) { refcheck; (*this) = static_cast<T*>(oref.get()); refcheck; }
template<class O> inline void reset(O * oref) { refcheck; (*this) = static_cast<T*>(oref); refcheck; }
inline void reset() { refcheck; if (ac) ac->Release(); ac = NULL; }
};
/**
* This class can be used like a "synchronize" block in java as long
* as the object is an AddonClass. It can be used to synchronize on
* 'this' effectively creating the effect of a synchronize keyword
* on a method declaration.
*
* Keep in mind that this DOES NOT use 'monitor' semantics, but
* uses MUTEX semantics. That means that using this class, a thread
* can deadlock itself, while in java a synchronize keyword won't.
*/
class Synchronize : public CSingleLock
{
public:
inline Synchronize(const AddonClass& obj) : CSingleLock(obj.thisLock) {}
};
};
}
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