readth~1.cpp

This companion disc contains the source code for the sample programs presented in INSIDE VISUAL C++

// ReadThread.cpp (EX26A)

#include "StdAfx.h"
#include "Thread.h"

UINT ReadThreadProc(LPVOID pParam)
{
    USES_CONVERSION;
    LPSTORAGE pStgRoot = NULL;
    // doesn't work without STGM_SHARE_EXCLUSIVE
    g_nIndent = 0;
    if (::StgOpenStorage(T2COLE(g_szRootStorageName), NULL,
        STGM_READ | STGM_SHARE_EXCLUSIVE,
        NULL, 0, &pStgRoot) == S_OK) {
      ASSERT(pStgRoot!= NULL);
      ReadStorage(pStgRoot);
      pStgRoot->Release();
    }
    else {
      AfxMessageBox("Storage file not available or not readable");
    }
    AfxMessageBox("Read complete");
    return 0;
}

void ReadStorage(LPSTORAGE pStg)
// reads one storage -- recursive calls for substorages
{
    USES_CONVERSION;
    LPSTORAGE pSubStg = NULL;
    LPSTREAM pStream = NULL;
    LPENUMSTATSTG pEnum = NULL;
    LPMALLOC pMalloc = NULL; // for freeing statstg
    STATSTG statstg;
    ULONG nLength;
    BYTE buffer[101];

    g_nIndent++;
    ::CoGetMalloc(MEMCTX_TASK, &pMalloc); // assumes AfxOleInit
                                          //  was called
    VERIFY(pStg->EnumElements(0, NULL, 0, &pEnum) == S_OK);
    while (pEnum->Next(1, &statstg, NULL) == S_OK) {
      if (statstg.type == STGTY_STORAGE) {
        VERIFY(pStg->OpenStorage(statstg.pwcsName, NULL,
               STGM_READ | STGM_SHARE_EXCLUSIVE,
               NULL, 0, &pSubStg) == S_OK);
        ASSERT(pSubStg != NULL);
        TRACE("%0.*sStorage = %s\n", (g_nIndent - 1) * 4,
              g_szBlanks, OLE2CT(statstg.pwcsName));
        ReadStorage(pSubStg);
        pSubStg->Release();
      }
      else if (statstg.type == STGTY_STREAM) {
        VERIFY(pStg->OpenStream(statstg.pwcsName, NULL,
               STGM_READ | STGM_SHARE_EXCLUSIVE,
               0, &pStream) == S_OK);
        ASSERT(pStream != NULL);
        TRACE("%0.*sStream = %s\n", (g_nIndent - 1) * 4,
               g_szBlanks, OLE2CT(statstg.pwcsName));
        pStream->Read(buffer, 100, &nLength);
        buffer[nLength] = '\0';
        TRACE("%s\n", buffer);
        pStream->Release();
      }
      else {
        ASSERT(FALSE);  // LockBytes?
      }
      pMalloc->Free(statstg.pwcsName); // avoids memory leaks
    }
    pMalloc->Release();
    pEnum->Release();
    g_nIndent--;
}