[PATCH wayland-protocols v3] Add screensaver idle inhibitor protocol

[Pekka Paalanen]

On Thu, 24 Mar 2016 11:14:33 -0700
Bryce Harrington <bryce at osg.samsung.com> wrote:

> This interface allows disabling of screensaver/screenblanking on a
> per-surface basis.  As long as the surface remains visible and
> non-occluded it blocks the screensaver, etc. from activating on the
> output(s) that the surface is visible on.
> 
> To uninhibit, simply destroy the inhibitor object.

Hi,

ok, that sounds good.

> Signed-off-by: Bryce Harrington <bryce at bryceharrington.org>
> ---
> v2: Rename protocol to idle-inhibit
>  + Use "idle" rather than "screensaver".  People likely to be interested
>    in this protocol would know the difference between "blanking", "dpms",
>    and literal "screensavers", so don't lead them to think that this only
>    deals with the latter.  The protocol addresses all manner of idle
>    behaviors, so is a more accurate name.
>  + Standardize nomenclature to "idle-manager" and "inhibitor" for clarity.
>    "inhibition_inhibit" was just too cumbersome.

Alright!

> 
>  Makefile.am                                        |  1 +
>  unstable/idle-inhibit/README                       |  4 ++
>  unstable/idle-inhibit/idle-inhibit-unstable-v1.xml | 78 ++++++++++++++++++++++
>  3 files changed, 83 insertions(+)
>  create mode 100644 unstable/idle-inhibit/README
>  create mode 100644 unstable/idle-inhibit/idle-inhibit-unstable-v1.xml
> 
> diff --git a/Makefile.am b/Makefile.am
> index 5926a41..ac497d8 100644
> --- a/Makefile.am
> +++ b/Makefile.am
> @@ -5,6 +5,7 @@ unstable_protocols =								\
>  	unstable/text-input/text-input-unstable-v1.xml				\
>  	unstable/input-method/input-method-unstable-v1.xml			\
>  	unstable/xdg-shell/xdg-shell-unstable-v5.xml				\
> +	unstable/idle-inhibit/idle-inhibit-unstable-v1.xml	\
>  	$(NULL)
>  
>  nobase_dist_pkgdata_DATA =							\
> diff --git a/unstable/idle-inhibit/README b/unstable/idle-inhibit/README
> new file mode 100644
> index 0000000..396e871
> --- /dev/null
> +++ b/unstable/idle-inhibit/README
> @@ -0,0 +1,4 @@
> +Screensaver inhibition protocol
> +
> +Maintainers:
> +Bryce Harrington <bryce at osg.samsung.com>
> diff --git a/unstable/idle-inhibit/idle-inhibit-unstable-v1.xml b/unstable/idle-inhibit/idle-inhibit-unstable-v1.xml
> new file mode 100644
> index 0000000..a8c8a85
> --- /dev/null
> +++ b/unstable/idle-inhibit/idle-inhibit-unstable-v1.xml
> @@ -0,1 +1,78 @@
> +<?xml version="1.0" encoding="UTF-8"?>
> +<protocol name="idle_inhibit_unstable_v1">
> +
> +  <copyright>
> +    Copyright © 2015-2016 Samsung Electronics Co., Ltd
> +
> +    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>
> +
> +  <interface name="zwp_idle_inhibit_manager_v1" version="1">
> +    <description summary="control behavior when display idles">
> +      This interface permits inhibiting the idle behavior such as screen
> +      blanking, locking, and screensaving.  The client binds the idle manager
> +      globally, then creates idle-inhibitor objects for each 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>
> +
> +    <request name="create_inhibitor">
> +      <description summary="create a new inhibitor object">
> +	Create a new inhibitor object associated with the given surface.
> +      </description>
> +      <arg name="id" type="new_id" interface="zwp_idle_inhibitor_v1"/>
> +      <arg name="surface" type="object" interface="wl_surface"
> +	   summary="the surface that inhibits the idle behavior"/>
> +    </request>

This interface is missing a destructor. It is the only way the
compositor could destroy the wl_resource before the client disconnects.

All interfaces need a way to destroy the object.

> +  </interface>
> +
> +  <interface name="zwp_idle_inhibitor_v1" version="1">
> +    <description summary="context object for inhibiting idle behavior">
> +      An idle inhibitor prevents the output that the surface is visible on

"the associated surface", to be crystal clear.

> +      from being blanked, dimmed, locked, set to power save, or otherwise
> +      obscured due to lack of user interaction.  Any active screensaver
> +      processes are also temporarily blocked from displaying.
> +
> +      If the surface is destroyed, disabled, becomes occluded or otherwise

What does "disabled" mean? Are you looking for "unmapped"?

Should we say "completely occluded"?

> +      loses visibility, the screen behavior is restored to normal; if the

I'd change "the screen behavior is restored to normal" to "the
inhibitor becomes ineffective". Restoring to normal is a bit vague, and
might not even be true if there are other inhibitors in effect.

> +      surface subsequently regains visibility or is unoccluded, the inhibitor
> +      takes effect once again.

Strike "or is unoccluded", it's already covered by "regains
visibility", right?

> +
> +      Note that in the case of a compound window (a surface with
> +      sub-surfaces), a separate inhibitor object may be needed for each
> +      wl_surface.

In case of sub-surfaces, inheriting inhibitor effects would be much
better than having to explicitly set every wl_surface, as pointed out
in earlier reviews. I should have given that comment the first time.

> +    </description>
> +
> +    <request name="destroy" type="destructor">
> +      <description summary="destroy the idle inhibitor object">
> +	This restores screensaver/blanking/et al behaviors to their normal
> +	state and destructs the idle inhibitor object.

Or just: "This removes the inhibitor effect from the associated
wl_surface."

> +      </description>
> +    </request>
> +
> +  </interface>
> +</protocol>

Otherwise just wording nitpicks, but two things I would like to see
corrected:
- the missing destructor
- interaction with sub-surfaces

Should I go through the v3 Weston patches too, or do you want to revise
them according to protocol changes first?


Thanks,
pq
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