/*
* 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.flatten;
import com.google.common.base.CharEscapers;
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.AttrBundleReference;
import com.google.gxp.compiler.base.Concatenation;
import com.google.gxp.compiler.base.Conditional;
import com.google.gxp.compiler.base.ConvertibleToContent;
import com.google.gxp.compiler.base.ExceptionExpression;
import com.google.gxp.compiler.base.EscapeExpression;
import com.google.gxp.compiler.base.ExampleExpression;
import com.google.gxp.compiler.base.ExhaustiveExpressionVisitor;
import com.google.gxp.compiler.base.Expression;
import com.google.gxp.compiler.base.IsXmlExpression;
import com.google.gxp.compiler.base.OutputElement;
import com.google.gxp.compiler.base.Root;
import com.google.gxp.compiler.base.StringConstant;
import com.google.gxp.compiler.reparent.Attribute;
import com.google.gxp.compiler.schema.AttributeValidator;
import com.google.gxp.compiler.schema.DocType;
import com.google.gxp.compiler.schema.ElementValidator;
import com.google.gxp.compiler.schema.Schema;
import com.google.gxp.compiler.validate.ValidatedTree;
import java.util.*;
// TODO(laurence): if schema doesn't support SGML mode, use XML mode regardless
// of IsXmlExpression's value.
/**
* Flattens OutputElements (like HTML tags) into StringConstants.
*
* <p>For example:
*
* <center><img class=fig src="https://www.corp.google.com/eng/designdocs/gxp/java-rewrite/ContentFlattening.png"></center>
*
* <p>Note that the OutputElement is replaced with a pair of StringConstant
* nodes for the start and end tags.
*/
public class ContentFlattener implements Function<ValidatedTree, ContentFlattenedTree> {
public ContentFlattenedTree apply(ValidatedTree tree) {
AlertSetBuilder alertSetBuilder = new AlertSetBuilder(tree.getAlerts());
Root root = tree.getRoot().acceptVisitor(new Visitor(alertSetBuilder));
return new ContentFlattenedTree(tree.getSourcePosition(), alertSetBuilder.buildAndClear(),
root);
}
/**
* Visits the nodes of a ValidatedTree, and "flattens" certain nodes. The
* act of flattening converts nodes with n children into a pair of nodes with
* n siblings (or more, if the chidren were also flattened) between them, so
* the result of visiting a node is a list of nodes.
*/
private static class Visitor extends ExhaustiveExpressionVisitor {
private final AlertSink alertSink;
Visitor(AlertSink alertSink) {
this.alertSink = Preconditions.checkNotNull(alertSink);
}
private Expression flattenDocType(OutputElement element, DocType docType) {
Schema elementSchema = element.getSchema();
Expression xmlDoctype =
new StringConstant(element, elementSchema,
docType.toXml(element.getLocalName()));
Expression sgmlDoctype;
if (docType.isSgmlCompatible()) {
sgmlDoctype =
new StringConstant(element, elementSchema,
docType.toSgml(element.getLocalName()));
} else {
String exceptionMessage = String.format(
"Doctype '%s' incompatible with non-XML syntax",
docType.getName());
sgmlDoctype = new ExceptionExpression(
element.getSourcePosition(), elementSchema,
ExceptionExpression.Kind.NOT_SUPPORTED_IN_SGML_MODE,
exceptionMessage);
}
return new Conditional(element, elementSchema,
new IsXmlExpression(element, elementSchema),
xmlDoctype, sgmlDoctype);
}
private Expression flattenXmlns(OutputElement element) {
Schema elementSchema = element.getSchema();
String xmlns = elementSchema.getNamespaceUri();
List<Expression> concatList = Lists.newArrayList();
concatList.add(new StringConstant(element, elementSchema, " xmlns"));
if (elementSchema.getTagPrefix() != null) {
concatList.add(new StringConstant(element, elementSchema, ":"));
concatList.add(new StringConstant(element, elementSchema,
elementSchema.getTagPrefix()));
}
concatList.add(new StringConstant(element, elementSchema, "=\""));
concatList.add(new StringConstant(element, elementSchema,
CharEscapers.xmlEscaper().escape(xmlns)));
concatList.add(new StringConstant(element, elementSchema, "\""));
return new Conditional(
element, elementSchema,
new IsXmlExpression(element, elementSchema),
Concatenation.create(element.getSourcePosition(), elementSchema,
concatList),
new StringConstant(element, elementSchema, ""));
}
@Override
public Expression visitOutputElement(OutputElement element) {
List<Expression> values = Lists.newArrayList();
ElementValidator elementValidator = element.getValidator();
Schema elementSchema = element.getSchema();
String tagPrefix = elementSchema.getTagPrefix();
DocType docType = element.getDocType();
if (docType != null) {
values.add(flattenDocType(element, docType));
}
values.add(new StringConstant(element, elementSchema, "<"));
if (tagPrefix != null) {
values.add(new StringConstant(element, elementSchema, tagPrefix + ":"));
}
values.add(new StringConstant(element, elementSchema,
element.getLocalName()));
if (docType != null) {
values.add(flattenXmlns(element));
}
for (final Attribute attr : element.getAttributes()) {
AttributeValidator attrValidator = elementValidator.getAttributeValidator(attr.getName());
Expression empty = new StringConstant(attr, elementSchema, "");
if (attrValidator.isFlagSet(AttributeValidator.Flag.BOOLEAN)) {
Expression attrValue = attr.getValue().acceptVisitor(this);
if (attrValue.hasStaticString()) {
values.add(buildBooleanAttrExpression(attr, element));
} else {
if (attrValue instanceof ConvertibleToContent) {
ConvertibleToContent ctc = (ConvertibleToContent)attrValue;
attrValue = ctc.getSubexpression();
}
values.add(new Conditional(element, elementSchema,
attrValue,
buildBooleanAttrExpression(attr, element),
empty));
}
} else {
Expression condition = attr.getCondition();
if (condition != null) {
values.add(new Conditional(element, elementSchema, condition,
buildAttrExpression(attr, element), empty));
} else {
values.add(buildAttrExpression(attr, element));
}
}
}
for (String attrBundle : element.getAttrBundles()) {
values.add(new EscapeExpression(elementSchema,
new AttrBundleReference(element, attrBundle)));
}
if (elementValidator.isFlagSet(ElementValidator.Flag.NOENDTAG)) {
values.add(new Conditional(
element, elementSchema,
new IsXmlExpression(element, elementSchema),
new StringConstant(element, elementSchema, " /"),
new StringConstant(element, elementSchema, "")));
}
values.add(new StringConstant(element, elementSchema, ">"));
values.add(element.getContent().acceptVisitor(this));
if (!elementValidator.isFlagSet(ElementValidator.Flag.NOENDTAG)) {
values.add(new StringConstant(element, elementSchema, "</"));
if (tagPrefix != null) {
values.add(new StringConstant(element, elementSchema,
tagPrefix + ":"));
}
values.add(new StringConstant(element, elementSchema,
element.getLocalName() + ">"));
}
return Concatenation.create(element.getSourcePosition(), elementSchema, values);
}
/**
* Construct an Expression that represents an Attribute
*
* If the attribute value is dynamuc and if the attribute doesn't have
* an example set in the schama, then the entire expression is surrounded
* with a {@code ExampleExpression} making it so the attribute won't
* appear at all in the translation console example if this element is part
* of a Placeholder an a <gxp:msg> tag
*/
private Expression buildAttrExpression(Attribute attr,
OutputElement element) {
List<Expression> list = Lists.newArrayList();
list.add(new StringConstant(attr, element.getSchema(), " " + attr.getName() + "=\""));
Expression value = attr.getValue().acceptVisitor(this);
if (!value.hasStaticString()) {
value = new ExampleExpression(value, "");
}
list.add(value);
list.add(new StringConstant(attr, element.getSchema(), "\""));
return Concatenation.create(element.getSourcePosition(), element.getSchema(), list);
}
/**
* Constructs an Expression to output a boolean attribute.
* Example: selected="selected" if in XML mode else selected
*/
private Expression buildBooleanAttrExpression(Attribute attr, OutputElement element) {
Schema elementSchema = element.getSchema();
List<Expression> values = Lists.newArrayList();
values.add(new StringConstant(attr, elementSchema," " + attr.getName()));
values.add(new Conditional(
attr, elementSchema,
new IsXmlExpression(attr, elementSchema),
new StringConstant(attr, elementSchema,
"=\"" + attr.getName() + "\""),
new StringConstant(attr, elementSchema, "")));
return Concatenation.create(attr.getSourcePosition(), elementSchema, values);
}
}
}