/*
 * Copyright 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.gwt.dev.js.ast;

import com.google.gwt.dev.jjs.SourceInfo;
import com.google.gwt.dev.util.Util;

/**
 * A JavaScript regular expression.
 */
public final class JsRegExp extends JsValueLiteral {

  private String flags;

  private String pattern;

  public JsRegExp(SourceInfo sourceInfo) {
    super(sourceInfo);
  }

  @Override
  public boolean equals(Object that) {
    // It is OK to check instance of here as JsRegExp is final.
    if (!(that instanceof JsRegExp)) {
      return false;
    }
    return Util.equalsNullCheck(flags,((JsRegExp) that).flags) &&
        Util.equalsNullCheck(pattern,((JsRegExp) that).pattern);
  }

  public String getFlags() {
    return flags;
  }

  @Override
  public NodeKind getKind() {
    return NodeKind.REGEXP;
  }

  public String getPattern() {
    return pattern;
  }

  @Override
  public int hashCode() {
    int flagsHashCode = (flags != null) ? flags.hashCode() : 0;
    int patternHashCode = (pattern != null) ? pattern.hashCode() : 0;
    return flagsHashCode + 17 * patternHashCode;
  }

  @Override
  public boolean isBooleanFalse() {
    return false;
  }

  @Override
  public boolean isBooleanTrue() {
    return true;
  }

  @Override
  public boolean isDefinitelyNotNull() {
    return true;
  }

  @Override
  public boolean isDefinitelyNull() {
    return false;
  }

  @Override
  public boolean isInternable() {
    // JavaScript regexes are stateful, methods like RegExp.test(...) keep track of
    // the current match status in the regexp.
    return false;
  }

  public void setFlags(String suffix) {
    this.flags = suffix;
  }

  public void setPattern(String re) {
    this.pattern = re;
  }

  @Override
  public void traverse(JsVisitor v, JsContext ctx) {
    v.visit(this, ctx);
    v.endVisit(this, ctx);
  }
}