Implement directory download as ZIP

Thanks to the fdzipstream library [1] and zlib [2], it is possible to
generate ZIP files on-the-fly, therefore requiring no extra disk space
usage and only a small amount of memory.

Unfortunately, as of the time of this writing fdzipstream is not
packaged by any distributions yet [3], so it had to be imported as a git
submodule as a workaround.

While libarchive [4] could be an interesting alternative, writing ZIP
files is only supported by very recent versions (>= 3.8.0), which are
still not packaged by many distributions [5], either.

Moreover, libarchive is a package with several dependencies other than
zlib and is significantly larger compared to fdzipstreams, so
fdzipstreams was ultimately considered a better fit for this purpose.

[1]: https://github.com/CTrabant/fdzipstream.git
[2]: http://zlib.net/
[3]: https://repology.org/projects/?search=fdzipstream
[4]: https://www.libarchive.org/
[5]: https://repology.org/project/libarchive/versions

1 files changed, 8 insertions, 0 deletions

diff --git a/zip.h b/zip.h
new file mode 100644
index 0000000..79524b5
--- /dev/null
+++ b/zip.h
@@ -0,0 +1,8 @@
+#ifndef ZIP_H
+#define ZIP_H
+
+#include <libweb/http.h>
+
+int zip(const char *dir, struct http_response *r);
+
+#endif