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Viewing changes to bzrlib/atomicfile.py

  • Committer: Martin Pool
  • Date: 2005-05-12 02:19:09 UTC
  • Revision ID: mbp@sourcefrog.net-20050512021909-acb201f8ffc52b41
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bzrlib/atomicfile.py
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from warnings import warn
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class AtomicFile(object):
 
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class AtomicFile:
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    """A file that does an atomic-rename to move into place.
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    This also causes hardlinks to break when it's written out.
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                                             socket.gethostname())
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        self.realfilename = filename
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        self.f = open(self.tmpfilename, mode)
 
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        if encoding:
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            import codecs
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            self.f = codecs.open(self.tmpfilename, mode, encoding)
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        else:
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            self.f = open(self.tmpfilename, mode)
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            self.f = codecs.EncodedFile(self.f, encoding)
 
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        self.write = self.f.write
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        self.closed = False
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    def __repr__(self):
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        return '%s(%r)' % (self.__class__.__name__,
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                           self.realfilename)
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        self.closed = property(self.f.closed)
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    def commit(self):
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        """Close the file and move to final name."""
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        import sys, os
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        if self.closed:
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            raise Exception('%r is already closed' % self)
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        self.closed = True
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        self.f.close()
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        self.f = None
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        if sys.platform == 'win32':
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            # windows cannot rename over an existing file
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            try:
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                os.remove(self.realfilename)
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            except OSError, e:
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                import errno
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                if e.errno != errno.ENOENT:
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                    raise
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            os.remove(self.realfilename)
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        os.rename(self.tmpfilename, self.realfilename)
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    def abort(self):
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        """Discard temporary file without committing changes."""
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        import os
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        if self.closed:
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            raise Exception('%r is already closed' % self)
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        self.closed = True
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        self.f.close()
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        self.f = None
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        os.remove(self.tmpfilename)
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    def close(self):
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        """Discard the file unless already committed."""
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        if not self.closed:
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            self.abort()
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    def __del__(self):
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        if not self.closed:
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            warn("%r leaked" % self)
 
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