NAME

       wayland::server::data_offer_t - offer to transfer data

SYNOPSIS

       #include <wayland-server-protocol.hpp>

       Inherits wayland::server::resource_t.

   Public Member Functions
       std::function< void(uint32_t, std::string)> & on_accept ()
           accept one of the offered mime types
       std::function< void(std::string, int)> & on_receive ()
           request that the data is transferred
       std::function< void()> & on_destroy ()
           destroy data offer
       std::function< void()> & on_finish ()
           the offer will no longer be used
       std::function< void(data_device_manager_dnd_action, data_device_manager_dnd_action)> &
           on_set_actions ()
           set the available/preferred drag-and-drop actions
       void offer (std::string const &mime_type, bool post=true)
           advertise offered mime type
       void source_actions (data_device_manager_dnd_action const &source_actions, bool post=true)
           notify the source-side available actions
       bool can_source_actions () const
           Check whether the source_actions function is available with the currently bound
           version of the protocol.
       void action (data_device_manager_dnd_action const &dnd_action, bool post=true)
           notify the selected action
       bool can_action () const
           Check whether the action function is available with the currently bound version of the
           protocol.
       void post_invalid_finish (std::string const &msg)
           Post error: finish request was called untimely.
       void post_invalid_action_mask (std::string const &msg)
           Post error: action mask contains invalid values.
       void post_invalid_action (std::string const &msg)
           Post error: action argument has an invalid value.
       void post_invalid_offer (std::string const &msg)
           Post error: offer doesn't accept this request.
       bool proxy_has_object () const
           Check whether this wrapper actually wraps an object.
       void post_no_memory () const
       uint32_t get_id () const
       client_t get_client () const
       unsigned int get_version () const
       std::string get_class ()

   Static Public Attributes
       static constexpr std::uint32_t offer_since_version = 1
           Minimum protocol version required for the offer function.
       static constexpr std::uint32_t source_actions_since_version = 3
           Minimum protocol version required for the source_actions function.
       static constexpr std::uint32_t action_since_version = 3
           Minimum protocol version required for the action function.

Detailed Description

       offer to transfer data

       A wl_data_offer represents a piece of data offered for transfer by another client (the
       source client). It is used by the copy-and-paste and drag-and-drop mechanisms. The offer
       describes the different mime types that the data can be converted to and provides the
       mechanism for transferring the data directly from the source client.

       Definition at line 821 of file wayland-server-protocol.hpp.

Member Function Documentation

   void data_offer_t::action (data_device_manager_dnd_action const & dnd_action, bool post =
       true)
       notify the selected action

       Parameters
           dnd_action action selected by the compositor

       This event indicates the action selected by the compositor after matching the
       source/destination side actions. Only one action (or none) will be offered here.

       This event can be emitted multiple times during the drag-and-drop operation in response to
       destination side action changes through wl_data_offer.set_actions.

       This event will no longer be emitted after wl_data_device.drop happened on the drag-and-
       drop destination, the client must honor the last action received, or the last preferred
       one set through wl_data_offer.set_actions when handling an 'ask' action.

       Compositors may also change the selected action on the fly, mainly in response to keyboard
       modifier changes during the drag-and-drop operation.

       The most recent action received is always the valid one. Prior to receiving
       wl_data_device.drop, the chosen action may change (e.g. due to keyboard modifiers being
       pressed). At the time of receiving wl_data_device.drop the drag-and-drop destination must
       honor the last action received.

       Action changes may still happen after wl_data_device.drop, especially on 'ask' actions,
       where the drag-and-drop destination may choose another action afterwards. Action changes
       happening at this stage are always the result of inter-client negotiation, the compositor
       shall no longer be able to induce a different action.

       Upon 'ask' actions, it is expected that the drag-and-drop destination may potentially
       choose a different action and/or mime type, based on wl_data_offer.source_actions and
       finally chosen by the user (e.g. popping up a menu with the available options). The final
       wl_data_offer.set_actions and wl_data_offer.accept requests must happen before the call to
       wl_data_offer.finish.

       Definition at line 1893 of file wayland-server-protocol.cpp.

   bool data_offer_t::can_action () const
       Check whether the action function is available with the currently bound version of the
       protocol.

       Definition at line 1898 of file wayland-server-protocol.cpp.

   bool data_offer_t::can_source_actions () const
       Check whether the source_actions function is available with the currently bound version of
       the protocol.

       Definition at line 1888 of file wayland-server-protocol.cpp.

   std::string wayland::server::resource_t::get_class () [inherited]
       Retrieve the interface name (class) of a resource object.

       Returns
           Interface name of the resource object.

   client_t wayland::server::resource_t::get_client () const [inherited]
       Get the associated client

       Returns
           the client that owns the resource.

   uint32_t wayland::server::resource_t::get_id () const [inherited]
       Get the internal ID of the resource

       Returns
           the internal ID of the resource

   unsigned int wayland::server::resource_t::get_version () const [inherited]
       Get interface version

       Returns
           Interface version this resource has been constructed with.

   void data_offer_t::offer (std::string const & mime_type, bool post = true)
       advertise offered mime type

       Parameters
           mime_type offered mime type

       Sent immediately after creating the wl_data_offer object. One event per offered mime type.

       Definition at line 1878 of file wayland-server-protocol.cpp.

   std::function< void(uint32_t, std::string)> & data_offer_t::on_accept ()
       accept one of the offered mime types

       Parameters
           serial serial number of the accept request
           mime_type mime type accepted by the client

       Indicate that the client can accept the given mime type, or NULL for not accepted.

       For objects of version 2 or older, this request is used by the client to give feedback
       whether the client can receive the given mime type, or NULL if none is accepted; the
       feedback does not determine whether the drag-and-drop operation succeeds or not.

       For objects of version 3 or newer, this request determines the final result of the drag-
       and-drop operation. If the end result is that no mime types were accepted, the drag-and-
       drop operation will be cancelled and the corresponding drag source will receive
       wl_data_source.cancelled. Clients may still use this event in conjunction with
       wl_data_source.action for feedback.

       Definition at line 1848 of file wayland-server-protocol.cpp.

   std::function< void()> & data_offer_t::on_destroy ()
       destroy data offer Destroy the data offer.

       Definition at line 1860 of file wayland-server-protocol.cpp.

   std::function< void()> & data_offer_t::on_finish ()
       the offer will no longer be used Notifies the compositor that the drag destination
       successfully finished the drag-and-drop operation.

       Upon receiving this request, the compositor will emit wl_data_source.dnd_finished on the
       drag source client.

       It is a client error to perform other requests than wl_data_offer.destroy after this one.
       It is also an error to perform this request after a NULL mime type has been set in
       wl_data_offer.accept or no action was received through wl_data_offer.action.

       If wl_data_offer.finish request is received for a non drag and drop operation, the
       invalid_finish protocol error is raised.

       Definition at line 1866 of file wayland-server-protocol.cpp.

   std::function< void(std::string, int)> & data_offer_t::on_receive ()
       request that the data is transferred

       Parameters
           mime_type mime type desired by receiver
           fd file descriptor for data transfer

       To transfer the offered data, the client issues this request and indicates the mime type
       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 then closes its
       end, at which point the transfer is complete.

       This request may happen multiple times for different mime types, both before and after
       wl_data_device.drop. Drag-and-drop destination clients may preemptively fetch data or
       examine it more closely to determine acceptance.

       Definition at line 1854 of file wayland-server-protocol.cpp.

   std::function< void(data_device_manager_dnd_action, data_device_manager_dnd_action)> &
       data_offer_t::on_set_actions ()
       set the available/preferred drag-and-drop actions

       Parameters
           dnd_actions actions supported by the destination client
           preferred_action action preferred by the destination client

       Sets the actions that the destination side client supports for this operation. This
       request may trigger the emission of wl_data_source.action and wl_data_offer.action events
       if the compositor needs to change the selected action.

       This request can be called multiple times throughout the drag-and-drop operation,
       typically in response to wl_data_device.enter or wl_data_device.motion events.

       This request determines the final result of the drag-and-drop operation. If the end result
       is that no action is accepted, the drag source will receive wl_data_source.cancelled.

       The dnd_actions argument must contain only values expressed in the
       wl_data_device_manager.dnd_actions enum, and the preferred_action argument must only
       contain one of those values set, otherwise it will result in a protocol error.

       While managing an 'ask' action, the destination drag-and-drop client may perform further
       wl_data_offer.receive requests, and is expected to perform one last
       wl_data_offer.set_actions request with a preferred action other than 'ask' (and optionally
       wl_data_offer.accept) before requesting wl_data_offer.finish, in order to convey the
       action selected by the user. If the preferred action is not in the
       wl_data_offer.source_actions mask, an error will be raised.

       If the 'ask' action is dismissed (e.g. user cancellation), the client is expected to
       perform wl_data_offer.destroy right away.

       This request can only be made on drag-and-drop offers, a protocol error will be raised
       otherwise.

       Definition at line 1872 of file wayland-server-protocol.cpp.

   void data_offer_t::post_invalid_action (std::string const & msg)
       Post error: action argument has an invalid value.

       Definition at line 1913 of file wayland-server-protocol.cpp.

   void data_offer_t::post_invalid_action_mask (std::string const & msg)
       Post error: action mask contains invalid values.

       Definition at line 1908 of file wayland-server-protocol.cpp.

   void data_offer_t::post_invalid_finish (std::string const & msg)
       Post error: finish request was called untimely.

       Definition at line 1903 of file wayland-server-protocol.cpp.

   void data_offer_t::post_invalid_offer (std::string const & msg)
       Post error: offer doesn't accept this request.

       Definition at line 1918 of file wayland-server-protocol.cpp.

   void wayland::server::resource_t::post_no_memory () const [inherited]
       Post 'not enough memory' error to the client

       If the compositor has not enough memory to fulfill a certail request of the client, this
       function can be called to notify the client of this circumstance.

   bool wayland::server::resource_t::proxy_has_object () const [inherited]
       Check whether this wrapper actually wraps an object.

       Returns
           true if there is an underlying object, false if this wrapper is empty

   void data_offer_t::source_actions (data_device_manager_dnd_action const & source_actions, bool
       post = true)
       notify the source-side available actions

       Parameters
           source_actions actions offered by the data source

       This event indicates the actions offered by the data source. It will be sent right after
       wl_data_device.enter, or anytime the source side changes its offered actions through
       wl_data_source.set_actions.

       Definition at line 1883 of file wayland-server-protocol.cpp.

Member Data Documentation

   constexpr std::uint32_t wayland::server::data_offer_t::action_since_version = 3 [static],
       [constexpr]
       Minimum protocol version required for the action function.

       Definition at line 1038 of file wayland-server-protocol.hpp.

   constexpr std::uint32_t wayland::server::data_offer_t::offer_since_version = 1 [static],
       [constexpr]
       Minimum protocol version required for the offer function.

       Definition at line 973 of file wayland-server-protocol.hpp.

   constexpr std::uint32_t wayland::server::data_offer_t::source_actions_since_version = 3
       [static],  [constexpr]
       Minimum protocol version required for the source_actions function.

       Definition at line 987 of file wayland-server-protocol.hpp.

Author

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