| # Copyright Bruno da Silva de Oliveira 2003. Use, modification and |
| # distribution is subject to the Boost Software License, Version 1.0. |
| # (See accompanying file LICENSE_1_0.txt or copy at |
| # http://www.boost.org/LICENSE_1_0.txt) |
| |
| import os |
| import md5 |
| |
| #============================================================================== |
| # SmartFile |
| #============================================================================== |
| class SmartFile(object): |
| ''' |
| A file-like object used for writing files. The given file will only be |
| actually written to disk if there's not a file with the same name, or if |
| the existing file is *different* from the file to be written. |
| ''' |
| |
| def __init__(self, filename, mode='w'): |
| self.filename = filename |
| self.mode = mode |
| self._contents = [] |
| self._closed = False |
| |
| |
| def __del__(self): |
| if not self._closed: |
| self.close() |
| |
| |
| def write(self, string): |
| self._contents.append(string) |
| |
| |
| def _dowrite(self, contents): |
| f = file(self.filename, self.mode) |
| f.write(contents) |
| f.close() |
| |
| |
| def _GetMD5(self, string): |
| return md5.new(string).digest() |
| |
| |
| def close(self): |
| # if the filename doesn't exist, write the file right away |
| this_contents = ''.join(self._contents) |
| if not os.path.isfile(self.filename): |
| self._dowrite(this_contents) |
| else: |
| # read the contents of the file already in disk |
| f = file(self.filename) |
| other_contents = f.read() |
| f.close() |
| # test the md5 for both files |
| this_md5 = self._GetMD5(this_contents) |
| other_md5 = self._GetMD5(other_contents) |
| if this_md5 != other_md5: |
| self._dowrite(this_contents) |
| self._closed = True |
