axmol/cocos/base/CCRef.cpp

/****************************************************************************
Copyright (c) 2010-2012 cocos2d-x.org
Copyright (c) 2013-2017 Chukong Technologies
Copyright (c) 2017-2018 Xiamen Yaji Software Co., Ltd.

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#include "base/CCRef.h"
#include "base/CCAutoreleasePool.h"
#include "base/ccMacros.h"
#include "base/CCScriptSupport.h"

#if CC_REF_LEAK_DETECTION
#include <algorithm>    // std::find
#include <thread>
#include <mutex>
#include <vector>
#endif

NS_CC_BEGIN

#if CC_REF_LEAK_DETECTION
static void trackRef(Ref* ref);
static void untrackRef(Ref* ref);
#endif

Ref::Ref()
: _referenceCount(1) // when the Ref is created, the reference count of it is 1
#if CC_ENABLE_SCRIPT_BINDING
, _luaID (0)
, _scriptObject(nullptr)
, _rooted(false)
#endif
{
#if CC_ENABLE_SCRIPT_BINDING
    static unsigned int uObjectCount = 0;
    _ID = ++uObjectCount;
#endif
    
#if CC_REF_LEAK_DETECTION
    trackRef(this);
#endif
}

Ref::~Ref()
{
#if CC_ENABLE_SCRIPT_BINDING
    ScriptEngineProtocol* pEngine = ScriptEngineManager::getInstance()->getScriptEngine();
    if (pEngine != nullptr && _luaID)
    {
        // if the object is referenced by Lua engine, remove it
        pEngine->removeScriptObjectByObject(this);
    }
#endif // CC_ENABLE_SCRIPT_BINDING

#if CC_REF_LEAK_DETECTION
    if (_referenceCount != 0)
        untrackRef(this);
#endif
}

void Ref::retain()
{
    CCASSERT(_referenceCount > 0, "reference count should be greater than 0");
    ++_referenceCount;
}

void Ref::release()
{
    CCASSERT(_referenceCount > 0, "reference count should be greater than 0");
    --_referenceCount;

    if (_referenceCount == 0)
    {
#if defined(COCOS2D_DEBUG) && (COCOS2D_DEBUG > 0)
        auto poolManager = PoolManager::getInstance();
        if (!poolManager->getCurrentPool()->isClearing() && poolManager->isObjectInPools(this))
        {
            // Trigger an assert if the reference count is 0 but the Ref is still in autorelease pool.
            // This happens when 'autorelease/release' were not used in pairs with 'new/retain'.
            //
            // Wrong usage (1):
            //
            // auto obj = Node::create();   // Ref = 1, but it's an autorelease Ref which means it was in the autorelease pool.
            // obj->autorelease();   // Wrong: If you wish to invoke autorelease several times, you should retain `obj` first.
            //
            // Wrong usage (2):
            //
            // auto obj = Node::create();
            // obj->release();   // Wrong: obj is an autorelease Ref, it will be released when clearing current pool.
            //
            // Correct usage (1):
            //
            // auto obj = Node::create();
            //                     |-   new Node();     // `new` is the pair of the `autorelease` of next line
            //                     |-   autorelease();  // The pair of `new Node`.
            //
            // obj->retain();
            // obj->autorelease();  // This `autorelease` is the pair of `retain` of previous line.
            //
            // Correct usage (2):
            //
            // auto obj = Node::create();
            // obj->retain();
            // obj->release();   // This `release` is the pair of `retain` of previous line.
            CCASSERT(false, "The reference shouldn't be 0 because it is still in autorelease pool.");
        }
#endif

#if CC_REF_LEAK_DETECTION
        untrackRef(this);
#endif
        delete this;
    }
}

Ref* Ref::autorelease()
{
    PoolManager::getInstance()->getCurrentPool()->addObject(this);
    return this;
}

unsigned int Ref::getReferenceCount() const
{
    return _referenceCount;
}

#if CC_REF_LEAK_DETECTION

static std::vector<Ref*> __refAllocationList;
static std::mutex __refMutex;

void Ref::printLeaks()
{
    std::lock_guard<std::mutex> refLockGuard(__refMutex);
    // Dump Ref object memory leaks
    if (__refAllocationList.empty())
    {
        log("[memory] All Ref objects successfully cleaned up (no leaks detected).\n");
    }
    else
    {
        log("[memory] WARNING: %d Ref objects still active in memory.\n", (int)__refAllocationList.size());

        for (const auto& ref : __refAllocationList)
        {
            CC_ASSERT(ref);
            const char* type = typeid(*ref).name();
            log("[memory] LEAK: Ref object '%s' still active with reference count %d.\n", (type ? type : ""), ref->getReferenceCount());
        }
    }
}

static void trackRef(Ref* ref)
{
    std::lock_guard<std::mutex> refLockGuard(__refMutex);
    CCASSERT(ref, "Invalid parameter, ref should not be null!");

    // Create memory allocation record.
    __refAllocationList.push_back(ref);
}

static void untrackRef(Ref* ref)
{
    std::lock_guard<std::mutex> refLockGuard(__refMutex);
    auto iter = std::find(__refAllocationList.begin(), __refAllocationList.end(), ref);
    if (iter == __refAllocationList.end())
    {
        log("[memory] CORRUPTION: Attempting to free (%s) with invalid ref tracking record.\n", typeid(*ref).name());
        return;
    }

    __refAllocationList.erase(iter);
}

#endif // #if CC_REF_LEAK_DETECTION


NS_CC_END