From e5f5a2ab23ace19c6de39512f76f8fed5f5ad912 Mon Sep 17 00:00:00 2001
From: Guido Guenther <agx@sigxcpu.org>
Date: Thu, 23 Aug 2007 15:47:20 +0200
Subject: Imported upstream version 0.6.21

---
 lib/SafeWriteFile.py | 81 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 81 insertions(+)
 create mode 100755 lib/SafeWriteFile.py

(limited to 'lib/SafeWriteFile.py')

diff --git a/lib/SafeWriteFile.py b/lib/SafeWriteFile.py
new file mode 100755
index 0000000..1777d36
--- /dev/null
+++ b/lib/SafeWriteFile.py
@@ -0,0 +1,81 @@
+# SafeWriteFile.py
+#
+# This file is a writable file object.  It writes to a specified newname,
+# and when closed, renames the file to the realname.  If the object is
+# deleted, without being closed, this rename isn't done.  If abort() is
+# called, it also disables the rename.
+#
+# Copyright 2001 Adam Heath <doogie@debian.org>
+#
+# This file is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+
+from types import StringType
+from shutil import copy2
+from string import find
+from os import rename
+
+class ObjectNotAllowed(Exception):
+    pass
+
+
+class InvalidMode(Exception):
+    pass
+
+
+class SafeWriteFile:
+    def __init__(self, newname, realname, mode="w", bufsize=-1):
+
+        if type(newname)!=StringType:
+            raise ObjectNotAllowed(newname)
+        if type(realname)!=StringType:
+            raise ObjectNotAllowed(realname)
+
+        if find(mode, "r")>=0:
+            raise InvalidMode(mode)
+        if find(mode, "a")>=0 or find(mode, "+") >= 0:
+            copy2(realname, newname)
+        self.fobj=open(newname, mode, bufsize)
+        self.newname=newname
+        self.realname=realname
+        self.__abort=0
+
+    def close(self):
+        self.fobj.close()
+        if not (self.closed and self.__abort):
+            rename(self.newname, self.realname)
+
+    def abort(self):
+        self.__abort=1
+
+    def __del__(self):
+        self.abort()
+        del self.fobj
+
+    def __getattr__(self, attr):
+        try:
+            return self.__dict__[attr]
+        except:
+            return eval("self.fobj." + attr)
+
+
+if __name__ == "__main__":
+    import time
+    f=SafeWriteFile("sf.new", "sf.data")
+    f.write("test\n")
+    f.flush()
+    time.sleep(1)
+    f.close()
+
+# vim:ts=4:sw=4:et:
-- 
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