repo: New Repo.get_packages_download_dir() method

Currently, the path where a package should be downloaded is computed in
several places. This patch introduces a single location for this
computation to reduce code duplication.
The patch also fixes usage of incorrect package path in
Package::get_package_path() call - the destdir config option was not
taken into account.

include/libdnf5/repo/repo.hpp

@@ -30,6 +30,7 @@ along with libdnf.  If not, see <https://www.gnu.org/licenses/>.
 #include "libdnf5/repo/repo_weak.hpp"
 #include "libdnf5/rpm/package.hpp"
 
+#include <filesystem>
 #include <memory>
 
 
@@ -372,6 +373,11 @@ class LIBDNF_API Repo {
     // Add xml comps file at `path` to the repository.
     LIBDNF_LOCAL void add_xml_comps(const std::string & path);
 
+    /// Gets path to the directory where repository packages are downloaded.
+    /// Takes destdir config option into account.
+    LIBDNF_LOCAL std::filesystem::path get_packages_download_dir() const;
+
+
     std::unique_ptr<Impl> p_impl;
 };
 

libdnf5/repo/package_downloader.cpp

@@ -115,13 +115,7 @@ PackageDownloader::~PackageDownloader() = default;
 
 
 void PackageDownloader::add(const libdnf5::rpm::Package & package, void * user_data) {
-    auto default_path = std::filesystem::path(package.get_repo()->get_cachedir()) / "packages";
-    auto & destdir_option = p_impl->base->get_config().get_destdir_option();
-    if (destdir_option.empty()) {
-        add(package, default_path, user_data);
-    } else {
-        add(package, destdir_option.get_value(), user_data);
-    }
+    add(package, package.get_repo()->get_packages_download_dir(), user_data);
 }
 
 

libdnf5/repo/repo.cpp

@@ -626,5 +626,13 @@ void Repo::mark_fresh() {
     p_impl->expired = false;
 }
 
+std::filesystem::path Repo::get_packages_download_dir() const {
+    auto destdir_option = p_impl->base->get_config().get_destdir_option();
+    if (destdir_option.empty()) {
+        return std::filesystem::path(get_cachedir()) / "packages";
+    } else {
+        return destdir_option.get_value();
+    }
+}
 
 }  // namespace libdnf5::repo

libdnf5/rpm/package.cpp

@@ -392,7 +392,7 @@ std::string Package::get_package_path() const {
             return get_location();
         }
         // Returns the path to the cached file.
-        auto dir = std::filesystem::path(repo->get_cachedir()) / "packages";
+        auto dir = repo->get_packages_download_dir();
         return dir / std::filesystem::path(get_location()).filename();
     } else {
         return "";