Fix removing intervals in the interval tree.

ProtocolLib/src/main/java/com/comphenix/protocol/concurrency/AbstractIntervalTree.java

@@ -6,6 +6,7 @@ import java.util.NavigableMap;
 import java.util.Set;
 import java.util.TreeMap;
 
+import com.google.common.base.Objects;
 import com.google.common.collect.Range;
 import com.google.common.collect.Ranges;
 
@@ -32,24 +33,25 @@ public abstract class AbstractIntervalTree<TKey extends Comparable<TKey>, TValue
 	 * Represents a range and a value in this interval tree.
 	 */
 	public class Entry implements Map.Entry<Range<TKey>, TValue> {
-		private final Range<TKey> key;
 		private EndPoint left;
 		private EndPoint right;
 
-		Entry(Range<TKey> key, EndPoint left, EndPoint right) {
+		Entry(EndPoint left, EndPoint right) {
 			if (left == null)
 				throw new IllegalAccessError("left cannot be NUll");
 			if (right == null)
 				throw new IllegalAccessError("right cannot be NUll");
+			if (left.key.compareTo(right.key) > 0)
+				throw new IllegalArgumentException(
+						"Left key (" + left.key + ") cannot be greater than the right key (" + right.key + ")");
 			
-			this.key = key;
 			this.left = left;
 			this.right = right;
 		}
 
 		@Override
 		public Range<TKey> getKey() {
-			return key;
+			return Ranges.closed(left.key, right.key);
 		}
 
 		@Override
@@ -66,6 +68,31 @@ public abstract class AbstractIntervalTree<TKey extends Comparable<TKey>, TValue
 			right.value = value;
 			return old;
 		}
+		
+		@SuppressWarnings("rawtypes")
+		@Override
+		public boolean equals(Object obj) {
+			// Quick equality check
+			if (obj == this) {
+				return true;
+			} else if (obj instanceof AbstractIntervalTree.Entry) {
+				return Objects.equal(left.key, ((AbstractIntervalTree.Entry) obj).left.key) &&
+					   Objects.equal(right.key, ((AbstractIntervalTree.Entry) obj).right.key) &&
+					   Objects.equal(left.value, ((AbstractIntervalTree.Entry) obj).left.value);
+			} else {
+				return false;
+			}
+		}
+		
+		@Override
+		public int hashCode() {
+			return Objects.hashCode(left.key, right.key, left.value);
+		}
+		
+		@Override
+		public String toString() {
+			return String.format("Value %s at [%s, %s]", left.value, left.key, right.key);
+		}
 	}
 	
 	/**
@@ -79,8 +106,12 @@ public abstract class AbstractIntervalTree<TKey extends Comparable<TKey>, TValue
 		// The value this range contains
 		public TValue value;
 		
-		public EndPoint(State state, TValue value) {
+		// The key of this end point
+		public TKey key;
+
+		public EndPoint(State state, TKey key, TValue value) {
 			this.state = state;
+			this.key = key;
 			this.value = value;
 		}	
 	}
@@ -107,31 +138,46 @@ public abstract class AbstractIntervalTree<TKey extends Comparable<TKey>, TValue
 		checkBounds(lowerBound, upperBound);
 		NavigableMap<TKey, EndPoint> range = bounds.subMap(lowerBound, true, upperBound, true);
 		
-		boolean emptyRange = range.isEmpty();
-		TKey first = !emptyRange ? range.firstKey() : null;
-		TKey last = !emptyRange ? range.lastKey() : null;
+		EndPoint first = getNextEndPoint(lowerBound, true); 
+		EndPoint last = getPreviousEndPoint(upperBound, true);
+		
+		// Used while resizing intervals
+		EndPoint previous = null;
+		EndPoint next = null;
 		
 		Set<Entry> resized = new HashSet<Entry>();
 		Set<Entry> removed = new HashSet<Entry>();
 		
 		// Remove the previous element too. A close end-point must be preceded by an OPEN end-point.
-		if (first != null && range.get(first).state == State.CLOSE) {
-			TKey key = bounds.floorKey(first);
-			EndPoint removedPoint = removeIfNonNull(key);
+		if (first != null && first.state == State.CLOSE) {
+			previous = getPreviousEndPoint(first.key, false);
 			
 			// Add the interval back
-			if (removedPoint != null && preserveDifference) {
-				resized.add(putUnsafe(key, decrementKey(lowerBound), removedPoint.value));
+			if (previous != null) {
+				removed.add(getEntry(previous, first));
 			}
 		}
 		
 		// Get the closing element too.
-		if (last != null && range.get(last).state == State.OPEN) {
-			TKey key = bounds.ceilingKey(last);
-			EndPoint removedPoint = removeIfNonNull(key);
+		if (last != null && last.state == State.OPEN) {
+			next = getNextEndPoint(last.key, false);
 		
-			if (removedPoint != null && preserveDifference) {
-				resized.add(putUnsafe(incrementKey(upperBound), key, removedPoint.value));
+			if (next != null) {
+				removed.add(getEntry(last, next));
+			} 
+		}
+		
+		// Now remove both ranges
+		removeEntrySafely(previous, first);
+		removeEntrySafely(last, next);
+		
+		// Add new resized intervals
+		if (preserveDifference) {
+			if (previous != null) {
+				resized.add(putUnsafe(previous.key, decrementKey(lowerBound), previous.value));
+			}
+			if (next != null) {
+				resized.add(putUnsafe(incrementKey(upperBound), next.key, next.value));
 			}
 		}
 		
@@ -140,7 +186,6 @@ public abstract class AbstractIntervalTree<TKey extends Comparable<TKey>, TValue
 		invokeEntryRemoved(removed);
 		
 		if (preserveDifference) {
-			invokeEntryRemoved(resized);
 			invokeEntryAdded(resized);
 		}
 		
@@ -149,12 +194,30 @@ public abstract class AbstractIntervalTree<TKey extends Comparable<TKey>, TValue
 		return removed;
 	}
 	
-	// Helper
-	private EndPoint removeIfNonNull(TKey key) {
-		if (key != null) {
-			return bounds.remove(key);
+	/**
+	 * Retrieve the entry from a given set of end points.
+	 * @param left - leftmost end point.
+	 * @param right - rightmost end point.
+	 * @return The associated entry.
+	 */
+	protected Entry getEntry(EndPoint left, EndPoint right) {
+		if (left == null)
+			throw new IllegalArgumentException("left endpoint cannot be NULL.");
+		if (right == null)
+			throw new IllegalArgumentException("right endpoint cannot be NULL.");
+		
+		// Make sure the order is correct
+		if (right.key.compareTo(left.key) < 0) {
+			return getEntry(right, left);
 		} else {
-			return null;
+			return new Entry(left, right);
+		}
+	}
+	
+	private void removeEntrySafely(EndPoint left, EndPoint right) {
+		if (left != null && right != null) {
+			bounds.remove(left.key);
+			bounds.remove(right.key);
 		}
 	}
 	
@@ -165,7 +228,7 @@ public abstract class AbstractIntervalTree<TKey extends Comparable<TKey>, TValue
 		if (endPoint != null) {
 			endPoint.state = State.BOTH;
 		} else {
-			endPoint = new EndPoint(state, value);
+			endPoint = new EndPoint(state, key, value);
 			bounds.put(key, endPoint);
 		}
 		return endPoint;
@@ -199,8 +262,7 @@ public abstract class AbstractIntervalTree<TKey extends Comparable<TKey>, TValue
 			EndPoint left = addEndPoint(lowerBound, value, State.OPEN);
 			EndPoint right = addEndPoint(upperBound, value, State.CLOSE);
 
-			Range<TKey> range = Ranges.closed(lowerBound, upperBound);
-			return new Entry(range, left, right);
+			return new Entry(left, right);
 		} else {
 			return null;
 		}
@@ -261,11 +323,12 @@ public abstract class AbstractIntervalTree<TKey extends Comparable<TKey>, TValue
 			switch (entry.getValue().state) {
 			case BOTH:
 				EndPoint point = entry.getValue();
-				destination.add(new Entry(Ranges.singleton(entry.getKey()), point, point));
+				destination.add(new Entry(point, point));
 				break;
 			case CLOSE:
-				Range<TKey> range = Ranges.closed(last.getKey(), entry.getKey());
-				destination.add(new Entry(range, last.getValue(), entry.getValue()));
+				if (last != null) {
+					destination.add(new Entry(last.getValue(), entry.getValue()));
+				}
 				break;
 			case OPEN:
 				// We don't know the full range yet
@@ -284,7 +347,7 @@ public abstract class AbstractIntervalTree<TKey extends Comparable<TKey>, TValue
 	public void putAll(AbstractIntervalTree<TKey, TValue> other) {
 		// Naively copy every range.
 		for (Entry entry : other.entrySet()) {
-			put(entry.key.lowerEndpoint(), entry.key.upperEndpoint(), entry.getValue());
+			put(entry.left.key, entry.right.key, entry.getValue());
 		}
 	}
 	
@@ -303,7 +366,7 @@ public abstract class AbstractIntervalTree<TKey extends Comparable<TKey>, TValue
 	}
 	
 	/**
-	 * Get the end-point composite associated with this key.
+	 * Get the left-most end-point associated with this key.
 	 * @param key - key to search for.
 	 * @return The end point found, or NULL.
 	 */
@@ -311,22 +374,60 @@ public abstract class AbstractIntervalTree<TKey extends Comparable<TKey>, TValue
 		EndPoint ends = bounds.get(key);
 		
 		if (ends != null) {
-			// This is a piece of cake
-			return ends;
-		} else {
+			// Always return the end point to the left
+			if (ends.state == State.CLOSE) {
+				Map.Entry<TKey, EndPoint> left = bounds.floorEntry(decrementKey(key));
+				return left != null ? left.getValue() : null;
 				
+			} else {
+				return ends;
+			}
+			
+		} else {
 			// We need to determine if the point intersects with a range
-			TKey left = bounds.floorKey(key);
+			Map.Entry<TKey, EndPoint> left = bounds.floorEntry(key);
 			
 			// We only need to check to the left
-			if (left != null && bounds.get(left).state == State.OPEN) {
-				return bounds.get(left);
+			if (left != null && left.getValue().state == State.OPEN) {
+				return left.getValue();
 			} else {
 				return null;
 			}
 		}
 	}
 	
+	/**
+	 * Get the previous end point of a given key.
+	 * @param point - the point to search with.
+	 * @param inclusive - whether or not to include the current point in the search.
+	 * @return The previous end point of a given given key, or NULL if not found.
+	 */
+	protected EndPoint getPreviousEndPoint(TKey point, boolean inclusive) {
+		if (point != null) {
+			Map.Entry<TKey, EndPoint> previous = bounds.floorEntry(inclusive ? point : decrementKey(point));
+		
+			if (previous != null) 
+				return previous.getValue();
+		}
+		return null;
+	}
+	
+	/**
+	 * Get the next end point of a given key.
+	 * @param point - the point to search with.
+	 * @param inclusive - whether or not to include the current point in the search.
+	 * @return The next end point of a given given key, or NULL if not found.
+	 */
+	protected EndPoint getNextEndPoint(TKey point, boolean inclusive) {
+		if (point != null) {
+			Map.Entry<TKey, EndPoint> next = bounds.ceilingEntry(inclusive ? point : incrementKey(point));
+		
+			if (next != null) 
+				return next.getValue();
+		}
+		return null;
+	}
+
 	private void invokeEntryAdded(Entry added) {
 		if (added != null) {
 			onEntryAdded(added);