[PATCH] Introduce keyboard grabbing protocol
Giulio Camuffo
giuliocamuffo at gmail.com
Tue Aug 30 10:18:29 UTC 2016
Hi,
i have a couple of comments below
2016-08-30 11:54 GMT+02:00 Olivier Fourdan <ofourdan at redhat.com>:
> This patch introduces a new protocol for grabbing a keyboard.
>
> Signed-off-by: Olivier Fourdan <ofourdan at redhat.com>
> ---
> Makefile.am | 1 +
> configure.ac | 2 +-
> unstable/keyboard-grab/README | 4 +
> .../keyboard-grab/keyboard-grab-unstable-v1.xml | 136 +++++++++++++++++++++
> 4 files changed, 142 insertions(+), 1 deletion(-)
> create mode 100644 unstable/keyboard-grab/README
> create mode 100644 unstable/keyboard-grab/keyboard-grab-unstable-v1.xml
>
> diff --git a/Makefile.am b/Makefile.am
> index e693afa..9ab5dc7 100644
> --- a/Makefile.am
> +++ b/Makefile.am
> @@ -12,6 +12,7 @@ unstable_protocols = \
> unstable/tablet/tablet-unstable-v2.xml \
> unstable/xdg-foreign/xdg-foreign-unstable-v1.xml \
> unstable/idle-inhibit/idle-inhibit-unstable-v1.xml \
> + unstable/keyboard-grab/keyboard-grab-unstable-v1.xml \
> $(NULL)
>
> stable_protocols = \
> diff --git a/configure.ac b/configure.ac
> index 4c43daa..cae4a56 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -1,7 +1,7 @@
> AC_PREREQ([2.64])
>
> m4_define([wayland_protocols_major_version], [1])
> -m4_define([wayland_protocols_minor_version], [7])
> +m4_define([wayland_protocols_minor_version], [8])
> m4_define([wayland_protocols_version],
> [wayland_protocols_major_version.wayland_protocols_minor_version])
>
> diff --git a/unstable/keyboard-grab/README b/unstable/keyboard-grab/README
> new file mode 100644
> index 0000000..1a6529f
> --- /dev/null
> +++ b/unstable/keyboard-grab/README
> @@ -0,0 +1,4 @@
> +keyboard grabbing protocol
> +
> +Maintainers:
> +Olivier Fourdan <fourdan at gmail.com>
> diff --git a/unstable/keyboard-grab/keyboard-grab-unstable-v1.xml b/unstable/keyboard-grab/keyboard-grab-unstable-v1.xml
> new file mode 100644
> index 0000000..31d5a6a
> --- /dev/null
> +++ b/unstable/keyboard-grab/keyboard-grab-unstable-v1.xml
> @@ -0,0 +1,136 @@
> +<?xml version="1.0" encoding="UTF-8"?>
> +<protocol name="keyboard_grab_unstable_v1">
> +
> + <copyright>
> + Copyright © 2016 Red Hat Inc.
> +
> + Permission is hereby granted, free of charge, to any person obtaining a
> + copy of this software and associated documentation files (the "Software"),
> + to deal in the Software without restriction, including without limitation
> + the rights to use, copy, modify, merge, publish, distribute, sublicense,
> + and/or sell copies of the Software, and to permit persons to whom the
> + Software is furnished to do so, subject to the following conditions:
> +
> + The above copyright notice and this permission notice (including the next
> + paragraph) shall be included in all copies or substantial portions of the
> + Software.
> +
> + THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
> + THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> + FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
> + DEALINGS IN THE SOFTWARE.
> + </copyright>
> +
> + <description summary="Protocol for grabbing the keyboard">
> + This protocol specifies a way for a client to request all keyboard
> + events to be forwarded to a surface.
> +
> + A possible use case for this is a virtual machine or a remote
> + connection viewer where all key events must be sent to the specific
> + surface, ignoring the compositor own's shortcuts.
> +
> + Another use case is Xwayland. Unlike the X11 protocol, Wayland
> + doesn't have the notion of active grab on the keyboard. When an
> + X11 client acquires an active grab on the keyboard, all key events
> + are reported only to the grabbing X11 client.
> + When running in Xwayland, X11 applications may acquire an active
> + grab but that cannot be translated to the Wayland compositor who
> + may set the input focus to some other surface, thus breaking the
> + X11 client assumption that all key events are reported.
I can understand the Xwayland use, but not the VM one. If i'm using a
VM i expect it to receive key events when focused, not otherwise. If
the point of this is just to inhibit the compositor's shortcuts than i
think the protocol should just do that, and not do an actual grab.
Additionally, as a user i'm not sure i would want my shortcuts to stop
working, ever...
> +
> + When a client requests a keyboard grab, the Wayland compositor may
> + either inform or ask the user for the right to forward all key
> + events to the given client surface.
> +
> + Warning! The protocol described in this file is experimental and
> + backward incompatible changes may be made. Backward compatible
> + changes may be added together with the corresponding interface
> + version bump.
> + Backward incompatible changes are done by bumping the version
> + number in the protocol and interface names and resetting the
> + interface version. Once the protocol is to be declared stable, the
> + 'z' prefix and the version number in the protocol and interface
> + names are removed and the interface version number is reset.
> + </description>
> +
> + <interface name="zwp_keyboard_grab_v1" version="1">
> + <description summary="interface for grabbing the keyboard">
> + A global interface used for grabbing the keyboard.
> + </description>
> +
> + <enum name="error">
> + <description summary="wp_keyboard_grab error values">
> + These errors can be emitted in response to wp_keyboard_grab
> + requests.
> + </description>
> + <entry name="already_grabbed" value="1"
> + summary="keyboard already grabbed"/>
> + <entry name="grab_denied" value="2"
> + summary="keyboard grab was denied"/>
> + </enum>
> +
> + <request name="grab_keyboard">
> + <description summary="grab the keyboard to a surface">
> + The grab_keyboard request can be used by the client to ask for a
> + grab of the keyboard, effectively reporting all key events to a
> + surface.
> +
> + This request may not take effect immediately; later, when the
> + compositor implementation-specific grab requirements are satisfied,
> + the keyboard grab will be activated and the compositor sends a
> + "grabbed" event.
> +
> + The protocol provides no guarantee that the grab is ever satisfied,
> + and does not require the compositor to send an error if the grab
> + cannot ever be satisfied. It is thus possible to request a keyboard
> + grab that will never be effective.
> +
> + The compositor may deny a grab request from the client, in which
> + case an error "grab_denied" will be raised.
> +
> + There may not be another keyboard grab requested or active on any
> + surface for any of the wl_keyboard objects of the seat of the
> + passed keyboard when requesting a grab. If there is, an error
> + "already_grabbed" will be raised.
I don't think it makes sense to send errors for those, it seems like
both cases are out of the client's direct control and as such the
client cannot be sure to avoid them, so it should survive when they
happen.
Cheers,
Giulio
> +
> + A surface may receive keyboard focus without the grab being
> + activated.
> +
> + The request creates a new object wp_grabbed_keyboard which is used
> + to interact with the grab as well as receive updates about its
> + state. See the the description of wp_grabbed_keyboard for further
> + information.
> + </description>
> +
> + <arg name="id" type="new_id" interface="zwp_keyboard_grab_v1"/>
> + <arg name="surface" type="object" interface="wl_surface"
> + summary="surface to report keyboard events to"/>
> + <arg name="keyboard" type="object" interface="wl_keyboard"
> + summary="the keyboard that should be grabbed"/>
> + </request>
> +
> + <request name="destroy" type="destructor">
> + <description summary="destroy the grabbed keyboard object">
> + Destroy the grabbed keyboard object. If applicable, the compositor
> + will ungrab the keyboard.
> + </description>
> + </request>
> +
> + <event name="grabbed">
> + <description summary="grab activation event">
> + Notification that the keyboard grab of the seat's keyboard is
> + activated.
> + </description>
> + </event>
> +
> + <event name="ungrabbed">
> + <description summary="grab deactivation event">
> + Notification that the keyboard grab of the seat's keyboard is no
> + longer active. The object is now defunct and should be destroyed.
> + </description>
> + </event>
> + </interface>
> +</protocol>
> --
> 2.7.4
>
>
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