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# This file is part of Buildbot.  Buildbot 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, version 2. 

# 

# 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, write to the Free Software Foundation, Inc., 51 

# Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. 

# 

# Copyright Buildbot Team Members 

 

""" 

Miscellaneous utilities; these should be imported from C{buildbot.util}, not 

directly from this module. 

""" 

 

from twisted.python import log 

from twisted.internet import defer 

 

def deferredLocked(lock_or_attr): 

    def decorator(fn): 

        def wrapper(*args, **kwargs): 

            lock = lock_or_attr 

            if isinstance(lock, basestring): 

                lock = getattr(args[0], lock) 

            d = lock.acquire() 

            d.addCallback(lambda _ : fn(*args, **kwargs)) 

            def release(val): 

                lock.release() 

                return val 

            d.addBoth(release) 

            return d 

        return wrapper 

    return decorator 

 

class SerializedInvocation(object): 

    def __init__(self, method): 

        self.method = method 

        self.running = False 

        self.pending_deferreds = [] 

 

    def __call__(self): 

        d = defer.Deferred() 

        self.pending_deferreds.append(d) 

        if not self.running: 

            self.start() 

        return d 

 

    def start(self): 

        self.running = True 

        invocation_deferreds = self.pending_deferreds 

        self.pending_deferreds = [] 

        d = self.method() 

        d.addErrback(log.err, 'in invocation of %r' % (self.method,)) 

 

        def notify_callers(_): 

            for d in invocation_deferreds: 

                d.callback(None) 

        d.addCallback(notify_callers) 

 

        def next(_): 

            self.running = False 

            if self.pending_deferreds: 

                self.start() 

            else: 

                self._quiet() 

        d.addBoth(next) 

 

    def _quiet(self): # hook for tests 

        pass