mirror of
https://github.com/python/cpython.git
synced 2025-11-04 07:31:38 +00:00
044e8d866f
Frozen modules must be added to several files in order to work properly. Before this change this had to be done manually. Here we add a tool to generate the relevant lines in those files instead. This helps us avoid mistakes and omissions. https://bugs.python.org/issue45019
52 lines
1.5 KiB
Python
52 lines
1.5 KiB
Python
"""
|
|
A script that replaces an old file with a new one, only if the contents
|
|
actually changed. If not, the new file is simply deleted.
|
|
|
|
This avoids wholesale rebuilds when a code (re)generation phase does not
|
|
actually change the in-tree generated code.
|
|
"""
|
|
|
|
import contextlib
|
|
import os
|
|
import os.path
|
|
import sys
|
|
|
|
|
|
@contextlib.contextmanager
|
|
def updating_file_with_tmpfile(filename, tmpfile=None):
|
|
"""A context manager for updating a file via a temp file.
|
|
|
|
The context manager provides two open files: the source file open
|
|
for reading, and the temp file, open for writing.
|
|
|
|
Upon exiting: both files are closed, and the source file is replaced
|
|
with the temp file.
|
|
"""
|
|
# XXX Optionally use tempfile.TemporaryFile?
|
|
if not tmpfile:
|
|
tmpfile = filename + '.tmp'
|
|
elif os.path.isdir(tmpfile):
|
|
tmpfile = os.path.join(tmpfile, filename + '.tmp')
|
|
|
|
with open(tmpfile, 'w') as outfile:
|
|
with open(filename) as infile:
|
|
yield infile, outfile
|
|
update_file_with_tmpfile(filename, tmpfile)
|
|
|
|
|
|
def update_file_with_tmpfile(filename, tmpfile):
|
|
with open(filename, 'rb') as f:
|
|
old_contents = f.read()
|
|
with open(tmpfile, 'rb') as f:
|
|
new_contents = f.read()
|
|
if old_contents != new_contents:
|
|
os.replace(tmpfile, filename)
|
|
else:
|
|
os.unlink(tmpfile)
|
|
|
|
|
|
if __name__ == '__main__':
|
|
if len(sys.argv) != 3:
|
|
print("Usage: %s <path to be updated> <path with new contents>" % (sys.argv[0],))
|
|
sys.exit(1)
|
|
update_file_with_tmpfile(sys.argv[1], sys.argv[2])
|