Preparations for precedence graph

CupPlugin/src/de/tum/in/www2/cupplugin/views/CupConflictsView.java

@@ -5,6 +5,7 @@ import java.util.EnumSet;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Set;
 
 import org.eclipse.jface.text.BadLocationException;
 import org.eclipse.jface.text.IDocument;
@@ -86,16 +87,22 @@ public class CupConflictsView extends FailableView implements ICupEditorPageVisi
 		//TODO: Can I do this? Does the terminal class properly implement all the required things?
 		private HashMap<terminal,Precedence.Type> precs = new HashMap<>();
 		
+		// Edges are stored in reverse order (i.e. there is a edge from a to b iff b has a higher 
+		// precedence than a)
+		private HashMap<terminal,Set<terminal>> edges = new HashMap<>();
+		
 		public boolean isResolvedInFavorOfShift(ShiftReduceDetails srd){
 			if(!srd.reduce.equals(srd.shift))
-				return precs.containsKey(srd.shift);
+				//TODO: Check if precedence set for terminal at all
+				return hasPrecedence(srd.reduce,srd.shift);
 			else
 				return precs.get(srd.shift) == Precedence.Type.Right;
 		}
 		
 		public boolean isResolvedInFavorOfReduce(ShiftReduceDetails srd) {
 			if(!srd.reduce.equals(srd.shift))
-				return precs.containsKey(srd.reduce);
+				//TODO: Check if precedence set for terminal at all
+				return hasPrecedence(srd.reduce,srd.shift);
 			else
 				return precs.get(srd.shift) == Precedence.Type.Left;
 		}
@@ -111,16 +118,67 @@ public class CupConflictsView extends FailableView implements ICupEditorPageVisi
 			return precs.containsKey(srd.shift) || precs.containsKey(srd.reduce);
 		}
 		
-		// Add with non-set precedence
+		// Add with non-set assoc
 		public void add(terminal t){
 			// We use NoPrec as a placeholder
 			precs.put(t, Precedence.Type.NoPrec);
+			edges.put(t, new HashSet<>());
+			
+			for(ConflictPanel c : conflictPanels){
+				c.markIfAffected(this);
+			}
+		}
+		
+		public void addPrecedence(terminal higher,terminal lower){
+			
+			// Make sure all terminals are represented within the precs
+			if(!precs.containsKey(higher)){
+				precs.put(higher, Precedence.Type.NoPrec);
+				edges.put(higher, new HashSet<>());
+			}
+			
+			if(!precs.containsKey(lower)){
+				precs.put(lower, Precedence.Type.NoPrec);
+				edges.put(lower, new HashSet<>());
+			}
+			
+			// Insert edge
+			edges.get(lower).add(higher);
 			
 			for(ConflictPanel c : conflictPanels){
 				c.markIfAffected(this);
 			}
 		}
 		
+		private boolean hasPrecedence(terminal t,terminal over){
+			// This works because we have guarantee that the graph is a DAG
+			HashSet<terminal> toCheck = new HashSet<>();
+			toCheck.addAll(edges.get(over));
+			
+			// TODO:Sure ?
+			if(toCheck.size() == 0){
+				return true;
+			}
+			
+			while(toCheck.size() > 0){
+				if(toCheck.contains(t)){
+					return true;
+				}
+				else {
+					HashSet<terminal> next = new HashSet<>();
+					
+					for(terminal x : toCheck){
+						next.addAll(edges.get(x));
+					}
+					
+					toCheck = next;
+				}
+			}
+			
+			
+			return false;
+		}
+		
 		public void setAssoc(terminal t,Precedence.Type p){
 			if(precs.get(t) != Precedence.Type.NoPrec){
 				throw new IllegalStateException();
@@ -131,6 +189,10 @@ public class CupConflictsView extends FailableView implements ICupEditorPageVisi
 				c.markIfAffected(this);
 			}
 		}
+	
+		public boolean isActive(){
+			return precs.size() != 0;
+		}
 	}
 	
 	class ShiftReduceDetails {
@@ -519,6 +581,8 @@ public class CupConflictsView extends FailableView implements ICupEditorPageVisi
 
 		}
 		
+		//What if dropdown switched back to choose?
+		
 		public void markIfAffected(PrecedenceToInsert pti){
 			if(conflict instanceof ShiftReduceConflict && pti.isAffected(srdetails)){
 				
@@ -590,6 +654,11 @@ public class CupConflictsView extends FailableView implements ICupEditorPageVisi
 				if(resolutionOptions.getSelectionIndex() == 0){
 					return;
 				}
+				
+				if(currentPrecs.isActive()) {
+					// That should not happen, if we are inside a connected conflict, button is disabled
+					return;
+				}
 			
 
 				if(!srdetails.reduce.equals(srdetails.shift)){
@@ -641,7 +710,12 @@ public class CupConflictsView extends FailableView implements ICupEditorPageVisi
 
 			@Override
 			public void widgetSelected(SelectionEvent e) {
-				if(partOfCurrentConnected && srdetails.reduce.equals(srdetails.shift)){
+				if(!partOfCurrentConnected) {
+					return;
+				}
+				
+				// We need to insert a assoc
+				if(srdetails.reduce.equals(srdetails.shift)){
 					if(resolutionOptions.getSelectionIndex() == 1) { //Shift
 						forceEnableDropdown = true;
 						currentPrecs.setAssoc(srdetails.shift,Precedence.Type.Right);
@@ -651,6 +725,27 @@ public class CupConflictsView extends FailableView implements ICupEditorPageVisi
 						currentPrecs.setAssoc(srdetails.shift,Precedence.Type.Left);
 					}
 				}
+				else {
+					if(resolutionOptions.getSelectionIndex() == 1 && currentPrecs.isResolvedInFavorOfShift(srdetails)){
+						// Shift is current solution, Shift is desired
+						// Do nothing
+						return;
+					}
+					if(resolutionOptions.getSelectionIndex() == 2 && currentPrecs.isResolvedInFavorOfReduce(srdetails)){
+						// Reduce is current solution, Reduce is desired
+						// Do nothing
+						return;
+					}
+					
+					if(resolutionOptions.getSelectionIndex() == 1){ //Shift
+						currentPrecs.addPrecedence(srdetails.shift, srdetails.reduce);
+					}
+					
+					if(resolutionOptions.getSelectionIndex() == 2){ // Reduce
+						currentPrecs.addPrecedence(srdetails.reduce, srdetails.shift);
+					}
+				}
+				
 			}
 
 			@Override