[RFC wayland-protocols v4] Add Primary Selection Protocol Version 1
Jonas Ådahl
jadahl at gmail.com
Wed Feb 24 04:33:10 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.
>
>
> 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"/>
While reviewing the implementation, I noticed that while
wl_data_device.set_selection takes a serial, the set_selection here
doesn't. Does this mean that a client can set the selection without
foucus and without any user interaction?
It seems reasonable to me to require this as (not only offer.receive)
would require a valid serial to have any effect.
Jonas
> + </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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