1443651 - CreateUnique should not return failure when files already exist

Status: RESOLVED FIXED

(Core :: XPCOM, defect)

Description

[Kris Maglione [:kmag]]

CreateUnique currently only checks whether the failure code is NS_ERROR_FILE_ALREADY_EXISTS when trying to create a candidate filename. There are other ways that attempting to create an existing file can fail, particularly when that file is locked. When we get another failure code, we should check to see whether the file exists before treating it as a failure.

Comment 1

[Kris Maglione [:kmag]]

Attachment: Bug 1443651: Don't return failure for access denied from createUnique() if file exists.

There are ways for Create() to return access denied for files which already
exist, particularly in the case of locked files. When it does, createUnique()
should check whether the file exists before considering the attempt a failure.

Review commit: https://reviewboard.mozilla.org/r/225582/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/225582/

Comment 2

[Dave Townsend [:mossop]]

Comment on attachment 8956629 [details]
Bug 1443651: Don't return failure for access denied from createUnique() if file exists.

https://reviewboard.mozilla.org/r/225582/#review232200

Not a big fan of this approach but anything else is likely to be more complex than it is worth.

Comment 3

[Kris Maglione [:kmag]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/e957efe5d14c0a7a79483b477e9a6c9a8e7ddb3f
Bug 1443651: Don't return failure for access denied from createUnique() if file exists. r=Mossop

Comment 4

[Noemi Erli[:noemi_erli]]

https://hg.mozilla.org/mozilla-central/rev/e957efe5d14c