jhc.redsniff.internal.util.StringDiffFormatter.java Source code

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Here is the source code for jhc.redsniff.internal.util.StringDiffFormatter.java

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/*******************************************************************************
 * Copyright 2014 JHC Systems Limited
 *
 * 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 jhc.redsniff.internal.util;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import com.google.common.base.Joiner;
import com.google.common.base.Splitter;

import difflib.Chunk;
import difflib.Delta;
import difflib.Patch;
import difflib.myers.MyersDiff;

//TODO - tidy up. fix working for multi-line. increase sensitivity and adjust tests
public class StringDiffFormatter {

    private int sensitivity = 3;

    public String formatDifference(String expected, String actual, String format) {
        List<String> expectedLines = Splitter.on("|||").splitToList(expected);
        List<String> actualLines = Splitter.on("|||").splitToList(actual);

        MyersDiff myersDiff = new MyersDiff();
        Patch diff = myersDiff.diff(expectedLines, actualLines);

        List<String> expectedDifferences = new ArrayList<>(expectedLines.size());
        expectedDifferences.addAll(expectedLines);
        List<String> actualDifferences = new ArrayList<>(actualLines.size());
        actualDifferences.addAll(actualLines);

        for (Delta delta : diff.getDeltas()) {

            List<String> orig = (List<String>) delta.getOriginal().getLines();
            List<String> rev = (List<String>) delta.getRevised().getLines();

            String origString = Joiner.on("\n").join(orig);
            List<String> origCharList = asStringList(origString);
            String revString = Joiner.on("\n").join(rev);
            List<String> revCharList = asStringList(revString);

            List<Delta> inlineDeltas = myersDiff.diff(origCharList, revCharList).getDeltas();

            if (inlineDeltas.size() < sensitivity) {
                Collections.reverse(inlineDeltas);
                for (Delta inlineDelta : inlineDeltas) {
                    Chunk inlineOrig = inlineDelta.getOriginal();
                    Chunk inlineRev = inlineDelta.getRevised();
                    origString = highlight(origString, inlineOrig.getPosition(),
                            inlineOrig.getPosition() + inlineOrig.size());
                    revString = highlight(revString, inlineRev.getPosition(),
                            inlineRev.getPosition() + inlineRev.size());
                }
            } else {
                Delta firstDelta = inlineDeltas.get(0);
                Delta lastDelta = inlineDeltas.get(inlineDeltas.size() - 1);
                origString = highlight(origString, firstDelta.getOriginal().getPosition(),
                        lastDelta.getOriginal().getPosition() + lastDelta.getOriginal().size());
                revString = highlight(revString, firstDelta.getRevised().getPosition(),
                        lastDelta.getRevised().getPosition() + lastDelta.getRevised().size());

            }

            expectedDifferences.set(delta.getOriginal().getPosition(), origString);
            actualDifferences.set(delta.getRevised().getPosition(), revString);

        }
        String formattedExpected = "";
        for (int i = 0; i < expectedDifferences.size(); i++) {
            String diffLine = expectedDifferences.get(i);
            String line = diffLine != null ? diffLine : expectedLines.get(i);
            formattedExpected += line;
        }
        String formattedActual = "";
        for (int i = 0; i < actualDifferences.size(); i++) {
            String diffLine = actualDifferences.get(i);
            String line = diffLine != null ? diffLine : actualLines.get(i);
            formattedActual += line;
        }
        return String.format(format, formattedActual, formattedExpected);
    }

    private List<String> asStringList(String revString) {
        List<String> strList = new ArrayList<String>(revString.length());
        for (Character c : revString.toCharArray())
            strList.add(c.toString());
        return strList;
    }

    private String highlight(String string, int start, int end) {
        return string.substring(0, start) + "[" + string.substring(start, end) + "]" + string.substring(end);
    }

}