blob: 218020b5c6844ca9bbe4483623e798c6c7118da0 [file] [log] [blame]
#!/usr/bin/env python3
#
# Copyright (c) 2015 Apple Inc. All rights reserved.
# Copyright (c) 2009 Google Inc. All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
# THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
# BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
# THE POSSIBILITY OF SUCH DAMAGE.
# A writer that only updates file if it actually changed.
import os
class LazyFileWriter:
def __init__(self, filepath, force_output):
self._filepath = filepath
self._output = ""
self.force_output = force_output
def write(self, text):
self._output += text
def close(self):
text_changed = True
self._output = self._output.rstrip() + "\n"
try:
if self.force_output:
raise
read_file = open(self._filepath, "r")
old_text = read_file.read()
read_file.close()
text_changed = old_text != self._output
except:
# Ignore, just overwrite by default
pass
if text_changed or self.force_output:
dirname = os.path.dirname(self._filepath)
if not os.path.isdir(dirname):
os.makedirs(dirname)
out_file = open(self._filepath, "w")
out_file.write(self._output)
out_file.close()