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#!/usr/bin/env python
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# Copyright 2011-2012 GRNET S.A. All rights reserved.
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#
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# Redistribution and use in source and binary forms, with or
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# without modification, are permitted provided that the following
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# conditions are met:
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#
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#   1. Redistributions of source code must retain the above
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#      copyright notice, this list of conditions and the following
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#      disclaimer.
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#
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#   2. Redistributions in binary form must reproduce the above
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#      copyright notice, this list of conditions and the following
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#      disclaimer in the documentation and/or other materials
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#      provided with the distribution.
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#
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# THIS SOFTWARE IS PROVIDED BY GRNET S.A. ``AS IS'' AND ANY EXPRESS
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# OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL GRNET S.A OR
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# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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# USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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# AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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# POSSIBILITY OF SUCH DAMAGE.
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#
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# The views and conclusions contained in the software and
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# documentation are those of the authors and should not be
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# interpreted as representing official policies, either expressed
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# or implied, of GRNET S.A.
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from sqlalchemy import create_engine
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from sqlalchemy import Table, Column, String, MetaData
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from sqlalchemy.sql import select
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from django.conf import settings
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from pithos.backends.modular import ModularBackend
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class Migration(object):
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    def __init__(self, db):
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        self.engine = create_engine(db)
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        self.metadata = MetaData(self.engine)
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        #self.engine.echo = True
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        self.conn = self.engine.connect()
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        options = getattr(settings, 'BACKEND', None)[1]
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        self.backend = ModularBackend(*options)
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    def execute(self):
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        pass
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class Cache():
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    def __init__(self, db):
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        self.engine = create_engine(db)
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        metadata = MetaData(self.engine)
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        columns = []
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        columns.append(Column('path', String(2048), primary_key=True))
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        columns.append(Column('hash', String(255)))
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        self.files = Table('files', metadata, *columns)
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        self.conn = self.engine.connect()
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        self.engine.echo = True
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        metadata.create_all(self.engine)
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    def put(self, path, hash):
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        # Insert or replace.
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        s = self.files.delete().where(self.files.c.path == path)
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        r = self.conn.execute(s)
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        r.close()
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        s = self.files.insert()
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        r = self.conn.execute(s, {'path': path, 'hash': hash})
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        r.close()
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    def get(self, path):
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        s = select([self.files.c.hash], self.files.c.path == path)
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        r = self.conn.execute(s)
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        l = r.fetchone()
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        r.close()
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        if not l:
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            return l
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        return l[0]