import cPickle
import shelve
import conf
import last

class Data:
    """Data file management."""

    def load(self):
        """Load from data file. 
        
        Last books list, show_license, version; store in local vars.
        """

        sh = shelve.open(conf.datafile)
        try:
            self.version      = sh["version"]
            self.show_license = sh["show_license"]
            self.last_list   = sh["last"]
        except KeyError:
            self.version      = conf.__version__
            self.show_license = 1
            self.last_list    = []

        if self.version != conf.__version__:
            print """
            Datafile %s is from an older version of PyBook; if
            you get strange errors, delete it and run PyBook again.
            """ % conf.datafile
        self.booklist = cPickle.load(open(conf.booklist))

    def save(self):
        """Write data file: version, show_license, last booklist
        booklist."""

        sh = shelve.open(conf.datafile)
        sh["version"]      = conf.__version__
        sh["show_license"] = self.show_license
        sh["last"]         = last.lst
        sh.close()

# vim: sts=4:ts=8:et:sw=4