cocos2dx CCHttpRequest里面的内存引用计数的故事

最新推荐文章于 2025-08-16 11:18:44 发布

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最新推荐文章于 2025-08-16 11:18:44 发布

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文章标签：游戏 lua python

原文链接：https://my.oschina.net/u/186074/blog/150497

本文详细解析了Cocos2d-x框架中CCHttpRequest类的生命周期，包括创建、引用计数变化、自动释放过程以及如何在Lua回调函数中正确处理HTTP请求结束时的内存释放，以避免内存泄露。

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CCHttpRequest 本身是一个CCObject 对象，用于lua的create函数默认会retain request对象一次，因此需要在lua的callback函数里面处理结束request之后，需要release对象否则会内存泄露。

实际的引用计数变化的过程如下：

new 引用计数 = 1

autorelease 引用计数先变成2 再变成1 ，将对象加入自动释放池子里面之后，对象引用计数会+1, 接着会调用对象的release方法，对象引用计数又减去1

retain 引用计数变成 2

start 开始http请求，对象加入schedule 的列表里面引用计数+1 引用计数变成3

update 过程中，到下一个update循环的时候，对象的引用计数会减去1，因为自动释放池子release了这个对象，这时候引用计数变成2

http请求处理结束，update函数里面检测结束，取消schedule 更新，但是因为当前在函数体内，所以不会立即release掉request对象，而是等待本次回合结束的时候再release对象

http请求结束，在callback函数里面release 掉对象，引用计数-1 变成 1

在本次更新回合结束，schedule模块，将标记删除的对象的引用计数-1，引用计数 = 0 对象被删除掉。

#include "network/CCHttpRequest.h"
#include "network/CCHttpRequest_impl.h"
#include "cocos2d.h"

#include "CCLuaEngine.h"

using namespace cocos2d;

NS_CC_EXT_BEGIN

CCHttpRequest* CCHttpRequest::createWithUrl(CCHttpRequestDelegate* delegate,
                                            const char* url,
                                            CCHttpRequestMethod method,
                                            bool isAutoReleaseOnFinish)
{
    CCHttpRequest* request = new CCHttpRequest(delegate, url, method, isAutoReleaseOnFinish);
    request->initHttpRequest();
    request->autorelease();
    if (isAutoReleaseOnFinish)
    {
        request->retain();
    }
    return request;
}

CCHttpRequest* CCHttpRequest::createWithUrlLua(int nHandler, const char* url, bool isGet)
{
    CCHttpRequest* request = new CCHttpRequest(NULL, url, isGet?CCHttpRequestMethodGET:CCHttpRequestMethodPOST, true);
    request->m_luaHandler = nHandler;
    request->initHttpRequest();
    request->autorelease();
    request->retain();
    CCLog("request count is? %d", request->retainCount());
    return request;
}

bool CCHttpRequest::initHttpRequest(void)
{
    m_request = new CCHttpRequest_impl(m_url.c_str(), m_method);
    return true;
}

CCHttpRequest::~CCHttpRequest(void)
{
    delete (CCHttpRequest_impl*)m_request;
}

void CCHttpRequest::addRequestHeader(const char* key, const char* value)
{
    if (key && value)
    {
        ((CCHttpRequest_impl*)m_request)->addRequestHeader(key, value);
    }
}

void CCHttpRequest::addPostValue(const char* key, const char* value)
{
    if (key && value)
    {
        ((CCHttpRequest_impl*)m_request)->addPostValue(key, value);
    }
}

void CCHttpRequest::setPostData(const char* data)
{
    if (data)
    {
        ((CCHttpRequest_impl*)m_request)->setPostData(data);
    }
}

void CCHttpRequest::setTimeout(float timeout)
{
    ((CCHttpRequest_impl*)m_request)->setTimeout(timeout);
}

bool CCHttpRequest::getIsInProgress(void)
{
    return ((CCHttpRequest_impl*)m_request)->getIsInProgress();
}

void CCHttpRequest::start(bool isCached)
{
    CCDirector::sharedDirector()->getScheduler()->unscheduleUpdateForTarget(this);
    if (((CCHttpRequest_impl*)m_request)->start())
    {
        CCDirector::sharedDirector()->getScheduler()->scheduleUpdateForTarget(this, 0, false);
    }
}

void CCHttpRequest::cancel(void)
{
    CCDirector::sharedDirector()->getScheduler()->unscheduleUpdateForTarget(this);
    ((CCHttpRequest_impl*)m_request)->cancel();
}

void CCHttpRequest::clearDelegatesAndCancel(void)
{
    m_delegate = NULL;
    cancel();
}

int CCHttpRequest::getResponseStatusCode(void) {
    return ((CCHttpRequest_impl*)m_request)->getResponseStatusCode();
}

const char* CCHttpRequest::getResponseString(void)
{
    return ((CCHttpRequest_impl*)m_request)->getResposeString().c_str();
}

const void* CCHttpRequest::getResponseData(int* dataLength)
{
    return ((CCHttpRequest_impl*)m_request)->getResponseData();
}

int CCHttpRequest::getResponseDataLength()
{
    return ((CCHttpRequest_impl*)m_request)->getResponseDataLength();
}

CCHttpRequestError  CCHttpRequest::getErrorCode(void)
{
    return ((CCHttpRequest_impl*)m_request)->getErrorCode();
}

const char* CCHttpRequest::getErrorMessage(void)
{
    return ((CCHttpRequest_impl*)m_request)->getErrorMessage();
}

void CCHttpRequest::update(float dt)
{
    CCLog("update Request state %d", retainCount());
    CCHttpRequest_impl* request = (CCHttpRequest_impl*)m_request;
    if (!request || !request->getIsInProgress())
    {
        CCDirector::sharedDirector()->getScheduler()->unscheduleUpdateForTarget(this);
    }
    
    if (request->getIsCompleted())
    {
        if (m_delegate) m_delegate->requestFinished(this);
        
        if (m_luaHandler)
        {
			bool isSuc = (request->getErrorCode()==CCHttpRequestErrorNone);
			CCLuaEngine* engine = CCLuaEngine::defaultEngine();

			engine->getLuaStack()->clean();
			engine->getLuaStack()->pushBoolean(isSuc);
			engine->getLuaStack()->executeFunctionByHandler(m_luaHandler, 1);
            CCLog("afterHandler retainCount %d", retainCount());
			/*
            cocos2d::CCLuaValueDict dict;
            dict["name"] = cocos2d::CCLuaValue::stringValue("completed");
            dict["request"] = cocos2d::CCLuaValue::ccobjectValue(this, "CCHttpRequest");
            cocos2d::CCLuaEngine* engine = cocos2d::CCLuaEngine::defaultEngine();
            engine->cleanStack();
            engine->pushCCLuaValueDict(dict);
            engine->executeFunctionByHandler(m_luaHandler, 1);
			*/
        }
        
    }
    else if (request->getIsCancelled())
    {
        if (m_delegate) m_delegate->requestFailed(this);
        
        if (m_luaHandler)
        {
			CCLuaEngine* engine = CCLuaEngine::defaultEngine();

			engine->getLuaStack()->clean();
			engine->getLuaStack()->pushBoolean(false);
			engine->getLuaStack()->executeFunctionByHandler(m_luaHandler, 1);
			/*
            cocos2d::CCLuaValueDict dict;
            dict["name"] = cocos2d::CCLuaValue::stringValue("failed");
            dict["request"] = cocos2d::CCLuaValue::ccobjectValue(this, "CCHttpRequest");
            cocos2d::CCLuaEngine* engine = cocos2d::CCLuaEngine::defaultEngine();
            engine->cleanStack();
            engine->pushCCLuaValueDict(dict);
            engine->executeFunctionByHandler(m_luaHandler, 1);
			*/
        }
    }
}

NS_CC_EXT_END

转载于:https://my.oschina.net/u/186074/blog/150497