[Rd] Sweave resource leak: leftover temp files (PR#7998)

[murdoch@stats.uwo.ca]

On 7/12/2005 8:58 AM, Prof Brian Ripley wrote:
> On Tue, 12 Jul 2005, Duncan Murdoch wrote:
> 
>> Prof Brian Ripley wrote:
>>> This is actually a Windows bug.  Those files are unlink()ed, and it seems 
>>> Windows is not respecting that (not an unknown phenomenon).  I have tried a 
>>> few workarounds, and am about to commit one that seems to work.
>>
>> I guess you mean the C unlink, since I don't see the R unlink being called.
> 
> Yes, I do, but the R unlink calls the C unlink and so has the same 
> problem.
> 
>> Generally deletes fail on Windows when files are locked, e.g. open for 
>> reading or writing.  I haven't seen Windows file deletes fail in other 
>> circumstances, so I suspect this was an R, MinGW or MSVCRT bug rather than a 
>> Windows bug.
> 
> But unlink() is required by POSIX to work when files are open, so it is a 
> MSVCRT `feature' (and that is part of Windows since Win95 OSR2).  Indeed, 
> there is nothing in the MSDN documentation on unlink() that says anything 
> about not working if files are `locked'.
> 
> If people use the same name and arg sequence of a standard library call 
> and partially implement it without saying so or mentioning the 
> restrictions I believe it is perfectly reasonable to call that a bug.

This is documented in the API call DeleteFile.  I wouldn't call MSVCRT 
part of Windows, but I guess this is the same thing as saying that Linux 
is the kernel, not the whole collection of things you get in a Linux 
distribution.

Windows provides a different mechanism for this, the 
FILE_FLAG_DELETE_ON_CLOSE flag to CreateFile().  Your patch has solved 
the problem, so I can't see that it would be worthwhile using this, but 
one way to implement the POSIX behaviour would be to open a file with 
this flag, then immediately close it.  As long as all other handles to 
the file are eventually closed the file should be deleted.

Duncan


> 
>>
>> Duncan Murdoch
>>> 
>>> No files are left over on a decent operating system, e.g. Solaris or FC3 
>>> Linux.
>>> 
>>> On Fri, 8 Jul 2005 murdoch at stats.uwo.ca wrote:
>>> 
>>> 
>>>> Harold, I've taken a closer look at your example and I'd call this an
>>>> Sweave bug.  It creates tempfiles each time you run it, and doesn't
>>>> delete them at the end.  For example:
>>>> 
>>>> 
>>>>> list.files(tempdir())
>>>> 
>>>> character(0)
>>>> 
>>>>> testfile <- system.file("Sweave", "Sweave-test-1.Rnw", package = "utils")
>>>>> Sweave(testfile, out="junk.tex")
>>>> 
>>>> Writing to file junk.tex
>>>> Processing code chunks ...
>>>> 1 : print term verbatim
>>>> 2 : term hide
>>>> 3 : echo print term verbatim
>>>> 4 : term verbatim
>>>> 5 : echo term verbatim
>>>> 6 : echo term verbatim eps pdf
>>>> 7 : echo term verbatim eps pdf
>>>> 
>>>> You can now run LaTeX on 'junk.tex'
>>>> 
>>>>> list.files(tempdir())
>>>> 
>>>> [1] "Rf10523" "Rf13872" "Rf17129" "Rf2055"  "Rf2203"  "Rf2403"  "Rf27095"
>>>> [8] "Rf2892"  "Rf31415" "Rf5290"  "Rf6251"  "Rf6482"  "Rf7055"  "Rf724"
>>>> 
>>>>> Sweave(testfile, out="C:/temp/junk.tex")
>>>> 
>>>> Writing to file C:/temp/junk.tex
>>>> Processing code chunks ...
>>>> 1 : print term verbatim
>>>> 2 : term hide
>>>> 3 : echo print term verbatim
>>>> 4 : term verbatim
>>>> 5 : echo term verbatim
>>>> 6 : echo term verbatim eps pdf
>>>> 7 : echo term verbatim eps pdf
>>>> 
>>>> You can now run LaTeX on 'C:/temp/junk.tex'
>>>> 
>>>>> list.files(tempdir())
>>>> 
>>>> [1] "Rf10523" "Rf12679" "Rf1311"  "Rf13484" "Rf13872" "Rf17129" "Rf17288"
>>>> [8] "Rf2055"  "Rf21774" "Rf2203"  "Rf23417" "Rf2403"  "Rf27095" "Rf2892"
>>>> [15] "Rf29444" "Rf31128" "Rf31415" "Rf32520" "Rf3338"  "Rf5290"  "Rf5551"
>>>> [22] "Rf6251"  "Rf6482"  "Rf7055"  "Rf724"   "Rf7543"  "Rf758"   "Rf7673"
>>>> 
>>>>> unlink(list.files(tempdir(),full=T))
>>>>> list.files(tempdir())
>>>> 
>>>> character(0)
>>>> 
>>>> Harold:  a workaround for this would be to wrap your Sweave call in
>>>> something like this:
>>>> 
>>>> keep <- list.files(tempdir(), full=TRUE)  # keep previous temp files
>>>> 
>>>> ... Call Sweave here ...
>>>> 
>>>> temps <- list.files(tempdir(), full=TRUE)
>>>> unlink(temps[!(temps %in% keep)])  # delete the newly created ones
>>>> 
>>>> ______________________________________________
>>>> R-devel at r-project.org mailing list
>>>> https://stat.ethz.ch/mailman/listinfo/r-devel
>>>> 
>>>> 
>>> 
>>> 
>>
>>
>