nim-chronos/chronos/ioselects/ioselectors_poll.nim

311 lines
8.7 KiB
Nim

#
#
# Nim's Runtime Library
# (c) Copyright 2016 Eugene Kabanov
#
# See the file "copying.txt", included in this
# distribution, for details about the copyright.
#
# This module implements Posix poll().
import posix, times
# Maximum number of events that can be returned
const MAX_POLL_EVENTS = 64
when hasThreadSupport:
type
SelectorImpl[T] = object
maxFD : int
pollcnt: int
fds: ptr SharedArray[SelectorKey[T]]
pollfds: ptr SharedArray[TPollFd]
count: int
lock: Lock
Selector*[T] = ptr SelectorImpl[T]
else:
type
SelectorImpl[T] = object
maxFD : int
pollcnt: int
fds: seq[SelectorKey[T]]
pollfds: seq[TPollFd]
count: int
Selector*[T] = ref SelectorImpl[T]
type
SelectEventImpl = object
rfd: cint
wfd: cint
SelectEvent* = ptr SelectEventImpl
when hasThreadSupport:
template withPollLock[T](s: Selector[T], body: untyped) =
acquire(s.lock)
{.locks: [s.lock].}:
try:
body
finally:
release(s.lock)
else:
template withPollLock(s, body: untyped) =
body
proc newSelector*[T](): Selector[T] =
var a = RLimit()
if getrlimit(posix.RLIMIT_NOFILE, a) != 0:
raiseIOSelectorsError(osLastError())
var maxFD = int(a.rlim_max)
when hasThreadSupport:
result = cast[Selector[T]](allocShared0(sizeof(SelectorImpl[T])))
result.maxFD = maxFD
result.fds = allocSharedArray[SelectorKey[T]](maxFD)
result.pollfds = allocSharedArray[TPollFd](maxFD)
initLock(result.lock)
else:
result = Selector[T]()
result.maxFD = maxFD
result.fds = newSeq[SelectorKey[T]](maxFD)
result.pollfds = newSeq[TPollFd](maxFD)
for i in 0 ..< maxFD:
result.fds[i].ident = InvalidIdent
proc close*[T](s: Selector[T]) =
when hasThreadSupport:
deinitLock(s.lock)
deallocSharedArray(s.fds)
deallocSharedArray(s.pollfds)
deallocShared(cast[pointer](s))
template pollAdd[T](s: Selector[T], sock: cint, events: set[Event]) =
withPollLock(s):
var pollev: cshort = 0
if Event.Read in events: pollev = pollev or POLLIN
if Event.Write in events: pollev = pollev or POLLOUT
s.pollfds[s.pollcnt].fd = cint(sock)
s.pollfds[s.pollcnt].events = pollev
inc(s.count)
inc(s.pollcnt)
template pollUpdate[T](s: Selector[T], sock: cint, events: set[Event]) =
withPollLock(s):
var i = 0
var pollev: cshort = 0
if Event.Read in events: pollev = pollev or POLLIN
if Event.Write in events: pollev = pollev or POLLOUT
while i < s.pollcnt:
if s.pollfds[i].fd == sock:
s.pollfds[i].events = pollev
break
inc(i)
doAssert(i < s.pollcnt,
"Descriptor [" & $sock & "] is not registered in the queue!")
template pollRemove[T](s: Selector[T], sock: cint) =
withPollLock(s):
var i = 0
while i < s.pollcnt:
if s.pollfds[i].fd == sock:
if i == s.pollcnt - 1:
s.pollfds[i].fd = 0
s.pollfds[i].events = 0
s.pollfds[i].revents = 0
else:
while i < (s.pollcnt - 1):
s.pollfds[i].fd = s.pollfds[i + 1].fd
s.pollfds[i].events = s.pollfds[i + 1].events
inc(i)
break
inc(i)
dec(s.pollcnt)
dec(s.count)
template checkFd(s, f) =
if f >= s.maxFD:
raiseIOSelectorsError("Maximum number of descriptors is exhausted!")
proc registerHandle*[T](s: Selector[T], fd: int | SocketHandle,
events: set[Event], data: T) =
var fdi = int(fd)
s.checkFd(fdi)
doAssert(s.fds[fdi].ident == InvalidIdent)
setKey(s, fdi, events, 0, data)
if events != {}: s.pollAdd(fdi.cint, events)
proc updateHandle*[T](s: Selector[T], fd: int | SocketHandle,
events: set[Event]) =
let maskEvents = {Event.Timer, Event.Signal, Event.Process, Event.Vnode,
Event.User, Event.Oneshot, Event.Error}
let fdi = int(fd)
s.checkFd(fdi)
var pkey = addr(s.fds[fdi])
doAssert(pkey.ident != InvalidIdent,
"Descriptor [" & $fdi & "] is not registered in the queue!")
doAssert(pkey.events * maskEvents == {})
if pkey.events != events:
if pkey.events == {}:
s.pollAdd(fd.cint, events)
else:
if events != {}:
s.pollUpdate(fd.cint, events)
else:
s.pollRemove(fd.cint)
pkey.events = events
proc registerEvent*[T](s: Selector[T], ev: SelectEvent, data: T) =
var fdi = int(ev.rfd)
doAssert(s.fds[fdi].ident == InvalidIdent, "Event is already registered in the queue!")
var events = {Event.User}
setKey(s, fdi, events, 0, data)
events.incl(Event.Read)
s.pollAdd(fdi.cint, events)
proc unregister*[T](s: Selector[T], fd: int|SocketHandle) =
let fdi = int(fd)
s.checkFd(fdi)
var pkey = addr(s.fds[fdi])
doAssert(pkey.ident != InvalidIdent,
"Descriptor [" & $fdi & "] is not registered in the queue!")
pkey.ident = InvalidIdent
if pkey.events != {}:
pkey.events = {}
s.pollRemove(fdi.cint)
proc unregister*[T](s: Selector[T], ev: SelectEvent) =
let fdi = int(ev.rfd)
s.checkFd(fdi)
var pkey = addr(s.fds[fdi])
doAssert(pkey.ident != InvalidIdent, "Event is not registered in the queue!")
doAssert(Event.User in pkey.events)
pkey.ident = InvalidIdent
pkey.events = {}
s.pollRemove(fdi.cint)
proc newSelectEvent*(): SelectEvent =
var fds: array[2, cint]
if posix.pipe(fds) != 0:
raiseIOSelectorsError(osLastError())
setNonBlocking(fds[0])
setNonBlocking(fds[1])
result = cast[SelectEvent](allocShared0(sizeof(SelectEventImpl)))
result.rfd = fds[0]
result.wfd = fds[1]
proc trigger*(ev: SelectEvent) =
var data: uint64 = 1
if posix.write(ev.wfd, addr data, sizeof(uint64)) != sizeof(uint64):
raiseIOSelectorsError(osLastError())
proc close*(ev: SelectEvent) =
let res1 = posix.close(ev.rfd)
let res2 = posix.close(ev.wfd)
deallocShared(cast[pointer](ev))
if res1 != 0 or res2 != 0:
raiseIOSelectorsError(osLastError())
proc selectInto*[T](s: Selector[T], timeout: int,
results: var openarray[ReadyKey]): int =
var maxres = MAX_POLL_EVENTS
if maxres > len(results):
maxres = len(results)
verifySelectParams(timeout)
s.withPollLock():
let count = posix.poll(addr(s.pollfds[0]), Tnfds(s.pollcnt), timeout)
if count < 0:
result = 0
let err = osLastError()
if cint(err) != EINTR:
raiseIOSelectorsError(err)
elif count == 0:
result = 0
else:
var i = 0
var k = 0
var rindex = 0
while (i < s.pollcnt) and (k < count) and (rindex < maxres):
let revents = s.pollfds[i].revents
if revents != 0:
let fd = s.pollfds[i].fd
var pkey = addr(s.fds[fd])
var rkey = ReadyKey(fd: int(fd), events: {})
if (revents and POLLIN) != 0:
rkey.events.incl(Event.Read)
if Event.User in pkey.events:
var data: uint64 = 0
if posix.read(fd, addr data, sizeof(uint64)) != sizeof(uint64):
let err = osLastError()
if err != OSErrorCode(EAGAIN):
raiseIOSelectorsError(err)
else:
# someone already consumed event data
inc(i)
continue
rkey.events = {Event.User}
if (revents and POLLOUT) != 0:
rkey.events.incl(Event.Write)
if (revents and POLLERR) != 0 or (revents and POLLHUP) != 0 or
(revents and POLLNVAL) != 0:
rkey.events.incl(Event.Error)
results[rindex] = rkey
s.pollfds[i].revents = 0
inc(rindex)
inc(k)
inc(i)
result = k
proc select*[T](s: Selector[T], timeout: int): seq[ReadyKey] =
result = newSeq[ReadyKey](MAX_POLL_EVENTS)
let count = selectInto(s, timeout, result)
result.setLen(count)
template isEmpty*[T](s: Selector[T]): bool =
(s.count == 0)
proc contains*[T](s: Selector[T], fd: SocketHandle|int): bool {.inline.} =
return s.fds[fd.int].ident != InvalidIdent
proc getData*[T](s: Selector[T], fd: SocketHandle|int): var T =
let fdi = int(fd)
s.checkFd(fdi)
if fdi in s:
result = s.fds[fdi].data
proc setData*[T](s: Selector[T], fd: SocketHandle|int, data: T): bool =
let fdi = int(fd)
s.checkFd(fdi)
if fdi in s:
s.fds[fdi].data = data
result = true
template withData*[T](s: Selector[T], fd: SocketHandle|int, value,
body: untyped) =
mixin checkFd
let fdi = int(fd)
s.checkFd(fdi)
if fdi in s:
var value = addr(s.getData(fdi))
body
template withData*[T](s: Selector[T], fd: SocketHandle|int, value, body1,
body2: untyped) =
mixin checkFd
let fdi = int(fd)
s.checkFd(fdi)
if fdi in s:
var value = addr(s.getData(fdi))
body1
else:
body2
proc getFd*[T](s: Selector[T]): int =
return -1