1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/xpcom/io/nsISafeOutputStream.idl Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,39 @@
1.4 +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
1.5 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.6 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.7 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.8 +
1.9 +#include "nsISupports.idl"
1.10 +
1.11 +/**
1.12 + * This interface provides a mechanism to control an output stream
1.13 + * that takes care not to overwrite an existing target until it is known
1.14 + * that all writes to the destination succeeded.
1.15 + *
1.16 + * An object that supports this interface is intended to also support
1.17 + * nsIOutputStream.
1.18 + *
1.19 + * For example, a file output stream that supports this interface writes to
1.20 + * a temporary file, and moves it over the original file when |finish| is
1.21 + * called only if the stream can be successfully closed and all writes
1.22 + * succeeded. If |finish| is called but something went wrong during
1.23 + * writing, it will delete the temporary file and not touch the original.
1.24 + * If the stream is closed by calling |close| directly, or the stream
1.25 + * goes away, the original file will not be overwritten, and the temporary
1.26 + * file will be deleted.
1.27 + *
1.28 + * Currently, this interface is implemented only for file output streams.
1.29 + */
1.30 +[scriptable, uuid(5f914307-5c34-4e1f-8e32-ec749d25b27a)]
1.31 +interface nsISafeOutputStream : nsISupports
1.32 +{
1.33 + /**
1.34 + * Call this method to close the stream and cause the original target
1.35 + * to be overwritten. Note: if any call to |write| failed to write out
1.36 + * all of the data given to it, then calling this method will |close| the
1.37 + * stream and return failure. Further, if closing the stream fails, this
1.38 + * method will return failure. The original target will be overwritten only
1.39 + * if all calls to |write| succeeded and the stream was successfully closed.
1.40 + */
1.41 + void finish();
1.42 +};
