2020-04-17 17:18:13 -06:00

77 lines
1.8 KiB
Nim

## Nim-LibP2P
## Copyright (c) 2020 Status Research & Development GmbH
## Licensed under either of
## * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
## * MIT license ([LICENSE-MIT](LICENSE-MIT))
## at your option.
## This file may not be copied, modified, or distributed except according to
## those terms.
import chronos
# TODO: Rework without methods
type
Source*[T] = iterator(): Future[T] {.closure.}
Through*[T] = proc(i: Source[T]): Source[T]
Sink*[T] = proc(i: Source[T]): Future[void]
Duplex*[T] = Source[T] | Sink[T]
Stream*[T] = ref object of RootObj
name*: string
closed*: bool
eof*: bool
sourceImpl*: proc (s: Stream[T]): Source[T] {.gcsafe.}
sinkImpl*: proc(s: Stream[T]): Sink[T] {.gcsafe.}
iterator items*[T](i: Source[T]): Future[T] =
while true:
var item = i()
if i.finished:
break
yield item
proc source*[T](s: Stream[T]): Source[T] =
if not isNil(s.sourceImpl):
return s.sourceImpl(s)
proc sink*[T](s: Stream[T]): Sink[T] =
if not isNil(s.sinkImpl):
return s.sinkImpl(s)
proc atEof*[T](s: Stream[T]): bool =
s.eof
proc close*[T](s: Stream[T]) {.async.} =
s.closed = true
template toFuture*[T](v: T): Future[T] =
var fut = newFuture[T]()
fut.complete(v)
fut
template pipe*[T](s: Stream[T] | Source[T],
t: varargs[Through[T]]): Source[T] =
var pipeline: Source[T]
when s is Source[T]:
pipeline = s
elif s is Stream[T]:
pipeline = s.source
for i in t:
pipeline = i(pipeline)
pipeline
template pipe*[T](s: Stream[T] | Source[T],
t: varargs[Through[T]],
x: Stream[T] | Sink[T]): Future[void] =
var pipeline = pipe(s, t)
var terminal: Future[void]
when x is Stream[T]:
terminal = x.sink()(pipeline)
elif x is Sink[T]:
terminal = x(pipeline)
terminal