[RFC wayland-protocols v4] Add Primary Selection Protocol Version 1

Jonas Ådahl jadahl at gmail.com
Mon Feb 22 07:53:38 UTC 2016


On Sat, Feb 20, 2016 at 01:31:59AM +0100, Carlos Garnacho wrote:
> From: Lyude <cpaul at redhat.com>
> 
> This primary selection is similar in spirit to the eponimous
> in X11, allowing a quick "select text + middle click" shortcut
> to copying and pasting.
> 
> It's otherwise very similar to it wayland counterpart, and
> explicitly made consistent with it.
> 
> Signed-off-by: Lyude <cpaul at redhat.com>
> Signed-off-by: Carlos Garnacho <carlosg at gnome.org>
> ---
> After having talked with Lyude, I'll be trying to move this ahead.
> 
> Changes since v3:
> - Added a rather verbose protocol description, including a
>   high-level overview of the workings.
> - Made event emission 1:1 with wayland core protocol selections,
>   wp_primary_selection_offer.offer events are now expected to be
>   emitted between wp_primary_data_device.data_offer and 
>   wp_primary_data_device.selection
> - Improved wording here and there.
> - Added serial argument to wp_primary_data_offer.receive that can be
>   used to match against recent events.


Overall good. Some comments inline. With those fixed, this is
Reviewed-by: Jonas Ådahl <jadahl at gmail.com>

> 
> 
>  Makefile.am                                        |   1 +
>  unstable/primary-selection/README                  |   4 +
>  .../primary-selection-unstable-v1.xml              | 229 +++++++++++++++++++++
>  3 files changed, 234 insertions(+)
>  create mode 100644 unstable/primary-selection/README
>  create mode 100644 unstable/primary-selection/primary-selection-unstable-v1.xml
> 
> diff --git a/Makefile.am b/Makefile.am
> index 57d0023..eefa20f 100644
> --- a/Makefile.am
> +++ b/Makefile.am
> @@ -7,6 +7,7 @@ unstable_protocols =								\
>  	unstable/xdg-shell/xdg-shell-unstable-v5.xml				\
>  	unstable/relative-pointer/relative-pointer-unstable-v1.xml		\
>  	unstable/pointer-constraints/pointer-constraints-unstable-v1.xml	\
> +	unstable/primary-selection/primary-selection-unstable-v1.xml		\
>  	$(NULL)
>  
>  stable_protocols =								\
> diff --git a/unstable/primary-selection/README b/unstable/primary-selection/README
> new file mode 100644
> index 0000000..6d8c0c6
> --- /dev/null
> +++ b/unstable/primary-selection/README
> @@ -0,0 +1,4 @@
> +Primary selection protocol
> +
> +Maintainers:
> +Lyude <cpaul at redhat.com>

Any reason for the "anti-spam" thing here? The E-mail address is already
available all over the place anyway (commit author, commit body).

> diff --git a/unstable/primary-selection/primary-selection-unstable-v1.xml b/unstable/primary-selection/primary-selection-unstable-v1.xml
> new file mode 100644
> index 0000000..a3618d5
> --- /dev/null
> +++ b/unstable/primary-selection/primary-selection-unstable-v1.xml
> @@ -0,0 +1,229 @@
> +<?xml version="1.0" encoding="UTF-8"?>
> +<protocol name="primary_selection_unstable_v1">
> +  <copyright>
> +    Copyright © 2015 Red Hat

2016 now as well?

> +
> +    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="Primary selection protocol">
> +    This protocol provides the ability to have a primary selection device to
> +    match that of the X server. This primary selection is a shortcut to the
> +    common clipboard selection, where text just needs to be selected in order
> +    to allow copying it elsewhere. The de facto way to perform this action
> +    is the middle mouse button, although it is not limited to this one.
> +
> +    Clients wishing to honor primary selection should create a primary
> +    selection source and set it as the selection through
> +    wp_primary_selection_device.set_selection whenever the text selection
> +    changes. In order to minimize calls in pointer-driven text selection,
> +    it should happen only once after the operation finished. Similarly,
> +    a NULL source should be set when text is unselected.

Does this mean that a client may not create one source object, and just
keep the same as text is selected, while only setting a NULL source if
text was unselected?

> +
> +    wp_primary_selection_offer objects are first announced through the
> +    wp_primary_selection_device.data_offer event. Immediately after this event,
> +    the primary data offer will emit wp_primary_selection_offer.offer events
> +    to let know of the mime types being offered.
> +
> +    When the primary selection changes, the client with the keyboard focus
> +    will receive wp_primary_selection_device.selection events. Only the client
> +    with the keyboard focus will receive such events with a non-NULL
> +    wp_primary_selection_offer. Across keyboard focus changes, previously
> +    focused clients will receive wp_primary_selection_device.events with a
> +    NULL wp_primary_selection_offer.
> +
> +    In order to request the primary selection data, the client must pass
> +    a recent serial pertaining to the press event that is triggering the
> +    operation, if the compositor deems the serial valid and recent, the
> +    wp_primary_selection_source.send event will happen in the other end
> +    to let the transfer begin. The client owning the primary selection
> +    should write the requested data, and close the file descriptor
> +    immediately.
> +
> +    If the primary selection owner client disappeared during the transfer,
> +    the client reading the data will receive a
> +    wp_primary_selection_device.selection event with a NULL
> +    wp_primary_selection_offer, the client should take this as a hint
> +    to finish the reads related to the no longer existing offer.
> +
> +    The primary selection owner should be checking for errors during
> +    writes, merely cancelling the ongoing transfer if any happened.
> +  </description>
> +
> +  <interface name="zwp_primary_selection_device_manager_v1" version="1">
> +    <description summary="X primary selection emulation">
> +      The primary selection device manager is the base interface of primary
> +      selection, it allows to create wp_primary_selection_source objects, as
> +      well as retrieving the per-seat wp_primary_selection_device objects.

This should contain information that it is a singleton global object.

> +    </description>
> +
> +    <request name="create_source">
> +      <description summary="create a new primary selection source">
> +	Create a new primary selection source.
> +      </description>
> +      <arg name="id" type="new_id" interface="zwp_primary_selection_source_v1"/>
> +    </request>
> +
> +    <request name="get_device">
> +      <description summary="primary selection device manager">
> +	Singleton global object that manages the zwp_primary_selection_device_v1
> +	objects for each wl_seat.

The summary and description seems to describe manager interface.

> +      </description>
> +      <arg name="id" type="new_id" interface="zwp_primary_selection_device_v1"/>
> +      <arg name="seat" type="object" interface="wl_seat"/>
> +    </request>
> +
> +    <request name="destroy" type="destructor">
> +      <description summary="destroy the primary selection device manager">
> +	Destroy the primary selection device manager.
> +      </description>
> +    </request>
> +  </interface>
> +
> +  <interface name="zwp_primary_selection_device_v1" version="1">
> +    <request name="set_selection">
> +      <description summary="set the primary selection">
> +	Set the current contents of the primary selection buffer. This clears
> +	anything which was previously held in the primary selection buffer.

This doesn't set any buffer content any more, it just sets the source
object.

> +      </description>
> +      <arg name="source" type="object" interface="zwp_primary_selection_source_v1" allow-null="true"/>
> +    </request>
> +
> +    <event name="data_offer">
> +      <description summary="introduce a new wp_primary_selection_offer">
> +	Introduces a new wp_primary_selection_offer object that may be used
> +	to receive the current primary selection. Immediately following this
> +	event, the new wp_primary_selection_offer object will send
> +	wp_primary_selection_offer.offer events to describe the offered mime
> +	types.
> +      </description>
> +      <arg name="offer" type="new_id" interface="zwp_primary_selection_offer_v1"/>
> +    </event>
> +
> +    <event name="selection">
> +      <description summary="advertise a new primary selection">
> +	The wp_primary_selection_device.selection event is sent to notify the
> +	client of a new primary selection. This event is sent after the
> +	wp_primary_selection.data_offer event introducing this object, and after
> +	the offer has announced its mimetypes through
> +	wp_primary_selection_offer.offer.
> +
> +	The data_offer is valid until a new offer or NULL is received
> +	or until the client loses keyboard focus. The client must destroy the
> +	previous selection data_offer, if any, upon receiving this event.
> +      </description>
> +      <arg name="id" type="object" interface="zwp_primary_selection_offer_v1" allow-null="true"/>
> +    </event>
> +
> +    <request name="destroy" type="destructor">
> +      <description summary="destroy the primary selection device">
> +	Destroy the primary selection device.
> +      </description>
> +    </request>
> +  </interface>
> +
> +  <interface name="zwp_primary_selection_offer_v1" version="1">
> +    <description summary="offer to transfer primary selection contents">
> +      A wp_primary_selection_offer represents an offer to transfer the contents
> +      of the primary selection clipboard to the client. Similar to
> +      wl_data_offer, the offer also describes the different mime types that the
> +      data can be converted to and provides the mechanisms for transferring the

"transeferred as" instead of "converted to". Whether any conversion is
done is an implementation detail.

> +      data directly to the client.
> +    </description>
> +
> +    <request name="receive">
> +      <description summary="request that the data is transferred">
> +	To transfer the contents of the primary selection clipboard, the client
> +	issues this request and indicates the mime type that it wants to
> +	receive. The transfer happens through the passed file descriptor
> +	(typically created with the pipe system call). The source client writes
> +	the data in the mime type representation requested and then closes the
> +	file descriptor.
> +
> +	The receiving client reads from the read end of the pipe until EOF and
> +	closes its end, at which point the transfer is complete.
> +
> +	The given serial may be used by the compositor in order to determine
> +	whether the receive request will be honored or not. Clients should
> +	provide the button or key serial that is triggering the primary
> +	selection request. Compositors should ignore requests with serials
> +	that don't match any recent events, the file descriptor
> +	should be closed immediately in this case.
> +      </description>
> +      <arg name="mime_type" type="string"/>
> +      <arg name="fd" type="fd"/>
> +      <arg name="serial" type="uint" summary="serial of the press event"/>
> +    </request>
> +
> +    <request name="destroy" type="destructor">
> +      <description summary="destroy the primary selection offer">
> +	Destroy the primary selection offer.
> +      </description>
> +    </request>
> +
> +    <event name="offer">
> +      <description summary="advertise offered mime type">
> +	Sent immediately after creating announcing the wp_primary_selection_offer
> +	through wp_primary_selection_device.data_offer. One event is sent per
> +	offered mime type.
> +      </description>
> +      <arg name="mime_type" type="string"/>
> +    </event>
> +  </interface>
> +
> +  <interface name="zwp_primary_selection_source_v1" version="1">
> +    <description summary="offer to replace the contents of the primary selection">
> +      The source side of a wp_primary_selection_offer, it provides a way to
> +      describe the offered data and respond to requests to transfer the
> +      requested contents of the primary selection clipboard.
> +    </description>
> +
> +    <request name="offer">
> +      <description summary="add an offered mime type">
> +	This request adds a mime type to the set of mime types advertised to
> +	targets. Can be called several times to offer multiple types.
> +      </description>
> +      <arg name="mime_type" type="string"/>
> +    </request>
> +
> +    <request name="destroy" type="destructor">
> +      <description summary="destroy the primary selection source">
> +	Destroy the primary selection source.
> +      </description>
> +    </request>
> +
> +    <event name="send">
> +      <description summary="send the primary selection contents">
> +	Request for the current primary selection contents from the client.
> +	Send the specified mime type over the passed file descriptor, then
> +	close it.
> +      </description>
> +      <arg name="mime_type" type="string"/>
> +      <arg name="fd" type="fd"/>
> +    </event>
> +
> +    <event name="cancelled">
> +      <description summary="request for primary selection contents was canceled">
> +	This primary selection source is no longer valid. The client should
> +	clean up and destroy this primary selection source.
> +      </description>
> +    </event>
> +  </interface>
> +</protocol>
> -- 
> 2.5.0
> 
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