vcs: Add license header from the origin to geventcurl.

rhodecode/lib/vcs/geventcurl.py

@@ -1,224 +1,245 b''
 # -*- coding: utf-8 -*-
 
 # Copyright (C) 2016-2016  RhodeCode GmbH
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU Affero General Public License, version 3
 # (only), as published by the Free Software Foundation.
 #
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #
 # This program is dual-licensed. If you wish to learn more about the
 # RhodeCode Enterprise Edition, including its added features, Support services,
 # and proprietary license terms, please see https://rhodecode.com/licenses/
 
 """
 This serves as a drop in replacement for pycurl. It implements the pycurl Curl
 class in a way that is compatible with gevent.
 """
 
 
 import logging
 import gevent
 import pycurl
 
 # Import everything from pycurl.
 # This allows us to use this module as a drop in replacement of pycurl.
 from pycurl import *  # noqa
 
 from gevent import core
 from gevent.hub import Waiter
 
 
 log = logging.getLogger(__name__)
 
 
 class GeventCurlMulti(object):
     """
     Wrapper around pycurl.CurlMulti that integrates it into gevent's event
     loop.
+
+    Parts of this class are a modified version of code copied from the Tornado
+    Web Server project which is licensed under the Apache License, Version 2.0
+    (the "License"). To be more specific the code originates from this file:
+    https://github.com/tornadoweb/tornado/blob/stable/tornado/curl_httpclient.py
+
+    This is the original license header of the origin:
+
+        Copyright 2009 Facebook
+
+        Licensed under the Apache License, Version 2.0 (the "License"); you may
+        not use this file except in compliance with the License. You may obtain
+        a copy of the License at
+
+            http://www.apache.org/licenses/LICENSE-2.0
+
+        Unless required by applicable law or agreed to in writing, software
+        distributed under the License is distributed on an "AS IS" BASIS,
+        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+        implied. See the License for the specific language governing
+        permissions and limitations under the License.
     """
 
     def __init__(self, loop=None):
         self._watchers = {}
         self._timeout = None
         self.loop = loop or gevent.get_hub().loop
 
         # Setup curl's multi instance.
         self._curl_multi = pycurl.CurlMulti()
         self.setopt(pycurl.M_TIMERFUNCTION, self._set_timeout)
         self.setopt(pycurl.M_SOCKETFUNCTION, self._handle_socket)
 
     def __getattr__(self, item):
         """
         The pycurl.CurlMulti class is final and we cannot subclass it.
         Therefore we are wrapping it and forward everything to it here.
         """
         return getattr(self._curl_multi, item)
 
     def add_handle(self, curl):
         """
         Add handle variant that also takes care about the initial invocation of
         socket action method. This is done by setting an immediate timeout.
         """
         result = self._curl_multi.add_handle(curl)
         self._set_timeout(0)
         return result
 
     def _handle_socket(self, event, fd, multi, data):
         """
         Called by libcurl when it wants to change the file descriptors it cares
         about.
         """
         event_map = {
             pycurl.POLL_NONE: core.NONE,
             pycurl.POLL_IN: core.READ,
             pycurl.POLL_OUT: core.WRITE,
             pycurl.POLL_INOUT: core.READ | core.WRITE
         }
 
         if event == pycurl.POLL_REMOVE:
             watcher = self._watchers.pop(fd, None)
             if watcher is not None:
                 watcher.stop()
         else:
             gloop_event = event_map[event]
             watcher = self._watchers.get(fd)
             if watcher is None:
                 watcher = self.loop.io(fd, gloop_event)
                 watcher.start(self._handle_events, fd, pass_events=True)
                 self._watchers[fd] = watcher
             else:
                 if watcher.events != gloop_event:
                     watcher.stop()
                     watcher.events = gloop_event
                     watcher.start(self._handle_events, fd, pass_events=True)
 
     def _set_timeout(self, msecs):
         """
         Called by libcurl to schedule a timeout.
         """
         if self._timeout is not None:
             self._timeout.stop()
         self._timeout = self.loop.timer(msecs/1000.0)
         self._timeout.start(self._handle_timeout)
 
     def _handle_events(self, events, fd):
         action = 0
         if events & core.READ:
             action |= pycurl.CSELECT_IN
         if events & core.WRITE:
             action |= pycurl.CSELECT_OUT
         while True:
             try:
                 ret, num_handles = self._curl_multi.socket_action(fd, action)
             except pycurl.error, e:
                 ret = e.args[0]
             if ret != pycurl.E_CALL_MULTI_PERFORM:
                 break
         self._finish_pending_requests()
 
     def _handle_timeout(self):
         """
         Called by IOLoop when the requested timeout has passed.
         """
         if self._timeout is not None:
             self._timeout.stop()
             self._timeout = None
         while True:
             try:
                 ret, num_handles = self._curl_multi.socket_action(
                     pycurl.SOCKET_TIMEOUT, 0)
             except pycurl.error, e:
                 ret = e.args[0]
             if ret != pycurl.E_CALL_MULTI_PERFORM:
                 break
         self._finish_pending_requests()
 
         # In theory, we shouldn't have to do this because curl will call
         # _set_timeout whenever the timeout changes. However, sometimes after
         # _handle_timeout we will need to reschedule immediately even though
         # nothing has changed from curl's perspective. This is because when
         # socket_action is called with SOCKET_TIMEOUT, libcurl decides
         # internally which timeouts need to be processed by using a monotonic
         # clock (where available) while tornado uses python's time.time() to
         # decide when timeouts have occurred. When those clocks disagree on
         # elapsed time (as they will whenever there is an NTP adjustment),
         # tornado might call _handle_timeout before libcurl is ready. After
         # each timeout, resync the scheduled timeout with libcurl's current
         # state.
         new_timeout = self._curl_multi.timeout()
         if new_timeout >= 0:
             self._set_timeout(new_timeout)
 
     def _finish_pending_requests(self):
         """
         Process any requests that were completed by the last call to
         multi.socket_action.
         """
         while True:
             num_q, ok_list, err_list = self._curl_multi.info_read()
             for curl in ok_list:
                 curl.waiter.switch()
             for curl, errnum, errmsg in err_list:
                 curl.waiter.throw(Exception('%s %s' % (errnum, errmsg)))
             if num_q == 0:
                 break
 
 
 class GeventCurl(object):
     """
     Gevent compatible implementation of the pycurl.Curl class. Essentially a
     wrapper around pycurl.Curl with a customized perform method. It uses the
     GeventCurlMulti class to implement a blocking API to libcurl's "easy"
     interface.
     """
 
     # Reference to the GeventCurlMulti instance.
     _multi_instance = None
 
     def __init__(self):
         self._curl = pycurl.Curl()
 
     def __getattr__(self, item):
         """
         The pycurl.Curl class is final and we cannot subclass it. Therefore we
         are wrapping it and forward everything to it here.
         """
         return getattr(self._curl, item)
 
     @property
     def _multi(self):
         """
         Lazy property that returns the GeventCurlMulti instance. The value is
         cached as a class attribute. Therefore only one instance per process
         exists.
         """
         if GeventCurl._multi_instance is None:
             GeventCurl._multi_instance = GeventCurlMulti()
         return GeventCurl._multi_instance
 
     def perform(self):
         """
         This perform method is compatible with gevent because it uses gevent
         synchronization mechanisms to wait for the request to finish.
         """
         waiter = self._curl.waiter = Waiter()
         try:
             self._multi.add_handle(self._curl)
             response = waiter.get()
         finally:
             self._multi.remove_handle(self._curl)
             del self._curl.waiter
 
         return response
 
 # Curl is originally imported from pycurl. At this point we override it with
 # our custom implementation.
 Curl = GeventCurl