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#!/usr/bin/env python
#
#   Library:    pyflowctrl
#   Module:     treewalker2
#   Dependency:    core3
#   Examples:   
#

import os
from core3 import WAITING, PROCESSING
from core3 import EmptyStream, Stream, Process

class TreeWalker(Process):
    ''' Tree Walker '''
    def __init__(self):
        ''' __init__  '''
        super(TreeWalker, self).__init__()
        self.io = { 
            # directory_path - source directory
            'input': Stream(data_type='path'),
            # name      - filename or directory name
            'output': Stream(data_type='path'),
        }
        
    def __walktree(self, top):
        """ Directory walker """
        names = os.listdir(top)
        for name in names:
            if os.path.isdir(os.path.join(top, name)):
                for (newtop, children) in self.__walktree(os.path.join(top, name)):
                    yield newtop, children
        yield top, names

    def main(self):
        while True:
            try:
                path = self.io['input'].get()
            except EmptyStream:
                yield WAITING
                continue
                
            if not os.path.exists(path):
                raise IOError("%s does not exist" % path)
            self.io['output'].put(path)
            for path, names in self.__walktree(path):
                for name in names:
                    self.io['output'].put(os.path.join(path, name))
                    yield PROCESSING