Ausgabe der neuen DB Einträge

venv/lib/python3.9/site-packages/twisted/internet/pollreactor.py

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+# Copyright (c) Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+"""
+A poll() based implementation of the twisted main loop.
+
+To install the event loop (and you should do this before any connections,
+listeners or connectors are added)::
+
+    from twisted.internet import pollreactor
+    pollreactor.install()
+"""
+
+from __future__ import division, absolute_import
+
+# System imports
+import errno
+from select import error as SelectError, poll
+from select import POLLIN, POLLOUT, POLLHUP, POLLERR, POLLNVAL
+
+from zope.interface import implementer
+
+# Twisted imports
+from twisted.python import log
+from twisted.internet import posixbase
+from twisted.internet.interfaces import IReactorFDSet
+
+
+
+@implementer(IReactorFDSet)
+class PollReactor(posixbase.PosixReactorBase, posixbase._PollLikeMixin):
+    """
+    A reactor that uses poll(2).
+
+    @ivar _poller: A L{select.poll} which will be used to check for I/O
+        readiness.
+
+    @ivar _selectables: A dictionary mapping integer file descriptors to
+        instances of L{FileDescriptor} which have been registered with the
+        reactor.  All L{FileDescriptor}s which are currently receiving read or
+        write readiness notifications will be present as values in this
+        dictionary.
+
+    @ivar _reads: A dictionary mapping integer file descriptors to arbitrary
+        values (this is essentially a set).  Keys in this dictionary will be
+        registered with C{_poller} for read readiness notifications which will
+        be dispatched to the corresponding L{FileDescriptor} instances in
+        C{_selectables}.
+
+    @ivar _writes: A dictionary mapping integer file descriptors to arbitrary
+        values (this is essentially a set).  Keys in this dictionary will be
+        registered with C{_poller} for write readiness notifications which will
+        be dispatched to the corresponding L{FileDescriptor} instances in
+        C{_selectables}.
+    """
+
+    _POLL_DISCONNECTED = (POLLHUP | POLLERR | POLLNVAL)
+    _POLL_IN = POLLIN
+    _POLL_OUT = POLLOUT
+
+    def __init__(self):
+        """
+        Initialize polling object, file descriptor tracking dictionaries, and
+        the base class.
+        """
+        self._poller = poll()
+        self._selectables = {}
+        self._reads = {}
+        self._writes = {}
+        posixbase.PosixReactorBase.__init__(self)
+
+
+    def _updateRegistration(self, fd):
+        """Register/unregister an fd with the poller."""
+        try:
+            self._poller.unregister(fd)
+        except KeyError:
+            pass
+
+        mask = 0
+        if fd in self._reads:
+            mask = mask | POLLIN
+        if fd in self._writes:
+            mask = mask | POLLOUT
+        if mask != 0:
+            self._poller.register(fd, mask)
+        else:
+            if fd in self._selectables:
+                del self._selectables[fd]
+
+    def _dictRemove(self, selectable, mdict):
+        try:
+            # the easy way
+            fd = selectable.fileno()
+            # make sure the fd is actually real.  In some situations we can get
+            # -1 here.
+            mdict[fd]
+        except:
+            # the hard way: necessary because fileno() may disappear at any
+            # moment, thanks to python's underlying sockets impl
+            for fd, fdes in self._selectables.items():
+                if selectable is fdes:
+                    break
+            else:
+                # Hmm, maybe not the right course of action?  This method can't
+                # fail, because it happens inside error detection...
+                return
+        if fd in mdict:
+            del mdict[fd]
+            self._updateRegistration(fd)
+
+    def addReader(self, reader):
+        """Add a FileDescriptor for notification of data available to read.
+        """
+        fd = reader.fileno()
+        if fd not in self._reads:
+            self._selectables[fd] = reader
+            self._reads[fd] =  1
+            self._updateRegistration(fd)
+
+    def addWriter(self, writer):
+        """Add a FileDescriptor for notification of data available to write.
+        """
+        fd = writer.fileno()
+        if fd not in self._writes:
+            self._selectables[fd] = writer
+            self._writes[fd] =  1
+            self._updateRegistration(fd)
+
+    def removeReader(self, reader):
+        """Remove a Selectable for notification of data available to read.
+        """
+        return self._dictRemove(reader, self._reads)
+
+    def removeWriter(self, writer):
+        """Remove a Selectable for notification of data available to write.
+        """
+        return self._dictRemove(writer, self._writes)
+
+    def removeAll(self):
+        """
+        Remove all selectables, and return a list of them.
+        """
+        return self._removeAll(
+            [self._selectables[fd] for fd in self._reads],
+            [self._selectables[fd] for fd in self._writes])
+
+
+    def doPoll(self, timeout):
+        """Poll the poller for new events."""
+        if timeout is not None:
+            timeout = int(timeout * 1000) # convert seconds to milliseconds
+
+        try:
+            l = self._poller.poll(timeout)
+        except SelectError as e:
+            if e.args[0] == errno.EINTR:
+                return
+            else:
+                raise
+        _drdw = self._doReadOrWrite
+        for fd, event in l:
+            try:
+                selectable = self._selectables[fd]
+            except KeyError:
+                # Handles the infrequent case where one selectable's
+                # handler disconnects another.
+                continue
+            log.callWithLogger(selectable, _drdw, selectable, fd, event)
+
+    doIteration = doPoll
+
+    def getReaders(self):
+        return [self._selectables[fd] for fd in self._reads]
+
+
+    def getWriters(self):
+        return [self._selectables[fd] for fd in self._writes]
+
+
+
+def install():
+    """Install the poll() reactor."""
+    p = PollReactor()
+    from twisted.internet.main import installReactor
+    installReactor(p)
+
+
+__all__ = ["PollReactor", "install"]