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s.mli
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s.mli
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(*
* Copyright (c) 2013,2014 Citrix Systems Inc
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*)
module type EVENTS = sig
type 'a io
type port with sexp_of
(** an identifier for a source of events. Ports are allocated by calls to
[listen], then exchanged out-of-band (typically by xenstore) and
finally calls to [connect] creates a channel between the two domains.
Events are send and received over these channels. *)
val port_of_string: string -> [ `Ok of port | `Error of string ]
val string_of_port: port -> string
type channel with sexp_of
(** a channel is the connection between two domains and is used to send
and receive events. *)
type event with sexp_of
(** an event notification received from a remote domain. Events contain no
data and may be coalesced. Domains which are blocked will be woken up
by an event. *)
val initial: event
(** represents an event which 'fired' when the program started *)
val recv: channel -> event -> event Lwt.t
(** [recv channel event] blocks until the system receives an event
newer than [event] on channel [channel]. If an event is received
while we aren't looking then this will be remembered and the
next call to [after] will immediately unblock. If the system
is suspended and then resumed, all event channel bindings are invalidated
and this function will fail with Generation.Invalid *)
val send: channel -> unit io
(** [send channel] sends an event along [channel], to another domain
which will be woken up *)
val listen: int -> (port * channel) io
(** [listen domid] allocates a fresh port and event channel. The port
may be supplied to [connect] *)
val connect: int -> port -> channel io
(** [connect domid port] connects an event channel to [port] on [domid] *)
val close: channel -> unit io
(** [close channel] closes this side of an event channel *)
val description: string
(** Human-readable description suitable for help text or
a manpage *)
end