patch.py

   1 import re
   2 import sys
   3 import os.path
   4
   5 import db
   6 import dbcache
   7 from git import git
   8
   9 _boundary_line_regex = re.compile(r'^---')
  10 _diff_head_regex = re.compile(r'^diff --git a/(.*) b/(.*)$')
  11 _index_line_regex = re.compile(r'^index ([a-f0-9]{7,})\.\.([a-f0-9]{7,}) ')
  12 _all_zeros_regex = re.compile(r'^0+$')
  13
  14 class PatchError(Exception):
  15     pass
  16
  17 class Patch(object):
  18
  19     def __init__(self, data):
  20         self.blobs_pre = set()
  21         self.blobs_post = set()
  22         self.missing_files = False
  23         self.data = data
  24         self.notes = None
  25         self._parse(data)
  26
  27     def _parse(self, data):
  28         boundary_seen = False
  29         diff_seen = False
  30         filename = None
  31         notes = []
  32         for line in data.splitlines(True):
  33             if _boundary_line_regex.match(line):
  34                 boundary_seen = True
  35                 continue
  36             m = _diff_head_regex.match(line)
  37             if m:
  38                 diff_seen = True
  39                 # at least the 'pre' filename should exist
  40                 filename = m.group(1)
  41                 continue
  42             if diff_seen:
  43                 m = _index_line_regex.match(line)
  44                 if m:
  45                     if not _all_zeros_regex.match(m.group(1)):
  46                         self.blobs_pre.add(m.group(1))
  47                         self._check_file(filename)
  48                     self.blobs_post.add(m.group(2))
  49                 continue
  50             if boundary_seen:
  51                 notes.append(line)
  52         if diff_seen:
  53             self.notes = ''.join(notes)
  54
  55     def _check_file(self, name):
  56         if os.path.basename(name) not in dbcache.file_cache:
  57             self.missing_files = True
  58             print 'patch for missing file "%s"' % name
  59
  60     def apply(self):
  61         output, ret = git('am', input=self.data)
  62         if ret != 0:
  63             # clean up
  64             git('am', '--abort')
  65             git('reset', '--hard')
  66             raise PatchError()
  67         return output