winewayland.drv: Handle the wl_data_device::enter event.

Relay the event to the IDropTarget at the enter position, and notify the
Wayland compositor of any accepted format/mime type and actions.

The accepted mime type is set indirectly through IDropTarget_DragEnter
eventually calling our IDataObject_(Query)GetData implementation for the
associated data offer.

Signed-off-by: Alexandros Frantzis <alexandros.frantzis@collabora.com>

dlls/winewayland.drv/dllmain.c

@@ -24,6 +24,7 @@ typedef NTSTATUS (WINAPI *kernel_callback)(void *params, ULONG size);
 static const kernel_callback kernel_callbacks[] =
 {
     waylanddrv_client_create_clipboard_window,
+    waylanddrv_client_dnd,
 };
 
 C_ASSERT(NtUserDriverCallbackFirst + ARRAYSIZE(kernel_callbacks) == waylanddrv_client_func_last);

dlls/winewayland.drv/unixlib.h

@@ -26,6 +26,9 @@
 /* A pointer to memory that is guaranteed to be usable by both 32-bit and
  * 64-bit processes. */
 typedef UINT PTR32;
+/* A handle value that is guaranteed to be usable by both 32-bit and 64-bit
+ * processes. */
+typedef UINT HANDLE32;
 
 enum waylanddrv_unix_func
 {
@@ -71,9 +74,24 @@ struct waylanddrv_unix_data_offer_enum_formats_params
 enum waylanddrv_client_func
 {
     waylanddrv_client_func_create_clipboard_window = NtUserDriverCallbackFirst,
+    waylanddrv_client_func_dnd,
     waylanddrv_client_func_last
 };
 
 C_ASSERT(waylanddrv_client_func_last <= NtUserDriverCallbackLast + 1);
 
+enum waylanddrv_client_dnd_event
+{
+    CLIENT_DND_EVENT_ENTER,
+};
+
+struct waylanddrv_client_dnd_params
+{
+    UINT event;
+    HANDLE32 hwnd;
+    POINT point;
+    DWORD drop_effect;
+    PTR32 data_object;
+};
+
 #endif /* __WINE_WAYLANDDRV_UNIXLIB_H */

dlls/winewayland.drv/wayland_data_device.c

@@ -88,6 +88,20 @@ static char *normalize_mime_type(const char *mime)
     return new_mime;
 }
 
+static DWORD dnd_actions_to_drop_effect(uint32_t actions)
+{
+    DWORD drop_effect = 0;
+
+    if (actions & WL_DATA_DEVICE_MANAGER_DND_ACTION_COPY)
+        drop_effect |= DROPEFFECT_COPY;
+    if (actions & WL_DATA_DEVICE_MANAGER_DND_ACTION_MOVE)
+        drop_effect |= DROPEFFECT_MOVE;
+    if (actions & WL_DATA_DEVICE_MANAGER_DND_ACTION_ASK)
+        drop_effect |= DROPEFFECT_COPY | DROPEFFECT_MOVE;
+
+    return drop_effect;
+}
+
 /**********************************************************************
  *          wl_data_offer handling
  */
@@ -315,12 +329,58 @@ static void data_device_enter(void *data, struct wl_data_device *wl_data_device,
                               wl_fixed_t x_w, wl_fixed_t y_w,
                               struct wl_data_offer *wl_data_offer)
 {
+    struct waylanddrv_client_dnd_params params;
     struct wayland_data_device *data_device = data;
+    struct wayland_data_offer *data_offer;
+    struct wayland_surface *wayland_surface;
+    POINT point;
 
     /* Any previous dnd offer should have been freed by a drop or leave event. */
     assert(data_device->dnd_wl_data_offer == NULL);
 
     data_device->dnd_wl_data_offer = wl_data_offer;
+
+    if (!wl_data_offer)
+        return;
+
+    data_offer = wl_data_offer_get_user_data(wl_data_offer);
+
+    wayland_surface = wl_surface_get_user_data(wl_surface);
+
+    if (!wayland_surface || !wayland_surface->hwnd)
+        return;
+
+    data_device->dnd_enter_serial = serial;
+    data_device->dnd_surface = wayland_surface;
+    data_device->dnd_x = wl_fixed_to_int(x_w);
+    data_device->dnd_y = wl_fixed_to_int(y_w);
+
+    wayland_surface_coords_to_screen(data_device->dnd_surface,
+                                     data_device->dnd_x, data_device->dnd_y,
+                                     (int *)&point.x, (int *)&point.y);
+
+    TRACE("surface=%p hwnd=%p source_actions=%x action=%x\n",
+          data_device->dnd_surface, data_device->dnd_surface->hwnd,
+          data_offer->source_actions, data_offer->action);
+
+    /* Clear accepted_mime_type here. It should be eventually set by
+     * the DnD client call below. */
+    data_offer->accepted_mime_type = NULL;
+
+    params.event = CLIENT_DND_EVENT_ENTER;
+    params.hwnd = HandleToULong(data_device->dnd_surface->hwnd);
+    params.point = point;
+    params.drop_effect = dnd_actions_to_drop_effect(data_offer->source_actions);
+    params.data_object = PtrToUint(data_offer);
+
+    if (WAYLANDDRV_CLIENT_CALL(dnd, &params, sizeof(params)) != 0)
+        return;
+
+    wl_data_offer_set_actions(wl_data_offer, data_offer->source_actions,
+                              data_offer->action);
+    wl_data_offer_accept(wl_data_offer,
+                         data_device->dnd_enter_serial,
+                         data_offer->accepted_mime_type);
 }
 
 static void data_device_leave(void *data, struct wl_data_device *wl_data_device)

dlls/winewayland.drv/wayland_data_device_dll.c

@@ -18,6 +18,9 @@
  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  */
 
+#include "ntstatus.h"
+#define WIN32_NO_STATUS
+
 #include "waylanddrv_dll.h"
 
 #define COBJMACROS
@@ -183,6 +186,45 @@ static IDropTarget *drop_target_from_window_point(HWND hwnd, POINT point)
     return drop_target;
 }
 
+static NTSTATUS WINAPI waylanddrv_client_dnd_enter(void *params, ULONG size)
+{
+    struct waylanddrv_client_dnd_params *p = params;
+    IDropTarget *drop_target;
+    DWORD drop_effect = p->drop_effect;
+    IDataObject *data_object = UIntToPtr(p->data_object);
+    HRESULT hr;
+
+    /* If unixlib is 64 bits and PE is 32 bits, this will write a 32 bit
+     * pointer value to the bottom of 64 bit pointer variable, which works out
+     * fine due to little-endianness and the fact that lpVtbl has been zero
+     * initialized. */
+    data_object->lpVtbl = &dataOfferDataObjectVtbl;
+
+    drop_target = drop_target_from_window_point(ULongToHandle(p->hwnd), p->point);
+    if (!drop_target)
+        return STATUS_UNSUCCESSFUL;
+
+    hr = IDropTarget_DragEnter(drop_target, data_object, MK_LBUTTON,
+                               *(POINTL*)&p->point, &drop_effect);
+    IDropTarget_Release(drop_target);
+    if (FAILED(hr))
+        return STATUS_UNSUCCESSFUL;
+
+    return STATUS_SUCCESS;
+}
+
+NTSTATUS WINAPI waylanddrv_client_dnd(void *params, ULONG size)
+{
+    struct waylanddrv_client_dnd_params *p = params;
+
+    switch (p->event) {
+    case CLIENT_DND_EVENT_ENTER:
+        return waylanddrv_client_dnd_enter(params, size);
+    }
+
+    return STATUS_UNSUCCESSFUL;
+}
+
 /*********************************************************
  * Implementation of IDataObject for wayland data offers *
  *********************************************************/

dlls/winewayland.drv/wayland_surface.c

@@ -671,6 +671,7 @@ void wayland_surface_destroy(struct wayland_surface *surface)
 {
     struct wayland_pointer *pointer = &surface->wayland->pointer;
     struct wayland_keyboard *keyboard = &surface->wayland->keyboard;
+    struct wayland_data_device *data_device = &surface->wayland->data_device;
     struct wayland_surface *child, *child_tmp;
     struct wayland_output_ref *ref, *ref_tmp;
 
@@ -682,6 +683,9 @@ void wayland_surface_destroy(struct wayland_surface *surface)
     if (keyboard->focused_surface == surface)
         keyboard->focused_surface = NULL;
 
+    if (data_device->dnd_surface == surface)
+        data_device->dnd_surface = NULL;
+
     /* There are children left only when we force a destruction during
      * thread deinitialization, otherwise the children hold a reference
      * to the parent and won't let it be destroyed. */

dlls/winewayland.drv/waylanddrv.h

@@ -245,6 +245,10 @@ struct wayland_data_device
     struct wl_data_offer *clipboard_wl_data_offer;
     struct wl_data_offer *dnd_wl_data_offer;
     struct wl_data_source *wl_data_source;
+    uint32_t dnd_enter_serial;
+    struct wayland_surface *dnd_surface;
+    int dnd_x;
+    int dnd_y;
 };
 
 struct wayland_data_device_format

dlls/winewayland.drv/waylanddrv_dll.h

@@ -30,5 +30,6 @@
 #define WAYLANDDRV_UNIX_CALL(func, params) WINE_UNIX_CALL(waylanddrv_unix_func_ ## func, params)
 
 NTSTATUS WINAPI waylanddrv_client_create_clipboard_window(void *arg, ULONG size);
+NTSTATUS WINAPI waylanddrv_client_dnd(void *params, ULONG size);
 
 #endif /* __WINE_WAYLANDDRV_DLL_H */