auto_ptr is incompatible with STL containers; use a custom refcounted holder

stepmania/src/ActorCommands.h

@@ -3,7 +3,7 @@
 #ifndef ActorCommands_H
 #define ActorCommands_H
 
-#include <memory>	// auto_ptr
+#include "RageUtil_AutoPtr.h"
 class Commands;
 
 class ActorCommands
@@ -22,7 +22,7 @@ private:
 	CString m_sLuaFunctionName;
 };
 
-typedef auto_ptr<ActorCommands> apActorCommands;
+typedef AutoPtrCopyOnWrite<ActorCommands> apActorCommands;
 
 #endif
 

stepmania/src/Makefile.am

@@ -258,7 +258,8 @@ RageSurface_Load_XPM.cpp RageSurface_Load_XPM.h RageTexture.cpp RageTexture.h \
 RageSurface_Save_BMP.cpp RageSurface_Save_BMP.h \
 RageTextureID.cpp RageTextureID.h RageTextureManager.cpp RageTextureManager.h RageThreads.cpp RageThreads.h \
 RageTimer.cpp RageTimer.h RageTypes.h RageUtil.cpp RageUtil.h RageUtil_CharConversions.cpp RageUtil_CharConversions.h \
-RageUtil_BackgroundLoader.cpp RageUtil_BackgroundLoader.h RageUtil_FileDB.cpp RageUtil_FileDB.h RageUtil_CircularBuffer.h
+RageUtil_BackgroundLoader.cpp RageUtil_BackgroundLoader.h RageUtil_FileDB.cpp RageUtil_FileDB.h RageUtil_CircularBuffer.h \
+RageUtil_AutoPtr.h
 
 Actors = \
 Actor.cpp Actor.h ActorCollision.h ActorFrame.cpp ActorFrame.h \

stepmania/src/RageUtil_AutoPtr.h

@@ -0,0 +1,122 @@
+#ifndef RAGE_UTIL_AUTO_PTR_H
+#define RAGE_UTIL_AUTO_PTR_H
+
+/*
+ * This is a simple copy-on-write refcounted smart pointer.  Once constructed, all read-only
+ * access to the object is made without extra copying.  If you need read-write access, you
+ * can get a pointer with Get(), which will cause the object to deep-copy.  (Don't free
+ * the resulting pointer.)
+ *
+ * Note that there are no non-const operator* or operator-> overloads, because that would
+ * cause all const access by code with non-const permissions to deep-copy.  For example,
+ *
+ *   AutoPtrCopyOnWrite<int> a( new int(1) );
+ *   AutoPtrCopyOnWrite<int> b( a );
+ *   printf( "%i\n", *a );
+ *
+ * If we have a non-const operator*, this *a will use it (even though it only needs const
+ * access), and will copy the underlying object wastefully.  g++ std::string has this behavior,
+ * which is why it's important to qualify strings as "const" when const access is desired,
+ * but that's brittle, so let's make all potential deep-copying explicit.
+ */
+
+template<class T>
+class AutoPtrCopyOnWrite
+{
+public:
+	/* This constructor only exists to make us work with STL containers. */
+	inline AutoPtrCopyOnWrite()
+	{
+		m_pPtr = NULL;
+		m_iRefCount = new int(1);
+	}
+
+	explicit inline AutoPtrCopyOnWrite( T *p )
+	{
+		m_pPtr = p;
+		m_iRefCount = new int(1);
+	}
+
+	inline AutoPtrCopyOnWrite( const AutoPtrCopyOnWrite &rhs )
+	{
+		m_pPtr = rhs.m_pPtr;
+		m_iRefCount = rhs.m_iRefCount;
+		++(*m_iRefCount);
+	}
+
+	void Swap( AutoPtrCopyOnWrite<T> &rhs )
+	{
+		swap( m_pPtr, rhs.m_pPtr );
+		swap( m_iRefCount, rhs.m_iRefCount );
+	}
+
+	inline AutoPtrCopyOnWrite<T> &operator=( const AutoPtrCopyOnWrite &rhs )
+	{
+		AutoPtrCopyOnWrite<T> obj( rhs );
+		this->Swap( obj );
+		return *this;
+	}
+
+	~AutoPtrCopyOnWrite()
+	{
+		--(*m_iRefCount);
+		if( *m_iRefCount == 0 )
+		{
+			delete m_pPtr;
+			delete m_iRefCount;
+		}
+	}
+
+	/* Get a non-const pointer.  This will deep-copy the object if necessary. */
+	T *Get()
+	{
+		if( *m_iRefCount > 1 )
+		{
+			--*m_iRefCount;
+			m_pPtr = new T(*m_pPtr);
+			m_iRefCount = new int(1);
+		}
+
+		return m_pPtr;
+	}
+
+	const T &operator *() const { return *m_pPtr; }
+	const T *operator ->() const { return m_pPtr; }
+
+private:
+	T *m_pPtr;
+	int *m_iRefCount;
+};
+
+template<class T>
+inline void swap( AutoPtrCopyOnWrite<T> &a, AutoPtrCopyOnWrite<T> &b )
+{
+	a.Swap(b);
+}
+
+#endif
+
+/*
+ * (c) 2005 Glenn Maynard
+ * All rights reserved.
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, and/or sell copies of the Software, and to permit persons to
+ * whom the Software is furnished to do so, provided that the above
+ * copyright notice(s) and this permission notice appear in all copies of
+ * the Software and that both the above copyright notice(s) and this
+ * permission notice appear in supporting documentation.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF
+ * THIRD PARTY RIGHTS. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR HOLDERS
+ * INCLUDED IN THIS NOTICE BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL INDIRECT
+ * OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
+ * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+ * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+ * PERFORMANCE OF THIS SOFTWARE.
+ */

stepmania/src/StepMania.dsp

@@ -62,7 +62,7 @@ IntDir=.\../Debug6
 TargetDir=\temp\stepmania\Program
 TargetName=StepMania-debug
 SOURCE="$(InputPath)"
-PreLink_Cmds=archutils\Win32\verinc                                                                                                                                                                	cl                        /Zl                        /nologo                        /c                        verstub.cpp                        /Fo$(IntDir)\ 
+PreLink_Cmds=archutils\Win32\verinc                                                                                                                                                                 	cl                         /Zl                         /nologo                         /c                         verstub.cpp                         /Fo$(IntDir)\ 
 PostBuild_Cmds=archutils\Win32\mapconv $(IntDir)\$(TargetName).map $(TargetDir)\StepMania.vdi
 # End Special Build Tool
 
@@ -99,7 +99,7 @@ IntDir=.\../Release6
 TargetDir=\temp\stepmania\Program
 TargetName=StepMania
 SOURCE="$(InputPath)"
-PreLink_Cmds=archutils\Win32\verinc                                                                                                                                                                 	cl                                                                                                                          /Zl                                                                                                                          /nologo                                                                                                                          /c                                                                                                                          verstub.cpp                                                                                                                          /Fo$(IntDir)\ 
+PreLink_Cmds=archutils\Win32\verinc                                                                                                                                                                  	cl                                                                                                                           /Zl                                                                                                                           /nologo                                                                                                                           /c                                                                                                                           verstub.cpp                                                                                                                           /Fo$(IntDir)\ 
 PostBuild_Cmds=archutils\Win32\mapconv $(IntDir)\$(TargetName).map $(TargetDir)\StepMania.vdi
 # End Special Build Tool
 
@@ -604,6 +604,10 @@ SOURCE=.\RageUtil.h
 # End Source File
 # Begin Source File
 
+SOURCE=.\RageUtil_AutoPtr.h
+# End Source File
+# Begin Source File
+
 SOURCE=.\RageUtil_BackgroundLoader.cpp
 # End Source File
 # Begin Source File

stepmania/src/StepMania.vcproj

@@ -2138,6 +2138,9 @@ cl /Zl /nologo /c verstub.cpp /Fo"$(IntDir)"\
 			<File
 				RelativePath=".\RageUtil.h">
 			</File>
+			<File
+				RelativePath="RageUtil_AutoPtr.h">
+			</File>
 			<File
 				RelativePath="RageUtil_BackgroundLoader.cpp">
 			</File>