GNU bug report logs - #67926
29.1; fail to extract ZIP subfile named with [...]

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From: awrhygty <at> outlook.com
To: Eli Zaretskii <eliz <at> gnu.org>
Cc: 67926 <at> debbugs.gnu.org
Subject: bug#67926: 29.1; fail to extract ZIP subfile named with [...]
Date: Tue, 26 Dec 2023 23:51:01 +0900

Eli Zaretskii <eliz <at> gnu.org> writes:
>> This is because 'unzip.exe' treats subfilename arguments containing
>> '[...]' as subfilename patterns. This does not occur with '7z.exe'.
>
> Is there any way of making 'unzip' extract file[abc].txt by name,  by
> some kind of escaping or protecting the [...] wildcard from expansion?
> If there is such a way, we could try using it (maybe); if there's no
> such way, I will tag this bug "wontfix", since it isn't a problem with
> Emacs, but with the Windows build of 'unzip'.

There is a tricky way to specify "file[[]abc].txt".

I think that avoiding the use of unzip.exe/zip.exe solves problems about
directory names, archive names, subfile names.
Replacing #'archive-zip-extract with the form below,
ZIP subfiles can be extracted without unzip.exe.

(defun archive-zip-extract (archive name)
  (let* ((desc archive-subfile-mode)
         (buf (current-buffer))
         (bufname (buffer-file-name)))
    (set-buffer archive-superior-buffer)
    (save-restriction
      (widen)
      (let* ((file-beg archive-proper-file-start)
             (p0 (+ file-beg (archive--file-desc-pos desc)))
             (p  (+ file-beg (archive-l-e (+ p0 42) 4)))
             (bitflags (archive-l-e (+ p  6) 2))
             (method   (archive-l-e (+ p  8) 2))
             (compsize (archive-l-e (+ p0 20) 4))
             (fn-len   (archive-l-e (+ p 26) 2))
             (ex-len   (archive-l-e (+ p 28) 2))
             (data-beg (+ p 30 fn-len ex-len))
             (data-end (+ data-beg compsize))
             (coding-system-for-read  'no-conversion)
             (coding-system-for-write 'no-conversion)
             (default-directory temporary-file-directory))
        (cond ((/= 0 (logand bitflags 1))
               (message "Subfile is encrypted"))
              ((= method 0)
               (with-current-buffer buf
                 (insert-buffer-substring archive-superior-buffer
                                          data-beg data-end)))
              ((eq method 8)
               (let ((crc-32    (buffer-substring (+ p0 16) (+ p0 20)))
                     (orig-size (buffer-substring (+ p0 24) (+ p0 28)))
                     (proc (start-process "gzip" buf "gzip" "-cd"))
                     (header "\x1f\x8b\x08\0\0\0\0\0\0\0"))
                 (set-process-sentinel proc #'ignore)
                 (process-send-string proc header)
                 (process-send-region proc data-beg data-end)
                 (process-send-string proc crc-32)
                 (process-send-string proc orig-size)
                 (process-send-eof proc)
                 (accept-process-output proc nil nil t)
                 (delete-process proc)))
              ((eq method 12)
               (call-process-region data-beg data-end
                                    "bzip2" nil buf nil "-cd"))
              (t (message "Unknown compression method")))))
    (set-buffer buf)))

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