# Utilities for combining multiple module source files
# into one.

from xml.dom import minidom
from swordutils.xml import utils

class LazyNodes(object):
    # Pulling all the documents in at once uses up too much memory.
    # This class is responsible for acting as a replacement
    # 'childNodes' which loads documents one at a time,
    # does corrections on them and spews out the body nodes
    def __init__(self, maindoc, files, alterationfunc, nodepath):
        self.maindoc = maindoc # Don't actually need this
        self.files = files
        self.iterated_count = 0
        self.nodepath = nodepath
        self.alterationfunc = alterationfunc

    def __iter__(self):
        self.iterated_count += 1
        if self.iterated_count == 2:
            # We've got a big performance bug if this happens.
            raise Exception('Performance bug')
        for f in self.files:
            doc = minidom.parse(f)
            self.alterationfunc(doc)     
            body = utils.getNodesFromXPath(doc, self.nodepath)[0]
            for n in body.childNodes:
                yield n