nim-libp2p/libp2p/utility.nim

139 lines
3.9 KiB
Nim

# Nim-LibP2P
# Copyright (c) 2023 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.
{.push raises: [].}
import std/options, std/macros
import stew/[byteutils, results]
export results
template public* {.pragma.}
const
ShortDumpMax = 12
template compilesOr*(a, b: untyped): untyped =
when compiles(a):
a
else:
b
func shortLog*(item: openArray[byte]): string =
if item.len <= ShortDumpMax:
result = item.toHex()
else:
const
split = ShortDumpMax div 2
dumpLen = (ShortDumpMax * 2) + 3
result = newStringOfCap(dumpLen)
result &= item.toOpenArray(0, split - 1).toHex()
result &= "..."
result &= item.toOpenArray(item.len - split, item.high).toHex()
func shortLog*(item: string): string =
if item.len <= ShortDumpMax:
result = item
else:
const
split = ShortDumpMax div 2
dumpLen = ShortDumpMax + 3
result = newStringOfCap(dumpLen)
result &= item[0..<split]
result &= "..."
result &= item[(item.len - split)..item.high]
when defined(libp2p_agents_metrics):
import strutils
export split
proc safeToLowerAscii*(s: string): Result[string, cstring] =
try:
ok(s.toLowerAscii())
except CatchableError:
err("toLowerAscii failed")
const
KnownLibP2PAgents* {.strdefine.} = "nim-libp2p"
KnownLibP2PAgentsSeq* = KnownLibP2PAgents.safeToLowerAscii().tryGet().split(",")
template safeConvert*[T: SomeInteger, S: Ordinal](value: S): T =
## Converts `value` from S to `T` iff `value` is guaranteed to be preserved.
when int64(T.low) <= int64(S.low()) and uint64(T.high) >= uint64(S.high):
T(value)
else:
{.error: "Source and target types have an incompatible range low..high".}
proc capLen*[T](s: var seq[T], length: Natural) =
if s.len > length:
s.setLen(length)
template exceptionToAssert*(body: untyped): untyped =
block:
var res: type(body)
when defined(nimHasWarnBareExcept):
{.push warning[BareExcept]:off.}
try:
res = body
except CatchableError as exc: raise exc
except Defect as exc: raise exc
except Exception as exc: raiseAssert exc.msg
when defined(nimHasWarnBareExcept):
{.pop.}
res
template withValue*[T](self: Opt[T] | Option[T], value, body: untyped): untyped =
## This template provides a convenient way to work with `Option` types in Nim.
## It allows you to execute a block of code (`body`) only when the `Option` is not empty.
##
## `self` is the `Option` instance being checked.
## `value` is the variable name to be used within the `body` for the unwrapped value.
## `body` is a block of code that is executed only if `self` contains a value.
##
## The `value` within `body` is automatically unwrapped from the `Option`, making it
## simpler to work with without needing explicit checks or unwrapping.
##
## Example:
## ```nim
## let myOpt = Opt.some(5)
## myOpt.withValue(value):
## echo value # Will print 5
## ```
##
## Note: This is a template, and it will be inlined at the call site, offering good performance.
let temp = (self)
if temp.isSome:
let value {.inject.} = temp.get()
body
macro withValue*[T](self: Opt[T] | Option[T], value, body, elseStmt: untyped): untyped =
let elseBody = elseStmt[0]
quote do:
let temp = (`self`)
if temp.isSome:
let `value` {.inject.} = temp.get()
`body`
else:
`elseBody`
template valueOr*[T](self: Option[T], body: untyped): untyped =
let temp = (self)
if temp.isSome:
temp.get()
else:
body
template toOpt*[T, E](self: Result[T, E]): Opt[T] =
let temp = (self)
if temp.isOk:
when T is void: Result[void, void].ok()
else: Opt.some(temp.unsafeGet())
else:
Opt.none(type(T))