1 files changed, 160 insertions, 0 deletions
diff --git a/src/leap/services/abstractbootstrapper.py b/src/leap/services/abstractbootstrapper.py
new file mode 100644
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+++ b/src/leap/services/abstractbootstrapper.py
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+# -*- coding: utf-8 -*-
+# abstractbootstrapper.py
+# Copyright (C) 2013 LEAP
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# 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 General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+"""
+Abstract bootstrapper implementation
+"""
+import logging
+
+import requests
+
+from functools import partial
+
+from PySide import QtCore
+from twisted.internet import threads
+from leap.common.check import leap_assert, leap_assert_type
+
+logger = logging.getLogger(__name__)
+
+
+class AbstractBootstrapper(QtCore.QObject):
+    """
+    Abstract Bootstrapper that implements the needed deferred callbacks
+    """
+
+    PASSED_KEY = "passed"
+    ERROR_KEY = "error"
+
+    def __init__(self, bypass_checks=False):
+        """
+        Constructor for the abstract bootstrapper
+
+        :param bypass_checks: Set to true if the app should bypass
+                              first round of checks for CA
+                              certificates at bootstrap
+        :type bypass_checks: bool
+        """
+        QtCore.QObject.__init__(self)
+
+        leap_assert(self._gui_errback.im_func ==
+                    AbstractBootstrapper._gui_errback.im_func,
+                    "Cannot redefine _gui_errback")
+        leap_assert(self._errback.im_func ==
+                    AbstractBootstrapper._errback.im_func,
+                    "Cannot redefine _errback")
+        leap_assert(self._gui_notify.im_func ==
+                    AbstractBootstrapper._gui_notify.im_func,
+                    "Cannot redefine _gui_notify")
+
+        # **************************************************** #
+        # Dependency injection helpers, override this for more
+        # granular testing
+        self._fetcher = requests
+        # **************************************************** #
+
+        self._session = self._fetcher.session()
+        self._bypass_checks = bypass_checks
+        self._signal_to_emit = None
+        self._err_msg = None
+
+    def _gui_errback(self, failure):
+        """
+        Errback used to notify the GUI of a problem, it should be used
+        as the last errback of the whole chain.
+
+        Traps all exceptions if a signal is defined, otherwise it just
+        lets it continue.
+
+        NOTE: This method is final, it should not be redefined.
+
+        :param failure: failure object that Twisted generates
+        :type failure: twisted.python.failure.Failure
+        """
+        if self._signal_to_emit:
+            err_msg = self._err_msg \
+                if self._err_msg is not None \
+                else str(failure.value)
+            self._signal_to_emit.emit({
+                self.PASSED_KEY: False,
+                self.ERROR_KEY: err_msg
+            })
+            failure.trap(Exception)
+
+    def _errback(self, failure, signal=None):
+        """
+        Regular errback used for the middle of the chain. If it's
+        executed, the first one will set the signal to emit as
+        failure.
+
+        NOTE: This method is final, it should not be redefined.
+
+        :param failure: failure object that Twisted generates
+        :type failure: twisted.python.failure.Failure
+        :param signal: Signal to emit if it fails here first
+        :type signal: QtCore.SignalInstance
+
+        :returns: failure object that Twisted generates
+        :rtype: twisted.python.failure.Failure
+        """
+        if self._signal_to_emit is None:
+            self._signal_to_emit = signal
+        return failure
+
+    def _gui_notify(self, _, signal=None):
+        """
+        Callback used to notify the GUI of a success. Will emit signal
+        if specified
+
+        NOTE: This method is final, it should not be redefined.
+
+        :param _: IGNORED. Returned from the previous callback
+        :type _: IGNORED
+        :param signal: Signal to emit if it fails here first
+        :type signal: QtCore.SignalInstance
+        """
+        if signal:
+            logger.debug("Emitting %s" % (signal,))
+            signal.emit({self.PASSED_KEY: True, self.ERROR_KEY: ""})
+
+    def _callback_threader(self, cb, res, *args, **kwargs):
+        return threads.deferToThread(cb, res, *args, **kwargs)
+
+    def addCallbackChain(self, callbacks):
+        """
+        Creates a callback/errback chain on another thread using
+        deferToThread and adds the _gui_errback to the end to notify
+        the GUI on an error.
+
+        :param callbacks: List of tuples of callbacks and the signal
+                          associated to that callback
+        :type callbacks: list(tuple(func, func))
+        """
+        leap_assert_type(callbacks, list)
+
+        self._signal_to_emit = None
+        self._err_msg = None
+
+        d = None
+        for cb, sig in callbacks:
+            if d is None:
+                d = threads.deferToThread(cb)
+            else:
+                d.addCallback(partial(self._callback_threader, cb))
+            d.addErrback(self._errback, signal=sig)
+            d.addCallback(self._gui_notify, signal=sig)
+        d.addErrback(self._gui_errback)
+        return d