com.google.common.css.compiler.passes.EliminateEmptyRulesetNodes.java Source code

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Here is the source code for com.google.common.css.compiler.passes.EliminateEmptyRulesetNodes.java

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/*
 * Copyright 2009 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.common.css.compiler.passes;

import com.google.common.css.compiler.ast.CssCompilerPass;
import com.google.common.css.compiler.ast.CssRulesetNode;
import com.google.common.css.compiler.ast.DefaultTreeVisitor;
import com.google.common.css.compiler.ast.MutatingVisitController;

/**
 * A compiler pass that eliminates the empty ruleset nodes.
 *
 * @author oana@google.com (Oana Florescu)
 */
public class EliminateEmptyRulesetNodes extends DefaultTreeVisitor implements CssCompilerPass {

    private final MutatingVisitController visitController;

    public EliminateEmptyRulesetNodes(MutatingVisitController visitController) {
        this.visitController = visitController;
    }

    @Override
    public boolean enterRuleset(CssRulesetNode node) {
        if (node.getDeclarations().isEmpty()) {
            visitController.removeCurrentNode();
            return false;
        }
        return true;
    }

    @Override
    public void runPass() {
        visitController.startVisit(this);
    }
}