[1/2] mmsystem.dll16: fix MCI_STATUS mapping for digitalvideo

[Joerg-Cyril.Hoehle at t-systems.com]

Damjan,

@@ -407,6 +441,20 @@ static  MMSYSTEM_MapType	MCI_UnMapMsg16To32W(WORD wMsg, DWORD dwFlags, DWORD_PTR
+            mdsp16->dwCallback = mdsp32w->dwCallback;
+            mdsp16->dwItem = mdsp32w->dwItem;
+            mdsp16->dwTrack = mdsp32w->dwTrack;
This is superfluous.  dwReturn is the only documented output.
This was different with your former MCI_WHERE patch, where a RECT is output.


I'd try hard not to turn one message call (Status) into 2 (GetDevCaps + Status).
I've seen logs of apps that continuously poll MCI_STATUS_POSITION.
Instead, I'd continue the path lead by winmm/mci.c:MCI_MapMsgAtoW:
Allocate the largest structure and fill it depending on dwFlags, e.g.:
    case MCI_OPEN:
        {   /* MCI_ANIM_OPEN_PARMS is the largest known MCI_OPEN_PARMS
             * structure, larger than MCI_WAVE_OPEN_PARMS */
BTW, I've a note that MCI_INFO needs similar treatment, but never wrote the patch...

Select the right set of flags to fill the slots, otherwise fallback to defaults like:
   /* We don't know how many DWORD follow, as
    * the structure depends on the device. */
   if (HIWORD(dwParam1))
       memcpy(&mci_openW->dwStyle, &mci_openA->dwStyle, sizeof(MCI_ANIM_OPEN_PARMSW) - sizeof(MCI_OPEN_PARMSW));

Of course, one may argue that this is a heuristic and can fail.  Well,
GetDevCaps is a heuristic as well that only supports devtype_digital_video.

An advantage IMHO of the existing approach is that
it does not invent within the same source code base
yet another mechanism to map 16 to 32 or A to W.  I'd rather follow the
existing model until the time it proves unbearable, or immediately switch
the *whole* code base to another model, not the single MCI_STATUS function.

For instance, you can argue that it makes sense for winmm
to cache the device type (winmm:MCI_Open has it in several cases).
It would arguably also make sense
to cache the MCI auto_open'ed property, but I digress.


Your MCI_get_device_type is bogus.  MCI_GETDEVCAPS_DEVICE_TYPE
belongs into dwItem, not dwFlags.

Regards,
 Jörg Höhle