Files
Nim/lib/pure/selectors.nim
2014-03-14 18:46:08 +00:00

270 lines
8.3 KiB
Nim

#
#
# Nimrod's Runtime Library
# (c) Copyright 2014 Dominik Picheta
#
# See the file "copying.txt", included in this
# distribution, for details about the copyright.
#
# TODO: Docs.
import tables, os, unsigned, hashes
when defined(linux): import posix, epoll
elif defined(windows): import winlean
proc hash*(x: TSocketHandle): THash {.borrow.}
proc `$`*(x: TSocketHandle): string {.borrow.}
type
TEvent* = enum
EvRead, EvWrite
PSelectorKey* = ref object
fd*: TSocketHandle
events*: set[TEvent] ## The events which ``fd`` listens for.
data*: PObject ## User object.
TReadyInfo* = tuple[key: PSelectorKey, events: set[TEvent]]
when defined(linux) or defined(nimdoc):
type
PSelector* = ref object
epollFD: cint
events: array[64, epoll_event]
fds: TTable[TSocketHandle, PSelectorKey]
proc createEventStruct(events: set[TEvent], fd: TSocketHandle): epoll_event =
if EvRead in events:
result.events = EPOLLIN
if EvWrite in events:
result.events = result.events or EPOLLOUT
result.events = result.events or EPOLLRDHUP
result.data.fd = fd.cint
proc register*(s: PSelector, fd: TSocketHandle, events: set[TEvent],
data: PObject): PSelectorKey {.discardable.} =
## Registers file descriptor ``fd`` to selector ``s`` with a set of TEvent
## ``events``.
var event = createEventStruct(events, fd)
if epoll_ctl(s.epollFD, EPOLL_CTL_ADD, fd, addr(event)) != 0:
OSError(OSLastError())
var key = PSelectorKey(fd: fd, events: events, data: data)
s.fds[fd] = key
result = key
proc update*(s: PSelector, fd: TSocketHandle,
events: set[TEvent]): PSelectorKey {.discardable.} =
## Updates the events which ``fd`` wants notifications for.
if s.fds[fd].events != events:
var event = createEventStruct(events, fd)
s.fds[fd].events = events
if epoll_ctl(s.epollFD, EPOLL_CTL_MOD, fd, addr(event)) != 0:
OSError(OSLastError())
result = s.fds[fd]
proc unregister*(s: PSelector, fd: TSocketHandle): PSelectorKey {.discardable.} =
if epoll_ctl(s.epollFD, EPOLL_CTL_DEL, fd, nil) != 0:
let err = OSLastError()
if err.cint notin {ENOENT, EBADF}: # TODO: Why do we sometimes get an EBADF? Is this normal?
OSError(err)
result = s.fds[fd]
s.fds.del(fd)
proc close*(s: PSelector) =
if s.epollFD.close() != 0: OSError(OSLastError())
dealloc(addr s.events) # TODO: Test this
proc epollHasFd(s: PSelector, fd: TSocketHandle): bool =
result = true
var event = createEventStruct(s.fds[fd].events, fd)
if epoll_ctl(s.epollFD, EPOLL_CTL_MOD, fd, addr(event)) != 0:
let err = osLastError()
if err.cint in {ENOENT, EBADF}:
return false
OSError(OSLastError())
proc select*(s: PSelector, timeout: int): seq[TReadyInfo] =
##
## The ``events`` field of the returned ``key`` contains the original events
## for which the ``fd`` was bound. This is contrary to the ``events`` field
## of the ``TReadyInfo`` tuple which determines which events are ready
## on the ``fd``.
result = @[]
let evNum = epoll_wait(s.epollFD, addr s.events[0], 64.cint, timeout.cint)
if evNum < 0: OSError(OSLastError())
if evNum == 0: return @[]
for i in 0 .. <evNum:
let fd = s.events[i].data.fd.TSocketHandle
var evSet: set[TEvent] = {}
if (s.events[i].events and EPOLLIN) != 0: evSet = evSet + {EvRead}
if (s.events[i].events and EPOLLOUT) != 0: evSet = evSet + {EvWrite}
let selectorKey = s.fds[fd]
assert selectorKey != nil
result.add((selectorKey, evSet))
#echo("Epoll: ", result[i].key.fd, " ", result[i].events, " ", result[i].key.events)
proc newSelector*(): PSelector =
new result
result.epollFD = epoll_create(64)
result.events = cast[array[64, epoll_event]](alloc0(sizeof(epoll_event)*64))
result.fds = initTable[TSocketHandle, PSelectorKey]()
if result.epollFD < 0:
OSError(OSLastError())
proc contains*(s: PSelector, fd: TSocketHandle): bool =
## Determines whether selector contains a file descriptor.
if s.fds.hasKey(fd):
# Ensure the underlying epoll instance still contains this fd.
result = epollHasFd(s, fd)
else:
return false
proc contains*(s: PSelector, key: PSelectorKey): bool =
## Determines whether selector contains this selector key. More accurate
## than checking if the file descriptor is in the selector because it
## ensures that the keys are equal. File descriptors may not always be
## unique especially when an fd is closed and then a new one is opened,
## the new one may have the same value.
return key.fd in s and s.fds[key.fd] == key
proc `[]`*(s: PSelector, fd: TSocketHandle): PSelectorKey =
## Retrieves the selector key for ``fd``.
return s.fds[fd]
elif defined(windows):
type
PSelector* = ref object
fds: TTable[TSocketHandle, PSelectorKey]
proc register*(s: PSelector, fd: TSocketHandle, events: set[TEvent],
data: PObject): PSelectorKey {.discardable.} =
if s.fds.hasKey(fd):
raise newException(EInvalidValue, "File descriptor already exists.")
var sk = PSelectorKey(fd: fd, events: events, data: data)
s.fds[fd] = sk
result = sk
proc update*(s: PSelector, fd: TSocketHandle,
events: set[TEvent]): PSelectorKey {.discardable.} =
## Updates the events which ``fd`` wants notifications for.
if not s.fds.hasKey(fd):
raise newException(EInvalidValue, "File descriptor not found.")
s.fds[fd].events = events
result = s.fds[fd]
proc unregister*(s: PSelector, fd: TSocketHandle): PSelectorKey {.discardable.} =
result = s.fds[fd]
s.fds.del(fd)
proc close*(s: PSelector) = nil
proc timeValFromMilliseconds(timeout: int): TTimeVal =
if timeout != -1:
var seconds = timeout div 1000
result.tv_sec = seconds.int32
result.tv_usec = ((timeout - seconds * 1000) * 1000).int32
proc createFdSet(rd, wr: var TFdSet, fds: TTable[TSocketHandle, PSelectorKey],
m: var int) =
FD_ZERO(rd); FD_ZERO(wr)
for k, v in pairs(fds):
if EvRead in v.events:
m = max(m, int(k))
FD_SET(k, rd)
if EvWrite in v.events:
m = max(m, int(k))
FD_SET(k, wr)
proc getReadyFDs(rd, wr: var TFdSet, fds: TTable[TSocketHandle, PSelectorKey]):
seq[TReadyInfo] =
result = @[]
for k, v in pairs(fds):
var events: set[TEvent] = {}
if FD_ISSET(k, rd) != 0'i32:
events = events + {EvRead}
if FD_ISSET(k, wr) != 0'i32:
events = events + {EvWrite}
result.add((v, events))
proc select(fds: TTable[TSocketHandle, PSelectorKey], timeout = 500):
seq[TReadyInfo] =
var tv {.noInit.}: TTimeVal = timeValFromMilliseconds(timeout)
var rd, wr: TFdSet
var m = 0
createFdSet(rd, wr, fds, m)
var retCode = 0
if timeout != -1:
retCode = int(select(TSocketHandle(m+1), addr(rd), addr(wr), nil, addr(tv)))
else:
retCode = int(select(TSocketHandle(m+1), addr(rd), addr(wr), nil, nil))
if retCode < 0:
OSError(OSLastError())
elif retCode == 0:
return @[]
else:
return getReadyFDs(rd, wr, fds)
proc select*(s: PSelector, timeout: int): seq[TReadyInfo] =
result = select(s.fds, timeout)
proc newSelector*(): PSelector =
new result
result.fds = initTable[TSocketHandle, PSelectorKey]()
proc contains*(s: PSelector, fd: TSocketHandle): bool =
return s.fds.hasKey(fd)
proc `[]`*(s: PSelector, fd: TSocketHandle): PSelectorKey =
return s.fds[fd]
elif defined(bsd) or defined(macosx):
# TODO: kqueue
{.error: "Sorry your platform is not supported yet.".}
else:
{.error: "Sorry your platform is not supported.".}
when isMainModule:
# Select()
import sockets
type
PSockWrapper = ref object of PObject
sock: TSocket
var sock = socket()
sock.setBlocking(false)
sock.connect("irc.freenode.net", TPort(6667))
var selector = newSelector()
var data = PSockWrapper(sock: sock)
let key = selector.register(sock.getFD, {EvWrite}, data)
var i = 0
while true:
let ready = selector.select(1000)
echo ready.len
if ready.len > 0: echo ready[0].events
i.inc
if i == 6:
assert selector.unregister(sock.getFD).fd == sock.getFD
selector.close()
break