Merge branch 'wip/session-restore' into 'main'

staging: Add xdg-session-management protocol

See merge request wayland/wayland-protocols!18
This commit is contained in:
Jonas Ådahl 2025-12-16 12:25:04 +01:00
commit ae9549219a
3 changed files with 323 additions and 0 deletions

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@ -70,6 +70,7 @@ staging_protocols = {
'tearing-control': ['v1'],
'xdg-activation': ['v1'],
'xdg-dialog': ['v1'],
'xdg-session-management': ['v1'],
'xdg-system-bell': ['v1'],
'xdg-toplevel-drag': ['v1'],
'xdg-toplevel-icon': ['v1'],

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@ -0,0 +1,5 @@
xdg session management protocol
Maintainers:
Jonas Ådahl <jadahl@gmail.com>
Mike Blumenkrantz <michael.blumenkrantz@gmail.com>

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@ -0,0 +1,317 @@
<?xml version="1.0" encoding="UTF-8"?>
<protocol name="xdg_session_management_v1">
<copyright>
Copyright 2018 Mike Blumenkrantz
Copyright 2018 Samsung Electronics Co., Ltd
Copyright 2018 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 managing application sessions">
This description provides a high-level overview of the interplay between
the interfaces defined this protocol. For details, see the protocol
specification.
The xdg_session_manager protocol declares interfaces necessary to
allow clients to restore toplevel state from previous executions. The
xdg_session_manager_v1.get_session request can be used to obtain a
xdg_session_v1 resource representing the state of a set of toplevels.
Clients may obtain the session string to use in future calls through
the xdg_session_v1.created event. Compositors will use this string
as an identifiable token for future runs, possibly storing data about
the related toplevels in persistent storage. Clients that wish to
track sessions in multiple environments may use the $XDG_CURRENT_DESKTOP
environment variable.
Toplevels are managed through the xdg_session_v1.add_toplevel and
xdg_session_v1.remove_toplevel pair of requests. Clients will explicitly
request a toplevel to be restored according to prior state through the
xdg_session_v1.restore_toplevel request before the toplevel is mapped.
Compositors may store session information up to any arbitrary level, and
apply any limits and policies to the amount of data stored and its lifetime.
Clients must account for missing sessions and partial session restoration.
Warning! The protocol described in this file is currently in the testing
phase. Backward compatible changes may be added together with the
corresponding interface version bump. Backward incompatible changes can
only be done by creating a new major version of the extension.
</description>
<interface name="xdg_session_manager_v1" version="1">
<description summary="manage sessions for applications">
The xdg_session_manager_v1 interface defines base requests for creating and
managing a session for an application. Sessions persist across application
and compositor restarts unless explicitly destroyed. A session is created
for the purpose of maintaining an application's xdg_toplevel surfaces
across compositor or application restarts. The compositor should remember
as many states as possible for surfaces in a given session, but there is
no requirement for which states must be remembered.
Policies such as cache eviction are declared an implementation detail of
the compositor. Clients should account for no longer existing sessions.
</description>
<enum name="error">
<entry name="in_use" summary="a requested session is already in use"
value="1"/>
<entry name="invalid_session_id" summary="invalid session identifier"
value="2"/>
</enum>
<enum name="reason">
<description summary="reason for getting a session">
The reason may determine in what way a session restores the window
management state of associated toplevels.
For example newly launched applications might be launched on the active
workspace with restored size and position, while a recovered
application might restore additional state such as active workspace and
stacking order.
</description>
<entry name="launch" value="1">
<description summary="an app is newly launched">
A new app instance is launched, for example from an app launcher.
</description>
</entry>
<entry name="recover" value="2">
<description summary="an app recovered">
A app instance is recovering from for example a compositor or app crash.
</description>
</entry>
<entry name="session_restore" value="3">
<description summary="an app restored">
A app instance is restored, for example part of a restored session, or
restored from having been temporarily terminated due to resource
constraints.
</description>
</entry>
</enum>
<request name="destroy" type="destructor">
<description summary="Destroy this object">
This has no effect other than to destroy the xdg_session_manager object.
</description>
</request>
<request name="get_session">
<description summary="create or restore a session">
Create a session object corresponding to either an existing session
identified by the given session identifier string or a new session.
While the session object exists, the session is considered to be "in
use".
If a identifier string represents a session that is currently actively
in use by the the same client, an 'in_use' error is raised. If some
other client is currently using the same session, the new session will
replace managing the associated state.
NULL is passed to initiate a new session. If a session_id is passed
which does not represent a valid session, the compositor treats it as if
NULL had been passed.
The session id string must be UTF-8 encoded. It is also limited by the
maximum length of wayland messages (around 4KB). The 'invalid_session_id'
protocol error will be raised if an invalid string is provided.
A client is allowed to have any number of in use sessions at the same
time.
</description>
<arg name="id" type="new_id" interface="xdg_session_v1"/>
<arg name="reason" type="uint" enum="reason"
summary="reason for session"/>
<arg name="session_id" type="string"
summary="the session to restore"
allow-null="true"/>
</request>
</interface>
<interface name="xdg_session_v1" version="1">
<description summary="A session for an application">
A xdg_session_v1 object represents a session for an application. While the
object exists, all surfaces which have been added to the session will
have states stored by the compositor which can be reapplied at a later
time. Two sessions cannot exist for the same identifier string.
States for surfaces added to a session are automatically updated by the
compositor when they are changed.
</description>
<enum name="error">
<entry name="name_in_use"
summary="toplevel name is already in use"
value="1"/>
<entry name="already_mapped"
summary="toplevel was already mapped when restored"
value="2"/>
<entry name="invalid_name"
summary="provided toplevel name is invalid"
value="3"/>
</enum>
<request name="destroy" type="destructor">
<description summary="Destroy the session">
Destroy a session object, preserving the current state but not continuing
to make further updates if state changes occur. This makes the associated
xdg_toplevel_session_v1 objects inert.
</description>
</request>
<request name="remove" type="destructor">
<description summary="Remove the session">
Remove the session, making it no longer available for restoration. A
compositor should in response to this request remove the data related to
this session from its storage.
</description>
</request>
<request name="add_toplevel">
<description summary="add a new surface to the session">
Attempt to add a given surface to the session. The passed name is used
to identify what window is being restored, and may be used to store
window specific state within the session.
The name given to the toplevel must not correspond to any previously
existing toplevel names in the session. If the name matches an already
known toplevel name in the session, a 'name_in_use' protocol error will
be raised.
This request will return a xdg_toplevel_session_v1 for later
manipulation. As this resource is created from an empty initial state,
compositors must not emit a xdg_toplevel_session_v1.restored event for
resources created through this request.
The name string must be UTF-8 encoded. It is also limited by the maximum
length of wayland messages (around 4KB). The 'invalid_name' protocol
error will be raised if an invalid string is provided.
</description>
<arg name="id" type="new_id" interface="xdg_toplevel_session_v1"/>
<arg name="toplevel" type="object" interface="xdg_toplevel"/>
<arg name="name" type="string" summary="name identifying the toplevel"/>
</request>
<request name="restore_toplevel">
<description summary="restore a surface state">
Inform the compositor that the toplevel associated with the passed name
should have its window management state restored.
If the toplevel name was previously granted to another xdg_toplevel,
the 'name_in_use' protocol error will be raised.
This request must be called prior to the first commit on the associated
wl_surface after creating the toplevel, otherwise an 'already_mapped'
error is raised.
As part of the initial configure sequence, if the toplevel was
successfully restored, a xdg_toplevel_session_v1.restored event is
emitted. If the toplevel name was not known in the session, this request
will be equivalent to the xdg_toplevel_session_v1.add_toplevel request,
and no such event will be emitted. See the xdg_toplevel_session_v1.restored
event for further details.
The name string must be UTF-8 encoded. It is also limited by the maximum
length of wayland messages (around 4KB). The 'invalid_name' protocol
error will be raised if an invalid string is provided.
</description>
<arg name="id" type="new_id" interface="xdg_toplevel_session_v1"/>
<arg name="toplevel" type="object" interface="xdg_toplevel"/>
<arg name="name" type="string" summary="name identifying the toplevel"/>
</request>
<request name="remove_toplevel">
<description summary="remove a surface from the session">
Remove a specified surface from the session and render any related
xdg_toplevel_session_v1 object inert. The compositor should remove any
data related to the toplevel in the corresponding session from its internal
storage.
The window is specified by its name in the session. The name string
must be encoded in UTF-8, and it is limited in size by the maximum
length of wayland messages (around 4KB).
</description>
<arg name="name" type="string" summary="name identifying the toplevel"/>
</request>
<event name="created">
<description summary="newly-created session id">
Emitted at most once some time after getting a new session object. It
means that no previous state was restored, and a new session was created.
The passed id can be persistently stored and used to restore previous
sessions.
</description>
<arg name="session_id" type="string"/>
</event>
<event name="restored">
<description summary="the session has been restored">
Emitted at most once some time after getting a new session object. It
means that previous state was at least partially restored. The same id
can again be used to restore previous sessions.
</description>
</event>
<event name="replaced">
<description summary="the session has been replaced">
Emitted at most once, if the session was taken over by some other
client. When this happens, the session and all its toplevel session
objects become inert, and should be destroyed.
</description>
</event>
</interface>
<interface name="xdg_toplevel_session_v1" version="1">
<description summary="A session for an application">
A xdg_toplevel_session_v1 resource acts as a handle for the given
toplevel in the session. It allows for receiving events after a
toplevel state was restored, and has the requests to manage them.
</description>
<request name="destroy" type="destructor">
<description summary="Destroy the object">
Destroy the object. This has no effect over window management of the
associated toplevel.
</description>
</request>
<request name="rename">
<description summary="change the name of toplevel session">
Renames the toplevel session. The new name can be used in subsequent requests
to identify this session object. The state associated with this toplevel
session will be preserved.
If the xdg_session_v1 already contains a toplevel with the specified name,
the 'name_in_use' protocol error will be raised.
</description>
<arg name="name" type="string" summary="new name to identify the toplevel"/>
</request>
<event name="restored">
<description summary="a toplevel's session has been restored">
The "restored" event is emitted prior to the first
xdg_toplevel.configure for the toplevel. It will only be emitted after
xdg_session_v1.restore_toplevel, and the initial empty surface state has
been applied, and it indicates that the surface's session is being
restored with this configure event.
</description>
</event>
</interface>
</protocol>