dump IPropertyStore

dump_IPropertyStore.cpp

#include <atlbase.h>
#include <atlcom.h>
#include <atlcomcli.h>
#include <comdef.h>
#include <Propvarutil.h>
#include <shobjidl.h>
#include <atlsafe.h>
#include <strsafe.h>
#pragma comment(lib, "Propsys.lib")

static void throw_if_(HRESULT hr, const char* name)
{
    if (!SUCCEEDED(hr))
    {
        wprintf(L"%S:\n", name);
        throw _com_error(hr);
    }
}

#define throw_if(x) throw_if_((x), #x)

static void print_variant(CComVariant& var)
{
    if (var.vt == (VT_ARRAY | VT_BSTR))
    {
        CComSafeArray<BSTR> sa;
        sa.Attach(V_ARRAY(&var));
        LONG lower = sa.GetLowerBound();
        LONG upper = sa.GetUpperBound();
        wprintf(L" [ ");
        for (LONG l = lower; l <= upper; ++l)
        {
            CComBSTR tmp = sa.GetAt(l);
            wprintf(L"%s'%s'", l != lower ? L", " : L"", (WCHAR*)tmp);
        }
        wprintf(L" ]");
        return;
    }

    HRESULT hr = var.ChangeType(VT_BSTR);
    if (SUCCEEDED(hr))
    {
        wprintf(L"'%s'", var.bstrVal);
    }
    else
    {
        wprintf(L"[Failed converting 0x%x to VT_BSTR]", var.vt);
    }

}


static void test_propstore(const wchar_t* name)
{
    CComPtr<IPropertyStore> spStore;
    throw_if(SHGetPropertyStoreFromParsingName(name, NULL, GPS_BESTEFFORT, __uuidof(IPropertyStore), (void**)&spStore));

    DWORD cnt = 0;
    throw_if(spStore->GetCount(&cnt));
    wprintf(L"%d properties for %s\n", cnt, name);
    for (DWORD n = 0; n < cnt; ++n)
    {
        PROPERTYKEY key;
        throw_if(spStore->GetAt(n, &key));
        CComVariant var;
        PROPVARIANT prop;
        throw_if(spStore->GetValue(key, &prop));
        throw_if(PropVariantToVariant(&prop, &var));
        PropVariantClear(&prop);

        CComHeapPtr<WCHAR> pszName;
        HRESULT hr = PSGetNameFromPropertyKey(key, &pszName);
        if (!SUCCEEDED(hr))
        {
            WCHAR buf[512];
            throw_if(PSStringFromPropertyKey(key, buf, _countof(buf)));
            wprintf(L"  [%s] = ", buf);
        }
        else
        {
            wprintf(L"  %s = ", (WCHAR*)pszName);
        }

        print_variant(var);
        wprintf(L"\n");
    }
}

int wmain(int argc, wchar_t* argv[])
{
    CoInitialize(NULL);
    for (int n = 1; n < argc; ++n)
    {
        test_propstore(argv[n]);
    }
    if (argc == 1)
        test_propstore(L"c:\\Windows\\Media\\Alarm01.wav");

    return 0;
}

suggest adding following between line 36 and 37
sa.Detach();

otherwise you could encounter some exception due to the fact that the attached var is destroyed premature