src/scripts/utilities.py

   1 from filecmp import dircmp
   2 from hashlib import sha256
   3 from io import StringIO
   4 import shutil
   5 import os
   6
   7 class WrappedStringIO(StringIO):
   8     """A wrapper around StringIO to allow writing str objects"""
   9     def write(self, s):
  10         if isinstance(s, str):
  11             s = unicode(s)
  12         super(WrappedStringIO, self).write(s)
  13
  14 class UpdateFileWriter:
  15     """A file-like context object which will only write to a file if the result would be different
  16
  17     Attributes:
  18         filename (str): The name of the file to update
  19         stream (WrappedStringIO): The file-like stream provided upon context enter
  20
  21     Args:
  22         filename (str): Sets the filename attribute
  23     """
  24     filemode = 'w'
  25
  26     def __init__(self, filename):
  27         self.filename = filename
  28         self.stream = None
  29
  30     def __enter__(self):
  31         self.stream = WrappedStringIO()
  32         return self.stream
  33
  34     def __exit__(self, exc_type, exc_value, traceback):
  35         if exc_value is None:
  36             new_content = self.stream.getvalue()
  37             new_hash = sha256()
  38             cur_hash = sha256()
  39
  40             try:
  41                 with open(self.filename, 'r') as fstream:
  42                     cur_hash.update(fstream.read())
  43                 file_found = True
  44             except IOError:
  45                 file_found = False
  46
  47             if file_found:
  48                 new_hash.update(new_content)
  49                 update = new_hash.digest() != cur_hash.digest()
  50             else:
  51                 update = True
  52
  53             if update:
  54                 with open(self.filename, 'w') as fstream:
  55                     fstream.write(new_content)
  56
  57         self.stream.close()
  58
  59 def open_for_update(filename):
  60     return UpdateFileWriter(filename)
  61
  62 def walk_recursively_and_update(dcmp):
  63     #for different Files Copy from right to left
  64     for name in dcmp.diff_files:
  65         srcpath = dcmp.right + "/" + name
  66         destpath = dcmp.left + "/" + name
  67         print("Updating %s" % (destpath))
  68         if  os.path.isfile(srcpath):
  69             shutil.copyfile(srcpath, destpath)
  70         else :
  71             raise Exception("path: " + srcpath + "is neither a file or folder")
  72
  73     #copy right only files
  74     for name in dcmp.right_only:
  75         srcpath = dcmp.right + "/" + name
  76         destpath = dcmp.left + "/" + name
  77         print("Updating %s" % (destpath))
  78         if  os.path.isfile(srcpath):
  79             shutil.copyfile(srcpath, destpath)
  80         elif  os.path.isdir(srcpath):
  81             shutil.copytree(srcpath, destpath)
  82         else :
  83             raise Exception("path: " + srcpath + "is neither a file or folder")
  84
  85     #delete left only files
  86     for name in dcmp.left_only:
  87         path = dcmp.left + "/" + name
  88         print("Deleting %s" % (path))
  89         if  os.path.isfile(path):
  90             os.remove(path)
  91         elif  os.path.isdir(path):
  92             shutil.rmtree(path)
  93         else :
  94             raise Exception("path: " + path + "is neither a file or folder")
  95
  96     #call recursively
  97     for sub_dcmp in dcmp.subdirs.values():
  98         walk_recursively_and_update(sub_dcmp)
  99
 100 def UpdateDirectory(destpath,srcpath):
 101
 102     print("Updating %s with %s" % (destpath,srcpath))
 103     if not os.path.exists(destpath):
 104         os.makedirs(destpath)
 105     dcmp = dircmp(destpath,srcpath)
 106     walk_recursively_and_update(dcmp)