nimbus-eth1/nimbus/sync/misc/timer_helper.nim

46 lines
1.9 KiB
Nim

# Nimbus
# Copyright (c) 2018-2021 Status Research & Development GmbH
# Licensed under either of
# * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or
# http://www.apache.org/licenses/LICENSE-2.0)
# * MIT license ([LICENSE-MIT](LICENSE-MIT) or
# http://opensource.org/licenses/MIT)
# at your option. This file may not be copied, modified, or
# distributed except according to those terms.
import
chronos
{.push raises: [].}
# Use `safeSetTimer` consistently, with a `ref T` argument if including one.
type
SafeCallbackFunc*[T] = proc (objectRef: ref T) {.gcsafe, raises: [Defect].}
SafeCallbackFuncVoid* = proc () {.gcsafe, raises: [Defect].}
proc safeSetTimer*[T](at: Moment, cb: SafeCallbackFunc[T],
objectRef: ref T = nil): TimerCallback =
## Like `setTimer` but takes a typed `ref T` argument, which is passed to the
## callback function correctly typed. Stores the `ref` in a closure to avoid
## garbage collection memory corruption issues that occur when the `setTimer`
## pointer argument is used.
proc chronosTimerSafeCb(udata: pointer) = cb(objectRef)
return setTimer(at, chronosTimerSafeCb)
proc safeSetTimer*[T](at: Moment, cb: SafeCallbackFuncVoid): TimerCallback =
## Like `setTimer` but takes no pointer argument. The callback function
## takes no arguments.
proc chronosTimerSafeCb(udata: pointer) = cb()
return setTimer(at, chronosTimerSafeCb)
proc setTimer*(at: Moment, cb: CallbackFunc, udata: pointer): TimerCallback
{.error: "Do not use setTimer with a `pointer` type argument".}
## `setTimer` with a non-nil pointer argument is dangerous because
## the pointed-to object is often freed or garbage collected before the
## timer callback runs. Call `setTimer` with a `ref` argument instead.
proc setTimer*(at: Moment, cb: CallbackFunc): TimerCallback =
chronos.setTimer(at, cb, nil)
# End