INFO: Save Message to MSG Compound File

#define INITGUID
#include <objbase.h>

#define USES_IID_IMessage

#include <mapix.h>
#include <mapitags.h>
#include <mapidefs.h>
#include <mapiutil.h>
#include <mapiguid.h>
#include <imessage.h>

// {00020D0B-0000-0000-C000-000000000046}
DEFINE_GUID(CLSID_MailMessage,
0x00020D0B,
0x0000, 0x0000, 0xC0, 0x00, 0x0, 0x00, 0x0, 0x00, 0x00, 0x46);

HRESULT SaveToMSG ( LPMESSAGE pMessage )
{
    HRESULT hRes = S_OK;
    LPSPropValue pSubject = NULL;
    LPSTORAGE pStorage = NULL;
    LPMSGSESS pMsgSession =  NULL;
    LPMESSAGE pIMsg = NULL;
    SizedSPropTagArray ( 7, excludeTags );
    char szPath[_MAX_PATH];
    char strAttachmentFile[_MAX_PATH];
    LPWSTR lpWideCharStr = NULL;
    ULONG cbStrSize = 0L;

    // create the file name in the directory where "TMP" is defined
    // with subject as the filename and ".msg" extension.

    // get temp file directory
    GetTempPath(_MAX_PATH, szPath);

    // get subject line of message to copy. This will be used as the
    // new file name.
    HrGetOneProp( pMessage, PR_SUBJECT, &pSubject );

    // fuse path, subject, and suffix into one string
    strcpy ( strAttachmentFile, szPath );
    strcat ( strAttachmentFile, pSubject->Value.lpszA  );
    strcat ( strAttachmentFile, ".msg");

    // get memory allocation function
    LPMALLOC pMalloc = MAPIGetDefaultMalloc();

    // Convert new file name to WideChar
    cbStrSize = MultiByteToWideChar (CP_ACP,
                                     MB_PRECOMPOSED,
                                     strAttachmentFile,
                                     -1, lpWideCharStr, 0);

    MAPIAllocateBuffer ( cbStrSize * sizeof(WCHAR),
                            (LPVOID *)&lpWideCharStr );

    MultiByteToWideChar (CP_ACP,
                         MB_PRECOMPOSED,
                         strAttachmentFile,
                         -1, lpWideCharStr, cbStrSize );

    // create compound file
    hRes = ::StgCreateDocfile(lpWideCharStr,
                              STGM_READWRITE |
                              STGM_TRANSACTED |
                              STGM_CREATE, 0, &pStorage);

    // Open an IMessage session.
    hRes = ::OpenIMsgSession(pMalloc, 0, &pMsgSession);

    // Open an IMessage interface on an IStorage object
    hRes = ::OpenIMsgOnIStg(pMsgSession,
                            MAPIAllocateBuffer,
                            MAPIAllocateMore,
                            MAPIFreeBuffer,
                            pMalloc,
                            NULL,
                            pStorage,
                            NULL, 0, 0, &pIMsg);

    // write the CLSID to the IStorage instance - pStorage. This will
    // only work with clients that support this compound document type
    // as the storage medium. If the client does not support
    // CLSID_MailMessage as the compound document, you will have to use
    // the CLSID that it does support.
    hRes = WriteClassStg(pStorage, CLSID_MailMessage );

    // Specify properties to exclude in the copy operation. These are
    // the properties that Exchange excludes to save bits and time.
    // Should not be necessary to exclude these, but speeds the process
    // when a lot of messages are being copied.
    excludeTags.cValues = 7;
    excludeTags.aulPropTag[0] = PR_ACCESS;
    excludeTags.aulPropTag[1] = PR_BODY;
    excludeTags.aulPropTag[2] = PR_RTF_SYNC_BODY_COUNT;
    excludeTags.aulPropTag[3] = PR_RTF_SYNC_BODY_CRC;
    excludeTags.aulPropTag[4] = PR_RTF_SYNC_BODY_TAG;
    excludeTags.aulPropTag[5] = PR_RTF_SYNC_PREFIX_COUNT;
    excludeTags.aulPropTag[6] = PR_RTF_SYNC_TRAILING_COUNT;

    // copy message properties to IMessage object opened on top of
    // IStorage.
    hRes = pMessage->CopyTo(0, NULL,
                            (LPSPropTagArray)&excludeTags,
                            NULL, NULL,
                            (LPIID)&IID_IMessage,
                            pIMsg, 0, NULL );

    // save changes to IMessage object.
    pIMsg -> SaveChanges ( KEEP_OPEN_READWRITE );

    // save changes in storage of new doc file
    hRes = pStorage -> Commit(STGC_DEFAULT);

    // free objects and clean up memory
    MAPIFreeBuffer ( lpWideCharStr );
    pStorage->Release();
    pIMsg->Release();
    CloseIMsgSession ( pMsgSession );

    pStorage = NULL;
    pIMsg = NULL;
    pMsgSession = NULL;
    lpWideCharStr = NULL;

    return hRes;
}