| /******************************************************************************* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| ******************************************************************************/ |
| package org.apache.sling.scripting.sightly.impl.compiler.optimization; |
| |
| import java.util.HashMap; |
| import java.util.Map; |
| |
| import org.apache.sling.scripting.sightly.compiler.expression.ExpressionNode; |
| import org.apache.sling.scripting.sightly.compiler.expression.nodes.Identifier; |
| import org.apache.sling.scripting.sightly.compiler.expression.nodes.MapLiteral; |
| import org.apache.sling.scripting.sightly.compiler.expression.nodes.NullLiteral; |
| import org.apache.sling.scripting.sightly.compiler.expression.nodes.PropertyAccess; |
| import org.apache.sling.scripting.sightly.compiler.expression.nodes.StringConstant; |
| import org.apache.sling.scripting.sightly.compiler.commands.Command; |
| import org.apache.sling.scripting.sightly.compiler.commands.CommandStream; |
| import org.apache.sling.scripting.sightly.compiler.commands.VariableBinding; |
| import org.apache.sling.scripting.sightly.impl.compiler.util.expression.NodeTransformer; |
| import org.apache.sling.scripting.sightly.impl.compiler.util.stream.EmitterVisitor; |
| import org.apache.sling.scripting.sightly.impl.compiler.PushStream; |
| import org.apache.sling.scripting.sightly.impl.compiler.util.stream.Streams; |
| import org.apache.sling.scripting.sightly.impl.compiler.visitor.TrackingVisitor; |
| |
| /** |
| * This optimization handles variables initialized to map literals. It initially assigns the values in the map to variables and wherever |
| * the map literal is accessed, the property access is replaced with the value variable, thus removing the need for a map lookup. |
| */ |
| public final class SyntheticMapRemoval extends TrackingVisitor<MapLiteral> implements EmitterVisitor { |
| |
| public static final StreamTransformer TRANSFORMER = new StreamTransformer() { |
| @Override |
| public CommandStream transform(CommandStream inStream) { |
| return Streams.map(inStream, new SyntheticMapRemoval()); |
| } |
| }; |
| |
| private static final String VARIABLE_MARKER = "_field$_"; |
| |
| private final PushStream outputStream = new PushStream(); |
| private final NodeTransformer transformer = new PropertyAccessTransformer(); |
| |
| private SyntheticMapRemoval() { |
| } |
| |
| @Override |
| public void visit(VariableBinding.Start variableBindingStart) { |
| ExpressionNode node = variableBindingStart.getExpression(); |
| String variable = variableBindingStart.getVariableName(); |
| ExpressionNode transformed = transform(node); |
| if (transformed instanceof MapLiteral) { |
| MapLiteral newLiteral = overrideMap(variable, (MapLiteral) transformed); |
| tracker.pushVariable(variable, newLiteral); |
| transformed = newLiteral; |
| } else { |
| tracker.pushVariable(variable, null); |
| } |
| outputStream.write(new VariableBinding.Start(variable, transformed)); |
| } |
| |
| @Override |
| public void visit(VariableBinding.End variableBindingEnd) { |
| Map.Entry<String, MapLiteral> entry = tracker.peek(); |
| super.visit(variableBindingEnd); |
| MapLiteral literal = entry.getValue(); |
| if (literal != null) { |
| //need to un-bind all the introduced variables |
| for (int i = 0; i < literal.getMap().size(); i++) { |
| outputStream.write(VariableBinding.END); |
| } |
| } |
| } |
| |
| private ExpressionNode transform(ExpressionNode node) { |
| return transformer.transform(node); |
| } |
| |
| private MapLiteral overrideMap(String variableName, MapLiteral mapLiteral) { |
| Map<String, ExpressionNode> newLiteral = new HashMap<>(); |
| for (Map.Entry<String, ExpressionNode> entry : mapLiteral.getMap().entrySet()) { |
| String property = entry.getKey(); |
| ExpressionNode valueNode = entry.getValue(); |
| String valueVariable = valueVariableName(variableName, property); |
| newLiteral.put(property, new Identifier(valueVariable)); |
| outputStream.write(new VariableBinding.Start(valueVariable, valueNode)); |
| } |
| return new MapLiteral(newLiteral); |
| } |
| |
| private String valueVariableName(String variableName, String propertyName) { |
| return variableName + VARIABLE_MARKER + propertyName; |
| } |
| |
| @Override |
| protected MapLiteral assignDefault(Command command) { |
| return null; |
| } |
| |
| @Override |
| public void onCommand(Command command) { |
| outputStream.write(command); |
| } |
| |
| @Override |
| public PushStream getOutputStream() { |
| return outputStream; |
| } |
| |
| private class PropertyAccessTransformer extends NodeTransformer { |
| @Override |
| public ExpressionNode evaluate(PropertyAccess propertyAccess) { |
| ExpressionNode target = propertyAccess.getTarget(); |
| String variable = extractIdentifier(target); |
| if (variable != null) { |
| MapLiteral literal = tracker.get(variable); |
| if (literal != null) { |
| String property = extractProperty(propertyAccess.getProperty()); |
| if (property != null) { |
| ExpressionNode replacementNode = literal.getValue(property); |
| if (replacementNode == null) { |
| replacementNode = NullLiteral.INSTANCE; |
| } |
| return replacementNode; |
| } |
| } |
| } |
| return super.evaluate(propertyAccess); |
| } |
| |
| private String extractProperty(ExpressionNode expressionNode) { |
| if (expressionNode instanceof StringConstant) { |
| return ((StringConstant) expressionNode).getText(); |
| } |
| return null; |
| } |
| |
| private String extractIdentifier(ExpressionNode node) { |
| if (node instanceof Identifier) { |
| return ((Identifier) node).getName(); |
| } |
| return null; |
| } |
| } |
| } |