Change TrailEntry so it uses a StepsID instead of a Steps*.

Now Edit Mode can change the Steps pointers without causing crashes
because of the Trails.  (Exception: deleted song or steps.)

stepmania/src/StepsUtil.h

@@ -69,6 +69,7 @@ namespace StepsUtil
 
 class StepsID
 {
+private:
 	StepsType st;
 	Difficulty dc;
 	RString sDescription;
@@ -89,6 +90,13 @@ public:
 	static void ClearCache();
 	
 	StepsType GetStepsType() const { return st; }
+
+	bool operator==( const StepsID &other ) const
+	{
+#define X(x) (x == other.x)
+		return X(st) && X(dc) && X(sDescription) && X(uHash);
+#undef X
+	}
 };
 
 #endif

stepmania/src/Trail.cpp

@@ -21,7 +21,7 @@ bool TrailEntry::operator== ( const TrailEntry &rhs ) const
 #define EQUAL(a) (a==rhs.a)
 	return 
 		EQUAL(pSong) &&
-		EQUAL(pSteps) &&
+		EQUAL(m_StepsID) &&
 		EQUAL(Modifiers) &&
 		EQUAL(Attacks) &&
 		EQUAL(bSecret) &&
@@ -32,12 +32,12 @@ bool TrailEntry::operator== ( const TrailEntry &rhs ) const
 
 Steps *TrailEntry::GetSteps() const
 {
-	return pSteps;
+	return m_StepsID.ToSteps( pSong, false );
 }
 
 void TrailEntry::SetSteps(Steps *steps)
 {
-	pSteps = steps;
+	m_StepsID.FromSteps( steps );
 }
 
 bool TrailEntry::ContainsTransformOrTurn() const

stepmania/src/Trail.h

@@ -4,8 +4,9 @@
 #define TRAIL_H
 
 #include "Attack.h"
-#include "RadarValues.h"
 #include "Difficulty.h"
+#include "RadarValues.h"
+#include "StepsUtil.h"
 
 class Song;
 class Steps;
@@ -16,7 +17,6 @@ struct TrailEntry
 public:
 	TrailEntry(): 
 		pSong(NULL), 
-		pSteps(NULL),
 		bSecret(false),
 		iLowMeter(-1),
 		iHighMeter(-1),
@@ -29,7 +29,7 @@ public:
 	bool		ContainsTransformOrTurn() const;
 
 	Song*		pSong;
-	Steps*		pSteps;
+	StepsID		m_StepsID;
 	RString		Modifiers;
 	AttackArray	Attacks;
 	bool		bSecret;	// show "???"