nimforum mirror - Error with extracting zipfiles

achesak (orginal) [2014-08-03T01:53:52+02:00] view original

I'm trying to write something to extract the contents from zipfiles (using the zipfiles module), but I keep running into an error.

Error:


Traceback (most recent call last)
epub.nim(98)             epub
epub.nim(78)             unpackEPUB
zipfiles.nim(160)        extractFile
zipfiles.nim(151)        extractFile
streams.nim(51)          atEnd
SIGSEGV: Illegal storage access. (Attempt to read from nil?)

Code that causes the error:


proc unpackEPUB*(filename : string, destination : string): bool =
    var archive : TZipArchive
    var state : bool = archive.open(filename, fmRead)
    if not state:
        return false
    for i in walkFiles(archive):
        archive.extractFile(i, destination & i)
    return true

echo(unpackEPUB("test.epub", "/home/adam/"))

Code compiles successfully, but seems to run into a problem when it comes to the file streams. The files are definitely there, as walkFiles() gives them all. Any help would be appreciated.

gradha (orginal) [2014-08-03T17:46:19+02:00] view original

Admiral ackbar doesn't believe the zipfiles module was ever meant to be used for extraction. The first thing extractFile does is call getStream() which mentions:

## The returned stream does not support the `setPosition`, `getPosition`,
## `writeData` or `atEnd` methods.

Immediately after that call atEnd() is used. Maybe that module is half finished and that's why there is an undocumented wrapper for libzzip which presumably offers read access only to zip files?

Araq (orginal) [2014-08-03T20:55:48+02:00] view original

The zipfiles module is used to create the "installer" zip files. I have no idea whether it is supposed to support extraction or not, I wrote it years ago. In any case we should at least improve its docs.

achesak (orginal) [2014-08-05T00:26:13+02:00] view original

Huh, okay, thanks anyway.

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