c++ - COM/ActiveX 和下载地址

Question

我有一个 ActiveX，它向服务器询问 URL 并下载/读取数据并要求新的数据缓冲区直到完成。数据被正确读取，但如果我观察任务管理器，IE 的内存和句柄会上升，而且永远不会下降。进程资源管理器显示句柄是缓存文件。

int AXGetUrl(char*     url,
             void*     buffer,   
             int       buffer_size,
             void*     pUnk)
{
char                    buffer2[256];
int                     rc;
HRESULT                 rc2;
ULONG                   buffer_len;
ULONG                   buffer_len2;
IStream*                pStream;
char                    newurl[1024];
ULONG64                 RequestBytes;
CURLCallBack            UCB;

    //Initialize
    rc = 0;
    rc2 = 0;
    memset(newurl,
           0x00,
           sizeof(newurl));
    buffer_len = 0;
    pStream = NULL;
    RequestBytes = 0;
    strcpy(newurl,
           url);

    rc = URLOpenBlockingStream((IUnknown *)pUnk,
                               url,
                               &pStream,
                               0,
                               &UCB);    
    while (rc == 0)
        {
        if  (pStream != NULL)
            {
            rc2 = pStream->Read(buffer,
                                buffer_size,
                                &buffer_len);
            RequestBytes = RequestBytes + buffer_len;

            pStream->Release();        
            pStream = NULL;

            buildnewurl(newurl,
                        RequestBytes);
            rc = URLOpenBlockingStream((IUnknown *)pUnk,
                                       newurl,
                                       &pStream,
                                       0,
                                       &UCB);
            }
        else
            {
            rc = 1;
            }
        }

    return (rc);
}

更新：

#include "stdafx.h"
#include "Test.h"

Test::Test()
{
}
Test::~Test()
{
}

HRESULT Test::FinalConstruct()
{
void*       pUnk = NULL;
void*       buffer = NULL;
int         buffer_size = 131072;
ULONG       buffer_len = 0;
HRESULT     rc = 0;
HRESULT     rc2 = 0;
IStream*    pStream = NULL;
int         counter = 0;
char        url[1024];

    rc = QueryInterface(IID_IUnknown, &pUnk);
    buffer = malloc(buffer_size);
    if  (buffer != NULL)
        {
        //Get URL
        sprintf(url,
                "http://search.yahoo.com/search?p=%d",
                counter);
        rc = URLOpenBlockingStream((IUnknown *)pUnk,
                                    url,
                                    &pStream,
                                    0,
                                    NULL);    
        while (rc == 0)
            {
            if  (pStream != NULL)
                {
                rc2 = pStream->Read(buffer,
                                    buffer_size,
                                    &buffer_len);
                pStream->Release();        
                pStream = NULL;

                counter++;
                if (counter == 15)
                    {
                    break;
                    }
                sprintf(url,
                        "http://search.yahoo.com/search?p=%d",
                        counter);
                rc = URLOpenBlockingStream((IUnknown *)pUnk,
                                           url,
                                           &pStream,
                                           0,
                                           NULL);
                }
            else
                {
                rc = 1;
                }
            }
        free(buffer);
        }

    return (S_OK);
}

void Test::FinalRelease()
{
    return;
}

Answer 1

您正在调用“URLOpenBlockingStream”以检索流对象，但它返回的流永远不会被删除。假设这IStream是一个 COM 对象，您需要在Release()完成后调用pStream...

rc = URLOpenBlockingStream((IUnknown *)pUnk,
                           url,
                           &pStream,
                           0,
                           &UCB);
while (rc == 0)
{
    // ... your code here...
}

if(pStream != NULL)
{
    pStream->Release();
}