Move builtinFetchurl to its own file

src/libstore/builtins/fetchurl.cc

@@ -0,0 +1,73 @@
+#include "builtins.hh"
+#include "download.hh"
+#include "store-api.hh"
+#include "archive.hh"
+#include "compression.hh"
+
+namespace nix {
+
+void builtinFetchurl(const BasicDerivation & drv, const std::string & netrcData)
+{
+    /* Make the host's netrc data available. Too bad curl requires
+       this to be stored in a file. It would be nice if we could just
+       pass a pointer to the data. */
+    if (netrcData != "") {
+        settings.netrcFile = "netrc";
+        writeFile(settings.netrcFile, netrcData, 0600);
+    }
+
+    auto getAttr = [&](const string & name) {
+        auto i = drv.env.find(name);
+        if (i == drv.env.end()) throw Error(format("attribute '%s' missing") % name);
+        return i->second;
+    };
+
+    auto fetch = [&](const string & url) {
+        /* No need to do TLS verification, because we check the hash of
+           the result anyway. */
+        DownloadRequest request(url);
+        request.verifyTLS = false;
+        request.decompress = false;
+
+        /* Note: have to use a fresh downloader here because we're in
+           a forked process. */
+        auto data = makeDownloader()->download(request);
+        assert(data.data);
+
+        return data.data;
+    };
+
+    std::shared_ptr<std::string> data;
+
+    if (getAttr("outputHashMode") == "flat")
+        for (auto hashedMirror : settings.hashedMirrors.get())
+            try {
+                if (!hasSuffix(hashedMirror, "/")) hashedMirror += '/';
+                auto ht = parseHashType(getAttr("outputHashAlgo"));
+                data = fetch(hashedMirror + printHashType(ht) + "/" + Hash(getAttr("outputHash"), ht).to_string(Base16, false));
+                break;
+            } catch (Error & e) {
+                debug(e.what());
+            }
+
+    if (!data) data = fetch(getAttr("url"));
+
+    Path storePath = getAttr("out");
+
+    auto unpack = drv.env.find("unpack");
+    if (unpack != drv.env.end() && unpack->second == "1") {
+        if (string(*data, 0, 6) == string("\xfd" "7zXZ\0", 6))
+            data = decompress("xz", *data);
+        StringSource source(*data);
+        restorePath(storePath, source);
+    } else
+        writeFile(storePath, *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);
+    }
+}
+
+}