Decompress from stream

[NobodyXu]

Here in cargo-binstall, we are forced to write the downloaded file first to the disk, then pass it to ZipArchiver whereas all the other algorithms we support (gzip, xzip and zstd) have a streaming interface that just accepts BufRead (and Read for convenience).

Is it possible for zip to have a streaming interface that takes BufRead?

[NobodyXu]

@zamazan4ik Can we have this feature in zip?

[zamazan4ik]

Yes, you can. But this library is in maintenance-only state. So if you want to implement it, the best idea is prepare a PR and send it here :) I will try to review and merge it.

[NobodyXu]

I have zero knowledge on zip's codebase, but I will spend my time to understand and hopefully it won't be too complicated to add this feature.

[NobodyXu]

I just realized that zip keeps its central directory at the end of the file, so it is possible to parse the local file header first and extract them, then parses the central directory and set the attributes of the files/dirs created.

Sounds feasible but it would be quite complex and I'd better create a new type specifically for this functionality.

@zamazan4ik Does that sound good to you? Is there anything I miss regarding zip format?

[zamazan4ik]

@NobodyXu unfortunately, I am not the good person for asking questions about ZIP details :) @Plecra I guess you know much more details

[NobodyXu]

Aha, I just realized that zip::read_zipfile_from_stream can be used to decompress from stream, but it has one problem:

It's missing unix_mode data which are crucial for my application.

Perhaps I can implement something atop it, or I can expose the central directory so that user can parse that themselves.