dupeguru/base/py/ignore.py

# Created By: Virgil Dupras
# Created On: 2006/05/02
# $Id$
# Copyright 2009 Hardcoded Software (http://www.hardcoded.net)
# 
# This software is licensed under the "HS" License as described in the "LICENSE" file, 
# which should be included with this package. The terms are also available at 
# http://www.hardcoded.net/licenses/hs_license

from hsutil.files import FileOrPath

import xml.dom.minidom

class IgnoreList(object):
    """An ignore list implementation that is iterable, filterable and exportable to XML.
    
    Call Ignore to add an ignore list entry, and AreIgnore to check if 2 items are in the list.
    When iterated, 2 sized tuples will be returned, the tuples containing 2 items ignored together.
    """
    #---Override
    def __init__(self):
        self._ignored = {}
        self._count = 0
    
    def __iter__(self):
        for first,seconds in self._ignored.iteritems():
            for second in seconds:
                yield (first,second)
    
    def __len__(self):
        return self._count
    
    #---Public
    def AreIgnored(self,first,second):
        def do_check(first,second):
            try:
                matches = self._ignored[first]
                return second in matches
            except KeyError:
                return False
        
        return do_check(first,second) or do_check(second,first)
    
    def Clear(self):
        self._ignored = {}
        self._count = 0
    
    def Filter(self,func):
        """Applies a filter on all ignored items, and remove all matches where func(first,second)
        doesn't return True.
        """
        filtered = IgnoreList()
        for first,second in self:
            if func(first,second):
                filtered.Ignore(first,second)
        self._ignored = filtered._ignored
        self._count = filtered._count
    
    def Ignore(self,first,second):
        if self.AreIgnored(first,second):
            return
        try:
            matches = self._ignored[first]
            matches.add(second)
        except KeyError:
            try:
                matches = self._ignored[second]
                matches.add(first)
            except KeyError:
                matches = set()
                matches.add(second)
                self._ignored[first] = matches
        self._count += 1
    
    def load_from_xml(self,infile):
        """Loads the ignore list from a XML created with save_to_xml.
        
        infile can be a file object or a filename.
        """
        try:
            doc = xml.dom.minidom.parse(infile)
        except Exception:
            return
        file_nodes = doc.getElementsByTagName('file')
        for fn in file_nodes:
            if not fn.getAttributeNode('path'):
                continue
            file_path = fn.getAttributeNode('path').nodeValue
            subfile_nodes = fn.getElementsByTagName('file')
            for sfn in subfile_nodes:
                if not sfn.getAttributeNode('path'):
                    continue
                subfile_path = sfn.getAttributeNode('path').nodeValue
                self.Ignore(file_path,subfile_path)
    
    def save_to_xml(self,outfile):
        """Create a XML file that can be used by load_from_xml.
        
        outfile can be a file object or a filename.
        """
        doc = xml.dom.minidom.Document()
        root = doc.appendChild(doc.createElement('ignore_list'))
        for file,subfiles in self._ignored.items():
            file_node = root.appendChild(doc.createElement('file'))
            if isinstance(file,unicode):
                file = file.encode('utf-8')
            file_node.setAttribute('path',file)
            for subfile in subfiles:
                subfile_node = file_node.appendChild(doc.createElement('file'))
                if isinstance(subfile,unicode):
                    subfile = subfile.encode('utf-8')
                subfile_node.setAttribute('path',subfile)
        with FileOrPath(outfile, 'wb') as fp:
            doc.writexml(fp,'\t','\t','\n',encoding='utf-8')