Implement index tracking to optimize list operations

src/main/java/ch/njol/skript/expressions/ExprAmount.java

@@ -11,6 +11,7 @@
 import ch.njol.skript.lang.ExpressionList;
 import ch.njol.skript.lang.ExpressionType;
 import ch.njol.skript.lang.SkriptParser.ParseResult;
+import ch.njol.skript.lang.Variable;
 import ch.njol.skript.lang.util.SimpleExpression;
 import ch.njol.skript.lang.util.common.AnyAmount;
 import ch.njol.skript.util.LiteralUtils;
@@ -42,6 +43,7 @@ public class ExprAmount extends SimpleExpression<Number> {
 	@SuppressWarnings("null")
 	private ExpressionList<?> exprs;
 	private @Nullable Expression<AnyAmount> any;
+	private @Nullable Variable<?> list;
 
 	@Override
 	public boolean init(Expression<?>[] exprs, int matchedPattern, Kleenean isDelayed, ParseResult parseResult) {
@@ -54,7 +56,6 @@ public boolean init(Expression<?>[] exprs, int matchedPattern, Kleenean isDelaye
 		this.exprs = exprs[0] instanceof ExpressionList<?> exprList
 				? exprList
 				: new ExpressionList<>(new Expression<?>[]{ exprs[0] }, Object.class, false);
-
 		this.exprs = (ExpressionList<?>) LiteralUtils.defendExpression(this.exprs);
 		if (!LiteralUtils.canInitSafely(this.exprs)) {
 			return false;
@@ -65,13 +66,20 @@ public boolean init(Expression<?>[] exprs, int matchedPattern, Kleenean isDelaye
 			return false;
 		}
 
+		if (exprs[0] instanceof Variable<?> variable)
+			this.list = variable;
+
 		return true;
 	}
 
 	@Override
 	protected Number[] get(Event event) {
 		if (any != null)
 			return new Number[] {any.getOptionalSingle(event).orElse(() -> 0).amount()};
+
+		if (list != null)
+			return new Long[]{(long) list.size(event)};
+
 		return new Long[]{(long) exprs.getArray(event).length};
 	}
 

src/main/java/ch/njol/skript/lang/Variable.java

@@ -14,6 +14,8 @@
 import ch.njol.skript.structures.StructVariables.DefaultVariables;
 import ch.njol.skript.util.StringMode;
 import ch.njol.skript.util.Utils;
+import com.google.common.base.Preconditions;
+import org.skriptlang.skript.util.IndexTrackingTreeMap;
 import ch.njol.skript.variables.Variables;
 import ch.njol.util.Kleenean;
 import ch.njol.util.Pair;
@@ -446,7 +448,7 @@ private T[] getConvertedArray(Event event) {
 	}
 
 	private void set(Event event, @Nullable Object value) {
-		Variables.setVariable("" + name.toString(event), value, event, local);
+		Variables.setVariable(name.toString(event), value, event, local);
 	}
 
 	private void setIndex(Event event, String index, @Nullable Object value) {
@@ -456,6 +458,33 @@ private void setIndex(Event event, String index, @Nullable Object value) {
 		Variables.setVariable(name.substring(0, name.length() - 1) + index, value, event, local);
 	}
 
+	public int size(Event event) {
+		Preconditions.checkState(list, "Cannot get the size of a single variable");
+		Map<?, ?> map = (Map<?, ?>) getRaw(event);
+		if (map == null)
+			return 0;
+
+		int size = map.size();
+		if (map.containsKey(null)) // if we're trying to get the size of {_list::*}, exclude {_list} from being counted
+			size--;
+
+		if (!(map instanceof IndexTrackingTreeMap<?> indexTrackingMap)) {
+			for (Object value : map.values()) {
+				if (value instanceof Map<?, ?> sublist && !sublist.containsKey(null))
+					size--;
+			}
+			return size;
+		}
+
+		Collection<String> sublistIndices = indexTrackingMap.mapIndices();
+		for (String sublistIndex : sublistIndices) {
+			if (!((Map<?, ?>) map.get(sublistIndex)).containsKey(null))
+				size--;
+		}
+
+		return size;
+	}
+
 	@Override
 	public Class<?> @Nullable [] acceptChange(ChangeMode mode) {
 		if (!list && mode == ChangeMode.SET)
@@ -494,22 +523,6 @@ public void change(Event event, Object @NotNull [] delta, ChangeMode mode, @NotN
 	public void change(Event event, Object @Nullable [] delta, ChangeMode mode) throws UnsupportedOperationException {
 		switch (mode) {
 			case DELETE:
-				if (list) {
-					ArrayList<String> toDelete = new ArrayList<>();
-					Map<String, Object> map = (Map<String, Object>) getRaw(event);
-					if (map == null)
-						return;
-					for (Entry<String, Object> entry : map.entrySet()) {
-						if (entry.getKey() != null){
-							toDelete.add(entry.getKey());
-						}
-					}
-					for (String index : toDelete) {
-						assert index != null;
-						setIndex(event, index, null);
-					}
-				}
-
 				set(event, null);
 				break;
 			case SET:
@@ -594,6 +607,13 @@ public void change(Event event, Object @Nullable [] delta, ChangeMode mode) thro
 						}
 					} else {
 						assert mode == ChangeMode.ADD;
+						if (map instanceof IndexTrackingTreeMap<Object> indexTrackingMap) {
+							for (Object value : delta) {
+								int index = indexTrackingMap.nextOpenIndex();
+								setIndex(event, String.valueOf(index), value);
+							}
+							return;
+						}
 						int i = 1;
 						for (Object value : delta) {
 							if (map != null)

src/main/java/ch/njol/skript/variables/VariablesMap.java

@@ -3,6 +3,7 @@
 import ch.njol.skript.lang.Variable;
 import ch.njol.util.StringUtils;
 import org.jetbrains.annotations.Nullable;
+import org.skriptlang.skript.util.IndexTrackingTreeMap;
 
 import java.util.Comparator;
 import java.util.HashMap;
@@ -216,7 +217,7 @@ void setVariable(String name, @Nullable Object value) {
 					break;
 				} else if (value != null) {
 					// Create child node, add it to parent and continue iteration
-					childNode = new TreeMap<>(VARIABLE_NAME_COMPARATOR);
+					childNode = new IndexTrackingTreeMap<>(VARIABLE_NAME_COMPARATOR);
 
 					parent.put(childNodeName, childNode);
 					parent = (TreeMap<String, Object>) childNode;
@@ -269,7 +270,7 @@ void setVariable(String name, @Nullable Object value) {
 					break;
 				} else if (value != null) {
 					// Need to continue iteration, create new child node and put old value in it
-					TreeMap<String, Object> newChildNodeMap = new TreeMap<>(VARIABLE_NAME_COMPARATOR);
+					TreeMap<String, Object> newChildNodeMap = new IndexTrackingTreeMap<>(VARIABLE_NAME_COMPARATOR);
 					newChildNodeMap.put(null, childNode);
 
 					// Add new child node to parent
@@ -334,7 +335,7 @@ public VariablesMap copy() {
 	 */
 	@SuppressWarnings("unchecked")
 	private static TreeMap<String, Object> copyTreeMap(TreeMap<String, Object> original) {
-		TreeMap<String, Object> copy = new TreeMap<>(VARIABLE_NAME_COMPARATOR);
+		TreeMap<String, Object> copy = new IndexTrackingTreeMap<>(VARIABLE_NAME_COMPARATOR);
 
 		for (Entry<String, Object> child : original.entrySet()) {
 			String key = child.getKey();

src/main/java/org/skriptlang/skript/common/properties/expressions/PropExprAmount.java

@@ -6,6 +6,7 @@
 import ch.njol.skript.lang.Expression;
 import ch.njol.skript.lang.ExpressionList;
 import ch.njol.skript.lang.SkriptParser.ParseResult;
+import ch.njol.skript.lang.Variable;
 import ch.njol.skript.util.LiteralUtils;
 import ch.njol.util.Kleenean;
 import org.bukkit.event.Event;
@@ -40,6 +41,7 @@ public static void register(SyntaxRegistry registry, Origin origin) {
 	}
 
 	private ExpressionList<?> exprs;
+	private @Nullable Variable<?> list;
 	private boolean useProperties;
 
 	@Override
@@ -48,13 +50,14 @@ public boolean init(Expression<?>[] expressions, int matchedPattern, Kleenean is
 		// amounts of x, y -> property
 		// amount of x, y -> list length
 		useProperties = parseResult.hasTag("s") || expressions[0].isSingle();
-		if (useProperties) {
+		if (useProperties)
 			return super.init(expressions, matchedPattern, isDelayed, parseResult);
-		} else {
-			// if exprlist or varlist, count elements
-			this.exprs = asExprList(expressions[0]);
-			return LiteralUtils.canInitSafely(this.exprs);
-		}
+
+		// if exprlist or varlist, count elements
+		this.exprs = asExprList(expressions[0]);
+		if (expressions[0] instanceof Variable<?> variable)
+			this.list = variable;
+		return LiteralUtils.canInitSafely(this.exprs);
 	}
 
 	/**
@@ -78,6 +81,10 @@ public static ExpressionList<?> asExprList(Expression<?> expr) {
 	protected Object @Nullable [] get(Event event) {
 		if (useProperties)
 			return super.get(event);
+
+		if (list != null)
+			return new Long[]{(long) list.size(event)};
+
 		return new Long[]{(long) exprs.getArray(event).length};
 	}
 

src/main/java/org/skriptlang/skript/common/properties/expressions/PropExprNumber.java

@@ -6,6 +6,7 @@
 import ch.njol.skript.lang.Expression;
 import ch.njol.skript.lang.ExpressionList;
 import ch.njol.skript.lang.SkriptParser.ParseResult;
+import ch.njol.skript.lang.Variable;
 import ch.njol.skript.util.LiteralUtils;
 import ch.njol.util.Kleenean;
 import org.bukkit.event.Event;
@@ -37,27 +38,33 @@ public static void register(SyntaxRegistry registry, Origin origin) {
 	}
 
 	private ExpressionList<?> exprs;
+	private @Nullable Variable<?> list;
 	private boolean useProperties;
 
 	@Override
 	public boolean init(Expression<?>[] expressions, int matchedPattern, Kleenean isDelayed, ParseResult parseResult) {
-		// size[s] of x -> property
-		// sizes of x, y -> property
-		// size of x, y -> list length
+		// number[s] of x -> property
+		// numbers of x, y -> property
+		// number of x, y -> list length
 		useProperties = parseResult.hasTag("s") || expressions[0].isSingle();
-		if (useProperties) {
+		if (useProperties)
 			return super.init(expressions, matchedPattern, isDelayed, parseResult);
-		} else {
-			// if exprlist or varlist, count elements
-			this.exprs = PropExprAmount.asExprList(expressions[0]);
-			return LiteralUtils.canInitSafely(this.exprs);
-		}
+
+		// if exprlist or varlist, count elements
+		this.exprs = PropExprAmount.asExprList(expressions[0]);
+		if (expressions[0] instanceof Variable<?> variable)
+			this.list = variable;
+		return LiteralUtils.canInitSafely(this.exprs);
 	}
 
 	@Override
 	protected Object @Nullable [] get(Event event) {
 		if (useProperties)
 			return super.get(event);
+
+		if (list != null)
+			return new Long[]{(long) list.size(event)};
+
 		return new Long[]{(long) exprs.getArray(event).length};
 	}
 

src/main/java/org/skriptlang/skript/common/properties/expressions/PropExprSize.java

@@ -6,6 +6,7 @@
 import ch.njol.skript.lang.Expression;
 import ch.njol.skript.lang.ExpressionList;
 import ch.njol.skript.lang.SkriptParser.ParseResult;
+import ch.njol.skript.lang.Variable;
 import ch.njol.skript.util.LiteralUtils;
 import ch.njol.util.Kleenean;
 import org.bukkit.event.Event;
@@ -37,6 +38,7 @@ public static void register(SyntaxRegistry registry, Origin origin) {
 	}
 
 	private ExpressionList<?> exprs;
+	private @Nullable Variable<?> list;
 	private boolean useProperties;
 
 	@Override
@@ -45,19 +47,24 @@ public boolean init(Expression<?>[] expressions, int matchedPattern, Kleenean is
 		// sizes of x, y -> property
 		// size of x, y -> list length
 		useProperties = parseResult.hasTag("s") || expressions[0].isSingle();
-		if (useProperties) {
+		if (useProperties)
 			return super.init(expressions, matchedPattern, isDelayed, parseResult);
-		} else {
-			// if exprlist or varlist, count elements
-			this.exprs = PropExprAmount.asExprList(expressions[0]);
-			return LiteralUtils.canInitSafely(this.exprs);
-		}
+
+		// if exprlist or varlist, count elements
+		this.exprs = PropExprAmount.asExprList(expressions[0]);
+		if (expressions[0] instanceof Variable<?> variable)
+			this.list = variable;
+		return LiteralUtils.canInitSafely(this.exprs);
 	}
 
 	@Override
 	protected Object @Nullable [] get(Event event) {
 		if (useProperties)
 			return super.get(event);
+
+		if (list != null)
+			return new Long[]{(long) list.size(event)};
+
 		return new Long[]{(long) exprs.getArray(event).length};
 	}