eu.numberfour.n4js.antlr.AntlrToolFacadeWithInjectedCode.java Source code

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Here is the source code for eu.numberfour.n4js.antlr.AntlrToolFacadeWithInjectedCode.java

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/**
 * Copyright (c) 2016 NumberFour AG.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *   NumberFour AG - Initial API and implementation
 */
package eu.numberfour.n4js.antlr;

import java.io.File;
import java.io.IOException;
import java.util.List;

import org.eclipse.xtext.generator.parser.antlr.AntlrToolFacade;

import com.google.common.base.Charsets;
import com.google.common.collect.Lists;
import com.google.common.io.Files;

/**
 * Post processor for the generated Antlr grammar that injects code into the generated grammar file.
 *
 * See also <a href="https://raw.github.com/ohboyohboyohboy/antlr3/master/samples/other/ES3.g3">ES3.g3</a> and <a href=
 * "http://git.eclipse.org/c/dltk/org.eclipse.dltk.javascript.git/tree/plugins/org.eclipse.dltk.javascript.parser/src/org/eclipse/dltk/javascript/parser/JS.g"
 * >JS.g</a>
 */
public class AntlrToolFacadeWithInjectedCode extends AntlrToolFacade {

    private final List<CodeIntoGrammarInjector> steps = Lists.newArrayList();

    /**
     * Adds another step to the processing chain.
     */
    public void addStep(CodeIntoGrammarInjector step) {
        steps.add(step);
    }

    @Override
    public void runWithEncodingAndParams(String grammarFullPath, String explicitEncoding, String... furtherArgs) {
        injectCode(grammarFullPath);
        super.runWithEncodingAndParams(grammarFullPath, explicitEncoding, furtherArgs);
    }

    private void injectCode(String grammarFullPath) {
        try {
            String grammarContent = Files.toString(new File(grammarFullPath), Charsets.UTF_8);
            if (grammarFullPath.endsWith("Lexer.g")) {
                grammarContent = processLexerGrammar(grammarContent);
            } else if (grammarFullPath.endsWith("Parser.g")) {
                grammarContent = processParserGrammar(grammarContent);
            } else {
                throw new IllegalArgumentException(grammarFullPath);
            }
            Files.write(grammarContent, new File(grammarFullPath), Charsets.UTF_8);
        } catch (IOException e) {
            throw new RuntimeException();
        }
    }

    private String processParserGrammar(String grammarContent) {
        String result = grammarContent;
        for (CodeIntoGrammarInjector step : steps) {
            result = step.processParserGrammar(result);
        }
        return result;
    }

    private String processLexerGrammar(String grammarContent) {
        String result = grammarContent;
        for (CodeIntoGrammarInjector step : steps) {
            result = step.processLexerGrammar(result);
        }
        return result;
    }

}