--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/WebKitTools/Scripts/webkitpy/common/net/networktransaction.py	Fri Sep 17 09:02:29 2010 +0300
@@ -0,0 +1,68 @@
+# Copyright (C) 2010 Google Inc. All rights reserved.
+# 
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+# 
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+# 
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+import logging
+import time
+
+from webkitpy.thirdparty.autoinstalled.mechanize import HTTPError
+from webkitpy.common.system.deprecated_logging import log
+
+
+_log = logging.getLogger(__name__)
+
+
+class NetworkTimeout(Exception):
+    pass
+
+
+class NetworkTransaction(object):
+    def __init__(self, initial_backoff_seconds=10, grown_factor=1.5, timeout_seconds=10*60):
+        self._initial_backoff_seconds = initial_backoff_seconds
+        self._grown_factor = grown_factor
+        self._timeout_seconds = timeout_seconds
+
+    def run(self, request):
+        self._total_sleep = 0
+        self._backoff_seconds = self._initial_backoff_seconds
+        while True:
+            try:
+                return request()
+            except HTTPError, e:
+                self._check_for_timeout()
+                _log.warn("Received HTTP status %s from server.  Retrying in "
+                          "%s seconds..." % (e.code, self._backoff_seconds))
+                self._sleep()
+
+    def _check_for_timeout(self):
+        if self._total_sleep + self._backoff_seconds > self._timeout_seconds:
+            raise NetworkTimeout()
+
+    def _sleep(self):
+        time.sleep(self._backoff_seconds)
+        self._total_sleep += self._backoff_seconds
+        self._backoff_seconds *= self._grown_factor