Merge lp:~diegosarmentero/ubuntuone-client/darwin-fsevents-1 into lp:ubuntuone-client

[Diego Sarmentero]

- Some refactoring to support mac os filesystem notifications in the future (LP: #1013323).

[lp:~diegosarmentero/ubuntuone-client/darwin-fsevents-1]

1259. By Diego Sarmentero on 2012-06-14

Fixing encoding problem on pyinotify_agnostic

[Diego Sarmentero (diegosarmentero)]

The only real changes for pyinotify_agnostic are:
- Adding import sys

and:

805def simple(self, s, attribute):
806 + if isinstance(s, unicode):
807 + s = s.encode(sys.getfilesystemencoding(), 'replace')

[Alejandro J. Cura (alecu)]

Nice branch so far, here's a small comment:
----
The decorators like: "skip_if_darwin_and_uses_metadata_older_than_5"
Instead of having a pair of decorators for both darwin and windows, I think they should be merged so they are called something like "skip_if_not_linux_and_uses..."

review: Needs Fixing

[Diego Sarmentero (diegosarmentero)]

> Nice branch so far, here's a small comment:
> ----
> The decorators like: "skip_if_darwin_and_uses_metadata_older_than_5"
> Instead of having a pair of decorators for both darwin and windows, I think
> they should be merged so they are called something like
> "skip_if_not_linux_and_uses..."

Fixed

[Diego Sarmentero (diegosarmentero)]

Branch reverted, because we really need the two different skips for different situations.

[Alejandro J. Cura (alecu)]

Here are some more comments that I didn't think of on my first review:

----

This first decorator makes sense; I'm not sure about the other two.
Anyway, the string in the first one is wrong:

+skip_if_darwin_and_uses_metadata_older_than_5 = \
+ skipIfOS('darwin',
+ 'In windows there is no need to migrate metadata older than v5.')

Do we know of any Read/Only issue on darwin to justify this decorator?

+skip_if_darwin_and_uses_readonly = \
+ skipIfOS('darwin', 'Can not test RO shares until bug #820350 is resolved.')

We may have some missing or out of order events in darwin, but we surely need to apply this decorator to the specific tests that fail with darwin, and we have to make sure we don't do a blanket decoration of the same test cases than in windows. In any case, we need a new bug with the darwin specifics.

+skip_if_darwin_missing_fs_event = \
+ skipIfOS('darwin', 'Fails due to missing/out of order FS events, '
+ 'see bug #820598.')

[lp:~diegosarmentero/ubuntuone-client/darwin-fsevents-1]

1260. By Diego Sarmentero on 2012-06-21

branch fixed according comments in the mp

[Diego Sarmentero (diegosarmentero)]

> Here are some more comments that I didn't think of on my first review:
>
> ----
>
> This first decorator makes sense; I'm not sure about the other two.
> Anyway, the string in the first one is wrong:
>
> +skip_if_darwin_and_uses_metadata_older_than_5 = \
> + skipIfOS('darwin',
> + 'In windows there is no need to migrate metadata older than
> v5.')
>
>
> Do we know of any Read/Only issue on darwin to justify this decorator?
>
> +skip_if_darwin_and_uses_readonly = \
> + skipIfOS('darwin', 'Can not test RO shares until bug #820350 is
> resolved.')
>
>
> We may have some missing or out of order events in darwin, but we surely need
> to apply this decorator to the specific tests that fail with darwin, and we
> have to make sure we don't do a blanket decoration of the same test cases than
> in windows. In any case, we need a new bug with the darwin specifics.
>
> +skip_if_darwin_missing_fs_event = \
> + skipIfOS('darwin', 'Fails due to missing/out of order FS events, '
> + 'see bug #820598.')

I removed the decorators that weren't being used, and leave "skip_if_darwin_missing_fs_event", because we are using it for some tests in futures branches of the darwin implementation.

[Alejandro J. Cura (alecu)]

Looks good so far. +1

review: Approve

[Manuel de la Peña (mandel)]

Looks good, this will be nice to merge with my work so far.

review: Approve

=== modified file 'contrib/testing/testcase.py'
--- contrib/testing/testcase.py	2012-05-22 14:07:55 +0000
+++ contrib/testing/testcase.py	2012-06-21 17:37:46 +0000
@@ -197,7 +197,7 @@
 
     cancel_download = cancel_upload = download = upload = make_dir = disconnect
     make_file = move = unlink = list_shares = disconnect
-    list_volumes = create_share = create_udf = inquire_free_space =  disconnect
+    list_volumes = create_share = create_udf = inquire_free_space = disconnect
     inquire_account_info = delete_volume = change_public_access = disconnect
     query_volumes = get_delta = rescan_from_scratch = delete_share = disconnect
     node_is_with_queued_move = cleanup = get_public_files = disconnect
@@ -302,7 +302,7 @@
         mmtree(path): support read-only shares
         makedirs(path): support read-only shares
     """
-    MAX_FILENAME = 32 # some platforms limit lengths of filenames
+    MAX_FILENAME = 32  # some platforms limit lengths of filenames
     tunnel_runner_class = FakeTunnelRunner
 
     def mktemp(self, name='temp'):
@@ -448,7 +448,7 @@
     def __init__(self, root_path):
         """ Creates the instance"""
         self.root = volume_manager.Root(node_id="root_node_id", path=root_path)
-        self.shares = {'':self.root}
+        self.shares = {'': self.root}
         self.udfs = {}
         self.log = logging.getLogger('ubuntuone.SyncDaemon.VM-test')
 
@@ -686,3 +686,7 @@
 skip_if_win32_missing_fs_event = \
     skipIfOS('win32', 'Fails due to missing/out of order FS events, '
                       'see bug #820598.')
+
+skip_if_darwin_missing_fs_event = \
+    skipIfOS('darwin', 'Fails due to missing/out of order FS events, '
+                      'see bug #820598.')
 
=== modified file 'tests/platform/filesystem_notifications/__init__.py'
--- tests/platform/filesystem_notifications/__init__.py	2012-04-30 15:19:03 +0000
+++ tests/platform/filesystem_notifications/__init__.py	2012-06-21 17:37:46 +0000
@@ -25,3 +25,58 @@
 # version.  If you delete this exception statement from all source
 # files in the program, then also delete it here.
 """Platform/File System Notifications test code."""
+
+import logging
+
+from twisted.internet import defer
+
+from ubuntuone.syncdaemon import (
+    event_queue,
+    filesystem_manager,
+)
+from contrib.testing import testcase
+from ubuntuone.devtools.handlers import MementoHandler
+from ubuntuone.syncdaemon.tritcask import Tritcask
+
+
+class BaseFSMonitorTestCase(testcase.BaseTwistedTestCase):
+    """Test the structures where we have the path/watch."""
+
+    timeout = 3
+
+    @defer.inlineCallbacks
+    def setUp(self):
+        """Set up."""
+        yield super(BaseFSMonitorTestCase, self).setUp()
+        fsmdir = self.mktemp('fsmdir')
+        partials_dir = self.mktemp('partials_dir')
+        self.root_dir = self.mktemp('root_dir')
+        self.vm = testcase.FakeVolumeManager(self.root_dir)
+        self.tritcask_dir = self.mktemp("tritcask_dir")
+        self.db = Tritcask(self.tritcask_dir)
+        self.fs = filesystem_manager.FileSystemManager(fsmdir, partials_dir,
+                                                       self.vm, self.db)
+        self.fs.create(path=self.root_dir, share_id='', is_dir=True)
+        self.fs.set_by_path(path=self.root_dir,
+                            local_hash=None, server_hash=None)
+        eq = event_queue.EventQueue(self.fs)
+
+        self.deferred = deferred = defer.Deferred()
+
+        class HitMe(object):
+            # class-closure, cannot use self, pylint: disable-msg=E0213
+            def handle_default(innerself, event, **args):
+                deferred.callback(True)
+
+        eq.subscribe(HitMe())
+        self.monitor = eq.monitor
+        self.log_handler = MementoHandler()
+        self.log_handler.setLevel(logging.DEBUG)
+        self.monitor.log.addHandler(self.log_handler)
+
+    @defer.inlineCallbacks
+    def tearDown(self):
+        """Clean up the tests."""
+        self.monitor.shutdown()
+        self.monitor.log.removeHandler(self.log_handler)
+        yield super(BaseFSMonitorTestCase, self).tearDown()
 
=== modified file 'tests/platform/filesystem_notifications/test_linux.py'
--- tests/platform/filesystem_notifications/test_linux.py	2012-05-23 13:06:42 +0000
+++ tests/platform/filesystem_notifications/test_linux.py	2012-06-21 17:37:46 +0000
@@ -30,23 +30,17 @@
 # files in the program, then also delete it here.
 """Tests for the Event Queue."""
 
-import logging
 import os
 
 from twisted.internet import defer, reactor
 from twisted.trial.unittest import TestCase as PlainTestCase
 
-from ubuntuone.syncdaemon import (
-    event_queue,
-    filesystem_manager,
-)
 from contrib.testing import testcase
-from ubuntuone.devtools.handlers import MementoHandler
 from ubuntuone.syncdaemon import volume_manager
-from ubuntuone.syncdaemon.tritcask import Tritcask
 from ubuntuone.platform.filesystem_notifications import (
     linux as filesystem_notifications,
 )
+from tests.platform.filesystem_notifications import BaseFSMonitorTestCase
 
 # We normally access to private attribs in tests
 # pylint: disable=W0212
@@ -101,50 +95,6 @@
         self.assertFalse(processor.timer.active())
 
 
-
-class BaseFSMonitorTestCase(testcase.BaseTwistedTestCase):
-    """Test the structures where we have the path/watch."""
-
-    timeout = 3
-
-    @defer.inlineCallbacks
-    def setUp(self):
-        """Set up."""
-        yield super(BaseFSMonitorTestCase, self).setUp()
-        fsmdir = self.mktemp('fsmdir')
-        partials_dir = self.mktemp('partials_dir')
-        self.root_dir = self.mktemp('root_dir')
-        self.vm = testcase.FakeVolumeManager(self.root_dir)
-        self.tritcask_dir = self.mktemp("tritcask_dir")
-        self.db = Tritcask(self.tritcask_dir)
-        self.fs = filesystem_manager.FileSystemManager(fsmdir, partials_dir,
-                                                       self.vm, self.db)
-        self.fs.create(path=self.root_dir, share_id='', is_dir=True)
-        self.fs.set_by_path(path=self.root_dir,
-                            local_hash=None, server_hash=None)
-        eq = event_queue.EventQueue(self.fs)
-
-        self.deferred = deferred = defer.Deferred()
-
-        class HitMe(object):
-            # class-closure, cannot use self, pylint: disable-msg=E0213
-            def handle_default(innerself, event, **args):
-                deferred.callback(True)
-
-        eq.subscribe(HitMe())
-        self.monitor = eq.monitor
-        self.log_handler = MementoHandler()
-        self.log_handler.setLevel(logging.DEBUG)
-        self.monitor.log.addHandler(self.log_handler)
-
-    @defer.inlineCallbacks
-    def tearDown(self):
-        """Clean up the tests."""
-        self.monitor.shutdown()
-        self.monitor.log.removeHandler(self.log_handler)
-        yield super(BaseFSMonitorTestCase, self).tearDown()
-
-
 class WatchManagerTests(BaseFSMonitorTestCase):
     """Test the structures where we have the path/watch."""
 
@@ -222,7 +172,8 @@
         self.monitor._general_watchs = {'/path1/foo': 1, '/other': 2}
         self.monitor._ancestors_watchs = {'/foo': 3}
         self.monitor.inotify_watch_fix('/path1/foo', '/path1/new')
-        self.assertEqual(self.monitor._general_watchs, {'/path1/new': 1, '/other': 2})
+        self.assertEqual(self.monitor._general_watchs,
+            {'/path1/new': 1, '/other': 2})
         self.assertEqual(self.monitor._ancestors_watchs, {'/foo': 3})
 
     def test_fix_path_ancestors(self):
@@ -231,7 +182,8 @@
         self.monitor._ancestors_watchs = {'/oth': 1, '/other': 2}
         self.monitor.inotify_watch_fix('/oth', '/baz')
         self.assertEqual(self.monitor._general_watchs, {'/bar': 3})
-        self.assertEqual(self.monitor._ancestors_watchs, {'/baz': 1, '/other': 2})
+        self.assertEqual(self.monitor._ancestors_watchs,
+            {'/baz': 1, '/other': 2})
 
 
 class DynamicHitMe(object):
 
=== renamed file 'tests/platform/filesystem_notifier/test_windows.py' => 'tests/platform/filesystem_notifications/test_pyinotify_agnostic.py'
--- tests/platform/filesystem_notifier/test_windows.py	2012-05-14 21:24:24 +0000
+++ tests/platform/filesystem_notifications/test_pyinotify_agnostic.py	2012-06-21 17:37:46 +0000
@@ -30,6 +30,8 @@
 # files in the program, then also delete it here.
 """Test for the pyinotify implementation on windows."""
 
+import sys
+
 from twisted.internet import defer
 from twisted.trial.unittest import TestCase
 
@@ -51,7 +53,8 @@
         attr = 'attribute'
         self.format[attr] = attr
         value = u'ñoño'
-        expected_result = (attr + value.encode('mbcs', 'replace') +
+        expected_result = (attr + value.encode(
+                           sys.getfilesystemencoding(), 'replace') +
                            self.format['normal'])
         self.assertEqual(expected_result, self.formatter.simple(value, attr))
 
 
=== removed directory 'tests/platform/filesystem_notifier'
=== removed file 'tests/platform/filesystem_notifier/__init__.py'
--- tests/platform/filesystem_notifier/__init__.py	2012-05-14 19:04:43 +0000
+++ tests/platform/filesystem_notifier/__init__.py	1970-01-01 00:00:00 +0000
@@ -1,27 +0,0 @@
-# Copyright 2012 Canonical Ltd.
-#
-# This program is free software: you can redistribute it and/or modify it
-# under the terms of the GNU General Public License version 3, 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 warranties of
-# MERCHANTABILITY, SATISFACTORY QUALITY, 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/>.
-#
-# In addition, as a special exception, the copyright holders give
-# permission to link the code of portions of this program with the
-# OpenSSL library under certain conditions as described in each
-# individual source file, and distribute linked combinations
-# including the two.
-# You must obey the GNU General Public License in all respects
-# for all of the code used other than OpenSSL.  If you modify
-# file(s) with this exception, you may extend this exception to your
-# version of the file(s), but you are not obligated to do so.  If you
-# do not wish to do so, delete this exception statement from your
-# version.  If you delete this exception statement from all source
-# files in the program, then also delete it here.
-"""Platform/File System Notifier (Pyinotify agnostic) test code."""
 
=== modified file 'ubuntuone/platform/filesystem_notifications/pyinotify_agnostic.py'
--- ubuntuone/platform/filesystem_notifications/pyinotify_agnostic.py	2012-05-14 20:38:23 +0000
+++ ubuntuone/platform/filesystem_notifications/pyinotify_agnostic.py	2012-06-21 17:37:46 +0000
@@ -1,518 +1,518 @@
-#!/usr/bin/env python
-
-# pyinotify.py - python interface to inotify
-# Copyright (c) 2010 Sebastien Martini <[e-mail]>
-#
-# Permission is hereby granted, free of charge, to any person obtaining a copy
-# of this software and associated documentation files (the "Software"), to deal
-# in the Software without restriction, including without limitation the rights
-# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-# copies of the Software, and to permit persons to whom the Software is
-# furnished to do so, subject to the following conditions:
-#
-# The above copyright notice and this permission notice shall be included in
-# all copies or substantial portions of the Software.
-#
-# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-# THE SOFTWARE.
-"""Platform agnostic code grabed from pyinotify."""
-import logging
-import os
-import sys
-
-COMPATIBILITY_MODE = False
-
-class PyinotifyError(Exception):
-    """Indicates exceptions raised by a Pyinotify class."""
-    pass
-
-
-class RawOutputFormat:
-    """
-    Format string representations.
-    """
-    def __init__(self, format=None):
-        self.format = format or {}
-
-    def simple(self, s, attribute):
-        if isinstance(s, unicode):
-            s = s.encode('mbcs', 'replace')
-        else:
-            s = str(s)
-        return (self.format.get(attribute, '') + s +
-                self.format.get('normal', ''))
-
-    def punctuation(self, s):
-        """Punctuation color."""
-        return self.simple(s, 'normal')
-
-    def field_value(self, s):
-        """Field value color."""
-        return self.simple(s, 'purple')
-
-    def field_name(self, s):
-        """Field name color."""
-        return self.simple(s, 'blue')
-
-    def class_name(self, s):
-        """Class name color."""
-        return self.format.get('red', '') + self.simple(s, 'bold')
-
-output_format = RawOutputFormat()
-
-
-class EventsCodes:
-    """
-    Set of codes corresponding to each kind of events.
-    Some of these flags are used to communicate with inotify, whereas
-    the others are sent to userspace by inotify notifying some events.
-
-    @cvar IN_ACCESS: File was accessed.
-    @type IN_ACCESS: int
-    @cvar IN_MODIFY: File was modified.
-    @type IN_MODIFY: int
-    @cvar IN_ATTRIB: Metadata changed.
-    @type IN_ATTRIB: int
-    @cvar IN_CLOSE_WRITE: Writtable file was closed.
-    @type IN_CLOSE_WRITE: int
-    @cvar IN_CLOSE_NOWRITE: Unwrittable file closed.
-    @type IN_CLOSE_NOWRITE: int
-    @cvar IN_OPEN: File was opened.
-    @type IN_OPEN: int
-    @cvar IN_MOVED_FROM: File was moved from X.
-    @type IN_MOVED_FROM: int
-    @cvar IN_MOVED_TO: File was moved to Y.
-    @type IN_MOVED_TO: int
-    @cvar IN_CREATE: Subfile was created.
-    @type IN_CREATE: int
-    @cvar IN_DELETE: Subfile was deleted.
-    @type IN_DELETE: int
-    @cvar IN_DELETE_SELF: Self (watched item itself) was deleted.
-    @type IN_DELETE_SELF: int
-    @cvar IN_MOVE_SELF: Self (watched item itself) was moved.
-    @type IN_MOVE_SELF: int
-    @cvar IN_UNMOUNT: Backing fs was unmounted.
-    @type IN_UNMOUNT: int
-    @cvar IN_Q_OVERFLOW: Event queued overflowed.
-    @type IN_Q_OVERFLOW: int
-    @cvar IN_IGNORED: File was ignored.
-    @type IN_IGNORED: int
-    @cvar IN_ONLYDIR: only watch the path if it is a directory (new
-                      in kernel 2.6.15).
-    @type IN_ONLYDIR: int
-    @cvar IN_DONT_FOLLOW: don't follow a symlink (new in kernel 2.6.15).
-                          IN_ONLYDIR we can make sure that we don't watch
-                          the target of symlinks.
-    @type IN_DONT_FOLLOW: int
-    @cvar IN_MASK_ADD: add to the mask of an already existing watch (new
-                       in kernel 2.6.14).
-    @type IN_MASK_ADD: int
-    @cvar IN_ISDIR: Event occurred against dir.
-    @type IN_ISDIR: int
-    @cvar IN_ONESHOT: Only send event once.
-    @type IN_ONESHOT: int
-    @cvar ALL_EVENTS: Alias for considering all of the events.
-    @type ALL_EVENTS: int
-    """
-
-    # The idea here is 'configuration-as-code' - this way, we get
-    # our nice class constants, but we also get nice human-friendly text
-    # mappings to do lookups against as well, for free:
-    FLAG_COLLECTIONS = {'OP_FLAGS': {
-        'IN_ACCESS'        : 0x00000001,  # File was accessed
-        'IN_MODIFY'        : 0x00000002,  # File was modified
-        'IN_ATTRIB'        : 0x00000004,  # Metadata changed
-        'IN_CLOSE_WRITE'   : 0x00000008,  # Writable file was closed
-        'IN_CLOSE_NOWRITE' : 0x00000010,  # Unwritable file closed
-        'IN_OPEN'          : 0x00000020,  # File was opened
-        'IN_MOVED_FROM'    : 0x00000040,  # File was moved from X
-        'IN_MOVED_TO'      : 0x00000080,  # File was moved to Y
-        'IN_CREATE'        : 0x00000100,  # Subfile was created
-        'IN_DELETE'        : 0x00000200,  # Subfile was deleted
-        'IN_DELETE_SELF'   : 0x00000400,  # Self (watched item itself)
-                                          # was deleted
-        'IN_MOVE_SELF'     : 0x00000800,  # Self(watched item itself) was moved
-        },
-                        'EVENT_FLAGS': {
-        'IN_UNMOUNT'       : 0x00002000,  # Backing fs was unmounted
-        'IN_Q_OVERFLOW'    : 0x00004000,  # Event queued overflowed
-        'IN_IGNORED'       : 0x00008000,  # File was ignored
-        },
-                        'SPECIAL_FLAGS': {
-        'IN_ONLYDIR'       : 0x01000000,  # only watch the path if it is a
-                                          # directory
-        'IN_DONT_FOLLOW'   : 0x02000000,  # don't follow a symlink
-        'IN_MASK_ADD'      : 0x20000000,  # add to the mask of an already
-                                          # existing watch
-        'IN_ISDIR'         : 0x40000000,  # event occurred against dir
-        'IN_ONESHOT'       : 0x80000000,  # only send event once
-        },
-                        }
-
-    def maskname(mask):
-        """
-        Returns the event name associated to mask. IN_ISDIR is appended to
-        the result when appropriate. Note: only one event is returned, because
-        only one event can be raised at a given time.
-
-        @param mask: mask.
-        @type mask: int
-        @return: event name.
-        @rtype: str
-        """
-        ms = mask
-        name = '%s'
-        if mask & IN_ISDIR:
-            ms = mask - IN_ISDIR
-            name = '%s|IN_ISDIR'
-        return name % EventsCodes.ALL_VALUES[ms]
-
-    maskname = staticmethod(maskname)
-
-
-# So let's now turn the configuration into code
-EventsCodes.ALL_FLAGS = {}
-EventsCodes.ALL_VALUES = {}
-for flagc, valc in EventsCodes.FLAG_COLLECTIONS.items():
-    # Make the collections' members directly accessible through the
-    # class dictionary
-    setattr(EventsCodes, flagc, valc)
-
-    # Collect all the flags under a common umbrella
-    EventsCodes.ALL_FLAGS.update(valc)
-
-    # Make the individual masks accessible as 'constants' at globals() scope
-    # and masknames accessible by values.
-    for name, val in valc.items():
-        globals()[name] = val
-        EventsCodes.ALL_VALUES[val] = name
-
-
-# all 'normal' events
-ALL_EVENTS = reduce(lambda x, y: x | y, EventsCodes.OP_FLAGS.values())
-EventsCodes.ALL_FLAGS['ALL_EVENTS'] = ALL_EVENTS
-EventsCodes.ALL_VALUES[ALL_EVENTS] = 'ALL_EVENTS'
-
-
-class _Event:
-    """
-    Event structure, represent events raised by the system. This
-    is the base class and should be subclassed.
-
-    """
-    def __init__(self, dict_):
-        """
-        Attach attributes (contained in dict_) to self.
-
-        @param dict_: Set of attributes.
-        @type dict_: dictionary
-        """
-        for tpl in dict_.items():
-            setattr(self, *tpl)
-
-    def __repr__(self):
-        """
-        @return: Generic event string representation.
-        @rtype: str
-        """
-        s = ''
-        for attr, value in sorted(self.__dict__.items(), key=lambda x: x[0]):
-            if attr.startswith('_'):
-                continue
-            if attr == 'mask':
-                value = hex(getattr(self, attr))
-            elif isinstance(value, basestring) and not value:
-                value = "''"
-            s += ' %s%s%s' % (output_format.field_name(attr),
-                              output_format.punctuation('='),
-                              output_format.field_value(value))
-
-        s = '%s%s%s %s' % (output_format.punctuation('<'),
-                           output_format.class_name(self.__class__.__name__),
-                           s,
-                           output_format.punctuation('>'))
-        return s
-
-    def __str__(self):
-        return repr(self)
-
-
-class _RawEvent(_Event):
-    """
-    Raw event, it contains only the informations provided by the system.
-    It doesn't infer anything.
-    """
-    def __init__(self, wd, mask, cookie, name):
-        """
-        @param wd: Watch Descriptor.
-        @type wd: int
-        @param mask: Bitmask of events.
-        @type mask: int
-        @param cookie: Cookie.
-        @type cookie: int
-        @param name: Basename of the file or directory against which the
-                     event was raised in case where the watched directory
-                     is the parent directory. None if the event was raised
-                     on the watched item itself.
-        @type name: string or None
-        """
-        # Use this variable to cache the result of str(self), this object
-        # is immutable.
-        self._str = None
-        # name: remove trailing '\0'
-        d = {'wd': wd,
-             'mask': mask,
-             'cookie': cookie,
-             'name': name.rstrip('\0')}
-        _Event.__init__(self, d)
-        logging.debug(str(self))
-
-    def __str__(self):
-        if self._str is None:
-            self._str = _Event.__str__(self)
-        return self._str
-
-
-class Event(_Event):
-    """
-    This class contains all the useful informations about the observed
-    event. However, the presence of each field is not guaranteed and
-    depends on the type of event. In effect, some fields are irrelevant
-    for some kind of event (for example 'cookie' is meaningless for
-    IN_CREATE whereas it is mandatory for IN_MOVE_TO).
-
-    The possible fields are:
-      - wd (int): Watch Descriptor.
-      - mask (int): Mask.
-      - maskname (str): Readable event name.
-      - path (str): path of the file or directory being watched.
-      - name (str): Basename of the file or directory against which the
-              event was raised in case where the watched directory
-              is the parent directory. None if the event was raised
-              on the watched item itself. This field is always provided
-              even if the string is ''.
-      - pathname (str): Concatenation of 'path' and 'name'.
-      - src_pathname (str): Only present for IN_MOVED_TO events and only in
-              the case where IN_MOVED_FROM events are watched too. Holds the
-              source pathname from where pathname was moved from.
-      - cookie (int): Cookie.
-      - dir (bool): True if the event was raised against a directory.
-
-    """
-    def __init__(self, raw):
-        """
-        Concretely, this is the raw event plus inferred infos.
-        """
-        _Event.__init__(self, raw)
-        self.maskname = EventsCodes.maskname(self.mask)
-        if COMPATIBILITY_MODE:
-            self.event_name = self.maskname
-        try:
-            if self.name:
-                self.pathname = os.path.abspath(os.path.join(self.path,
-                                                             self.name))
-            else:
-                self.pathname = os.path.abspath(self.path)
-        except AttributeError, err:
-            # Usually it is not an error some events are perfectly valids
-            # despite the lack of these attributes.
-            logging.debug(err)
-
-
-class ProcessEventError(PyinotifyError):
-    """
-    ProcessEventError Exception. Raised on ProcessEvent error.
-    """
-    def __init__(self, err):
-        """
-        @param err: Exception error description.
-        @type err: string
-        """
-        PyinotifyError.__init__(self, err)
-
-
-class _ProcessEvent:
-    """
-    Abstract processing event class.
-    """
-    def __call__(self, event):
-        """
-        To behave like a functor the object must be callable.
-        This method is a dispatch method. Its lookup order is:
-          1. process_MASKNAME method
-          2. process_FAMILY_NAME method
-          3. otherwise calls process_default
-
-        @param event: Event to be processed.
-        @type event: Event object
-        @return: By convention when used from the ProcessEvent class:
-                 - Returning False or None (default value) means keep on
-                 executing next chained functors (see chain.py example).
-                 - Returning True instead means do not execute next
-                   processing functions.
-        @rtype: bool
-        @raise ProcessEventError: Event object undispatchable,
-                                  unknown event.
-        """
-        stripped_mask = event.mask - (event.mask & IN_ISDIR)
-        maskname = EventsCodes.ALL_VALUES.get(stripped_mask)
-        if maskname is None:
-            raise ProcessEventError("Unknown mask 0x%08x" % stripped_mask)
-
-        # 1- look for process_MASKNAME
-        meth = getattr(self, 'process_' + maskname, None)
-        if meth is not None:
-            return meth(event)
-        # 2- look for process_FAMILY_NAME
-        meth = getattr(self, 'process_IN_' + maskname.split('_')[1], None)
-        if meth is not None:
-            return meth(event)
-        # 3- default call method process_default
-        return self.process_default(event)
-
-    def __repr__(self):
-        return '<%s>' % self.__class__.__name__
-
-
-class ProcessEvent(_ProcessEvent):
-    """
-    Process events objects, can be specialized via subclassing, thus its
-    behavior can be overriden:
-
-    Note: you should not override __init__ in your subclass instead define
-    a my_init() method, this method will be called automatically from the
-    constructor of this class with its optionals parameters.
-
-      1. Provide specialized individual methods, e.g. process_IN_DELETE for
-         processing a precise type of event (e.g. IN_DELETE in this case).
-      2. Or/and provide methods for processing events by 'family', e.g.
-         process_IN_CLOSE method will process both IN_CLOSE_WRITE and
-         IN_CLOSE_NOWRITE events (if process_IN_CLOSE_WRITE and
-         process_IN_CLOSE_NOWRITE aren't defined though).
-      3. Or/and override process_default for catching and processing all
-         the remaining types of events.
-    """
-    pevent = None
-
-    def __init__(self, pevent=None, **kargs):
-        """
-        Enable chaining of ProcessEvent instances.
-
-        @param pevent: Optional callable object, will be called on event
-                       processing (before self).
-        @type pevent: callable
-        @param kargs: This constructor is implemented as a template method
-                      delegating its optionals keyworded arguments to the
-                      method my_init().
-        @type kargs: dict
-        """
-        self.pevent = pevent
-        self.my_init(**kargs)
-
-    def my_init(self, **kargs):
-        """
-        This method is called from ProcessEvent.__init__(). This method is
-        empty here and must be redefined to be useful. In effect, if you
-        need to specifically initialize your subclass' instance then you
-        just have to override this method in your subclass. Then all the
-        keyworded arguments passed to ProcessEvent.__init__() will be
-        transmitted as parameters to this method. Beware you MUST pass
-        keyword arguments though.
-
-        @param kargs: optional delegated arguments from __init__().
-        @type kargs: dict
-        """
-        pass
-
-    def __call__(self, event):
-        stop_chaining = False
-        if self.pevent is not None:
-            # By default methods return None so we set as guideline
-            # that methods asking for stop chaining must explicitely
-            # return non None or non False values, otherwise the default
-            # behavior will be to accept chain call to the corresponding
-            # local method.
-            stop_chaining = self.pevent(event)
-        if not stop_chaining:
-            return _ProcessEvent.__call__(self, event)
-
-    def nested_pevent(self):
-        return self.pevent
-
-    def process_IN_Q_OVERFLOW(self, event):
-        """
-        By default this method only reports warning messages, you can
-        overredide it by subclassing ProcessEvent and implement your own
-        process_IN_Q_OVERFLOW method. The actions you can take on receiving
-        this event is either to update the variable max_queued_events in order
-        to handle more simultaneous events or to modify your code in order to
-        accomplish a better filtering diminishing the number of raised events.
-        Because this method is defined, IN_Q_OVERFLOW will never get
-        transmitted as arguments to process_default calls.
-
-        @param event: IN_Q_OVERFLOW event.
-        @type event: dict
-        """
-        logging.warning('Event queue overflowed.')
-
-    def process_default(self, event):
-        """
-        Default processing event method. By default does nothing. Subclass
-        ProcessEvent and redefine this method in order to modify its behavior.
-
-        @param event: Event to be processed. Can be of any type of events but
-                      IN_Q_OVERFLOW events (see method process_IN_Q_OVERFLOW).
-        @type event: Event instance
-        """
-        pass
-
-
-class PrintAllEvents(ProcessEvent):
-    """
-    Dummy class used to print events strings representations. For instance this
-    class is used from command line to print all received events to stdout.
-    """
-    def my_init(self, out=None):
-        """
-        @param out: Where events will be written.
-        @type out: Object providing a valid file object interface.
-        """
-        if out is None:
-            out = sys.stdout
-        self._out = out
-
-    def process_default(self, event):
-        """
-        Writes event string representation to file object provided to
-        my_init().
-
-        @param event: Event to be processed. Can be of any type of events but
-                      IN_Q_OVERFLOW events (see method process_IN_Q_OVERFLOW).
-        @type event: Event instance
-        """
-        self._out.write(str(event))
-        self._out.write('\n')
-        self._out.flush()
-
-
-class WatchManagerError(Exception):
-    """
-    WatchManager Exception. Raised on error encountered on watches
-    operations.
-
-    """
-    def __init__(self, msg, wmd):
-        """
-        @param msg: Exception string's description.
-        @type msg: string
-        @param wmd: This dictionary contains the wd assigned to paths of the
-                    same call for which watches were successfully added.
-        @type wmd: dict
-        """
-        self.wmd = wmd
-        Exception.__init__(self, msg)
+#!/usr/bin/env python
+
+# pyinotify.py - python interface to inotify
+# Copyright (c) 2010 Sebastien Martini <[e-mail]>
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+"""Platform agnostic code grabed from pyinotify."""
+import logging
+import os
+import sys
+
+COMPATIBILITY_MODE = False
+
+class PyinotifyError(Exception):
+    """Indicates exceptions raised by a Pyinotify class."""
+    pass
+
+
+class RawOutputFormat:
+    """
+    Format string representations.
+    """
+    def __init__(self, format=None):
+        self.format = format or {}
+
+    def simple(self, s, attribute):
+        if isinstance(s, unicode):
+            s = s.encode(sys.getfilesystemencoding(), 'replace')
+        else:
+            s = str(s)
+        return (self.format.get(attribute, '') + s +
+                self.format.get('normal', ''))
+
+    def punctuation(self, s):
+        """Punctuation color."""
+        return self.simple(s, 'normal')
+
+    def field_value(self, s):
+        """Field value color."""
+        return self.simple(s, 'purple')
+
+    def field_name(self, s):
+        """Field name color."""
+        return self.simple(s, 'blue')
+
+    def class_name(self, s):
+        """Class name color."""
+        return self.format.get('red', '') + self.simple(s, 'bold')
+
+output_format = RawOutputFormat()
+
+
+class EventsCodes:
+    """
+    Set of codes corresponding to each kind of events.
+    Some of these flags are used to communicate with inotify, whereas
+    the others are sent to userspace by inotify notifying some events.
+
+    @cvar IN_ACCESS: File was accessed.
+    @type IN_ACCESS: int
+    @cvar IN_MODIFY: File was modified.
+    @type IN_MODIFY: int
+    @cvar IN_ATTRIB: Metadata changed.
+    @type IN_ATTRIB: int
+    @cvar IN_CLOSE_WRITE: Writtable file was closed.
+    @type IN_CLOSE_WRITE: int
+    @cvar IN_CLOSE_NOWRITE: Unwrittable file closed.
+    @type IN_CLOSE_NOWRITE: int
+    @cvar IN_OPEN: File was opened.
+    @type IN_OPEN: int
+    @cvar IN_MOVED_FROM: File was moved from X.
+    @type IN_MOVED_FROM: int
+    @cvar IN_MOVED_TO: File was moved to Y.
+    @type IN_MOVED_TO: int
+    @cvar IN_CREATE: Subfile was created.
+    @type IN_CREATE: int
+    @cvar IN_DELETE: Subfile was deleted.
+    @type IN_DELETE: int
+    @cvar IN_DELETE_SELF: Self (watched item itself) was deleted.
+    @type IN_DELETE_SELF: int
+    @cvar IN_MOVE_SELF: Self (watched item itself) was moved.
+    @type IN_MOVE_SELF: int
+    @cvar IN_UNMOUNT: Backing fs was unmounted.
+    @type IN_UNMOUNT: int
+    @cvar IN_Q_OVERFLOW: Event queued overflowed.
+    @type IN_Q_OVERFLOW: int
+    @cvar IN_IGNORED: File was ignored.
+    @type IN_IGNORED: int
+    @cvar IN_ONLYDIR: only watch the path if it is a directory (new
+                      in kernel 2.6.15).
+    @type IN_ONLYDIR: int
+    @cvar IN_DONT_FOLLOW: don't follow a symlink (new in kernel 2.6.15).
+                          IN_ONLYDIR we can make sure that we don't watch
+                          the target of symlinks.
+    @type IN_DONT_FOLLOW: int
+    @cvar IN_MASK_ADD: add to the mask of an already existing watch (new
+                       in kernel 2.6.14).
+    @type IN_MASK_ADD: int
+    @cvar IN_ISDIR: Event occurred against dir.
+    @type IN_ISDIR: int
+    @cvar IN_ONESHOT: Only send event once.
+    @type IN_ONESHOT: int
+    @cvar ALL_EVENTS: Alias for considering all of the events.
+    @type ALL_EVENTS: int
+    """
+
+    # The idea here is 'configuration-as-code' - this way, we get
+    # our nice class constants, but we also get nice human-friendly text
+    # mappings to do lookups against as well, for free:
+    FLAG_COLLECTIONS = {'OP_FLAGS': {
+        'IN_ACCESS'        : 0x00000001,  # File was accessed
+        'IN_MODIFY'        : 0x00000002,  # File was modified
+        'IN_ATTRIB'        : 0x00000004,  # Metadata changed
+        'IN_CLOSE_WRITE'   : 0x00000008,  # Writable file was closed
+        'IN_CLOSE_NOWRITE' : 0x00000010,  # Unwritable file closed
+        'IN_OPEN'          : 0x00000020,  # File was opened
+        'IN_MOVED_FROM'    : 0x00000040,  # File was moved from X
+        'IN_MOVED_TO'      : 0x00000080,  # File was moved to Y
+        'IN_CREATE'        : 0x00000100,  # Subfile was created
+        'IN_DELETE'        : 0x00000200,  # Subfile was deleted
+        'IN_DELETE_SELF'   : 0x00000400,  # Self (watched item itself)
+                                          # was deleted
+        'IN_MOVE_SELF'     : 0x00000800,  # Self(watched item itself) was moved
+        },
+                        'EVENT_FLAGS': {
+        'IN_UNMOUNT'       : 0x00002000,  # Backing fs was unmounted
+        'IN_Q_OVERFLOW'    : 0x00004000,  # Event queued overflowed
+        'IN_IGNORED'       : 0x00008000,  # File was ignored
+        },
+                        'SPECIAL_FLAGS': {
+        'IN_ONLYDIR'       : 0x01000000,  # only watch the path if it is a
+                                          # directory
+        'IN_DONT_FOLLOW'   : 0x02000000,  # don't follow a symlink
+        'IN_MASK_ADD'      : 0x20000000,  # add to the mask of an already
+                                          # existing watch
+        'IN_ISDIR'         : 0x40000000,  # event occurred against dir
+        'IN_ONESHOT'       : 0x80000000,  # only send event once
+        },
+                        }
+
+    def maskname(mask):
+        """
+        Returns the event name associated to mask. IN_ISDIR is appended to
+        the result when appropriate. Note: only one event is returned, because
+        only one event can be raised at a given time.
+
+        @param mask: mask.
+        @type mask: int
+        @return: event name.
+        @rtype: str
+        """
+        ms = mask
+        name = '%s'
+        if mask & IN_ISDIR:
+            ms = mask - IN_ISDIR
+            name = '%s|IN_ISDIR'
+        return name % EventsCodes.ALL_VALUES[ms]
+
+    maskname = staticmethod(maskname)
+
+
+# So let's now turn the configuration into code
+EventsCodes.ALL_FLAGS = {}
+EventsCodes.ALL_VALUES = {}
+for flagc, valc in EventsCodes.FLAG_COLLECTIONS.items():
+    # Make the collections' members directly accessible through the
+    # class dictionary
+    setattr(EventsCodes, flagc, valc)
+
+    # Collect all the flags under a common umbrella
+    EventsCodes.ALL_FLAGS.update(valc)
+
+    # Make the individual masks accessible as 'constants' at globals() scope
+    # and masknames accessible by values.
+    for name, val in valc.items():
+        globals()[name] = val
+        EventsCodes.ALL_VALUES[val] = name
+
+
+# all 'normal' events
+ALL_EVENTS = reduce(lambda x, y: x | y, EventsCodes.OP_FLAGS.values())
+EventsCodes.ALL_FLAGS['ALL_EVENTS'] = ALL_EVENTS
+EventsCodes.ALL_VALUES[ALL_EVENTS] = 'ALL_EVENTS'
+
+
+class _Event:
+    """
+    Event structure, represent events raised by the system. This
+    is the base class and should be subclassed.
+
+    """
+    def __init__(self, dict_):
+        """
+        Attach attributes (contained in dict_) to self.
+
+        @param dict_: Set of attributes.
+        @type dict_: dictionary
+        """
+        for tpl in dict_.items():
+            setattr(self, *tpl)
+
+    def __repr__(self):
+        """
+        @return: Generic event string representation.
+        @rtype: str
+        """
+        s = ''
+        for attr, value in sorted(self.__dict__.items(), key=lambda x: x[0]):
+            if attr.startswith('_'):
+                continue
+            if attr == 'mask':
+                value = hex(getattr(self, attr))
+            elif isinstance(value, basestring) and not value:
+                value = "''"
+            s += ' %s%s%s' % (output_format.field_name(attr),
+                              output_format.punctuation('='),
+                              output_format.field_value(value))
+
+        s = '%s%s%s %s' % (output_format.punctuation('<'),
+                           output_format.class_name(self.__class__.__name__),
+                           s,
+                           output_format.punctuation('>'))
+        return s
+
+    def __str__(self):
+        return repr(self)
+
+
+class _RawEvent(_Event):
+    """
+    Raw event, it contains only the informations provided by the system.
+    It doesn't infer anything.
+    """
+    def __init__(self, wd, mask, cookie, name):
+        """
+        @param wd: Watch Descriptor.
+        @type wd: int
+        @param mask: Bitmask of events.
+        @type mask: int
+        @param cookie: Cookie.
+        @type cookie: int
+        @param name: Basename of the file or directory against which the
+                     event was raised in case where the watched directory
+                     is the parent directory. None if the event was raised
+                     on the watched item itself.
+        @type name: string or None
+        """
+        # Use this variable to cache the result of str(self), this object
+        # is immutable.
+        self._str = None
+        # name: remove trailing '\0'
+        d = {'wd': wd,
+             'mask': mask,
+             'cookie': cookie,
+             'name': name.rstrip('\0')}
+        _Event.__init__(self, d)
+        logging.debug(str(self))
+
+    def __str__(self):
+        if self._str is None:
+            self._str = _Event.__str__(self)
+        return self._str
+
+
+class Event(_Event):
+    """
+    This class contains all the useful informations about the observed
+    event. However, the presence of each field is not guaranteed and
+    depends on the type of event. In effect, some fields are irrelevant
+    for some kind of event (for example 'cookie' is meaningless for
+    IN_CREATE whereas it is mandatory for IN_MOVE_TO).
+
+    The possible fields are:
+      - wd (int): Watch Descriptor.
+      - mask (int): Mask.
+      - maskname (str): Readable event name.
+      - path (str): path of the file or directory being watched.
+      - name (str): Basename of the file or directory against which the
+              event was raised in case where the watched directory
+              is the parent directory. None if the event was raised
+              on the watched item itself. This field is always provided
+              even if the string is ''.
+      - pathname (str): Concatenation of 'path' and 'name'.
+      - src_pathname (str): Only present for IN_MOVED_TO events and only in
+              the case where IN_MOVED_FROM events are watched too. Holds the
+              source pathname from where pathname was moved from.
+      - cookie (int): Cookie.
+      - dir (bool): True if the event was raised against a directory.
+
+    """
+    def __init__(self, raw):
+        """
+        Concretely, this is the raw event plus inferred infos.
+        """
+        _Event.__init__(self, raw)
+        self.maskname = EventsCodes.maskname(self.mask)
+        if COMPATIBILITY_MODE:
+            self.event_name = self.maskname
+        try:
+            if self.name:
+                self.pathname = os.path.abspath(os.path.join(self.path,
+                                                             self.name))
+            else:
+                self.pathname = os.path.abspath(self.path)
+        except AttributeError, err:
+            # Usually it is not an error some events are perfectly valids
+            # despite the lack of these attributes.
+            logging.debug(err)
+
+
+class ProcessEventError(PyinotifyError):
+    """
+    ProcessEventError Exception. Raised on ProcessEvent error.
+    """
+    def __init__(self, err):
+        """
+        @param err: Exception error description.
+        @type err: string
+        """
+        PyinotifyError.__init__(self, err)
+
+
+class _ProcessEvent:
+    """
+    Abstract processing event class.
+    """
+    def __call__(self, event):
+        """
+        To behave like a functor the object must be callable.
+        This method is a dispatch method. Its lookup order is:
+          1. process_MASKNAME method
+          2. process_FAMILY_NAME method
+          3. otherwise calls process_default
+
+        @param event: Event to be processed.
+        @type event: Event object
+        @return: By convention when used from the ProcessEvent class:
+                 - Returning False or None (default value) means keep on
+                 executing next chained functors (see chain.py example).
+                 - Returning True instead means do not execute next
+                   processing functions.
+        @rtype: bool
+        @raise ProcessEventError: Event object undispatchable,
+                                  unknown event.
+        """
+        stripped_mask = event.mask - (event.mask & IN_ISDIR)
+        maskname = EventsCodes.ALL_VALUES.get(stripped_mask)
+        if maskname is None:
+            raise ProcessEventError("Unknown mask 0x%08x" % stripped_mask)
+
+        # 1- look for process_MASKNAME
+        meth = getattr(self, 'process_' + maskname, None)
+        if meth is not None:
+            return meth(event)
+        # 2- look for process_FAMILY_NAME
+        meth = getattr(self, 'process_IN_' + maskname.split('_')[1], None)
+        if meth is not None:
+            return meth(event)
+        # 3- default call method process_default
+        return self.process_default(event)
+
+    def __repr__(self):
+        return '<%s>' % self.__class__.__name__
+
+
+class ProcessEvent(_ProcessEvent):
+    """
+    Process events objects, can be specialized via subclassing, thus its
+    behavior can be overriden:
+
+    Note: you should not override __init__ in your subclass instead define
+    a my_init() method, this method will be called automatically from the
+    constructor of this class with its optionals parameters.
+
+      1. Provide specialized individual methods, e.g. process_IN_DELETE for
+         processing a precise type of event (e.g. IN_DELETE in this case).
+      2. Or/and provide methods for processing events by 'family', e.g.
+         process_IN_CLOSE method will process both IN_CLOSE_WRITE and
+         IN_CLOSE_NOWRITE events (if process_IN_CLOSE_WRITE and
+         process_IN_CLOSE_NOWRITE aren't defined though).
+      3. Or/and override process_default for catching and processing all
+         the remaining types of events.
+    """
+    pevent = None
+
+    def __init__(self, pevent=None, **kargs):
+        """
+        Enable chaining of ProcessEvent instances.
+
+        @param pevent: Optional callable object, will be called on event
+                       processing (before self).
+        @type pevent: callable
+        @param kargs: This constructor is implemented as a template method
+                      delegating its optionals keyworded arguments to the
+                      method my_init().
+        @type kargs: dict
+        """
+        self.pevent = pevent
+        self.my_init(**kargs)
+
+    def my_init(self, **kargs):
+        """
+        This method is called from ProcessEvent.__init__(). This method is
+        empty here and must be redefined to be useful. In effect, if you
+        need to specifically initialize your subclass' instance then you
+        just have to override this method in your subclass. Then all the
+        keyworded arguments passed to ProcessEvent.__init__() will be
+        transmitted as parameters to this method. Beware you MUST pass
+        keyword arguments though.
+
+        @param kargs: optional delegated arguments from __init__().
+        @type kargs: dict
+        """
+        pass
+
+    def __call__(self, event):
+        stop_chaining = False
+        if self.pevent is not None:
+            # By default methods return None so we set as guideline
+            # that methods asking for stop chaining must explicitely
+            # return non None or non False values, otherwise the default
+            # behavior will be to accept chain call to the corresponding
+            # local method.
+            stop_chaining = self.pevent(event)
+        if not stop_chaining:
+            return _ProcessEvent.__call__(self, event)
+
+    def nested_pevent(self):
+        return self.pevent
+
+    def process_IN_Q_OVERFLOW(self, event):
+        """
+        By default this method only reports warning messages, you can
+        overredide it by subclassing ProcessEvent and implement your own
+        process_IN_Q_OVERFLOW method. The actions you can take on receiving
+        this event is either to update the variable max_queued_events in order
+        to handle more simultaneous events or to modify your code in order to
+        accomplish a better filtering diminishing the number of raised events.
+        Because this method is defined, IN_Q_OVERFLOW will never get
+        transmitted as arguments to process_default calls.
+
+        @param event: IN_Q_OVERFLOW event.
+        @type event: dict
+        """
+        logging.warning('Event queue overflowed.')
+
+    def process_default(self, event):
+        """
+        Default processing event method. By default does nothing. Subclass
+        ProcessEvent and redefine this method in order to modify its behavior.
+
+        @param event: Event to be processed. Can be of any type of events but
+                      IN_Q_OVERFLOW events (see method process_IN_Q_OVERFLOW).
+        @type event: Event instance
+        """
+        pass
+
+
+class PrintAllEvents(ProcessEvent):
+    """
+    Dummy class used to print events strings representations. For instance this
+    class is used from command line to print all received events to stdout.
+    """
+    def my_init(self, out=None):
+        """
+        @param out: Where events will be written.
+        @type out: Object providing a valid file object interface.
+        """
+        if out is None:
+            out = sys.stdout
+        self._out = out
+
+    def process_default(self, event):
+        """
+        Writes event string representation to file object provided to
+        my_init().
+
+        @param event: Event to be processed. Can be of any type of events but
+                      IN_Q_OVERFLOW events (see method process_IN_Q_OVERFLOW).
+        @type event: Event instance
+        """
+        self._out.write(str(event))
+        self._out.write('\n')
+        self._out.flush()
+
+
+class WatchManagerError(Exception):
+    """
+    WatchManager Exception. Raised on error encountered on watches
+    operations.
+
+    """
+    def __init__(self, msg, wmd):
+        """
+        @param msg: Exception string's description.
+        @type msg: string
+        @param wmd: This dictionary contains the wd assigned to paths of the
+                    same call for which watches were successfully added.
+        @type wmd: dict
+        """
+        self.wmd = wmd
+        Exception.__init__(self, msg)