Issue #22826: The result of open() in Tools/freeze/bkfile.py is now better

compatible with regular files (in particular it now supports the context
management protocol).

1 files changed, 22 insertions, 45 deletions

diff --git a/Tools/freeze/bkfile.py b/Tools/freeze/bkfile.py
index 6abacc9..20a70b0 100644
--- a/Tools/freeze/bkfile.py
+++ b/Tools/freeze/bkfile.py
@@ -1,49 +1,26 @@
 from builtins import open as _orig_open
 
-class _BkFile:
-    def __init__(self, file, mode, bufsize):
-        import os
-        self.__filename = file
-        self.__backup = file + '~'
-        try:
-            os.unlink(self.__backup)
-        except OSError:
-            pass
-        try:
-            os.rename(file, self.__backup)
-        except OSError:
-            self.__backup = None
-        self.__file = _orig_open(file, mode, bufsize)
-        self.closed = self.__file.closed
-        self.fileno = self.__file.fileno
-        self.flush = self.__file.flush
-        self.isatty = self.__file.isatty
-        self.mode = self.__file.mode
-        self.name = self.__file.name
-        self.read = self.__file.read
-        try:
-            self.readinto = self.__file.readinto
-        except AttributeError:
-            pass
-        self.readline = self.__file.readline
-        self.readlines = self.__file.readlines
-        self.seek = self.__file.seek
-        self.tell = self.__file.tell
-        self.truncate = self.__file.truncate
-        self.write = self.__file.write
-        self.writelines = self.__file.writelines
-
-    def close(self):
-        self.__file.close()
-        if self.__backup is None:
-            return
-        import filecmp
-        if filecmp.cmp(self.__backup, self.__filename, shallow = 0):
-            import os
-            os.unlink(self.__filename)
-            os.rename(self.__backup, self.__filename)
-
-def open(file, mode = 'r', bufsize = -1):
+def open(file, mode='r', bufsize=-1):
     if 'w' not in mode:
         return _orig_open(file, mode, bufsize)
-    return _BkFile(file, mode, bufsize)
+    import os
+    backup = file + '~'
+    try:
+        os.unlink(backup)
+    except OSError:
+        pass
+    try:
+        os.rename(file, backup)
+    except OSError:
+        return _orig_open(file, mode, bufsize)
+    f = _orig_open(file, mode, bufsize)
+    _orig_close = f.close
+    def close():
+        _orig_close()
+        import filecmp
+        if filecmp.cmp(backup, file, shallow=False):
+            import os
+            os.unlink(file)
+            os.rename(backup, file)
+    f.close = close
+    return f