ApplyUtility::MakeCommonZone(): compute zone of a config object originated from an apply rule

refs #6919

lib/icinga/CMakeLists.txt

@@ -27,6 +27,7 @@ set(icinga_SOURCES
   i2-icinga.hpp icinga-itl.cpp
   apiactions.cpp apiactions.hpp
   apievents.cpp apievents.hpp
+  apply-utility.cpp apply-utility.hpp
   checkable.cpp checkable.hpp checkable-ti.hpp
   checkable-check.cpp checkable-comment.cpp checkable-dependency.cpp
   checkable-downtime.cpp checkable-event.cpp checkable-flapping.cpp

lib/icinga/apply-utility.cpp

@@ -0,0 +1,73 @@
+/* Icinga 2 | (c) 2019 Icinga GmbH | GPLv2+ */
+
+#include "base/debuginfo.hpp"
+#include "base/scriptframe.hpp"
+#include "base/value.hpp"
+#include "config/configcompiler.hpp"
+#include "config/expression.hpp"
+#include "icinga/apply-utility.hpp"
+#include <utility>
+#include <vector>
+
+using namespace icinga;
+
+/* Icinga DSL function which sets this.zone of a config object originated from an apply rule
+ * to either the zone of the config object the apply rule matched or the zone of the apply rule.
+ */
+static const Value l_MakeCommonZoneDsl = ([]() -> Value {
+	const char *dsl = R"EOF(
+
+function(parent_object_zone, apply_rule_zone) {
+	var child_zone = get_object(Zone, apply_rule_zone)
+
+	var common_zone = if (child_zone && child_zone.global) {
+		parent_object_zone
+	} else {
+		apply_rule_zone
+	}
+
+	if (common_zone != "") {
+		this.zone = common_zone
+	}
+}
+
+)EOF";
+
+	ScriptFrame frame (false);
+	auto expr (ConfigCompiler::CompileText("<anonymous>", dsl));
+
+	return std::move(expr->Evaluate(frame).GetValue());
+})();
+
+/**
+ * Create a DSL expression which sets this.zone of a config object originated from an apply rule
+ *
+ * @param parent_object_zone The zone of the config object the apply rule matched
+ * @param apply_rule_zone The zone of the apply rule
+ *
+ * @return The newly created DSL expression or nullptr if nothing to do
+ */
+std::unique_ptr<Expression> ApplyUtility::MakeCommonZone(String parent_object_zone, String apply_rule_zone, const DebugInfo& debug_info)
+{
+	if (parent_object_zone == apply_rule_zone) {
+		if (parent_object_zone.IsEmpty()) {
+			return nullptr;
+		}
+
+		/* this.zone = parent_object_zone */
+		return std::unique_ptr<Expression>(new SetExpression(MakeIndexer(ScopeThis, "zone"), OpSetLiteral, MakeLiteral(std::move(parent_object_zone)), debug_info));
+	}
+
+	std::vector<std::unique_ptr<Expression>> args;
+	args.reserve(3);
+	args.emplace_back(new GetScopeExpression(ScopeThis));
+	args.emplace_back(MakeLiteral(std::move(parent_object_zone)));
+	args.emplace_back(MakeLiteral(std::move(apply_rule_zone)));
+
+	/* l_MakeCommonZoneDsl.call(this, parent_object_zone, apply_rule_zone) */
+	return std::unique_ptr<Expression>(new FunctionCallExpression(
+		std::unique_ptr<Expression>(new IndexerExpression(MakeLiteral(l_MakeCommonZoneDsl), MakeLiteral("call"))),
+		std::move(args),
+		debug_info
+	));
+}

lib/icinga/apply-utility.hpp

@@ -0,0 +1,24 @@
+/* Icinga 2 | (c) 2019 Icinga GmbH | GPLv2+ */
+
+#ifndef APPLY_UTILITY_H
+#define APPLY_UTILITY_H
+
+#include "base/debuginfo.hpp"
+#include "base/string.hpp"
+#include "config/expression.hpp"
+#include <memory>
+#include <vector>
+
+namespace icinga
+{
+
+namespace ApplyUtility
+{
+
+std::unique_ptr<Expression> MakeCommonZone(String parent_object_zone, String apply_rule_zone, const DebugInfo& debug_info);
+
+}
+
+}
+
+#endif /* APPLY_UTILITY_H */