fixes java-diff-utils#41

Author: wumpz

src/main/java/com/github/difflib/text/DiffRowGenerator.java

@@ -29,6 +29,7 @@
 import java.util.function.Function;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
+import static java.util.stream.Collectors.toList;
 
 /**
  * This class for generating DiffRows for side-by-sidy view. You can customize the way of generating. For example, show
@@ -42,13 +43,16 @@
  *      ignoreWhiteSpaces(true).columnWidth(100).build();
  * </code>
  */
-public class DiffRowGenerator {
+public final class DiffRowGenerator {
 
     public static final BiPredicate<String, String> DEFAULT_EQUALIZER = Object::equals;
 
     public static final BiPredicate<String, String> IGNORE_WHITESPACE_EQUALIZER = (original, revised)
             -> adjustWhitespace(original).equals(adjustWhitespace(revised));
 
+    public static final Function<String, String> LINE_NORMALIZER_FOR_HTML = StringUtils::normalize;
+
+
     /**
      * Splitting lines by character to achieve char by char diff checking.
      */
@@ -60,6 +64,7 @@ public class DiffRowGenerator {
         return list;
     };
     public static final Pattern SPLIT_BY_WORD_PATTERN = Pattern.compile("\\s+|[,.\\[\\](){}/\\\\*+\\-#]");
+
     /**
      * Splitting lines by word to achieve word by word diff checking.
      */
@@ -144,6 +149,7 @@ static void wrapInTag(List<String> sequence, int startPosition,
     private final Function<Boolean, String> newTag;
     private final Function<Boolean, String> oldTag;
     private final boolean reportLinesUnchanged;
+    private final Function<String, String> lineNormalizer;
 
     private final boolean showInlineDiffs;
 
@@ -157,8 +163,10 @@ private DiffRowGenerator(Builder builder) {
         inlineDiffSplitter = builder.inlineDiffSplitter;
         equalizer = ignoreWhiteSpaces ? IGNORE_WHITESPACE_EQUALIZER : DEFAULT_EQUALIZER;
         reportLinesUnchanged = builder.reportLinesUnchanged;
+        lineNormalizer = builder.lineNormalizer;
 
         Objects.requireNonNull(inlineDiffSplitter);
+        Objects.requireNonNull(lineNormalizer);
     }
 
     /**
@@ -258,14 +266,20 @@ private DiffRow buildDiffRowWithoutNormalizing(Tag type, String orgline, String
                 StringUtils.wrapText(newline, columnWidth));
     }
 
+    List<String> normalizeLines(List<String> list) {
+        return list.stream()
+                .map(lineNormalizer::apply)
+                .collect(toList());
+    }
+
     /**
      * Add the inline diffs for given delta
      *
      * @param delta the given delta
      */
     private List<DiffRow> generateInlineDiffs(AbstractDelta<String> delta) throws DiffException {
-        List<String> orig = StringUtils.normalize(delta.getSource().getLines());
-        List<String> rev = StringUtils.normalize(delta.getTarget().getLines());
+        List<String> orig = normalizeLines(delta.getSource().getLines());
+        List<String> rev = normalizeLines(delta.getTarget().getLines());
         List<String> origList;
         List<String> revList;
         String joinedOrig = String.join("\n", orig);
@@ -334,9 +348,9 @@ private List<DiffRow> generateInlineDiffs(AbstractDelta<String> delta) throws Di
 
     private String preprocessLine(String line) {
         if (columnWidth == 0) {
-            return StringUtils.normalize(line);
+            return lineNormalizer.apply(line);
         } else {
-            return StringUtils.wrapText(StringUtils.normalize(line), columnWidth);
+            return StringUtils.wrapText(lineNormalizer.apply(line), columnWidth);
         }
     }
 
@@ -358,6 +372,7 @@ public static class Builder {
         private boolean mergeOriginalRevised = false;
         private boolean reportLinesUnchanged = false;
         private Function<String, List<String>> inlineDiffSplitter = SPLITTER_BY_CHARACTER;
+        private Function<String, String> lineNormalizer = LINE_NORMALIZER_FOR_HTML;
 
         private Builder() {
         }
@@ -463,5 +478,10 @@ public Builder inlineDiffBySplitter(Function<String, List<String>> inlineDiffSpl
             this.inlineDiffSplitter = inlineDiffSplitter;
             return this;
         }
+
+        public Builder lineNormalizer(Function<String, String> lineNormalizer) {
+            this.lineNormalizer = lineNormalizer;
+            return this;
+        }
     }
 }

src/main/java/com/github/difflib/text/StringUtils.java

@@ -34,12 +34,6 @@ public static String normalize(String str) {
         return htmlEntites(str).replace("\t", "    ");
     }
 
-    public static List<String> normalize(List<String> list) {
-        return list.stream()
-                .map(StringUtils::normalize)
-                .collect(toList());
-    }
-
     public static List<String> wrapText(List<String> list, int columnWidth) {
         return list.stream()
                 .map(line -> wrapText(line, columnWidth))

src/test/java/com/github/difflib/text/DiffRowGeneratorTest.java

@@ -5,6 +5,7 @@
 import java.io.IOException;
 import java.nio.file.Files;
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.List;
 import java.util.regex.Pattern;
 import static java.util.stream.Collectors.toList;
@@ -28,6 +29,16 @@ public void testGenerator_Default() throws DiffException {
         assertEquals(3, rows.size());
     }
 
+    /**
+     * Test of normalize method, of class StringUtils.
+     */
+    @Test
+    public void testNormalize_List() {
+        DiffRowGenerator generator = DiffRowGenerator.create()
+                .build();
+        assertEquals(Collections.singletonList("    test"), generator.normalizeLines(Collections.singletonList("\ttest")));
+    }
+
     @Test
     public void testGenerator_Default2() throws DiffException {
         String first = "anything \n \nother";
@@ -375,4 +386,23 @@ public void testGeneratorIssue22_3() throws DiffException {
         assertEquals("[[CHANGE,This is a test ~senctence~.,This is a test **for diffutils**.], [CHANGE,,**This is the second line.**], [CHANGE,,**And one more.**]]",
                 rows.toString());
     }
+
+    @Test
+    public void testGeneratorIssue41DefaultNormalizer() throws DiffException {
+        DiffRowGenerator generator = DiffRowGenerator.create()
+                .build();
+        List<DiffRow> rows = generator.generateDiffRows(Arrays.asList("<"), Arrays.asList("<"));
+        assertEquals("[[EQUAL,&lt;,&lt;]]", rows.toString());
+    }
+
+    @Test
+    public void testGeneratorIssue41UserNormalizer() throws DiffException {
+        DiffRowGenerator generator = DiffRowGenerator.create()
+                .lineNormalizer(str -> str.replace("\t", "    "))
+                .build();
+        List<DiffRow> rows = generator.generateDiffRows(Arrays.asList("<"), Arrays.asList("<"));
+        assertEquals("[[EQUAL,<,<]]", rows.toString());
+        rows = generator.generateDiffRows(Arrays.asList("\t<"), Arrays.asList("<"));
+        assertEquals("[[CHANGE,    <,<]]", rows.toString());
+    }
 }

src/test/java/com/github/difflib/text/StringUtilsTest.java

@@ -15,7 +15,6 @@
  */
 package com.github.difflib.text;
 
-import java.util.Collections;
 import static org.junit.Assert.*;
 import org.junit.Test;
 
@@ -41,14 +40,6 @@ public void testNormalize_String() {
         assertEquals("    test", StringUtils.normalize("\ttest"));
     }
 
-    /**
-     * Test of normalize method, of class StringUtils.
-     */
-    @Test
-    public void testNormalize_List() {
-        assertEquals(Collections.singletonList("    test"), StringUtils.normalize(Collections.singletonList("\ttest")));
-    }
-
     /**
      * Test of wrapText method, of class StringUtils.
      */