Q: IMarkupContainer

From:

"Jeffrey Walton" <noloader@gmail.com>

Newsgroups:

microsoft.public.vc.atl

Date:

24 Dec 2006 12:40:51 -0800

Message-ID:

<1166992851.522165.53660@i12g2000cwa.googlegroups.com>

Hi All,

The following code fails if I do not create the IPersistStreamInit
object (and call InitNew()). Loosely speaking, these are steps 3 and 4.
The code fails at pDocument->ParseString(...) because pContainer is
NULL.

My question is, why must I create an intialize a stream to parse an
in-memory document?

Eventually, I'm going to use Richard Lopes's code
(http://groups.google.com/group/microsoft.public.inetsdk.programming.webbrowser_ctl/tree/browse_frm/thread/96ea9f563945a5bb/165efdab2bab6538).
But I'm trying to learn my way around the parser now...

Jeff

//
// Code basis was presented by Asher Kobin
// in 'Lightweight HTML Parsing Using MSHTML'
//
// http://www.codeguru.com/Cpp/I-N/ieprogram/article.php/c4385
//

#define _WIN32_IE 0x0500 // IMarkupServices
#define _WIN32_DCOM // CoInitializeEx(...)

#pragma warning( disable: 4192 )
#pragma warning( disable: 4278 )
#import "mshtml.tlb" // MSHTML Namespace and Guids
#pragma warning( default: 4192 )
#pragma warning( default: 4278 )

#include <windows.h>
#include <atlbase.h> // CComPtr<>, CoInitializeEx, etc
#include <mshtml.h> // MSHTML Object and Interfaces
#include <assert.h>

// Standard C++ Library
#include <iostream>

VOID DumpError( UINT nWhere );
HRESULT hr = S_OK;

int main(int argc, char* argv[])
{
    MSHTML::IHTMLDocument2* pDocument = NULL;
    //IPersistStreamInit* pStream = NULL;
    MSHTML::IMarkupServices* pMarkupServices = NULL;
    MSHTML::IMarkupContainer* pContainer = NULL;
    MSHTML::IMarkupPointer* pBegin = NULL;
    MSHTML::IMarkupPointer* pEnd = NULL;
    MSHTML::IHTMLDocument2* pNewDocument = NULL;

    CComBSTR Page = OLESTR( "<HTML><HEAD><TITLE>Hello World</TITLE>"
);
             Page += OLESTR( "</HEAD><BODY><P>Hello
World</P></<BODY></HTML>" );
    try
    {

///////////////////////////////////////////////////////////////////

        hr = CoInitializeEx( NULL, COINIT_APARTMENTTHREADED );
        if( FAILED( hr ) ) { throw 1; }

///////////////////////////////////////////////////////////////////
        // Create a Document to bootstrap the process
        CoCreateInstance(CLSID_HTMLDocument, NULL,
                         CLSCTX_INPROC_SERVER, IID_IHTMLDocument2,
                         reinterpret_cast<PVOID*>( &pDocument) );
        if( NULL == pDocument ) { throw 2; }

///////////////////////////////////////////////////////////////////
        //hr = pDocument->QueryInterface( IID_IPersistStreamInit,
        // reinterpret_cast<PVOID*>(
&pStream ) );
        //if( FAILED( hr ) ) { throw 3; }

///////////////////////////////////////////////////////////////////
        //hr = pStream->InitNew();
        //if( FAILED( hr ) ) { throw 4; }

///////////////////////////////////////////////////////////////////
        hr = pDocument->QueryInterface( IID_IMarkupServices,
                                        reinterpret_cast<PVOID*>(
&pMarkupServices ) ) ;
        if( FAILED( hr ) ) { throw 5; }

///////////////////////////////////////////////////////////////////
        hr = pMarkupServices->CreateMarkupPointer( &pBegin );
        if( FAILED( hr ) ) { throw 6; }

///////////////////////////////////////////////////////////////////
        hr = pMarkupServices->CreateMarkupPointer( &pEnd );
        if( FAILED( hr ) ) { throw 7; }

///////////////////////////////////////////////////////////////////
        pMarkupServices->ParseString( Page, 0, &pContainer, pBegin,
pEnd );
        if( FAILED( hr ) ) { throw 8; }

///////////////////////////////////////////////////////////////////

        pContainer->QueryInterface( IID_IHTMLDocument,
(PVOID*)&pNewDocument );
        if( FAILED( hr ) ) { throw 9; }

///////////////////////////////////////////////////////////////////

///////////////////////////////////////////////////////////////////
        MSHTML::IHTMLElement* pElement = NULL;
        pNewDocument->get_body( &pElement );
        if( NULL != pElement )
        {
            CComBSTR Body;

            hr = pElement->get_innerText( &Body );

            if( S_OK == hr )
                { std::wcout << (wchar_t*) Body << std::endl; }

            pElement->Release();
        }

///////////////////////////////////////////////////////////////////

///////////////////////////////////////////////////////////////////
    }
    catch( UINT e )
    {
        DumpError( e );
    }

    if( NULL != pDocument ) { pDocument->Release(); }
    // if( NULL != pStream ) { pStream->Release(); }
    if( NULL != pMarkupServices ) { pMarkupServices->Release(); }
    if( NULL != pContainer ) { pContainer->Release(); }
    if( NULL != pBegin ) { pBegin->Release(); }
    if( NULL != pEnd ) { pEnd->Release(); }
    if( NULL != pNewDocument ) { pNewDocument->Release(); }

    CoUninitialize( );

    return HRESULT_CODE( hr );
}

VOID DumpError( UINT nWhere )
{
    CComBSTR error;

    switch( nWhere )
    {
        case 1:
        {
            error = L"CoInitializeEx";
            break;
        }

        case 2:
        {
            error = L"pDocument = NULL";
            break;
        }

        case 3:
        {
            error = L"pDocument->QueryInterface( IPersistStreamInit )";
            break;
        }

        case 4:
        {
            error = L"pStream->InitNew()";
            break;
        }

        case 5:
        {
            error = L"pDocument->QueryInterface( IMarkupServices )";
            break;
        }

        case 6:
        {
            error = L"pMarkupServices->CreateMarkupPointer( pBegin )";
            break;
        }

        case 7:
        {
            error = L"pMarkupServices->CreateMarkupPointer( pEnd )";
            break;
        }

        case 8:
        {
            error = L"pMarkupServices->ParseString()";
            break;
        }

        case 9:
        {
            error = L"pContainer->QueryInterface( NewDocument )";
            break;
        }

        default:
        {
            error = L"Unknown";
        }
    }

    std::wcout << std::endl;
    std::wcout << L"COM Error: " << std::endl << L" ";
    std::wcout << (wchar_t*)error << std::endl ;
    std::wcout << std::hex << L" 0x" <<hr;
    std::wcout << L" (Win32: " << std::dec << HRESULT_CODE( hr );
    std::wcout << L")" << std::endl;
}