// Copyright (C) 2005 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.caja.parser.js;
import com.google.caja.lexer.FilePosition;
import com.google.caja.lexer.TokenConsumer;
import com.google.caja.parser.ParseTreeNode;
import com.google.caja.reporting.RenderContext;
import com.google.caja.util.Pair;
import com.google.javascript.jscomp.jsonml.JsonML;
import com.google.javascript.jscomp.jsonml.TagType;
import java.util.List;
/**
* An if/else if/else statement.
*
* @author mikesamuel@gmail.com
*/
public final class Conditional extends AbstractStatement {
private static final long serialVersionUID = 7726408694815849867L;
/** @param value unused. This ctor is provided for reflection. */
@ReflectiveCtor
public Conditional(
FilePosition pos, Void value, List<? extends ParseTreeNode> children) {
super(pos, ParseTreeNode.class);
createMutation().appendChildren(children).execute();
}
public Conditional(
FilePosition pos, List<Pair<Expression, Statement>> ifClauses,
Statement elseClause) {
super(pos, ParseTreeNode.class);
if (ifClauses.isEmpty()) { throw new IllegalArgumentException(); }
Mutation m = createMutation();
for (Pair<Expression, Statement> p : ifClauses) {
Expression condition = p.a;
Statement then = p.b;
if (null == condition || null == then) {
throw new IllegalArgumentException();
}
m.appendChild(condition);
m.appendChild(then);
}
if (null != elseClause) {
m.appendChild(elseClause);
}
m.execute();
}
@Override
public Object getValue() { return null; }
public void render(RenderContext rc) {
TokenConsumer out = rc.getOut();
out.mark(getFilePosition());
List<? extends ParseTreeNode> children = children();
int i = 0;
int n = children.size();
for (; i + 2 <= n; i += 2) {
Expression condition = (Expression) children.get(i);
Statement body = (Statement) children.get(i + 1);
if (i != 0) {
out.consume("else");
}
out.consume("if");
out.consume("(");
condition.render(rc);
out.consume(")");
boolean hanging = body.hasHangingConditional();
if (hanging) { out.consume("{"); }
body.renderBlock(rc, i + 2 < n);
if (hanging) { out.consume("}"); }
}
if (i < n) {
Statement body = (Statement) children.get(i);
out.consume("else");
body.renderBlock(rc, false);
}
}
public boolean hasHangingConditional() {
List<? extends ParseTreeNode> children = children();
int n = children.size();
// If there is no else clause, then an else following would change the
// meaning.
if ((n & 1) == 0) { return true; }
// Otherwise if the else clause has a hanging conditional, then an else
// would change the meaning.
return ((Statement) children.get(n - 1)).hasHangingConditional();
}
public JsonML toJsonML() {
FilePosition tailPos = FilePosition.endOf(getFilePosition());
JsonML tail;
List<? extends ParseTreeNode> parts = children();
int k = parts.size();
if ((k & 1) == 0) {
tail = JsonMLBuilder.builder(TagType.EmptyStmt, tailPos).build();
} else {
tail = ((Statement) parts.get(--k)).toJsonML();
}
while (k != 0) {
Expression cond = (Expression) parts.get(k - 2);
Statement clause = (Statement) parts.get(k - 1);
FilePosition pos = k == 2 ? getFilePosition()
: FilePosition.span(cond.getFilePosition(), tailPos);
tail = JsonMLBuilder.builder(TagType.IfStmt, pos)
.addChild(cond)
.addChild(clause)
.addChild(tail)
.build();
k -= 2;
}
return tail;
}
}