From 339b8aef48c4ecb371f3f2f4abda41f6b9a3abd2 Mon Sep 17 00:00:00 2001
From: Gunnar Beutner <gunnar@beutner.name>
Date: Sun, 29 Mar 2015 22:26:07 +0200
Subject: [PATCH] Avoid unnecessary allocations in ScriptFrame::SetCurrentFrame

---
 lib/base/scriptframe.cpp | 43 +++++++++++++++++++++++++++-------------
 lib/base/scriptframe.hpp |  7 ++++---
 2 files changed, 33 insertions(+), 17 deletions(-)

diff --git a/lib/base/scriptframe.cpp b/lib/base/scriptframe.cpp
index 8e976c9b2..da03a99a0 100644
--- a/lib/base/scriptframe.cpp
+++ b/lib/base/scriptframe.cpp
@@ -22,39 +22,54 @@
 
 using namespace icinga;
 
-boost::thread_specific_ptr<ScriptFrame *> ScriptFrame::m_CurrentFrame;
+boost::thread_specific_ptr<std::stack<ScriptFrame *> > ScriptFrame::m_ScriptFrames;
 
 ScriptFrame::ScriptFrame(void)
 	: Locals(new Dictionary()), Self(ScriptGlobal::GetGlobals())
 {
-	NextFrame = GetCurrentFrame();
-	SetCurrentFrame(this);
+	PushFrame(this);
 }
 
 ScriptFrame::ScriptFrame(const Value& self)
 	: Locals(new Dictionary()), Self(self)
 {
-	NextFrame = GetCurrentFrame();
-	SetCurrentFrame(this);
+	PushFrame(this);
 }
 
 ScriptFrame::~ScriptFrame(void)
 {
-	ASSERT(GetCurrentFrame() == this);
-	SetCurrentFrame(NextFrame);
+	ScriptFrame *frame = PopFrame();
+	ASSERT(frame == this);
 }
 
 ScriptFrame *ScriptFrame::GetCurrentFrame(void)
 {
-	ScriptFrame **pframe = m_CurrentFrame.get();
+	std::stack<ScriptFrame *> *frames = m_ScriptFrames.get();
 
-	if (pframe)
-		return *pframe;
-	else
-		return NULL;
+	ASSERT(!frames->empty());
+	return frames->top();
 }
 
-void ScriptFrame::SetCurrentFrame(ScriptFrame *frame)
+ScriptFrame *ScriptFrame::PopFrame(void)
 {
-	m_CurrentFrame.reset(new ScriptFrame *(frame));
+	std::stack<ScriptFrame *> *frames = m_ScriptFrames.get();
+
+	ASSERT(!frames->empty());
+
+	ScriptFrame *frame = frames->top();
+	frames->pop();
+
+	return frame;
+}
+
+void ScriptFrame::PushFrame(ScriptFrame *frame)
+{
+	std::stack<ScriptFrame *> *frames = m_ScriptFrames.get();
+
+	if (!frames) {
+		frames = new std::stack<ScriptFrame *>();
+		m_ScriptFrames.reset(frames);
+	}
+
+	frames->push(frame);
 }
diff --git a/lib/base/scriptframe.hpp b/lib/base/scriptframe.hpp
index 73a67d248..f4e47151a 100644
--- a/lib/base/scriptframe.hpp
+++ b/lib/base/scriptframe.hpp
@@ -23,6 +23,7 @@
 #include "config/i2-config.hpp"
 #include "base/dictionary.hpp"
 #include <boost/thread/tss.hpp>
+#include <stack>
 
 namespace icinga
 {
@@ -31,7 +32,6 @@ struct I2_BASE_API ScriptFrame
 {
 	Dictionary::Ptr Locals;
 	Value Self;
-	ScriptFrame *NextFrame;
 
 	ScriptFrame(void);
 	ScriptFrame(const Value& self);
@@ -40,9 +40,10 @@ struct I2_BASE_API ScriptFrame
 	static ScriptFrame *GetCurrentFrame(void);
 
 private:
-	static boost::thread_specific_ptr<ScriptFrame *> m_CurrentFrame;
+	static boost::thread_specific_ptr<std::stack<ScriptFrame *> > m_ScriptFrames;
 
-	static void SetCurrentFrame(ScriptFrame *frame);
+	inline static void PushFrame(ScriptFrame *frame);
+	inline static ScriptFrame *PopFrame(void);
 };
 
 }