WIP: Add pijul fetcher

src/libfetchers/pijul.cc

@@ -0,0 +1,76 @@
+// #include "cache.hh"
+#include "fetchers.hh"
+#include "store-api.hh"
+
+// #include "fetch-settings.hh"
+
+#include <string.h>
+
+using namespace std::string_literals;
+
+namespace nix::fetchers {
+
+struct PijulInputScheme : InputScheme {
+  std::optional<Input> inputFromURL(const ParsedURL &url) const override {
+    if (url.scheme != "pijul+http" && url.scheme != "pijul+https")
+      return {};
+
+    auto url2(url);
+    url2.scheme = std::string(url2.scheme, 6);
+    url2.query.clear();
+
+    Attrs attrs;
+    attrs.emplace("type", "pijul");
+    attrs.emplace("url", url2.to_string());
+
+    return inputFromAttrs(attrs);
+  }
+
+  std::optional<Input> inputFromAttrs(const Attrs &attrs) const override {
+    if (maybeGetStrAttr(attrs, "type") != "pijul")
+      return {};
+
+    for (auto &[name, _] : attrs)
+      if (name != "type" && name != "url")
+        throw Error("unsupported Pijul input attribute '%s'", name);
+
+    parseURL(getStrAttr(attrs, "url"));
+
+    Input input;
+    input.attrs = attrs;
+    return input;
+  }
+
+  bool hasAllInfo(const Input &input) const override { return true; }
+
+  ParsedURL toURL(const Input &input) const override {
+    auto url = parseURL(getStrAttr(input.attrs, "url"));
+    if (url.scheme != "pijul")
+      url.scheme = "pijul+" + url.scheme;
+    return url;
+  }
+
+  std::pair<StorePath, Input> fetch(ref<Store> store,
+                                    const Input &_input) override {
+    Input input(_input);
+
+    Path tmpDir = createTempDir();
+    AutoDelete delTmpDir(tmpDir, true);
+    auto repoDir = tmpDir + "/source";
+
+    auto url = parseURL(getStrAttr(input.attrs, "url"));
+    auto repoUrl = url.base;
+
+    runProgram("pijul", true, {"clone", repoUrl, repoDir}, {}, true);
+    deletePath(repoDir + "/.pijul");
+
+    auto storePath = store->addToStore(input.getName(), repoDir);
+
+    return {std::move(storePath), input};
+  }
+};
+
+static auto rPijulInputScheme = OnStartup(
+    [] { registerInputScheme(std::make_unique<PijulInputScheme>()); });
+
+} // namespace nix::fetchers