Ruby Bindings: Implement Enumerable for iterable collections

bindings/libdnf5/advisory.i

@@ -6,6 +6,10 @@
 %module "libdnf5/advisory"
 #endif
 
+#if defined(SWIGRUBY)
+%mixin libdnf5::advisory::AdvisorySet "Enumerable";
+#endif
+
 %include <exception.i>
 %include <std_vector.i>
 
@@ -57,3 +61,8 @@
 %template(VectorAdvisoryReference) std::vector<libdnf5::advisory::AdvisoryReference>;
 
 add_iterator(AdvisorySet)
+
+#if defined(SWIGRUBY)
+fix_swigtype_trait(libdnf5::advisory::Advisory)
+#endif
+add_ruby_each(libdnf5::advisory::AdvisorySet)

bindings/libdnf5/common.i

@@ -134,6 +134,42 @@ del ClassName##__iter__
 #endif
 %enddef
 
+%define fix_swigtype_trait(ClassName)
+%traits_swigtype(ClassName)
+%fragment(SWIG_Traits_frag(ClassName));
+%enddef
+
+%define add_ruby_each(ClassName)
+#if defined(SWIGRUBY)
+/* Using swig::from method on a class instance (= $self in %extend blocks below) fails.
+ * We need to define these traits so that it compiles. This seems to be an issue related
+ * to namespacing:
+ * https://github.com/swig/swig/issues/973
+ * and to using a pointer in some places:
+ * https://github.com/swig/swig/issues/2938
+ */
+fix_swigtype_trait(ClassName)
+
+%extend ClassName {
+    VALUE each() {
+        // If no block is provided, returns Enumerator.
+        RETURN_ENUMERATOR(swig::from($self), 0, 0);
+
+        VALUE r;
+        auto i = self->begin();
+        auto e = self->end();
+
+        for (; i != e; ++i) {
+            r = swig::from(*i);
+            rb_yield(r);
+        }
+
+        return swig::from($self);
+    }
+}
+#endif
+%enddef
+
 %define add_str(ClassName)
 #if defined(SWIGPYTHON)
 %extend ClassName {

bindings/libdnf5/rpm.i

@@ -6,6 +6,13 @@
 %module "libdnf5/rpm"
 #endif
 
+#if defined(SWIGRUBY)
+// Mixin modules for Ruby. This has to be declared before inclusion of the
+// related header file.
+%mixin libdnf5::rpm::PackageSet "Enumerable";
+%mixin libdnf5::rpm::ReldepList "Enumerable";
+#endif
+
 %include <exception.i>
 %include <std_string.i>
 %include <std_vector.i>
@@ -99,6 +106,13 @@ add_hash(libdnf5::rpm::Package)
 add_iterator(PackageSet)
 add_iterator(ReldepList)
 
+add_ruby_each(libdnf5::rpm::PackageSet)
+// Reldep needs special treatment so that the add_ruby_each can use it.
+#if defined(SWIGRUBY)
+fix_swigtype_trait(libdnf5::rpm::Reldep)
+#endif
+add_ruby_each(libdnf5::rpm::ReldepList)
+
 %feature("director") TransactionCallbacks;
 %include "libdnf5/rpm/transaction_callbacks.hpp"
 wrap_unique_ptr(TransactionCallbacksUniquePtr, libdnf5::rpm::TransactionCallbacks);

test/ruby/libdnf5/rpm/test_package_query.rb

@@ -38,7 +38,6 @@ def test_filter_name()
         query.filter_name(["pkg"])
         assert_equal(1, query.size())
 
-        # TODO(dmach): implement each() so the query can be easily iterated or converted to an array
         actual = []
         it = query.begin()
         while it != query.end()
@@ -55,7 +54,6 @@ def test_filter_name()
         query.filter_name(["pk*"], Common::QueryCmp_GLOB)
         assert_equal(2, query.size())
 
-        # TODO(dmach): implement each() so the query can be easily iterated or converted to an array
         actual = []
         it = query.begin()
         while it != query.end()
@@ -65,4 +63,32 @@ def test_filter_name()
 
         assert_equal(["pkg-1.2-3.x86_64", "pkg-libs-1:1.3-4.x86_64"], actual)
     end
+
+    def test_implements_enumerable()
+        query = Rpm::PackageQuery.new(@base)
+        query.filter_name(["pkg"])
+        assert_equal(1, query.size())
+
+        # Using each() without a block should return Enumerator.
+        assert_instance_of(Enumerator, query.each)
+
+        # Using each() with a block should return the collection.
+        assert_instance_of(Rpm::PackageSet, query.each(&:get_name))
+
+        actual_nevra = query.map { |pkg| pkg.get_nevra }
+
+        assert_equal(["pkg-1.2-3.x86_64"], actual_nevra)
+
+        # ---
+
+        query = Rpm::PackageQuery.new(@base)
+        query.filter_name(["pk*"], Common::QueryCmp_GLOB)
+        assert_equal(2, query.size())
+
+        # Test other method than each that comes with Enumerable
+        actual = query.select { |pkg| pkg.get_name == "pkg-libs" }
+
+        assert_equal(1, actual.size)
+        assert_equal('pkg-libs-1:1.3-4.x86_64', actual.first.get_nevra)
+    end
 end