/*
* Copyright (C) 2008 Google Inc.
*
* Licensed 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 com.google.gxp.compiler.phinsert;
import com.google.common.base.Function;
import com.google.common.base.Preconditions;
import com.google.common.collect.Lists;
import com.google.gxp.compiler.alerts.AlertSetBuilder;
import com.google.gxp.compiler.alerts.AlertSink;
import com.google.gxp.compiler.base.Concatenation;
import com.google.gxp.compiler.base.ExhaustiveExpressionVisitor;
import com.google.gxp.compiler.base.Expression;
import com.google.gxp.compiler.base.NativeExpression;
import com.google.gxp.compiler.base.OutputElement;
import com.google.gxp.compiler.base.PlaceholderStart;
import com.google.gxp.compiler.base.PlaceholderEnd;
import com.google.gxp.compiler.base.Root;
import com.google.gxp.compiler.base.UnextractedMessage;
import com.google.gxp.compiler.base.Util;
import com.google.gxp.compiler.collapse.SpaceCollapsedTree;
import com.google.gxp.compiler.schema.Schema;
import java.util.List;
/**
* Inserts Placeholder nodes as appropriate for elements containing
* {@code gxp:ph} attributes.
*/
public class PlaceholderInserter implements Function<SpaceCollapsedTree, PlaceholderInsertedTree> {
public PlaceholderInsertedTree apply(SpaceCollapsedTree tree) {
AlertSetBuilder alertSetBuilder = new AlertSetBuilder(tree.getAlerts());
Root root = tree.getRoot().acceptVisitor(new Visitor(alertSetBuilder));
return new PlaceholderInsertedTree(tree.getSourcePosition(), alertSetBuilder.buildAndClear(),
root);
}
private static class Visitor extends ExhaustiveExpressionVisitor {
private final AlertSink alertSink;
private boolean insideMsg = false;
private boolean insidePh = false;
Visitor(AlertSink alertSink) {
this.alertSink = Preconditions.checkNotNull(alertSink);
}
@Override
public Expression visitNativeExpression(NativeExpression expr) {
String phName = expr.getPhName();
if (phName == null && insideMsg && !insidePh && expr.isTrivialEval()) {
phName = expr.getDefaultNativeCode();
}
if (phName == null) {
return expr;
}
Schema exprSchema = expr.getSchema();
List<Expression> values = Lists.newArrayList();
values.add(new PlaceholderStart(expr, exprSchema, phName, null));
values.add(expr);
values.add(new PlaceholderEnd(expr, exprSchema));
return Concatenation.create(expr.getSourcePosition(), exprSchema, values);
}
@Override
public Expression visitOutputElement(OutputElement element) {
String phName = element.getPhName();
if (phName == null) {
return super.visitOutputElement(element);
}
Schema elementSchema = element.getSchema();
boolean whitespaceContent = element.getContent().alwaysOnlyWhitespace();
List<Expression> values = Lists.newArrayList();
String name = whitespaceContent ? phName : phName + "_start";
values.add(new PlaceholderStart(element, elementSchema, name, null));
if (whitespaceContent) {
values.add(element);
} else {
List<Expression> contentValues = Lists.newArrayList();
contentValues.add(new PlaceholderEnd(element, elementSchema));
contentValues.add(element.getContent().acceptVisitor(this));
contentValues.add(new PlaceholderStart(element, elementSchema,
phName + "_end", null));
Expression content = Concatenation.create(element.getSourcePosition(),
null, contentValues);
boolean oldInsidePh = insidePh;
insidePh = true;
values.add(element.withAttributesAndContent(
Util.map(element.getAttributes(), getAttributeFunction()),
content));
insidePh = oldInsidePh;
}
values.add(new PlaceholderEnd(element, elementSchema));
return Concatenation.create(element.getSourcePosition(), elementSchema, values);
}
@Override
public Expression visitUnextractedMessage(UnextractedMessage msg) {
boolean oldInsideMsg = insideMsg;
boolean oldInsidePh = insidePh;
insideMsg = true;
insidePh = false;
Expression result = super.visitUnextractedMessage(msg);
insideMsg = oldInsideMsg;
insidePh = oldInsidePh;
return result;
}
@Override
public Expression visitPlaceholderStart(PlaceholderStart phStart) {
insidePh = true;
return super.visitPlaceholderStart(phStart);
}
@Override
public Expression visitPlaceholderEnd(PlaceholderEnd phEnd) {
insidePh = false;
return super.visitPlaceholderEnd(phEnd);
}
}
}