[PATCH weston v6 1/5] data-device: Implement DnD progress notification

Carlos Garnacho carlosg at gnome.org
Fri Jan 15 12:09:46 PST 2016


Hey Jonas,

On Fri, Jan 15, 2016 at 6:32 AM, Jonas Ådahl <jadahl at gmail.com> wrote:
> On Thu, Jan 14, 2016 at 11:43:39PM +0100, Carlos Garnacho wrote:
>> Weston now sends wl_data_source.dnd_drop_performed and .dnd_finished in
>> order to notify about the different phases of DnD.
>>
>> wl_data_source.cancelled is also used as mentioned in the docs, being
>> emitted also on DnD when the operation is meant to fail (eg. source
>> and dest didn't agree on a mimetype).
>>
>> The dnd demo is also fixed so the struct dnd_drag isn't leaked.
>>
>> https://bugs.freedesktop.org/show_bug.cgi?id=91943
>> https://bugs.freedesktop.org/show_bug.cgi?id=91944
>>
>> Changes since v5:
>>   - Dissociate source and offer after cancel. Updated to
>>     apply on top of c9f8f8a7f.
>>
>> Changes since v4:
>>   - Make wl_data_offer.finish with the wrong state an error.
>>
>> Changes since v3:
>>   - Fixed wl_data_source.dnd_finished vs cancelled emission on
>>     when interoperating with version < 3 drag destinations.
>>
>> Changes since v2:
>>   - Handle wl_data_offer.finish. Fixed commit log inconsistencies.
>>     Added version checks. Spaces vs tabs fixes. Fixed resource
>>     versioning.
>>
>> Changes since v1:
>>   - Updated to protocol v2.
>>
>> Signed-off-by: Carlos Garnacho <carlosg at gnome.org>
>> Reviewed-by: Michael Catanzaro <mcatanzaro at igalia.com>
>
> Mostly looks good to me. I have a couple of minor requests though. See
> inline comments. With those fixed, this is Reviewed-by: Jonas Ådahl
> <jadahl at gmail.com>.
>
>> ---
>>  clients/dnd.c     |  39 +++++++++++++++-----
>>  clients/window.c  |   3 +-
>>  src/compositor.h  |   3 ++
>>  src/data-device.c | 105 +++++++++++++++++++++++++++++++++++++++++++++++++-----
>>  4 files changed, 132 insertions(+), 18 deletions(-)
>>
>> diff --git a/clients/dnd.c b/clients/dnd.c
>> index e6a0c39..48111d9 100644
>> --- a/clients/dnd.c
>> +++ b/clients/dnd.c
>> @@ -318,14 +318,8 @@ data_source_send(void *data, struct wl_data_source *source,
>>  }
>>
>>  static void
>> -data_source_cancelled(void *data, struct wl_data_source *source)
>> +dnd_drag_destroy(struct dnd_drag *dnd_drag)
>>  {
>> -     struct dnd_drag *dnd_drag = data;
>> -
>> -     /* The 'cancelled' event means that the source is no longer in
>> -      * use by the drag (or current selection).  We need to clean
>> -      * up the drag object created and the local state. */
>> -
>>       wl_data_source_destroy(dnd_drag->data_source);
>>
>>       /* Destroy the item that has been dragged out */
>> @@ -339,10 +333,39 @@ data_source_cancelled(void *data, struct wl_data_source *source)
>>       free(dnd_drag);
>>  }
>>
>> +static void
>> +data_source_cancelled(void *data, struct wl_data_source *source)
>> +{
>> +     struct dnd_drag *dnd_drag = data;
>> +
>> +     /* The 'cancelled' event means that the source is no longer in
>> +      * use by the drag (or current selection).  We need to clean
>> +      * up the drag object created and the local state. */
>> +     dnd_drag_destroy(dnd_drag);
>> +}
>> +
>> +static void
>> +data_source_drop_performed(void *data, struct wl_data_source *source)
>> +{
>> +}
>> +
>> +static void
>> +data_source_drag_finished(void *data, struct wl_data_source *source)
>> +{
>> +     struct dnd_drag *dnd_drag = data;
>> +
>> +     /* The operation is already finished, we can destroy all
>> +      * related data.
>> +      */
>> +     dnd_drag_destroy(dnd_drag);
>> +}
>> +
>>  static const struct wl_data_source_listener data_source_listener = {
>>       data_source_target,
>>       data_source_send,
>> -     data_source_cancelled
>> +     data_source_cancelled,
>> +     data_source_drop_performed,
>> +     data_source_drag_finished,
>
> nit: These should be data_source_dnd_drop_performed and
> data_source_dnd_finished.

Indeed.

>
>>  };
>>
>>  static cairo_surface_t *
>> diff --git a/clients/window.c b/clients/window.c
>> index 5d69116..c93edb1 100644
>> --- a/clients/window.c
>> +++ b/clients/window.c
>> @@ -3726,6 +3726,7 @@ offer_io_func(struct task *task, uint32_t events)
>>
>>       if (len == 0) {
>>               close(offer->fd);
>> +             wl_data_offer_finish(offer->offer);
>>               data_offer_destroy(offer);
>>       }
>>  }
>> @@ -5318,7 +5319,7 @@ registry_handle_global(void *data, struct wl_registry *registry, uint32_t id,
>>               d->shm = wl_registry_bind(registry, id, &wl_shm_interface, 1);
>>               wl_shm_add_listener(d->shm, &shm_listener, d);
>>       } else if (strcmp(interface, "wl_data_device_manager") == 0) {
>> -             d->data_device_manager_version = MIN(version, 2);
>> +             d->data_device_manager_version = MIN(version, 3);
>>               d->data_device_manager =
>>                       wl_registry_bind(registry, id,
>>                                        &wl_data_device_manager_interface,
>> diff --git a/src/compositor.h b/src/compositor.h
>> index 130b258..8d6b051 100644
>> --- a/src/compositor.h
>> +++ b/src/compositor.h
>> @@ -317,6 +317,9 @@ struct weston_data_source {
>>       struct wl_resource *resource;
>>       struct wl_signal destroy_signal;
>>       struct wl_array mime_types;
>> +     struct weston_data_offer *offer;
>> +     struct weston_seat *seat;
>> +     bool accepted;
>>
>>       void (*accept)(struct weston_data_source *source,
>>                      uint32_t serial, const char *mime_type);
>> diff --git a/src/data-device.c b/src/data-device.c
>> index 54541b3..d2b89bb 100644
>> --- a/src/data-device.c
>> +++ b/src/data-device.c
>> @@ -62,12 +62,16 @@ data_offer_accept(struct wl_client *client, struct wl_resource *resource,
>>  {
>>       struct weston_data_offer *offer = wl_resource_get_user_data(resource);
>>
>> +     /* Protect against untimely calls from older data offers */
>> +     if (!offer->source || offer != offer->source->offer)
>> +             return;
>> +
>>       /* FIXME: Check that client is currently focused by the input
>>        * device that is currently dragging this data source.  Should
>>        * this be a wl_data_device request? */
>>
>> -     if (offer->source)
>> -             offer->source->accept(offer->source, serial, mime_type);
>> +     offer->source->accept(offer->source, serial, mime_type);
>> +     offer->source->accepted = mime_type != NULL;
>>  }
>>
>>  static void
>> @@ -76,7 +80,7 @@ data_offer_receive(struct wl_client *client, struct wl_resource *resource,
>>  {
>>       struct weston_data_offer *offer = wl_resource_get_user_data(resource);
>>
>> -     if (offer->source)
>> +     if (offer->source && offer == offer->source->offer)
>>               offer->source->send(offer->source, mime_type, fd);
>>       else
>>               close(fd);
>> @@ -88,10 +92,48 @@ data_offer_destroy(struct wl_client *client, struct wl_resource *resource)
>>       wl_resource_destroy(resource);
>>  }
>>
>> +static void
>> +data_offer_notify_finish(struct weston_data_offer *offer)
>> +{
>> +     /* Protect against untimely calls from older data offers */
>> +     if (!offer->source || offer != offer->source->offer)
>> +             return;
>> +
>> +     if (wl_resource_get_version(offer->source->resource) >=
>> +         WL_DATA_SOURCE_DND_FINISHED_SINCE_VERSION) {
>> +             wl_data_source_send_dnd_finished(offer->source->resource);
>> +     }
>> +
>> +     offer->source->offer = NULL;
>> +}
>> +
>> +static void
>> +data_offer_finish(struct wl_client *client, struct wl_resource *resource)
>> +{
>> +     struct weston_data_offer *offer = wl_resource_get_user_data(resource);
>> +
>> +     if (!offer->source || offer->source->offer != offer)
>> +             return;
>> +
>> +     /* Disallow finish while we have a grab driving drag-and-drop, or
>> +      * if the negotiation is not at the right stage
>> +      */
>> +     if (offer->source->seat ||
>> +         !offer->source->accepted) {
>> +             wl_resource_post_error(offer->resource,
>> +                                    WL_DATA_OFFER_ERROR_INVALID_FINISH,
>> +                                    "premature finish request");
>> +             return;
>> +     }
>> +
>> +     data_offer_notify_finish(offer);
>
> If you do as my suggestion regarding destroy_data_offer, this line could
> be replaced with
>
>         if (wl_resource_get_version(offer->source->resource) >=
>             WL_DATA_SOURCE_DND_FINISHED_SINCE_VERSION) {
>                 wl_data_source_send_dnd_finished(offer->source->resource);
>
> or otherwise remove the offer->source->offer check in
> data_offer_notify_finish().

I've gone for the latter (the check can indeed be removed), more
explanations below.

>
>> +}
>> +
>>  static const struct wl_data_offer_interface data_offer_interface = {
>>       data_offer_accept,
>>       data_offer_receive,
>>       data_offer_destroy,
>> +     data_offer_finish,
>>  };
>>
>>  static void
>> @@ -99,8 +141,21 @@ destroy_data_offer(struct wl_resource *resource)
>>  {
>>       struct weston_data_offer *offer = wl_resource_get_user_data(resource);
>>
>> -     if (offer->source)
>> +     if (offer->source) {
>> +             /* If the drag destination has version < 3, wl_data_offer.finish
>> +              * won't be called, so do this here as a safety net, because
>> +              * we still want the version >=3 drag source to be happy.
>> +              */
>> +             if (wl_resource_get_version(offer->source->resource) <
>> +                 WL_DATA_SOURCE_DND_FINISHED_SINCE_VERSION) {
>> +                     data_offer_notify_finish(offer);
>> +             } else {
>> +                     wl_data_source_send_cancelled(offer->source->resource);
>> +                     offer->source->offer = NULL;
>> +             }
>
> How about changing this function to
>
> static void
> destroy_data_offer(struct wl_resource *resource)
> {
>         struct weston_data_offer *offer = wl_resource_get_user_data(resource);
>
>         if (!offer->source)
>                 goto out;
>
>         wl_list_remove(&offer->source_destroy_listener.link);
>
>         if (offer->source->offer != offer)
>                 goto out;
>
>         /* Only cancel if the source object supports finishing. */
>         if (wl_resource_get_version(offer->source->resource) >=
>             WL_DATA_SOURCE_DND_FINISHED_SINCE_VERSION)
>                 wl_data_source_send_cancelled(offer->source->resource);
>
>         offer->source->offer = NULL;
>
> out:
>         free(offer);
> }
>
> This way you have the same semantics, and still clean up
> offer->source->offer (which is the only thing data_offer_notify_finish()
> does anyway here, without pretending to notify finish.

Oh, I see what confused you, actually a bug: we should be checking the
offer version before notify_finish(), not the source.

If we drag from a v3 data source to a v2 data offer, we must signal
wl_data_source.dnd_finished at some point, and the destructor seems
the most natural place since the offer wont get .finish() at any
point.

I renamed that function to be data_source_notify_finish(), since we
only manipulate the source there, and makes this a bit more clear.
I've however adapted the destroy_data_offer() code flow to be as you
suggest.

>
>> +
>>               wl_list_remove(&offer->source_destroy_listener.link);
>> +     }
>>       free(offer);
>>  }
>>
>> @@ -147,6 +202,9 @@ weston_data_source_send_offer(struct weston_data_source *source,
>>       wl_array_for_each(p, &source->mime_types)
>>               wl_data_offer_send_offer(offer->resource, *p);
>>
>> +     source->offer = offer;
>> +     source->accepted = false;
>> +
>>       return offer->resource;
>>  }
>>
>> @@ -272,6 +330,7 @@ weston_drag_set_focus(struct weston_drag *drag,
>>  {
>>       struct wl_resource *resource, *offer = NULL;
>>       struct wl_display *display = seat->compositor->wl_display;
>> +     struct weston_data_offer *data_offer;
>
> nit: You call the weston_data_offer "offer" everywhere else. I think
> it'd be better to stay consistent and rename the current "offer" to
> "offer_resource".

Sure.

Cheers,
  Carlos


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