eu.numberfour.n4js.antlr.internal.AntlrCodeQualityHelper.java Source code

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Here is the source code for eu.numberfour.n4js.antlr.internal.AntlrCodeQualityHelper.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.internal;

import java.io.File;
import java.io.IOException;
import java.nio.charset.Charset;
import java.util.Map;
import java.util.Set;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import com.google.common.collect.Maps;
import com.google.common.collect.Sets;
import com.google.common.io.Files;

import eu.numberfour.n4js.antlr.generator.NewlineNormalizer;

/**
 */
public class AntlrCodeQualityHelper {

    /**
     * Remove all unnecessary comments from the java code that was produced by Antlr
     */
    public static void stripUnnecessaryComments(String javaFile, Charset encoding) throws IOException {
        String content = Files.toString(new File(javaFile), encoding);
        content = new NewlineNormalizer().toUnixLineDelimiter(content);
        content = content.replaceAll("(?m)^(\\s+)// .*/(\\w+\\.g:.*)$", "$1// $2");
        content = content.replaceAll("(public String getGrammarFileName\\(\\) \\{ return \").*/(\\w+\\.g)(\"; \\})",
                "$1$2$3");
        Files.write(content, new File(javaFile), encoding);
    }

    /**
     * Remove all unnecessary comments from the lexer and the parser
     */
    public static void stripUnnecessaryComments(String lexer, String parser, Charset encoding) {
        try {
            stripUnnecessaryComments(lexer, encoding);
            stripUnnecessaryComments(parser, encoding);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    // public static final BitSet FOLLOW_Tilde_in_synpred90_InternalN4JSParser17129 = new BitSet(new
    // long[]{0x0000000000000002L});
    // ...........................1- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 2-
    // ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    private static final Pattern bitsetPattern = Pattern
            .compile("^\\s+public static final BitSet (FOLLOW_\\w+) = (.*);$", Pattern.MULTILINE);

    /**
     * Remove duplicate bitset declarations to reduce the size of the static initializer but keep the bitset
     * FOLLOW_ruleExpression_in_ruleExpressionStatement with a simplified name.
     */
    public static void removeDuplicateBitsets(String javaFile, Charset encoding) {
        try {
            //
            String content = Files.toString(new File(javaFile), encoding);
            StringBuilder newContent = new StringBuilder(content.length());
            Matcher matcher = bitsetPattern.matcher(content);
            int offset = 0;
            Map<String, String> bitsets = Maps.newHashMap();
            Map<String, String> namesToReplace = Maps.newHashMap();
            while (matcher.find(offset)) {
                String originalFieldName = matcher.group(1);
                String synthesizedFieldName = "FOLLOW_" + (bitsets.size() + 1);
                String bitset = matcher.group(2);
                String existing = bitsets.putIfAbsent(bitset, synthesizedFieldName);
                if (existing == null) {
                    existing = synthesizedFieldName;
                    newContent.append(content, offset, matcher.start(1));
                    newContent.append(synthesizedFieldName);
                    newContent.append(" = ");
                    newContent.append(bitset);
                }
                namesToReplace.put(originalFieldName, existing);
                if (originalFieldName.startsWith("FOLLOW_ruleExpression_in_ruleExpressionStatement")) {
                    newContent.append(content, offset, matcher.start(1));
                    newContent.append("FOLLOW_ruleExpression_in_ruleExpressionStatement = ");
                    newContent.append(existing);
                }
                offset = matcher.end(2);
            }
            newContent.append(content, offset, content.length());
            content = newContent.toString();
            newContent = new StringBuilder(content.length());
            String rawFollowPattern = "\\bFOLLOW_\\w+\\b";
            Pattern followPattern = Pattern.compile(rawFollowPattern);
            Matcher followMatcher = followPattern.matcher(content);
            Set<String> doNotReplace = Sets.newHashSet(bitsets.values());
            doNotReplace.add("FOLLOW_ruleExpression_in_ruleExpressionStatement");
            offset = 0;
            while (followMatcher.find(offset)) {
                String replaceMe = followMatcher.group();
                String replaceBy = namesToReplace.get(replaceMe);
                if (replaceBy == null) {
                    if (!doNotReplace.contains(replaceMe))
                        throw new IllegalStateException(replaceMe);
                    replaceBy = replaceMe;
                }
                newContent.append(content, offset, followMatcher.start());
                newContent.append(replaceBy);
                offset = followMatcher.end();
            }
            newContent.append(content, offset, content.length());
            Files.write(newContent, new File(javaFile), encoding);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }
}