Add Rugged::Config#snapshot.

Author: arthurschreiber

ext/rugged/rugged_config.c

@@ -306,6 +306,28 @@ static VALUE rb_git_config_open_default(VALUE klass)
 	return rugged_config_new(klass, Qnil, cfg);
 }
 
+/*
+ *  call-seq:
+ *    config.snapshot -> snapshot
+ *
+ *  Create a snapshot of the configuration.
+ *
+ *  Provides a consistent, read-only view of the configuration for
+ *  looking up complex values from a configuration.
+ */
+static VALUE rb_git_config_snapshot(VALUE self)
+{
+	git_config *config, *snapshot;
+
+	Data_Get_Struct(self, git_config, config);
+
+	rugged_exception_check(
+		git_config_snapshot(&snapshot, config)
+	);
+
+	return rugged_config_new(rb_obj_class(self), Qnil, snapshot);
+}
+
 void Init_rugged_config(void)
 {
 	/*
@@ -330,4 +352,5 @@ void Init_rugged_config(void)
 	rb_define_method(rb_cRuggedConfig, "each", rb_git_config_each_pair, 0);
 	rb_define_method(rb_cRuggedConfig, "to_hash", rb_git_config_to_hash, 0);
 
+	rb_define_method(rb_cRuggedConfig, "snapshot", rb_git_config_snapshot, 0);
 }

test/config_test.rb

@@ -21,6 +21,20 @@ def test_read_global_config_file
     assert config['user.name'] != nil
     assert_nil config['core.bare']
   end
+
+  def test_snapshot
+    config = Rugged::Config.new(File.join(@repo.path, 'config'))
+    config['old.value'] = 5
+
+    snapshot = config.snapshot
+    assert_equal '5', snapshot['old.value']
+
+    config['new.value'] = 42
+    config['old.value'] = 1337
+
+    assert_equal '5', snapshot['old.value']
+    assert_nil snapshot['new.value']
+  end
 end
 
 class ConfigWriteTest < Rugged::TestCase