com.google.common.css.compiler.passes.MarkNonFlippableNodes Maven / Gradle / Ivy

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Closure Stylesheets is an extension to CSS that adds variables, functions, conditionals, and mixins to standard CSS. The tool also supports minification, linting, RTL flipping, and CSS class renaming.
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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.annotations.VisibleForTesting;
import com.google.common.css.compiler.ast.*;

import java.util.logging.Logger;

/**
 * Compiler pass that traverses the tree and marks as non flippable the nodes
 * that should not be BiDi flipped.
 *
 * @author [email protected] (Oana Florescu)
 */
public class MarkNonFlippableNodes extends DefaultTreeVisitor
        implements CssCompilerPass {

    @VisibleForTesting
    static final String INVALID_NOFLIP_ERROR_MESSAGE =
            "@noflip must be moved outside of selector sequence since it applies " +
                    "to entire block.";

    private final VisitController visitController;
    private final ErrorManager errorManager;

    private static final Logger logger = Logger.getLogger(
            MarkNonFlippableNodes.class.getName());

    /**
     * String that matches the comment marking a rule that should not be
     * flipped.
     * TODO(oana): Expand this annotation and make it more flexible.
     */
    private static final String NOFLIP = "/* @noflip */";

    public MarkNonFlippableNodes(VisitController visitController,
                                 ErrorManager errorManager) {
        this.visitController = visitController;
        this.errorManager = errorManager;
    }

    /**
     * Returns whether the NOFLIP comment has been found among the comments of the
     * node.
     */
    private boolean hasNoFlip(CssNode node) {
        for (CssCommentNode comment : node.getComments()) {
            if (comment.getValue().equals(NOFLIP)) {
                return true;
            }
        }
        return false;
    }

    /**
     * Returns whether the node's parent is a ruleset where the first selector is
     * marked @noflip.
     */
    private boolean firstParentSelectorHasNoFlip(CssDeclarationBlockNode node) {
        CssNode parentNode = node.getParent();
        if (parentNode instanceof CssRulesetNode) {
            CssRulesetNode rulesetNode = (CssRulesetNode) parentNode;
            CssSelectorListNode selectors = rulesetNode.getSelectors();
            if (selectors.numChildren() == 0) {
                return false;
            }
            return !selectors.getChildAt(0).getShouldBeFlipped();
        }
        return false;
    }

    @Override
    public boolean enterMediaRule(CssMediaRuleNode node) {
        if (hasNoFlip(node)) {
            node.setShouldBeFlipped(false);
        }

        return true;
    }

    @Override
    public boolean enterSelector(CssSelectorNode node) {
        if (hasNoFlip(node)) {
            node.setShouldBeFlipped(false);
        }
        return true;
    }

    @Override
    public void leaveSelector(CssSelectorNode node) {
        for (CssRefinerNode refiner : node.getRefiners().getChildren()) {
            if (hasNoFlip(refiner)) {
                node.setShouldBeFlipped(false);
                return;
            }
        }
    }

    @Override
    public boolean enterRuleset(CssRulesetNode node) {
        // A ruleset can be inside a media rule or inside the root so we need to
        // check both its parent and its grandparent.
        // TODO(oana): Add enter and leave methods for the blocks inside a media or
        //     conditional rule to avoid calling the grandparent here.
        boolean noFlip = hasNoFlip(node) || !node.getParent().getShouldBeFlipped()
                || !node.getParent().getParent().getShouldBeFlipped();
        if (noFlip) {
            node.setShouldBeFlipped(false);
        }
        return true;
    }

    @Override
    public void leaveRuleset(CssRulesetNode node) {
        boolean firstSelector = true;
        CssSelectorListNode selectors = node.getSelectors();
        for (CssSelectorNode sel : selectors.childIterable()) {
            if (!sel.getShouldBeFlipped()) {
                if (!firstSelector) {
                    // Make sure no non-first selectors are marked @noflip.
                    errorManager.report(new GssError(INVALID_NOFLIP_ERROR_MESSAGE,
                            node.getSourceCodeLocation()));
                } else {
                    node.setShouldBeFlipped(false);
                    selectors.setShouldBeFlipped(false);
                }
                return;
            }
            firstSelector = false;
        }
    }

    @Override
    public boolean enterConditionalBlock(CssConditionalBlockNode node) {
        if (hasNoFlip(node) || !node.getParent().getShouldBeFlipped()
                || !node.getParent().getParent().getShouldBeFlipped()) {
            node.setShouldBeFlipped(false);
        }
        return true;
    }

    @Override
    public boolean enterConditionalRule(CssConditionalRuleNode node) {
        if (hasNoFlip(node) || !node.getParent().getShouldBeFlipped()) {
            node.setShouldBeFlipped(false);
        }
        return true;
    }

    @Override
    public boolean enterDeclarationBlock(CssDeclarationBlockNode node) {
        if (hasNoFlip(node) || !node.getParent().getShouldBeFlipped()
                || firstParentSelectorHasNoFlip(node)) {
            node.setShouldBeFlipped(false);
        }
        return true;
    }

    @Override
    public boolean enterDeclaration(CssDeclarationNode node) {
        if (hasNoFlip(node) || !node.getParent().getShouldBeFlipped()) {
            node.setShouldBeFlipped(false);
        }
        return true;
    }

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