From 85f8839af150f95e39dd962f20de8ca48b155215 Mon Sep 17 00:00:00 2001
From: "Alexander A. Klimov" <alexander.klimov@icinga.com>
Date: Wed, 9 Nov 2022 11:34:37 +0100
Subject: [PATCH] Expression#Evaluate(): avoid Defer, and malloc(), via
 try-catch

Defer is good for K. I. S. S., but with many objects
and apply rules Expression#Evaluate() is called very often.
---
 lib/config/expression.cpp | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/lib/config/expression.cpp b/lib/config/expression.cpp
index 09b860cde..a83177bc9 100644
--- a/lib/config/expression.cpp
+++ b/lib/config/expression.cpp
@@ -38,6 +38,8 @@ void Expression::ScriptBreakpoint(ScriptFrame& frame, ScriptError *ex, const Deb
 
 ExpressionResult Expression::Evaluate(ScriptFrame& frame, DebugHint *dhint) const
 {
+	ExpressionResult result (Empty);
+
 	try {
 #ifdef I2_DEBUG
 /*		std::ostringstream msgbuf;
@@ -48,11 +50,15 @@ ExpressionResult Expression::Evaluate(ScriptFrame& frame, DebugHint *dhint) cons
 
 		frame.IncreaseStackDepth();
 
-		Defer decreaseStackDepth([&frame]{
+		try {
+			result = DoEvaluate(frame, dhint);
+		} catch (...) {
 			frame.DecreaseStackDepth();
-		});
+			throw;
+		}
+
+		frame.DecreaseStackDepth();
 
-		ExpressionResult result = DoEvaluate(frame, dhint);
 		return result;
 	} catch (ScriptError& ex) {
 		ScriptBreakpoint(frame, &ex, GetDebugInfo());