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nim-chronos/chronos/selectors2.nim

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#
#
# 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 allows high-level and efficient I/O multiplexing.
##
## Supported OS primitives: ``epoll``, ``kqueue``, ``poll`` and
## Windows ``select``.
##
## To use threadsafe version of this module, it needs to be compiled
## with both ``-d:threadsafe`` and ``--threads:on`` options.
##
## Supported features: files, sockets, pipes, timers, processes, signals
## and user events.
##
## Fully supported OS: MacOSX, FreeBSD, OpenBSD, NetBSD, Linux (except
## for Android).
##
## Partially supported OS: Windows (only sockets and user events),
## Solaris (files, sockets, handles and user events).
## Android (files, sockets, handles and user events).
##
## TODO: ``/dev/poll``, ``event ports`` and filesystem events.
# Based on std/selectors, but with stricter exception handling and effect
# support - changes could potentially be backported to nim but are not
# backwards-compatible.
import os, nativesockets
const hasThreadSupport = compileOption("threads") and defined(threadsafe)
const ioselSupportedPlatform* = defined(macosx) or defined(freebsd) or
defined(netbsd) or defined(openbsd) or
defined(dragonfly) or
(defined(linux) and not defined(android))
## This constant is used to determine whether the destination platform is
## fully supported by ``ioselectors`` module.
const bsdPlatform = defined(macosx) or defined(freebsd) or
defined(netbsd) or defined(openbsd) or
defined(dragonfly)
when defined(nimdoc):
type
Selector*[T] = ref object
## An object which holds descriptors to be checked for read/write status
Event* {.pure.} = enum
## An enum which hold event types
Read, ## Descriptor is available for read
Write, ## Descriptor is available for write
Timer, ## Timer descriptor is completed
Signal, ## Signal is raised
Process, ## Process is finished
Vnode, ## BSD specific file change
User, ## User event is raised
Error, ## Error occurred while waiting for descriptor
VnodeWrite, ## NOTE_WRITE (BSD specific, write to file occurred)
VnodeDelete, ## NOTE_DELETE (BSD specific, unlink of file occurred)
VnodeExtend, ## NOTE_EXTEND (BSD specific, file extended)
VnodeAttrib, ## NOTE_ATTRIB (BSD specific, file attributes changed)
VnodeLink, ## NOTE_LINK (BSD specific, file link count changed)
VnodeRename, ## NOTE_RENAME (BSD specific, file renamed)
VnodeRevoke ## NOTE_REVOKE (BSD specific, file revoke occurred)
ReadyKey* = object
## An object which holds result for descriptor
fd* : int ## file/socket descriptor
events*: set[Event] ## set of events
errorCode*: OSErrorCode ## additional error code information for
## Error events
SelectEvent* = object
## An object which holds user defined event
proc newSelector*[T](): Selector[T] =
## Creates a new selector
proc close*[T](s: Selector[T]) =
## Closes the selector.
proc registerHandle*[T](s: Selector[T], fd: int | SocketHandle,
events: set[Event], data: T) =
## Registers file/socket descriptor ``fd`` to selector ``s``
## with events set in ``events``. The ``data`` is application-defined
## data, which will be passed when an event is triggered.
proc updateHandle*[T](s: Selector[T], fd: int | SocketHandle,
events: set[Event]) =
## Update file/socket descriptor ``fd``, registered in selector
## ``s`` with new events set ``event``.
proc registerTimer*[T](s: Selector[T], timeout: int, oneshot: bool,
data: T): int {.discardable.} =
## Registers timer notification with ``timeout`` (in milliseconds)
## to selector ``s``.
##
## If ``oneshot`` is ``true``, timer will be notified only once.
##
## Set ``oneshot`` to ``false`` if you want periodic notifications.
##
## The ``data`` is application-defined data, which will be passed, when
## the timer is triggered.
##
## Returns the file descriptor for the registered timer.
proc registerSignal*[T](s: Selector[T], signal: int,
data: T): int {.discardable.} =
## Registers Unix signal notification with ``signal`` to selector
## ``s``.
##
## The ``data`` is application-defined data, which will be
## passed when signal raises.
##
## Returns the file descriptor for the registered signal.
##
## **Note:** This function is not supported on ``Windows``.
proc registerProcess*[T](s: Selector[T], pid: int,
data: T): int {.discardable.} =
## Registers a process id (pid) notification (when process has
## exited) in selector ``s``.
##
## The ``data`` is application-defined data, which will be passed when
## process with ``pid`` has exited.
##
## Returns the file descriptor for the registered signal.
proc registerEvent*[T](s: Selector[T], ev: SelectEvent, data: T) =
## Registers selector event ``ev`` in selector ``s``.
##
## The ``data`` is application-defined data, which will be passed when
## ``ev`` happens.
proc registerVnode*[T](s: Selector[T], fd: cint, events: set[Event],
data: T) =
## Registers selector BSD/MacOSX specific vnode events for file
## descriptor ``fd`` and events ``events``.
## ``data`` application-defined data, which to be passed, when
## vnode event happens.
##
## **Note:** This function is supported only by BSD and MacOSX.
proc newSelectEvent*(): SelectEvent =
## Creates a new user-defined event.
proc trigger*(ev: SelectEvent) =
## Trigger event ``ev``.
proc close*(ev: SelectEvent) =
## Closes user-defined event ``ev``.
proc unregister*[T](s: Selector[T], ev: SelectEvent) =
## Unregisters user-defined event ``ev`` from selector ``s``.
proc unregister*[T](s: Selector[T], fd: int|SocketHandle|cint) =
## Unregisters file/socket descriptor ``fd`` from selector ``s``.
proc selectInto*[T](s: Selector[T], timeout: int,
results: var openarray[ReadyKey]): int =
## Waits for events registered in selector ``s``.
##
## The ``timeout`` argument specifies the maximum number of milliseconds
## the function will be blocked for if no events are ready. Specifying a
## timeout of ``-1`` causes the function to block indefinitely.
## All available events will be stored in ``results`` array.
##
## Returns number of triggered events.
proc select*[T](s: Selector[T], timeout: int): seq[ReadyKey] =
## Waits for events registered in selector ``s``.
##
## The ``timeout`` argument specifies the maximum number of milliseconds
## the function will be blocked for if no events are ready. Specifying a
## timeout of ``-1`` causes the function to block indefinitely.
##
## Returns a list of triggered events.
proc getData*[T](s: Selector[T], fd: SocketHandle|int): var T =
## Retrieves application-defined ``data`` associated with descriptor ``fd``.
## If specified descriptor ``fd`` is not registered, empty/default value
## will be returned.
proc setData*[T](s: Selector[T], fd: SocketHandle|int, data: var T): bool =
## Associate application-defined ``data`` with descriptor ``fd``.
##
## Returns ``true``, if data was successfully updated, ``false`` otherwise.
template isEmpty*[T](s: Selector[T]): bool = # TODO: Why is this a template?
## Returns ``true``, if there are no registered events or descriptors
## in selector.
template withData*[T](s: Selector[T], fd: SocketHandle|int, value,
body: untyped) =
## Retrieves the application-data assigned with descriptor ``fd``
## to ``value``. This ``value`` can be modified in the scope of
## the ``withData`` call.
##
## .. code-block:: nim
##
## s.withData(fd, value) do:
## # block is executed only if ``fd`` registered in selector ``s``
## value.uid = 1000
##
template withData*[T](s: Selector[T], fd: SocketHandle|int, value,
body1, body2: untyped) =
## Retrieves the application-data assigned with descriptor ``fd``
## to ``value``. This ``value`` can be modified in the scope of
## the ``withData`` call.
##
## .. code-block:: nim
##
## s.withData(fd, value) do:
## # block is executed only if ``fd`` registered in selector ``s``.
## value.uid = 1000
## do:
## # block is executed if ``fd`` not registered in selector ``s``.
## raise
##
proc contains*[T](s: Selector[T], fd: SocketHandle|int): bool {.inline.} =
## Determines whether selector contains a file descriptor.
proc getFd*[T](s: Selector[T]): int =
## Retrieves the underlying selector's file descriptor.
##
## For *poll* and *select* selectors ``-1`` is returned.
else:
import strutils
when hasThreadSupport:
import locks
type
SharedArray[T] = UncheckedArray[T]
proc allocSharedArray[T](nsize: int): ptr SharedArray[T] =
result = cast[ptr SharedArray[T]](allocShared0(sizeof(T) * nsize))
proc reallocSharedArray[T](sa: ptr SharedArray[T], nsize: int): ptr SharedArray[T] =
result = cast[ptr SharedArray[T]](reallocShared(sa, sizeof(T) * nsize))
proc deallocSharedArray[T](sa: ptr SharedArray[T]) =
deallocShared(cast[pointer](sa))
type
Event* {.pure.} = enum
Read, Write, Timer, Signal, Process, Vnode, User, Error, Oneshot,
Finished, VnodeWrite, VnodeDelete, VnodeExtend, VnodeAttrib, VnodeLink,
VnodeRename, VnodeRevoke
type
IOSelectorsException* = object of CatchableError
ReadyKey* = object
fd* : int
events*: set[Event]
errorCode*: OSErrorCode
SelectorKey[T] = object
ident: int
events: set[Event]
param: int
data: T
const
InvalidIdent = -1
proc raiseIOSelectorsError[T](message: T) =
var msg = ""
when T is string:
msg.add(message)
elif T is OSErrorCode:
msg.add(osErrorMsg(message) & " (code: " & $int(message) & ")")
else:
msg.add("Internal Error\n")
var err = newException(IOSelectorsException, msg)
raise err
proc setNonBlocking(fd: cint) {.inline.} =
setBlocking(fd.SocketHandle, false)
when not defined(windows):
import posix
template setKey(s, pident, pevents, pparam, pdata: untyped) =
var skey = addr(s.fds[pident])
skey.ident = pident
skey.events = pevents
skey.param = pparam
skey.data = data
when ioselSupportedPlatform:
template blockSignals(newmask: var Sigset, oldmask: var Sigset) =
when hasThreadSupport:
if posix.pthread_sigmask(SIG_BLOCK, newmask, oldmask) == -1:
raiseIOSelectorsError(osLastError())
else:
if posix.sigprocmask(SIG_BLOCK, newmask, oldmask) == -1:
raiseIOSelectorsError(osLastError())
template unblockSignals(newmask: var Sigset, oldmask: var Sigset) =
when hasThreadSupport:
if posix.pthread_sigmask(SIG_UNBLOCK, newmask, oldmask) == -1:
raiseIOSelectorsError(osLastError())
else:
if posix.sigprocmask(SIG_UNBLOCK, newmask, oldmask) == -1:
raiseIOSelectorsError(osLastError())
template clearKey[T](key: ptr SelectorKey[T]) =
var empty: T
key.ident = InvalidIdent
key.events = {}
key.data = empty
proc verifySelectParams(timeout: int) =
# Timeout of -1 means: wait forever
# Anything higher is the time to wait in milliseconds.
doAssert(timeout >= -1, "Cannot select with a negative value, got " & $timeout)
when defined(linux):
include ./ioselects/ioselectors_epoll
elif bsdPlatform:
include ./ioselects/ioselectors_kqueue
elif defined(windows):
include ./ioselects/ioselectors_select
elif defined(solaris):
include ./ioselects/ioselectors_poll # need to replace it with event ports
elif defined(genode):
include ./ioselects/ioselectors_select # TODO: use the native VFS layer
elif defined(nintendoswitch):
include ./ioselects/ioselectors_select
else:
include ./ioselects/ioselectors_poll
proc register*[T](s: Selector[T], fd: int | SocketHandle,
events: set[Event], data: T) {.deprecated: "use registerHandle instead".} =
## **Deprecated since v0.18.0:** Use ``registerHandle`` instead.
s.registerHandle(fd, events, data)
proc setEvent*(ev: SelectEvent) {.deprecated: "use trigger instead",
raises: [Defect, IOSelectorsException].} =
## Trigger event ``ev``.
##
## **Deprecated since v0.18.0:** Use ``trigger`` instead.
ev.trigger()
proc update*[T](s: Selector[T], fd: int | SocketHandle,
events: set[Event]) {.deprecated: "use updateHandle instead".} =
## Update file/socket descriptor ``fd``, registered in selector
## ``s`` with new events set ``event``.
##
## **Deprecated since v0.18.0:** Use ``updateHandle`` instead.
s.updateHandle()
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