From f07ffaee84cef2b28c9d49e388d30f1f8e22cfc5 Mon Sep 17 00:00:00 2001
From: Jean-Marc Lasgouttes <lasgouttes@lyx.org>
Date: Thu, 5 Mar 2015 16:30:22 +0100
Subject: [PATCH] Some code factorization for the Change template

The original motivation is to initialize the change_ member but do it only once.

This fixes coverity issue 23432.
---
 src/MetricsInfo.cpp | 10 ++--------
 src/MetricsInfo.h   | 12 +++++++-----
 2 files changed, 9 insertions(+), 13 deletions(-)

diff --git a/src/MetricsInfo.cpp b/src/MetricsInfo.cpp
index e68c18d79d..b75ec81108 100644
--- a/src/MetricsInfo.cpp
+++ b/src/MetricsInfo.cpp
@@ -186,9 +186,8 @@ ArrayChanger::ArrayChanger(MetricsBase & mb)
 /////////////////////////////////////////////////////////////////////////
 
 ShapeChanger::ShapeChanger(FontInfo & font, FontShape shape)
-	: Changer<FontInfo, FontShape>(font)
+	: Changer<FontInfo, FontShape>(font, font.shape())
 {
-	save_ = orig_.shape();
 	orig_.setShape(shape);
 }
 
@@ -213,7 +212,6 @@ StyleChanger::StyleChanger(MetricsBase & mb, Styles style)
 		  { 0, 0, -3, -5 },
 		  { 3, 3,  0, -2 },
 		  { 5, 5,  2,  0 } };
-	save_ = mb;
 	int t = diff[mb.style][style];
 	if (t > 0)
 		while (t--)
@@ -242,7 +240,6 @@ FontSetChanger::FontSetChanger(MetricsBase & mb, char const * name,
 	: Changer<MetricsBase>(mb), change_(really_change_font)
 {
 	if (change_) {
-		save_ = mb;
 		FontSize oldsize = save_.font.size();
 		ColorCode oldcolor = save_.font.color();
 		docstring const oldname = from_ascii(save_.fontname);
@@ -263,7 +260,6 @@ FontSetChanger::FontSetChanger(MetricsBase & mb, docstring const & name,
 	: Changer<MetricsBase>(mb), change_(really_change_font)
 {
 	if (change_) {
-		save_ = mb;
 		FontSize oldsize = save_.font.size();
 		ColorCode oldcolor = save_.font.color();
 		docstring const oldname = from_ascii(save_.fontname);
@@ -295,7 +291,6 @@ FontSetChanger::~FontSetChanger()
 WidthChanger::WidthChanger(MetricsBase & mb, int w)
 	: Changer<MetricsBase>(mb)
 {
-	save_ = mb;
 	mb.textwidth = w;
 }
 
@@ -314,10 +309,9 @@ WidthChanger::~WidthChanger()
 
 ColorChanger::ColorChanger(FontInfo & font, ColorCode color,
 			   bool really_change_color)
-	: Changer<FontInfo, ColorCode>(font), change_(really_change_color)
+	: Changer<FontInfo, ColorCode>(font, font.color()), change_(really_change_color)
 {
 	if (change_) {
-		save_ = font.color();
 		font.setColor(color);
 	}
 }
diff --git a/src/MetricsInfo.h b/src/MetricsInfo.h
index 05acbbbb04..88dd39fd7d 100644
--- a/src/MetricsInfo.h
+++ b/src/MetricsInfo.h
@@ -126,14 +126,16 @@ public:
 class TextMetricsInfo {};
 
 
-/// Generic base for temporarily changing things.
-/// The original state gets restored when the Changer is destructed.
+/// Generic base for temporarily changing things. The derived class is
+/// responsible for restoring the original state when the Changer is
+/// destructed.
 template <class Struct, class Temp = Struct>
 class Changer {
-public:
-	///
-	Changer(Struct & orig) : orig_(orig) {}
 protected:
+	///
+	Changer(Struct & orig, Temp const & save) : orig_(orig), save_(save) {}
+	///
+	Changer(Struct & orig) : orig_(orig), save_(orig) {}
 	///
 	Struct & orig_;
 	///
-- 
2.39.2