Ausgabe der neuen DB Einträge

venv/lib/python3.9/site-packages/twisted/spread/util.py

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+# -*- test-case-name: twisted.test.test_pb -*-
+
+# Copyright (c) Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+
+"""
+Utility classes for spread.
+"""
+
+from twisted.internet import defer
+from twisted.python.failure import Failure
+from twisted.spread import pb
+from twisted.protocols import basic
+from twisted.internet import interfaces
+
+from zope.interface import implementer
+
+
+class LocalMethod:
+    def __init__(self, local, name):
+        self.local = local
+        self.name = name
+
+    def __call__(self, *args, **kw):
+        return self.local.callRemote(self.name, *args, **kw)
+
+
+class LocalAsRemote:
+    """
+    A class useful for emulating the effects of remote behavior locally.
+    """
+    reportAllTracebacks = 1
+
+    def callRemote(self, name, *args, **kw):
+        """
+        Call a specially-designated local method.
+
+        self.callRemote('x') will first try to invoke a method named
+        sync_x and return its result (which should probably be a
+        Deferred).  Second, it will look for a method called async_x,
+        which will be called and then have its result (or Failure)
+        automatically wrapped in a Deferred.
+        """
+        if hasattr(self, 'sync_'+name):
+            return getattr(self, 'sync_'+name)(*args, **kw)
+        try:
+            method = getattr(self, "async_" + name)
+            return defer.succeed(method(*args, **kw))
+        except:
+            f = Failure()
+            if self.reportAllTracebacks:
+                f.printTraceback()
+            return defer.fail(f)
+
+    def remoteMethod(self, name):
+        return LocalMethod(self, name)
+
+
+class LocalAsyncForwarder:
+    """
+    A class useful for forwarding a locally-defined interface.
+    """
+
+    def __init__(self, forwarded, interfaceClass, failWhenNotImplemented=0):
+        assert interfaceClass.providedBy(forwarded)
+        self.forwarded = forwarded
+        self.interfaceClass = interfaceClass
+        self.failWhenNotImplemented = failWhenNotImplemented
+
+    def _callMethod(self, method, *args, **kw):
+        return getattr(self.forwarded, method)(*args, **kw)
+
+    def callRemote(self, method, *args, **kw):
+        if self.interfaceClass.queryDescriptionFor(method):
+            result = defer.maybeDeferred(self._callMethod, method, *args, **kw)
+            return result
+        elif self.failWhenNotImplemented:
+            return defer.fail(
+                Failure(NotImplementedError,
+                        "No Such Method in Interface: %s" % method))
+        else:
+            return defer.succeed(None)
+
+
+class Pager:
+    """
+    I am an object which pages out information.
+    """
+    def __init__(self, collector, callback=None, *args, **kw):
+        """
+        Create a pager with a Reference to a remote collector and
+        an optional callable to invoke upon completion.
+        """
+        if callable(callback):
+            self.callback = callback
+            self.callbackArgs = args
+            self.callbackKeyword = kw
+        else:
+            self.callback = None
+        self._stillPaging = 1
+        self.collector = collector
+        collector.broker.registerPageProducer(self)
+
+    def stillPaging(self):
+        """
+        (internal) Method called by Broker.
+        """
+        if not self._stillPaging:
+            self.collector.callRemote("endedPaging", pbanswer=False)
+            if self.callback is not None:
+                self.callback(*self.callbackArgs, **self.callbackKeyword)
+        return self._stillPaging
+
+    def sendNextPage(self):
+        """
+        (internal) Method called by Broker.
+        """
+        self.collector.callRemote("gotPage", self.nextPage(), pbanswer=False)
+
+    def nextPage(self):
+        """
+        Override this to return an object to be sent to my collector.
+        """
+        raise NotImplementedError()
+
+    def stopPaging(self):
+        """
+        Call this when you're done paging.
+        """
+        self._stillPaging = 0
+
+
+class StringPager(Pager):
+    """
+    A simple pager that splits a string into chunks.
+    """
+    def __init__(self, collector, st, chunkSize=8192, callback=None, *args, **kw):
+        self.string = st
+        self.pointer = 0
+        self.chunkSize = chunkSize
+        Pager.__init__(self, collector, callback, *args, **kw)
+
+    def nextPage(self):
+        val = self.string[self.pointer:self.pointer+self.chunkSize]
+        self.pointer += self.chunkSize
+        if self.pointer >= len(self.string):
+            self.stopPaging()
+        return val
+
+
+@implementer(interfaces.IConsumer)
+class FilePager(Pager):
+    """
+    Reads a file in chunks and sends the chunks as they come.
+    """
+
+    def __init__(self, collector, fd, callback=None, *args, **kw):
+        self.chunks = []
+        Pager.__init__(self, collector, callback, *args, **kw)
+        self.startProducing(fd)
+
+    def startProducing(self, fd):
+        self.deferred = basic.FileSender().beginFileTransfer(fd, self)
+        self.deferred.addBoth(lambda x : self.stopPaging())
+
+    def registerProducer(self, producer, streaming):
+        self.producer = producer
+        if not streaming:
+            self.producer.resumeProducing()
+
+    def unregisterProducer(self):
+        self.producer = None
+
+    def write(self, chunk):
+        self.chunks.append(chunk)
+
+    def sendNextPage(self):
+        """
+        Get the first chunk read and send it to collector.
+        """
+        if not self.chunks:
+            return
+        val = self.chunks.pop(0)
+        self.producer.resumeProducing()
+        self.collector.callRemote("gotPage", val, pbanswer=False)
+
+
+# Utility paging stuff.
+class CallbackPageCollector(pb.Referenceable):
+    """
+    I receive pages from the peer. You may instantiate a Pager with a
+    remote reference to me. I will call the callback with a list of pages
+    once they are all received.
+    """
+    def __init__(self, callback):
+        self.pages = []
+        self.callback = callback
+
+    def remote_gotPage(self, page):
+        self.pages.append(page)
+
+    def remote_endedPaging(self):
+        self.callback(self.pages)
+
+
+def getAllPages(referenceable, methodName, *args, **kw):
+    """
+    A utility method that will call a remote method which expects a
+    PageCollector as the first argument.
+    """
+    d = defer.Deferred()
+    referenceable.callRemote(methodName, CallbackPageCollector(d.callback), *args, **kw)
+    return d
+