com.google.common.css.compiler.ast.AbstractGssParser Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of closure-stylesheets Show documentation

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.

There is a newer version: 20160212

Show newest version

/*
 * 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.common.css.compiler.ast;

import com.google.common.collect.ImmutableList;
import com.google.common.css.SourceCode;

import java.util.List;

/**
 * Base parser implementation that delegates management of the underlying
 * JavaCC parser to the subclass. This class does not expose any public
 * methods; subclasses should expose an appropriate interface.
 *
 * @see GssParser
 */
public abstract class AbstractGssParser {

  protected static final StringCharStream EMPTY_CHAR_STREAM =
      new StringCharStream("");

  /**
   * Parses a list of GSS sources. Subclasses should use this method to do
   * the actual parsing of {@code SourceCode} objects. It will in turn call
   * the subclass's implementation of {@link #getParser()} as necessary.
   *
   * @param sources a list of GSS {@link SourceCode} objects to parse
   * @param errorHandling if error handling should be enabled. If this is
   *     {@code false}, no {@code GssParserException}s will be returned in
   *     the result.
   * @return ParseResult the result containing the {@link CssTree} and
   *     parsing errors
   */
  protected final ParseResult parseInternal(List sources,
      boolean errorHandling) throws GssParserException {
    SourceCode globalSourceCode = new SourceCode("global", null);
    CssBlockNode globalBlock =
        new CssBlockNode(false /* isEnclosedWithBraces */);
    CssTree tree = new CssTree(globalSourceCode, new CssRootNode(globalBlock));
    ImmutableList.Builder builder =
        ImmutableList.builder();
    for (SourceCode source : sources) {
      getParser().parse(globalBlock, source, errorHandling, builder);
    }
    return new ParseResult(tree, builder.build());
  }

  /**
   * Implementations must return an empty {@code GssParserCC} object. Whether
   * this object is actually new or not isn't important which allows pooling.
   */
  protected abstract GssParserCC getParser();

  protected static class ParseResult {
    private final CssTree cssTree;
    private final ImmutableList handledErrors;

    private ParseResult(CssTree cssTree,
        ImmutableList handledErrors) {
      this.cssTree = cssTree;
      this.handledErrors = handledErrors;
    }

    protected CssTree getCssTree() {
      return cssTree;
    }

    protected ImmutableList getHandledErrors() {
      return handledErrors;
    }
  }
}