user/src/com/google/gwt/resources/converter/UndefinedConstantVisitor.java

/*
 * Copyright 2014 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.resources.converter;

import com.google.gwt.core.ext.TreeLogger;
import com.google.gwt.core.ext.TreeLogger.Type;
import com.google.gwt.resources.css.ast.Context;
import com.google.gwt.resources.css.ast.CssProperty;
import com.google.gwt.resources.css.ast.CssRule;
import com.google.gwt.resources.css.ast.CssVisitor;
import com.google.gwt.thirdparty.guava.common.collect.Sets;

import java.util.List;
import java.util.Set;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * Converts upper case strings used in properties to lowercase if they are not defined
 * with a proper @def statement.
 */
public class UndefinedConstantVisitor extends CssVisitor {

  private final Set<String> gssContantNames;
  private final Pattern pattern = Pattern.compile("[A-Z][A-Z_0-9]+");
  private final Set<String> propertyNamesToSkip =
      Sets.newHashSet("filter", "-ms-filter", "font-family");
  private final boolean lenient;
  private final TreeLogger treeLogger;

  public UndefinedConstantVisitor(Set<String> gssContantNames, boolean lenient,
      TreeLogger treeLogger) {
    this.gssContantNames = gssContantNames;
    this.lenient = lenient;
    this.treeLogger = treeLogger;
  }

  @Override
  public boolean visit(CssRule x, Context ctx) {
    List<CssProperty> properties = x.getProperties();
    for (CssProperty cssProperty : properties) {
      if (propertyNamesToSkip.contains(cssProperty.getName())) {
        continue;
      }

      String cssPropertyString = cssProperty.getValues().toCss();
      Matcher matcher = pattern.matcher(cssPropertyString);

      boolean needsUpdate = false;

      while (matcher.find()) {
        String upperCaseString = matcher.group();
        if (!gssContantNames.contains(upperCaseString)) {
          treeLogger.log(Type.WARN, "Property '" + cssProperty.getName() + "' from rule '"
              + x.getSelectors().toString() + "' uses an undefined constant: "
              + upperCaseString);
          if (lenient) {
            treeLogger.log(Type.WARN, "turning '" + upperCaseString +
                    "' to lower case. This is probably not what you wanted here in the " +
                    "first place!");
            cssPropertyString =
                cssPropertyString.replace(upperCaseString, upperCaseString.toLowerCase());
            needsUpdate = true;
          } else {
            throw new Css2GssConversionException("Found undefined constant in input. "
                + cssProperty.getName() + "' from rule '" + x.getSelectors().toString()
                + "' undefined constant: " + upperCaseString);
          }
        }
      }

      if (needsUpdate) {
        cssProperty.setValue(new SimpleValue(cssPropertyString));
      }
    }
    return false;
  }
}