mirage-flow 1.1.0 · OCaml Package

Function-based flows.

type error

Type for errors.

val pp_error : Format.formatter -> error -> unit

Pretty-print errors.

include V1_LWT.FLOW with type error := error

type 'a io = 'a Lwt.t

The type for potentially blocking I/O operation

type buffer = Cstruct.t

The type for memory buffer.

type flow

The type for flows. A flow represents the state of a single stream that is connected to an endpoint.

val error_message : error -> string

Convert an error to a human-readable message, suitable for logging.

val read : flow -> [ `Ok of buffer | `Eof | `Error of error ] io

read flow will block until it either successfully reads a segment of data from the current flow, receives an Eof signifying that the connection is now closed, or an Error.

val write : flow -> buffer -> [ `Ok of unit | `Eof | `Error of error ] io

write flow buffer will block until buffer has been added to the send queue. 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, `Eof indicates that the connection is now closed and `Error indicates some other error.

val writev : flow -> buffer list -> [ `Ok of unit | `Eof | `Error of error ] io

writev flow buffers will block until the buffers have all been added to the send queue. There is no indication when the buffers have actually been read and, therefore, they must not be reused. The result `Ok () indicates success, `Eof indicates that the connection is now closed and `Error indicates some other error.

val close : flow -> unit io

close flow will flush all pending writes and signal 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 will 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).

The result unit io will become determined when the remote endpoint finishes calling write and calls close. At this point no data can flow in either direction and resources associated with the flow can be freed.

type refill = Cstruct.t -> int -> int -> int Lwt.t

The type for refill functions.

val make : 
  ?close:(unit -> unit Lwt.t) ->
  ?input:refill ->
  ?output:refill ->
  unit ->
  flow

make ~close ~input ~output () is a flow using input to refill its internal input buffer when needed and output to refill its external output buffer. It is using close to eventually clean-up other resources on close.

String flows

val input_string : string -> refill

input_string buf is the refill function reading its inputs from the string buf.

val output_string : string -> refill

output_string buf is the refill function writing its outputs in the buffer buf.

val string : ?input:string -> ?output:string -> unit -> flow

The flow built using input_string and output_string.

val input_strings : string list -> refill

input_strings bufs is the refill function reading its inputs from the list of buffers bufs. Empty strings are ignored.

val output_strings : string list -> refill

output_strings buf is the refill function writing its outputs in the list of buffers buf. Empty strings are ignored.

val strings : ?input:string list -> ?output:string list -> unit -> flow

The flow built using input_strings and output_strings.

Cstruct buffers flows

val input_cstruct : Cstruct.t -> refill

Same as input_string but for Cstruct.t buffers.

val output_cstruct : Cstruct.t -> refill

Same as output_string buf for Cstruct.t buffers.

val cstruct : ?input:Cstruct.t -> ?output:Cstruct.t -> unit -> flow

Same as string but for Cstruct.t buffers.

val input_cstructs : Cstruct.t list -> refill

Same as input_strings but for Cstruct.t buffers.

val output_cstructs : Cstruct.t list -> refill

Same as output_strings but for Cstruct.t buffers.

val cstructs : ?input:Cstruct.t list -> ?output:Cstruct.t list -> unit -> flow

Same as strings but for Cstruct.t buffers.

package mirage-flow

String flows

Cstruct buffers flows