Checking TreeH in LoadHit method to avoid segmentation fault when displaing merged...

diff --git a/MUON/AliMUONDisplay.cxx b/MUON/AliMUONDisplay.cxx
index cc44814e71a726795fd99471f11ccdd2c2f3c4fe..661c75a9086c7876dccc02cff233f3239b8e9900 100644 (file)
--- a/MUON/AliMUONDisplay.cxx
+++ b/MUON/AliMUONDisplay.cxx
@@ -961,19 +961,21 @@ void AliMUONDisplay::LoadHits(Int_t chamber)
     iChamber = &(pMUON->Chamber(chamber-1));
     Float_t zpos=iChamber->Z();
 
-    GetMUONData()->SetTreeAddress("H");
-    Int_t ntracks = (Int_t)GetMUONData()->TreeH()->GetEntries(); //skowron
-    Int_t nthits  = 0;
-    for (track = 0; track < ntracks; track++) {
+
+    if (GetMUONData()->TreeH()) {
+      GetMUONData()->SetTreeAddress("H");
+      Int_t ntracks = (Int_t)GetMUONData()->TreeH()->GetEntries(); //skowron
+      Int_t nthits  = 0;
+      for (track = 0; track < ntracks; track++) {
        GetMUONData()->ResetHits();
        GetMUONData()->GetTrack(track);//skowron
        TClonesArray *muonHits  = GetMUONData()->Hits();
        if (muonHits == 0) return;
        nthits += muonHits->GetEntriesFast();
-    } 
-    if (fPhits == 0) fPhits = new TObjArray(nthits);
-    Int_t nhold=0;
-    for (track=0; track<ntracks;track++) {
+      } 
+      if (fPhits == 0) fPhits = new TObjArray(nthits);
+      Int_t nhold=0;
+      for (track=0; track<ntracks;track++) {
        GetMUONData()->ResetHits();
        GetMUONData()->GetTrack(track);//skowron
        TClonesArray *muonHits  = GetMUONData()->Hits();
@@ -984,25 +986,26 @@ void AliMUONDisplay::LoadHits(Int_t chamber)
        AliMUONPoints *points = 0;
        Int_t npoints=1;
        for (Int_t hit=0;hit<nhits;hit++) {
-            mHit = (AliMUONHit*)muonHits->UncheckedAt(hit);
-            Int_t nch  = mHit->Chamber();              // chamber number
-            if (nch != chamber) continue;
-           //
-           // Retrieve info and set the objects
-           //
-           points = new AliMUONPoints(npoints);
-           fPhits->AddAt(points,nhold+hit);
-            points->SetMarkerColor(kRed);
-            points->SetMarkerStyle(5);
-            points->SetMarkerSize(1.);
-            points->SetParticle(mHit->Track());
-            points->SetHitIndex(hit);
-            points->SetTrackIndex(track);
-            points->SetDigitIndex(-1);
-           points->SetPoint(0,mHit->X(),mHit->Y(),zpos);
-           //      printf("%f and %f and %f\n",mHit->X(),mHit->Y(),mHit->Z());
+         mHit = (AliMUONHit*)muonHits->UncheckedAt(hit);
+         Int_t nch  = mHit->Chamber();              // chamber number
+         if (nch != chamber) continue;
+         //
+         // Retrieve info and set the objects
+         //
+         points = new AliMUONPoints(npoints);
+         fPhits->AddAt(points,nhold+hit);
+         points->SetMarkerColor(kRed);
+         points->SetMarkerStyle(5);
+         points->SetMarkerSize(1.);
+         points->SetParticle(mHit->Track());
+         points->SetHitIndex(hit);
+         points->SetTrackIndex(track);
+         points->SetDigitIndex(-1);
+         points->SetPoint(0,mHit->X(),mHit->Y(),zpos);
+         //        printf("%f and %f and %f\n",mHit->X(),mHit->Y(),mHit->Z());
        }
        nhold+=nhits;
+      }
     }
 }