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module Mirage_protocol : sig ... end
The type for flows. A flow represents the state of a single reliable stream stream that is connected to an endpoint.
include Mirage_flow.S
with type flow := flow
and type error = [ `Msg of string | `Not_found | `Cycle ]
The type for write errors.
val pp_write_error : write_error Fmt.t
pp_write_error
is the pretty-printer for write errors.
val read : flow -> (Cstruct.t Mirage_flow.or_eof, error) Stdlib.result Lwt.t
read flow
blocks until some data is available and returns a fresh buffer containing it.
The returned buffer will be of a size convenient to the flow implementation, but will always have at least 1 byte.
If the remote endpoint calls close
then calls to read
will keep returning data until all the in-flight data has been read. read flow
will return `Eof
when the remote endpoint has called close
and when there is no more in-flight data.
val write : flow -> Cstruct.t -> (unit, write_error) Stdlib.result Lwt.t
write flow buffer
writes a buffer to the flow. There is no indication when the buffer has actually been read and, therefore, it must not be reused. The contents may be transmitted in separate packets, depending on the underlying transport. The result Ok ()
indicates success, Error `Closed
indicates that the connection is now closed and therefore the data could not be written. Other errors are possible.
val writev : flow -> Cstruct.t list -> (unit, write_error) Stdlib.result Lwt.t
writev flow buffers
writes a sequence of buffers to the flow. There is no indication when the buffers have actually been read and, therefore, they must not be reused. The result Ok ()
indicates success, Error `Closed
indicates that the connection is now closed and therefore the data could not be written. Other errors are possible.
close flow
flushes all pending writes and signals the remote endpoint that there will be no future writes. Once the remote endpoint has read all pending data, it is expected that calls to read
on the remote return `Eof
.
Note it is still possible for the remote endpoint to write
to the flow and for the local endpoint to call read
. This state where the local endpoint has called close
but the remote endpoint has not called close
is similar to that of a half-closed TCP connection or a Unix socket after shutdown(SHUTDOWN_WRITE)
.
close flow
waits until the remote endpoint has also called close
before returning. At this point no data can flow in either direction and resources associated with the flow can be freed.
module Fun : sig ... end
val make : name:string -> 'edn value
make ~name
is a new witness.
replace w v ctx
replaces the value of w
by v
if it exists or bound w
to v
.
val empty : ctx
empty
is the empty context.
val register :
?priority:int ->
name:string ->
(module Mirage_protocol.S with type endpoint = 'edn and type flow = 'flow) ->
'edn value * ('edn, 'flow) protocol
register ?priority ~name (module Protocol)
registers the given Protocol
into the internal global Mimic's state as a possible transmission protocol available via resolve
.
?priority
is used to help mimic to choose between multiple solutions according to the given context. Mimic will choose the lower-priority solution.
name
helps the end-user to know which solution mimic will dynamically via log outputs.
register
returns 2 values:
module type REPR = sig ... end
repr protocol
gives a module definition with an OCaml constructor to help the end-user to destruct the structural type of a given flow
:
module Protocol
: Mirage_protocol.S with type flow = Lwt_unix.file_descr
let edn, protocol = Mimic.register ~name:"protocol" (module Protocol)
module R = (val (Mimic.repr protocol))
let () = Mimic.resolve ~ctx >>= function
| Ok (R.T lwt_unix_file_descr) -> ...
| ...
resolve ctx
tries to instantiate a flow
from the given ctx
.
equal a b
returns a proof that a
and b
are structurally equal.
unfold ctx
applies any functions available into the given ctx
and and possible to compute according to available values and return a list of what these functions return.
It's useful to do an introspection of what mimic
does when it resolve
s the given ctx
. From that and equal
, the user is able to introspect what mimic
generated and which protocol it is able to instantiate then.
al:resolve} is: {[ let resolve ctx = unfold ctx >>= function | Ok lst -> connect lst | Error _ as err -> Lwt.return err ]}