#2808: createDirectoryIfMissing should be atomic
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Reporter: EricKow | Owner: igloo
Type: merge | Status: new
Priority: normal | Milestone: 6.10.2
Component: libraries/directory | Version: 6.10.1
Severity: normal | Resolution:
Keywords: | Difficulty: Unknown
Testcase: | Os: Unknown/Multiple
Architecture: Unknown/Multiple |
------------------------------------+---------------------------------------
Changes (by simonmar):
* owner: simonmar => igloo
* type: bug => merge
Comment:
I've fixed the obvious race condition, but as Duncan says it's not
possible to make this function completely race-free. I think this is
enough to keep Eric happy, though.
{{{
Wed Nov 26 11:56:06 GMT 2008 Simon Marlow <[EMAIL PROTECTED]>
* add test for createDirectoryIfMissing (#2808)
Wed Nov 26 12:36:59 GMT 2008 Simon Marlow <[EMAIL PROTECTED]>
* avoid race conditions in createDirectoryIfMissing (#2808)
}}}
For reference the code is now:
{{{
createDirectoryIfMissing create_parents "" = return ()
createDirectoryIfMissing create_parents path0
= do r <- try $ createDirectory path
case (r :: Either IOException ()) of
Right _ -> return ()
Left e
| isAlreadyExistsError e -> return ()
| isDoesNotExistError e && create_parents -> do
createDirectoryIfMissing True (dropFileName path)
createDirectoryIfMissing True path
| otherwise -> throw e
where
-- we want createDirectoryIfMissing "a/" to behave like
-- createDirectoryIfMissing "a". Also, unless we apply
-- dropTrailingPathSeparator first, dropFileName won't drop
-- anything from "a/".
path = dropTrailingPathSeparator path0
}}}
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/2808#comment:5>
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