package_downloader: Handle local files

Local packages are not passed to librepo for download, but directly
copied to the destination directory.

libdnf5/repo/package_downloader.cpp

@@ -136,6 +136,8 @@ void PackageDownloader::download() try {
 
     auto & config = p_impl->base->get_config();
     auto use_cache_only = config.get_cacheonly_option().get_value() == "all";
+    // map package.location->destination
+    std::map<std::filesystem::path, std::filesystem::path> local_files;
 
     GError * err{nullptr};
 
@@ -150,6 +152,11 @@ void PackageDownloader::download() try {
 
         std::filesystem::create_directory(pkg_target.destination);
 
+        if (pkg_target.package.is_available_locally()) {
+            local_files[pkg_target.package.get_location()] = pkg_target.destination;
+            continue;
+        }
+
         if (auto * download_callbacks = pkg_target.package.get_base()->get_download_callbacks()) {
             pkg_target.user_cb_data = download_callbacks->add_new_download(
                 pkg_target.user_data,
@@ -181,6 +188,15 @@ void PackageDownloader::download() try {
         lr_targets.emplace_back(lr_target);
     }
 
+    // Copy local packages to their destination directories
+    for (const auto & [source, destination] : local_files) {
+        auto dest = destination / source.filename();
+        std::error_code ec;
+        if (!std::filesystem::equivalent(source, dest, ec)) {
+            std::filesystem::copy(source, dest, std::filesystem::copy_options::overwrite_existing);
+        }
+    }
+
     // Adding items to the end of GSList is slow. We go from the back and add items to the beginning.
     GSList * list{nullptr};
     for (auto it = lr_targets.rbegin(); it != lr_targets.rend(); ++it) {