org.sonar.api.batch.fs.internal.charhandler.FileHashComputer.java Source code

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Here is the source code for org.sonar.api.batch.fs.internal.charhandler.FileHashComputer.java

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/*
 * SonarQube
 * Copyright (C) 2009-2018 SonarSource SA
 * mailto:info AT sonarsource DOT com
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 3 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */
package org.sonar.api.batch.fs.internal.charhandler;

import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.CharacterCodingException;
import java.nio.charset.CharsetEncoder;
import java.nio.charset.CodingErrorAction;
import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;

import javax.annotation.CheckForNull;

import org.apache.commons.codec.binary.Hex;
import org.apache.commons.codec.digest.DigestUtils;

public class FileHashComputer extends CharHandler {
    private static final char LINE_FEED = '\n';

    private MessageDigest globalMd5Digest = DigestUtils.getMd5Digest();
    private StringBuilder sb = new StringBuilder();
    private final CharsetEncoder encoder;
    private final String filePath;

    public FileHashComputer(String filePath) {
        encoder = StandardCharsets.UTF_8.newEncoder().onMalformedInput(CodingErrorAction.REPLACE)
                .onUnmappableCharacter(CodingErrorAction.REPLACE);
        this.filePath = filePath;
    }

    @Override
    public void handleIgnoreEoL(char c) {
        sb.append(c);
    }

    @Override
    public void newLine() {
        sb.append(LINE_FEED);
        processBuffer();
        sb.setLength(0);
    }

    @Override
    public void eof() {
        if (sb.length() > 0) {
            processBuffer();
        }
    }

    private void processBuffer() {
        try {
            if (sb.length() > 0) {
                ByteBuffer encoded = encoder.encode(CharBuffer.wrap(sb));
                globalMd5Digest.update(encoded.array(), 0, encoded.limit());
            }
        } catch (CharacterCodingException e) {
            throw new IllegalStateException("Error encoding line hash in file: " + filePath, e);
        }
    }

    @CheckForNull
    public String getHash() {
        return Hex.encodeHexString(globalMd5Digest.digest());
    }
}