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

Carlos Garnacho carlosg at gnome.org
Sat Feb 20 00:31:59 UTC 2016


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.


 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>
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
+
+    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.
+
+    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.
+    </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.
+      </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.
+      </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
+      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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