From cd306c7d2b534fc6b163d80ea9c09f50d21932e2 Mon Sep 17 00:00:00 2001
From: "Alexander A. Klimov" <alexander.klimov@icinga.com>
Date: Fri, 24 Jan 2020 12:18:25 +0100
Subject: [PATCH] DSL: add xrange()

---
 lib/base/CMakeLists.txt      |  1 +
 lib/base/generator-range.cpp | 20 ++++++++++++++++++++
 lib/base/generator-range.hpp | 33 +++++++++++++++++++++++++++++++++
 lib/base/scriptutils.cpp     | 30 ++++++++++++++++++++++++++++++
 lib/base/scriptutils.hpp     |  2 ++
 5 files changed, 86 insertions(+)
 create mode 100644 lib/base/generator-range.cpp
 create mode 100644 lib/base/generator-range.hpp

diff --git a/lib/base/CMakeLists.txt b/lib/base/CMakeLists.txt
index 1cdf0a409..aefa1cd08 100644
--- a/lib/base/CMakeLists.txt
+++ b/lib/base/CMakeLists.txt
@@ -41,6 +41,7 @@ set(base_SOURCES
   generator-array.cpp generator-array.hpp
   generator-filter.cpp generator-filter.hpp
   generator-map.cpp generator-map.hpp
+  generator-range.cpp generator-map.hpp
   generator-unique.cpp generator-unique.hpp
   initialize.cpp initialize.hpp
   intrusive-ptr.hpp
diff --git a/lib/base/generator-range.cpp b/lib/base/generator-range.cpp
new file mode 100644
index 000000000..efb6c23aa
--- /dev/null
+++ b/lib/base/generator-range.cpp
@@ -0,0 +1,20 @@
+/* Icinga 2 | (c) 2020 Icinga GmbH | GPLv2+ */
+
+#include "base/generator-range.hpp"
+#include "base/objectlock.hpp"
+#include "base/value.hpp"
+
+using namespace icinga;
+
+bool GeneratorRange::GetNext(Value& out)
+{
+	ObjectLock oLock (this);
+
+	if (m_Current < m_Stop) {
+		out = m_Current;
+		m_Current += m_Step;
+		return true;
+	}
+
+	return false;
+}
diff --git a/lib/base/generator-range.hpp b/lib/base/generator-range.hpp
new file mode 100644
index 000000000..d2e5881b4
--- /dev/null
+++ b/lib/base/generator-range.hpp
@@ -0,0 +1,33 @@
+/* Icinga 2 | (c) 2020 Icinga GmbH | GPLv2+ */
+
+#ifndef GENERATOR_RANGE_H
+#define GENERATOR_RANGE_H
+
+#include "base/generator.hpp"
+#include "base/value.hpp"
+
+namespace icinga
+{
+
+/**
+ * Supplies items [start, stop), incrementing by step.
+ *
+ * @ingroup base
+ */
+class GeneratorRange final : public Generator
+{
+public:
+	inline GeneratorRange(double start, double stop, double step)
+		: m_Current(start), m_Stop(stop), m_Step(step)
+	{
+	}
+
+	bool GetNext(Value& out) override;
+
+private:
+	double m_Current, m_Stop, m_Step;
+};
+
+}
+
+#endif /* GENERATOR_RANGE_H */
diff --git a/lib/base/scriptutils.cpp b/lib/base/scriptutils.cpp
index 3611799ff..c59b7bf03 100644
--- a/lib/base/scriptutils.cpp
+++ b/lib/base/scriptutils.cpp
@@ -2,6 +2,8 @@
 
 #include "base/scriptutils.hpp"
 #include "base/function.hpp"
+#include "base/generator.hpp"
+#include "base/generator-range.hpp"
 #include "base/scriptframe.hpp"
 #include "base/exception.hpp"
 #include "base/utility.hpp"
@@ -32,6 +34,7 @@ REGISTER_SAFE_FUNCTION(System, union, &ScriptUtils::Union, "");
 REGISTER_SAFE_FUNCTION(System, intersection, &ScriptUtils::Intersection, "");
 REGISTER_FUNCTION(System, log, &ScriptUtils::Log, "severity:facility:value");
 REGISTER_FUNCTION(System, range, &ScriptUtils::Range, "start:end:increment");
+REGISTER_FUNCTION(System, xrange, &ScriptUtils::XRange, "start:end:increment");
 REGISTER_FUNCTION(System, exit, &Application::Exit, "status");
 REGISTER_SAFE_FUNCTION(System, typeof, &ScriptUtils::TypeOf, "value");
 REGISTER_SAFE_FUNCTION(System, keys, &ScriptUtils::Keys, "value");
@@ -380,6 +383,33 @@ Array::Ptr ScriptUtils::Range(const std::vector<Value>& arguments)
 	return new Array(std::move(result));
 }
 
+Generator::Ptr ScriptUtils::XRange(const std::vector<Value>& arguments)
+{
+	double start, end, increment;
+
+	switch (arguments.size()) {
+		case 1:
+			start = 0;
+			end = arguments[0];
+			increment = 1;
+			break;
+		case 2:
+			start = arguments[0];
+			end = arguments[1];
+			increment = 1;
+			break;
+		case 3:
+			start = arguments[0];
+			end = arguments[1];
+			increment = arguments[2];
+			break;
+		default:
+			BOOST_THROW_EXCEPTION(std::invalid_argument("Invalid number of arguments for xrange()"));
+	}
+
+	return new GeneratorRange(start, end, increment);
+}
+
 Type::Ptr ScriptUtils::TypeOf(const Value& value)
 {
 	return value.GetReflectionType();
diff --git a/lib/base/scriptutils.hpp b/lib/base/scriptutils.hpp
index 7bd3e8b9d..dc764dfcf 100644
--- a/lib/base/scriptutils.hpp
+++ b/lib/base/scriptutils.hpp
@@ -7,6 +7,7 @@
 #include "base/string.hpp"
 #include "base/array.hpp"
 #include "base/dictionary.hpp"
+#include "base/generator.hpp"
 #include "base/type.hpp"
 #include "base/configobject.hpp"
 
@@ -31,6 +32,7 @@ public:
 	static Array::Ptr Intersection(const std::vector<Value>& arguments);
 	static void Log(const std::vector<Value>& arguments);
 	static Array::Ptr Range(const std::vector<Value>& arguments);
+	static Generator::Ptr XRange(const std::vector<Value>& arguments);
 	static Type::Ptr TypeOf(const Value& value);
 	static Array::Ptr Keys(const Object::Ptr& obj);
 	static Dictionary::Ptr GetTemplate(const Value& vtype, const String& name);