From c9541eeeabee6691893be9b3ca728f97325bb305 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Andr=C3=A9=20P=C3=B6nitz?= <poenitz@gmx.net>
Date: Tue, 11 Dec 2001 07:38:02 +0000
Subject: [PATCH] Essentially Lars' "thread safe" patch

git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@3183 a592a061-630c-0410-9148-cb99ea01b6c8
---
 src/mathed/math_atom.C | 49 ++++++++++++++----------------------------
 src/mathed/math_atom.h | 30 +++++++++++++-------------
 2 files changed, 31 insertions(+), 48 deletions(-)

diff --git a/src/mathed/math_atom.C b/src/mathed/math_atom.C
index bcf72881cc..db9ab90bc5 100644
--- a/src/mathed/math_atom.C
+++ b/src/mathed/math_atom.C
@@ -1,15 +1,12 @@
 /*
- *  File:        math_inset.C
- *  Purpose:     Implementation of insets for mathed
- *  Author:      Alejandro Aguilar Sierra <asierra@servidor.unam.mx> 
- *  Created:     January 1996
- *  Description: 
+ *  File:        math_atom.C
+ *  Purpose:     Wrapper for MathInset * 
+ *  Author:      André Pönitz
+ *  Created:     July 2001
  *
- *  Dependencies: Xlib, XForms
+ *  Copyright: 2001 The LyX team
  *
- *  Copyright: 1996, 1997 Alejandro Aguilar Sierra
- *
- *   Version: 0.8beta.
+ *   Version: 1.2.0
  *
  *   You are free to use and modify this code under the terms of
  *   the GNU General Public Licence version 2 or later.
@@ -23,6 +20,7 @@
 #include "math_inset.h"
 #include "support/LAssert.h"
 
+#include <utility>
 
 MathAtom::MathAtom()
 	: nucleus_(0)
@@ -35,46 +33,31 @@ MathAtom::MathAtom(MathInset * p)
 
 
 MathAtom::MathAtom(MathAtom const & p)
-{
-	copy(p);
-}
+	: nucleus_(p.nucleus_ ? p.nucleus_->clone() : 0)
+{}
 
 
 void MathAtom::operator=(MathAtom const & p)
 {
-	if (this == &p)
+	if (&p == this)
 		return;
-	done();
-	copy(p);
+	MathAtom tmp(p);
+	std::swap(tmp.nucleus_, nucleus_);
 }
 
 
 MathAtom::~MathAtom()
 {
-	done();
+	delete nucleus_;
 }
 
 
 void MathAtom::reset(MathInset * p)
 {
-	done();
-	nucleus_ = p;
-}
-
-
-
-void MathAtom::done()
-{
+	if (p == nucleus_)
+		return;
 	delete nucleus_;
-}
-
-
-void MathAtom::copy(MathAtom const & p)
-{
-	//cerr << "calling MathAtom::copy\n";
-	nucleus_   = p.nucleus_;
-	if (nucleus_)
-		nucleus_ = nucleus_->clone();
+	nucleus_ = p;
 }
 
 
diff --git a/src/mathed/math_atom.h b/src/mathed/math_atom.h
index 8713c4113b..8e78a4b0c8 100644
--- a/src/mathed/math_atom.h
+++ b/src/mathed/math_atom.h
@@ -22,6 +22,10 @@ Ok: Implementing it thusly is not feasible since cursor movement gets
 hackish. We use MathAtom only as a wrapper around MathInset * with value
 semantics.
 
+The MathAtom owns the MathInset * and is responsible for proper cloning and
+destruction. Every MathInset * should be put into a MathAtom after its
+creation as soon as possible.
+
 Andre'
 
 */
@@ -30,31 +34,27 @@ class MathInset;
 
 class MathAtom {
 public: 
-	///
+	/// default constructor, object is useless, but we need it to put it into
+	// std::containers
 	MathAtom();
-	///
-	MathAtom(MathAtom const &);
-	///
+	/// the "real constructor"
 	explicit MathAtom(MathInset * p);
-	/// 
-	virtual ~MathAtom(); 
-	///
+	/// copy constructor, invokes nucleus_->clone()
+	MathAtom(MathAtom const &);
+	/// we really need to clean up
+	~MathAtom(); 
+	/// assignment invokes nucleus_->clone()
 	void operator=(MathAtom const &);
-	///
+	/// change inset under the hood
 	void reset(MathInset * p);
-	///
+	/// access to the inset
 	MathInset * nucleus() const;
-	///
+	/// access to the inset
 	MathInset * operator->() const;
 
 private:
 	///
 	MathInset * nucleus_;
-
-	/// raw copy
-	void copy(MathAtom const & p);
-	/// raw destruction
-	void done();
 };
 
 #endif
-- 
2.39.2