# Copyright 2013, Couchbase, Inc.

# All Rights Reserved

#

# 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.

"""

This file contains various utility classes for scheduling

and destroying events

"""

class EventQueue(object):

def __init__(self):

self.called = False

self.waiters = []

def fire_async(self, event):

"""

Fire this event 'immediately', but in the next event iteration

"""

def maybe_raise(self, *args, **kwargs):

"""

Given the arguments from '__call__', see if we should raise an error

"""

def call_single_success(self, event, *args, **kwargs):

"""

Call a single event with success

"""

def call_single_failure(self, event, *args, **kwargs):

"""

Call a single event with a failure. This will be from within

the 'except' block and thus will have sys.exc_info() available

"""

def schedule(self, event):

if self.called:

self.fire_async(event)

return

self.waiters.append(event)

def __hash__(self):

return hash(self.name)

def __len__(self):

return len(self.waiters)

def __iter__(self):

return iter(self.waiters)

def invoke_waiters(self, *args, **kwargs):

self.called = True

try:

self.maybe_raise(*args, **kwargs)

for event in self.waiters:

try:

self.call_single_success(event, *args, **kwargs)

except:

pass

except:

for event in self.waiters:

try:

self.call_single_failure(event, event, *args, **kwargs)

except Exception as e:

pass

self.waiters = None

def __call__(self, *args, **kwargs):

self.invoke_waiters(*args, **kwargs)