// 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.lexer.escaping.Escaping;
import com.google.caja.parser.ParseTreeNode;
import com.google.caja.reporting.RenderContext;
import java.io.Serializable;
import java.util.List;
/**
* A regular expression literal like <code>/foo/i</code>.
*
* @author mikesamuel@gmail.com
*/
public final class RegexpLiteral extends Literal {
private static final long serialVersionUID = 4158496971004173179L;
private final RegexpWrapper value;
/** @param children unused. This ctor is provided for reflection. */
@ReflectiveCtor
public RegexpLiteral(
FilePosition pos, RegexpWrapper value,
List<? extends ParseTreeNode> children) {
this(pos, value);
}
public RegexpLiteral(FilePosition pos, RegexpWrapper value) {
super(pos);
this.value = value;
}
public RegexpLiteral(FilePosition pos, String value) {
this(pos, new RegexpWrapper(value));
}
@Override
public RegexpWrapper getValue() {
return value;
}
@Override
public void render(RenderContext rc) {
TokenConsumer out = rc.getOut();
out.mark(getFilePosition());
String body = value.getMatchText();
String mods = value.getModifiers();
if ("".equals(body) || !areRegexpModifiersValid(mods)) {
// (new (/./.constructor))('', 'g')
out.consume("(");
out.consume("new");
out.consume("(");
out.consume("/./");
out.consume(".");
out.consume("constructor");
out.consume(")");
out.consume("(");
StringLiteral.renderUnquotedValue(body, rc);
out.consume(",");
StringLiteral.renderUnquotedValue(mods, rc);
out.consume(")");
out.consume(")");
} else {
StringBuilder sb = new StringBuilder();
sb.append('/');
Escaping.normalizeRegex(body, sb);
sb.append('/');
sb.append(mods);
out.consume(sb.toString());
}
}
public static class RegexpWrapper implements Serializable {
private static final long serialVersionUID = -5707593923346724185L;
private final String regexpText;
public RegexpWrapper(String s) {
if (null == s) { throw new NullPointerException(); }
this.regexpText = s;
}
@Override
public boolean equals(Object o) {
return o instanceof RegexpWrapper
&& ((RegexpWrapper) o).regexpText.equals(this.regexpText);
}
@Override
public int hashCode() {
return this.regexpText.hashCode() ^ 0x8aed26a5;
}
@Override
public String toString() {
return this.regexpText;
}
public static RegexpWrapper valueOf(String pattern, String modifiers) {
StringBuilder sb = new StringBuilder();
sb.append('/');
Escaping.normalizeRegex(pattern, sb);
sb.append('/').append(modifiers);
return new RegexpWrapper(sb.toString());
}
public String getMatchText() {
return regexpText.substring(1, regexpText.lastIndexOf('/'));
}
public String getModifiers() {
return regexpText.substring(regexpText.lastIndexOf('/') + 1);
}
}
@Override
public boolean getValueInBooleanContext() {
return true;
}
/**
* Modifiers are the letters allowed to follow a regular expression literal.
* Firefox does not recognize the "s" modifier, and no version of javascript
* deals with the "x" or "e" modifiers, so this regex matches g, i, and m in
* any order without duplicates.
*/
public static boolean areRegexpModifiersValid(String flags) {
final int GROUP = 1;
final int CASE_INSENSITIVE = 2;
final int MULTILINE = 4;
int seen = 0;
for (int i = 0, n = flags.length(); i < n; ++i) {
char flag = flags.charAt(i);
int flagMask;
switch (flag) {
case 'g':
flagMask = GROUP;
break;
case 'i':
flagMask = CASE_INSENSITIVE;
break;
case 'm':
flagMask = MULTILINE;
break;
default:
return false;
}
if ((seen & flagMask) != 0) {
return false;
}
seen = seen | flagMask;
}
return true;
}
// "function" on some interpreters, "object" on others.
public String typeOf() { return null; }
}