Implement support for signals

fixes #7744

lib/base/CMakeLists.txt

@@ -27,7 +27,7 @@ set(base_SOURCES
   convert.cpp debuginfo.cpp dictionary.cpp dynamicobject.cpp dynamicobject.thpp dynamictype.cpp
   exception.cpp fifo.cpp filelogger.cpp filelogger.thpp initialize.cpp json.cpp logger.cpp logger.thpp
   netstring.cpp networkstream.cpp object.cpp primitivetype.cpp process.cpp
-  ringbuffer.cpp scriptfunction.cpp scriptfunctionwrapper.cpp
+  ringbuffer.cpp scriptfunction.cpp scriptfunctionwrapper.cpp scriptsignal.cpp
   scriptutils.cpp scriptvariable.cpp serializer.cpp socket.cpp stacktrace.cpp
   statsfunction.cpp stdiostream.cpp stream.cpp streamlogger.cpp streamlogger.thpp string.cpp 
   sysloglogger.cpp sysloglogger.thpp tcpsocket.cpp thinmutex.cpp threadpool.cpp timer.cpp

lib/base/scriptsignal.cpp

@@ -0,0 +1,56 @@
+/******************************************************************************
+ * Icinga 2                                                                   *
+ * Copyright (C) 2012-2014 Icinga Development Team (http://www.icinga.org)    *
+ *                                                                            *
+ * This program is free software; you can redistribute it and/or              *
+ * modify it under the terms of the GNU General Public License                *
+ * as published by the Free Software Foundation; either version 2             *
+ * of the License, or (at your option) any later version.                     *
+ *                                                                            *
+ * This program is distributed in the hope that it will be useful,            *
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of             *
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the              *
+ * GNU General Public License for more details.                               *
+ *                                                                            *
+ * You should have received a copy of the GNU General Public License          *
+ * along with this program; if not, write to the Free Software Foundation     *
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.             *
+ ******************************************************************************/
+
+#include "base/scriptsignal.hpp"
+#include "base/scriptvariable.hpp"
+
+using namespace icinga;
+
+void ScriptSignal::AddSlot(const Callback& slot)
+{
+	m_Slots.push_back(slot);
+}
+
+Value ScriptSignal::Invoke(const std::vector<Value>& arguments)
+{
+	BOOST_FOREACH(const Callback& slot, m_Slots)
+		slot(arguments);
+}
+
+ScriptSignal::Ptr ScriptSignal::GetByName(const String& name)
+{
+	ScriptVariable::Ptr sv = ScriptVariable::GetByName(name);
+
+	if (!sv)
+		return ScriptSignal::Ptr();
+
+	return sv->GetData();
+}
+
+void ScriptSignal::Register(const String& name, const ScriptSignal::Ptr& function)
+{
+	ScriptVariable::Ptr sv = ScriptVariable::Set(name, function);
+	sv->SetConstant(true);
+}
+
+void ScriptSignal::Unregister(const String& name)
+{
+	ScriptVariable::Unregister(name);
+}
+

lib/base/scriptsignal.hpp

@@ -0,0 +1,65 @@
+/******************************************************************************
+ * Icinga 2                                                                   *
+ * Copyright (C) 2012-2014 Icinga Development Team (http://www.icinga.org)    *
+ *                                                                            *
+ * This program is free software; you can redistribute it and/or              *
+ * modify it under the terms of the GNU General Public License                *
+ * as published by the Free Software Foundation; either version 2             *
+ * of the License, or (at your option) any later version.                     *
+ *                                                                            *
+ * This program is distributed in the hope that it will be useful,            *
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of             *
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the              *
+ * GNU General Public License for more details.                               *
+ *                                                                            *
+ * You should have received a copy of the GNU General Public License          *
+ * along with this program; if not, write to the Free Software Foundation     *
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.             *
+ ******************************************************************************/
+
+#ifndef SCRIPTSIGNAL_H
+#define SCRIPTSIGNAL_H
+
+#include "base/i2-base.hpp"
+#include "base/value.hpp"
+#include <vector>
+#include <boost/function.hpp>
+
+namespace icinga
+{
+
+/**
+ * A signal that can be subscribed to by scripts.
+ *
+ * @ingroup base
+ */
+class I2_BASE_API ScriptSignal : public Object
+{
+public:
+	DECLARE_PTR_TYPEDEFS(ScriptSignal);
+
+	typedef boost::function<void (const std::vector<Value>& arguments)> Callback;
+
+	void AddSlot(const Callback& slot);
+	Value Invoke(const std::vector<Value>& arguments = std::vector<Value>());
+
+	static ScriptSignal::Ptr GetByName(const String& name);
+	static void Register(const String& name, const ScriptSignal::Ptr& signal);
+	static void Unregister(const String& name);
+
+private:
+	std::vector<Callback> m_Slots;
+};
+
+#define REGISTER_SCRIPTSIGNAL(name) \
+	namespace { namespace UNIQUE_NAME(sig) { namespace sig ## name { \
+		void RegisterSignal(void) { \
+			ScriptSignal::Ptr sig = new icinga::ScriptSignal(); \
+			ScriptSignal::Register(#name, sig); \
+		} \
+		INITIALIZE_ONCE(RegisterSignal); \
+	} } }
+
+}
+
+#endif /* SCRIPTSIGNAL_H */

lib/base/scriptutils.cpp

@@ -26,6 +26,7 @@
 #include "base/objectlock.hpp"
 #include "base/dynamictype.hpp"
 #include "base/application.hpp"
+#include "base/configerror.hpp"
 #include <boost/foreach.hpp>
 #include <boost/regex.hpp>
 #include <algorithm>
@@ -45,6 +46,7 @@ REGISTER_SCRIPTFUNCTION(typeof, &ScriptUtils::TypeOf);
 REGISTER_SCRIPTFUNCTION(keys, &ScriptUtils::Keys);
 REGISTER_SCRIPTFUNCTION(random, &Utility::Random);
 REGISTER_SCRIPTFUNCTION(__get_object, &ScriptUtils::GetObject);
+REGISTER_SCRIPTFUNCTION(assert, &ScriptUtils::Assert);
 
 bool ScriptUtils::Regex(const String& pattern, const String& text)
 {
@@ -218,3 +220,9 @@ DynamicObject::Ptr ScriptUtils::GetObject(const String& type, const String& name
 	return dtype->GetObject(name);
 }
 
+void ScriptUtils::Assert(const Value& arg)
+{
+	if (!arg.ToBool())
+		BOOST_THROW_EXCEPTION(ConfigError("Assertion failed"));
+}
+

lib/base/scriptutils.hpp

@@ -45,6 +45,7 @@ public:
 	static Type::Ptr TypeOf(const Value& value);
 	static Array::Ptr Keys(const Dictionary::Ptr& dict);
 	static DynamicObject::Ptr GetObject(const String& type, const String& name);
+	static void Assert(const Value& arg);
 
 private:
 	ScriptUtils(void);

lib/cli/daemoncommand.cpp

@@ -30,6 +30,7 @@
 #include "base/convert.hpp"
 #include "base/scriptvariable.hpp"
 #include "base/context.hpp"
+#include "base/scriptsignal.hpp"
 #include "config.h"
 #include <boost/program_options.hpp>
 #include <boost/tuple/tuple.hpp>
@@ -42,6 +43,7 @@ namespace po = boost::program_options;
 static po::variables_map g_AppParams;
 
 REGISTER_CLICOMMAND("daemon", DaemonCommand);
+REGISTER_SCRIPTSIGNAL(onload);
 
 static String LoadAppType(const String& typeSpec)
 {
@@ -156,6 +158,9 @@ static bool LoadConfigFiles(const boost::program_options::variables_map& vm, con
 
 	ScriptVariable::WriteVariablesFile(varsfile);
 
+	ScriptSignal::Ptr loadSignal = ScriptSignal::GetByName("onload");
+	loadSignal->Invoke();
+
 	return true;
 }
 

lib/config/config_lexer.ll

@@ -248,6 +248,7 @@ for				return T_APPLY_FOR;
 __function			return T_FUNCTION;
 __return			return T_RETURN;
 __for				return T_FOR;
+__signal			return T_SIGNAL;
 =\>				return T_FOLLOWS;
 \<\<				return T_SHIFT_LEFT;
 \>\>				return T_SHIFT_RIGHT;

lib/config/config_parser.yy

@@ -160,6 +160,7 @@ static void MakeRBinaryOp(Expression** result, Expression *left, Expression *rig
 %token T_FUNCTION "function (T_FUNCTION)"
 %token T_RETURN "return (T_RETURN)"
 %token T_FOR "for (T_FOR)"
+%token T_SIGNAL "signal (T_SIGNAL)"
 %token T_FOLLOWS "=> (T_FOLLOWS)"
 
 %type <text> identifier
@@ -802,6 +803,11 @@ rterm: T_STRING
 		$$ = new FunctionExpression("", *$3, aexpr, DebugInfoRange(@1, @5));
 		delete $3;
 	}
+	| T_SIGNAL identifier T_SET_ADD rterm
+	{
+		$$ = new SlotExpression($2, $4, DebugInfoRange(@1, @4));
+		free($2);
+	}
 	| T_FOR '(' identifier T_FOLLOWS identifier T_IN rterm ')' rterm_scope
 	{
 		$$ = new ForExpression($3, $5, $7, $9, DebugInfoRange(@1, @9));

lib/config/expression.cpp

@@ -26,6 +26,7 @@
 #include "base/json.hpp"
 #include "base/scriptfunction.hpp"
 #include "base/scriptvariable.hpp"
+#include "base/scriptsignal.hpp"
 #include "base/utility.hpp"
 #include "base/objectlock.hpp"
 #include "base/object.hpp"
@@ -427,6 +428,33 @@ Value FunctionExpression::DoEvaluate(const Object::Ptr& context, DebugHint *dhin
 	return func;
 }
 
+static void InvokeSlot(const Value& funcName, const std::vector<Value>& arguments)
+{
+	ScriptFunction::Ptr func;
+
+	if (funcName.IsObjectType<ScriptFunction>())
+		func = funcName;
+	else
+		func = ScriptFunction::GetByName(funcName);
+
+	if (!func)
+		BOOST_THROW_EXCEPTION(ConfigError("Function '" + funcName + "' does not exist."));
+
+	func->Invoke(arguments);
+}
+
+Value SlotExpression::DoEvaluate(const Object::Ptr& context, DebugHint *dhint) const
+{
+	ScriptSignal::Ptr sig = ScriptSignal::GetByName(m_Signal);
+
+	if (!sig)
+		BOOST_THROW_EXCEPTION(ConfigError("Signal '" + m_Signal + "' does not exist."));
+
+	sig->AddSlot(boost::bind(InvokeSlot, m_Slot->Evaluate(context), _1));
+
+	return Empty;
+}
+
 Value ApplyExpression::DoEvaluate(const Object::Ptr& context, DebugHint *dhint) const
 {
 	String name = m_Name->Evaluate(context, dhint);

lib/config/expression.hpp

@@ -581,6 +581,21 @@ private:
 	boost::shared_ptr<Expression> m_Expression;
 };
 
+class I2_CONFIG_API SlotExpression : public DebuggableExpression
+{
+public:
+	SlotExpression(const String& signal, Expression *slot, const DebugInfo& debugInfo = DebugInfo())
+		: DebuggableExpression(debugInfo), m_Signal(signal), m_Slot(slot)
+	{ }
+
+protected:
+	virtual Value DoEvaluate(const Object::Ptr& context, DebugHint *dhint) const;
+
+private:
+	String m_Signal;
+	Expression *m_Slot;
+};
+
 class I2_CONFIG_API ApplyExpression : public DebuggableExpression
 {
 public: