Support Nullsoft Installer self-extracting archive

[neuromancer]

Some Humble Bundle games installers are Nullsoft self-extracting archives. For instance, Darklands:

$ file Darklands_v1.0.exe 
Darklands_v1.0.exe: PE32 executable (GUI) Intel 80386, for MS Windows, Nullsoft Installer self-extracting archive
$ file -i Darklands_v1.0.exe 
Darklands_v1.0.exe: application/x-dosexec; charset=binary

Using innoextract will silently fail to extract it. It will be nice to support its installation, since file-roller can extract them out-of-the-box (I think it is using 7z)

[tkashkin]

Any reliable way to detect it except file <file>.exe | grep Nullsoft?

[neuromancer]

Not really. file should verify the NSIS signature:

https://github.com/kornelski/7z/blob/20e38032e62bd6bb3a176d51bce0558b16dd51e2/CPP/7zip/Archive/Nsis/NsisIn.h#L28

Do you want to avoid to use file?

[tkashkin]

I have added NSIS installer support, but file-roller doesn't seem to be able to correctly extract one NSIS installer I have found in my humble collection.

[neuromancer]

Works great!. I tested it with Command H.Q.. If it is not working for you, maybe your 7z binary was compiled without nsis support?

Anyway, my final suggestion for this feature is to change the name of the compatibility layer to avoid confuse the users: Innoextract is too specific now, since we can extract more types of installers.

[tkashkin]

No, it ignores compat tool at all if NSIS installer is detected. Innoextract is still correct because it uses innoextract.

[neuromancer]

Fair enough. Great work!

[tkashkin]

Btw I have added a wiki page about compat tools. You can edit wiki if you want and if you think something may be confusing for users. 🙂

[tkashkin]

I was implementing #106 and testing with Uplay. It's also NSIS installer and it doesn't unpack correctly for me.
Even if such unpacking works, installer still may do something itself (especially in cases like Uplay), and while it probably should work for most games, for some it won't.

For now I'll use file-roller for NSIS installers only if innoextract is selected and I will think how can it be solved properly. Maybe file-roller should be added as a separate compat tool.