imgdiff/trivial.py

   1 """This module provides classes to deal with
   2 unimportant difference in diff result.
   3 """
   4 import os
   5 import re
   6 import json
   7 import fnmatch
   8
   9
  10 class Conf(dict):
  11     """
  12     Configuration defining unimportant difference
  13     """
  14
  15     @classmethod
  16     def load(cls, filename):
  17         "Load config from file"
  18         with open(filename) as reader:
  19             txt = reader.read()
  20         txt.replace(os.linesep, '')
  21         data = json.loads(txt)
  22         return cls(data)
  23
  24
  25 class Rules(object):
  26     """
  27     Unimportant rules
  28     """
  29     def __init__(self, conf):
  30         self._rules = self._compile(conf)
  31
  32     def check_and_mark(self, item):
  33         """Check if there are unimportant differences in item.
  34         Mark them as ignore
  35         """
  36         for matcher, rule in self._rules:
  37             if matcher(item['filename']):
  38                 rule(item)
  39                 break
  40
  41     @staticmethod
  42     def _compile(conf):
  43         """Compile config item to matching rules
  44         """
  45         def new_matcher(pattern):
  46             """Supported file name pattern like:
  47             *.log
  48             partition_tab.txt
  49             /tmp/a.txt
  50             /dev/
  51             some/file.txt
  52             """
  53             if pattern.endswith(os.path.sep):  # direcotry name
  54                 pattern = pattern + '*'
  55
  56             bname = os.path.basename(pattern)
  57             if bname == pattern:  # only basename, ignore dirname
  58                 def matcher(filename):
  59                     "Matcher"
  60                     return fnmatch.fnmatch(os.path.basename(filename), pattern)
  61             else:
  62                 def matcher(filename):
  63                     "Matcher"
  64                     return fnmatch.fnmatch(filename, pattern)
  65
  66             matcher.__docstring__ = 'Match filename with pattern %s' % pattern
  67             return matcher
  68
  69         rules = []
  70         for pat in conf.get('ignoreFiles', []):
  71             matcher = new_matcher(pat)
  72             rules.append((matcher, ignore_file))
  73
  74         for entry in conf.get('ignoreLines', []):
  75             files = entry['Files']
  76             lines = entry['Lines']
  77             if isinstance(files, basestring):
  78                 files = [files]
  79             if isinstance(lines, basestring):
  80                 lines = [lines]
  81             ignore = IgnoreLines(lines)
  82             for pat in files:
  83                 matcher = new_matcher(pat)
  84                 rules.append((matcher, ignore))
  85
  86         return rules
  87
  88
  89 def ignore_file(onefile):
  90     """Mark whole file as trivial difference
  91     """
  92     onefile['ignore'] = True
  93
  94
  95 class IgnoreLines(object):
  96     """Mark certain lines in a file as trivial
  97     differences according to given patterns
  98     """
  99     def __init__(self, patterns):
 100         self.patterns = [re.compile(p) for p in patterns]
 101
 102     def is_unimportant(self, line):
 103         "Is this line trivial"
 104         for pat in self.patterns:
 105             if pat.match(line['text']):
 106                 return True
 107
 108     def __call__(self, onefile):
 109         "Mark lines as trivial"
 110         if onefile['type'] != 'onefilediff':
 111             return
 112
 113         def should_ignore(line):
 114             "Is this line trivial"
 115             if line['type'] in ('insert', 'delete'):
 116                 return self.is_unimportant(line)
 117             # else: context, no_newline_at_eof
 118             return True
 119
 120         all_ignored = True
 121         for section in onefile['sections']:
 122             for line in section['hunks']:
 123                 line['ignore'] = should_ignore(line)
 124                 all_ignored = all_ignored and line['ignore']
 125
 126         # if all lines are unimportant then the whole file is unimportant
 127         if all_ignored:
 128             onefile['ignore'] = True