Re: [PATCH v8 0/4] MR9045: windows.devices.enumeration: Add support for device properties in DeviceInformation objects.

[Rémi Bernon (＠rbernon)]

On Mon Sep 29 20:23:48 2025 +0000, Vibhav Pant wrote:
> Nvm, I could just call First twice, totally missed that >_<

Hmm... What about splitting this into separate helpers like this:

```
static HRESULT devpropcompkeys_init( DEVPROPCOMPKEY **keys, ULONG *keys_len, const DEVPROPCOMPKEY *values, ULONG len )
{
    if (!(*keys = calloc( len, sizeof( **keys ) ))) return E_OUTOFMEMORY;
    memcpy( *keys, values, len * sizeof( **keys ) );
    *keys_len = len;
    return S_OK;
}

static HRESULT count_iterable( IIterable_HSTRING *iterable, UINT *ret )
{
    IIterator_HSTRING *iter;
    UINT count = 0;
    boolean valid;
    HRESULT hr;

if (FAILED(hr = IIterable_HSTRING_First( iterable, &iter ))) return hr;
    for (hr = IIterator_HSTRING_get_HasCurrent( iter, &valid ); SUCCEEDED(hr) && valid;
         hr = IIterator_HSTRING_MoveNext( iter, &valid ))
        count++;
    IIterator_HSTRING_Release( iter );

*ret = count;
    return hr;
}

static HRESULT devpropcompkeys_append_names( DEVPROPCOMPKEY **keys, ULONG *keys_len, IIterable_HSTRING *names_iterable )
{
    IIterator_HSTRING *names;
    UINT len = *keys_len;
    DEVPROPCOMPKEY *tmp;
    boolean valid;
    HRESULT hr;
    UINT count;

if (FAILED(hr = count_iterable( names_iterable, &count ))) return hr;
    if (!(tmp = realloc( *keys, (len + count) * sizeof( **keys ) ))) return E_OUTOFMEMORY;
    *keys = tmp;

if (FAILED(hr = IIterable_HSTRING_First( names_iterable, &names ))) return hr;
    for (hr = IIterator_HSTRING_get_HasCurrent( names, &valid ); SUCCEEDED(hr) && valid;
         hr = IIterator_HSTRING_MoveNext( names, &valid ))
    {
        DEVPROPCOMPKEY key = {0};
        const WCHAR *buf;
        HSTRING name;

if (FAILED(hr = IIterator_HSTRING_get_Current( names, &name ))) break;
        buf = WindowsGetStringRawBuffer( name, NULL );
        if (buf[0] == '{')
            hr = PSPropertyKeyFromString( buf, (PROPERTYKEY *)&key.Key );
        else
            hr = PSGetPropertyKeyFromName( buf, (PROPERTYKEY *)&key.Key );
        WindowsDeleteString( name );
        if (FAILED(hr)) break;

if (devpropcompkey_buf_find_devpropkey( tmp, len, key.Key )) continue;
        (*keys)[len++] = key;
    }
    IIterator_HSTRING_Release( names );

*keys_len = len;
    return hr;
}
```

Then `devpropcompkeys_init` can be used to initialize from the static default properties, but `(keys, keys_len) == (NULL, 0)` would also be a valid initial value and can be passed to `devpropcompkeys_append_names`.

The `devpropcompkey_buf_find_devpropkey` call might or not be removed, depending on the other discussion above about duplicate values.