com.google.common.css.compiler.passes.TemplateCompactPrinter 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 2010 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.CssTree;
import com.google.common.css.compiler.ast.CssTreeVisitor;
import com.google.common.css.compiler.ast.VisitController;

/**
 * Printer for templates, which outputs GSS with holes to be filled
 * for references. In addition, the declaration boundaries are
 * explicitly noted, so that a declaration can be removed if it ends
 * up empty.
 *
 * @param  type of chunk id objects
 * @author [email protected] (Damian Gajda)
 */
public class TemplateCompactPrinter extends CompactPrinter {

    public static final char REFERENCE_START = '\u0123';
    public static final char REFERENCE_END = '\u0122';
    public static final char REFERENCE_START_OLD = '$';
    public static final char REFERENCE_END_OLD = '^';
    public static final char DECLARATION_START = '\u0105';
    public static final char DECLARATION_END = '\u0104';
    public static final char RULE_START = '\u0118';
    public static final char RULE_END = '\u0119';

    /**
     * Chunk to be printed by this printer.
     */
    protected final T chunk;

    // CodeBuffer with specific behavior for the printer
    private static final class CodeBufferForTemplate extends CodeBuffer {
        @Override
        public void deleteLastCharIfCharIs(char ch) {
            if (ch == ';' && getLastChar() == DECLARATION_END) {
                deleteLastChars(2);
                append(DECLARATION_END);
            } else {
                super.deleteLastCharIfCharIs(ch);
            }
        }
    }

    /**
     * Create a template printer for a given chunk.
     *
     * @param tree  CSS AST to be printed (with regard to a selected chunk)
     * @param chunk the chunk selected for printing
     */
    public TemplateCompactPrinter(CssTree tree, T chunk) {
        super(tree, new CodeBufferForTemplate(), null /* generator */);
        this.chunk = chunk;
    }

    @Override
    protected CssTreeVisitor createVisitor(VisitController visitController, CodeBuffer buffer) {
        return new TemplateCompactPrintingVisitor<>(visitController, chunk, buffer);
    }
}