You need to close the output port after `gunzip-through-ports` finishes.
At Tue, 30 Oct 2018 16:32:04 +0100, "'Paulo Matos' via Racket Users" wrote:
> Hi,
>
> I have quite a few large files that I want to gzip to a single file
> (without an intermediate concatenation) and then later gunzip.
> Interestingly the gunzipping is blocking on a read-line. I wonder if
> this is because I cannot use gzip-through-ports the way I am doing it or
> if there's a bug somewhere.
>
> Generate 3 files with:
> $ base64 /dev/urandom | head -c 1000000 > foo3
> $ base64 /dev/urandom | head -c 1000000 > foo2
> $ base64 /dev/urandom | head -c 1000000 > foo1
>
> Now run the code:
> ```
> #lang racket
>
> (require file/gzip
> file/gunzip)
>
> (define paths '("foo1" "foo2" "foo3"))
>
> ;; compress
> (printf "compressing~n")
> (call-with-atomic-output-file "foo.gz"
> (lambda (op p)
> (for ([f (in-list paths)])
> (call-with-input-file f
> (lambda (i) (gzip-through-ports i op #false (current-seconds)))
> #:mode 'binary))))
>
> ;; decompress
> (printf "decompressing~n")
> (define-values (in out) (make-pipe))
> (void
> (thread
> (thunk
> (call-with-input-file "foo.gz"
> (lambda (cin)
> (gunzip-through-ports cin out))
> #:mode 'binary))))
> (call-with-atomic-output-file "foo.txt"
> (lambda (op p)
> (let loop ([l (read-line in)])
> (unless (eof-object? l)
> (write l op)
> (loop (read-line in))))))
>
> ```
>
> This is going to block in a read-line, and I have a suspicion that it
> blocks at the end of a compressed file. Is there a reason for it
> blocking? Note that if you `zcat foo.gz | less` you can see the whole
> file, so I am suspicious that something might be wrong with
> gunzip-through-ports.
>
> Any suggestions to improve this?
>
> Thanks,
>
> --
> Paulo Matos
>
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