nix-super/src/libstore/builtins.cc

#include "builtins.hh"
#include "download.hh"
#include "store-api.hh"
#include "archive.hh"
#include "compression.hh"

namespace nix {

void builtinFetchurl(const BasicDerivation & drv)
{
    auto url = drv.env.find("url");
    if (url == drv.env.end()) throw Error("attribute ‘url’ missing");

    /* No need to do TLS verification, because we check the hash of
       the result anyway. */
    DownloadOptions options;
    options.verifyTLS = false;

    /* Show a progress indicator, even though stderr is not a tty. */
    options.showProgress = DownloadOptions::yes;

    auto data = makeDownloader()->download(url->second, options);
    assert(data.data);

    auto out = drv.env.find("out");
    if (out == drv.env.end()) throw Error("attribute ‘out’ missing");

    Path storePath = out->second;

    auto unpack = drv.env.find("unpack");
    if (unpack != drv.env.end() && unpack->second == "1") {
        if (string(*data.data, 0, 6) == string("\xfd" "7zXZ\0", 6))
            data.data = decompress("xz", *data.data);
        StringSource source(*data.data);
        restorePath(storePath, source);
    } else
        writeFile(storePath, *data.data);

    auto executable = drv.env.find("executable");
    if (executable != drv.env.end() && executable->second == "1") {
        if (chmod(storePath.c_str(), 0755) == -1)
            throw SysError(format("making ‘%1%’ executable") % storePath);
    }
}

}