harddata.py

#!/usr/bin/python
# -*- coding: utf-8 -*-
#    ******  The Cloud Toolbox v0.1.2******
#    This is the cloud toolbox -- a single module used in several packages
#    found at <https://github.com/cloudformdesign>
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#
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#    Copyright (c) 2013 Garrett Berg cloudformdesign.com
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#    <https://github.com/cloudformdesign/cloudtb>
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import time
import math
import cPickle

import tempfiles

import logtools
logtools.setup_logger(logtools.logging.DEBUG)
LOG = logtools.get_logger(__name__)

def harddata_base(object):
    MIN_KEEP_TIME = 0.5
    def __init__(self, data):
        self._data = data
        self._last_accessed = time.time()
        self._access_counter = 1
        self._THREAD_hold = False
        self._datafile = None        
        self._get_tempfile()
    
    def _get_tempfile(self):
        assert(self._datafile == None)
        self._datafile = tempfiles.get_temp_file()
    
    def _getdata(self):
        '''The primary magic that stores the data'''
        # TODO: need to figure out how threading works here with
        # data stuff. Can't have them fighting        
        self._last_accessed = time.time()
        self._access_counter += 1
        try:
            return self._data
        except AttributeError:
            self._data = self._load_data()
            return self._data
    
    def _load_data(self):
        '''loads the data from temp file'''
        self._data = cPickle.load(self._datafile)        
        
    def _store_data(self):
        '''Stores the data. Hasn't been accessed for a while'''
        self._access_counter = 0
        cPickle.dump(self._data, self._datafile, 
                     protocol = cPickle.HIGHEST_PROTOCOL)
        del self._data
        
    def _check(self):
        '''checks to see if it's data needs to be stored'''
        # TODO: Threading stuff, how to request lock?
        now = time.time()
        sroot = int(math.sqrt(self._access_counter)) + 1
        self._access_counter = sroot
        if now - self._last_accessed < self.MIN_KEEP_TIME:
            return
        
        if sroot > 100:
            return
        else:
            self._store_data()